Influenza Situation Update| 1 Bi-weekly Influenza Situation Update 31 January 2024 Virological Surveillance Summary The total number of specimens and number of positive specimens reported to FluNet by Western Pacific Region countries and areas between week 1 and week 3 of 2024 are presented in Table 1 below. Influenza A and B are co-circulating, however, the majority of cases reported in week 1 to week 3 of 2024 have been Influenza A (H3) (Figure 1). Caution should be taken when interpreting this data as there are reporting delays. Table 1: Cumulative data reported to FluNet from Western Pacific Region, week 1 to week 3, 2024 Country (most recent week of report) Total number of specimens processed Total number of influenza-positive specimens Australia (3 of 2024) 6,110 183 Cambodia (2 of 2024) 185 16 China (3 of 2024) 112,562 35,012 Fiji (3 of 2024) 214 4 Japan (2 of 2024) - 22 Lao People's Democratic Republic (3 of 2024) 329 44 Malaysia (3 of 2024) 2,654 241 Mongolia (3 of 2024) 903 248 New Zealand (50 of 2023) - - Philippines (2 of 2024) 182 15 Republic of Korea (2 of 2024) 682 250 Singapore (3 of 2024) 973 305 Viet Nam (2 of 2024) 12 0 Grand Total 124,806 36,340 Figure 1: Number of specimens positive for influenza by subtype, Western Pacific Region, week 3, 2023 to week 3, 2024 (Source: WHO FLUNET) Influenza surveillance summary Influenza surveillance in the WHO Western Pacific Region is based on outpatient and inpatient indicator- based surveillance (IBS) systems, as well as event-based surveillance. Case definitions, population groups included and data formats differ among countries. This influenza surveillance summary includes countries and areas where routine IBS is conducted and information is available. Influenza Situation Update| 2 Bi-weekly Influenza Situation Update 31 January 2024 The WHO surveillance case definition for influenza-like illness (ILI) is an acute respiratory infection with a measured fever of ≥38oC and cough, with symptom onset within the last 10 days. For SARI, it is an acute respiratory infection (ARI) with a history of fever or measured fever of ≥38oC and cough, with symptom onset within 10 days that requires hospitalization. Sentinel site data should be interpreted with caution since the number of sites reporting may vary between weeks. Countries in the temperate zone of the Northern Hemisphere In countries within the temperate zone of the Northern Hemisphere, ILI and influenza activity are similar to the corresponding period from previous years. Outpatient ILI Surveillance China (North) During week 3, sentinel hospitals in the northern provinces reported ILI% of 6.0%, which is lower than the last week (7.1%), higher than the same week of 2021-2023 (2.6%, 3.1% and 2.0%) (Figure 2). Figure 2: Percentage of visits for ILI at sentinel hospitals in northern China, 2020-2024 (as of week 3) (Source: China National Influenza Center) Influenza Situation Update| 3 Bi-weekly Influenza Situation Update 31 January 2024 Mongolia There was no update in this reporting period. During week 45 of 2023, the ILI activity in Mongolia increased to 38 ILI cases per 10,000 population. This is above the upper tolerance limit (Figure 3). Figure 3: Proportion of outpatient ILI visits per 10,000 people in Mongolia, 2021 (from week 16-49) -2023 (as of week 45) (Source: Mongolia National Influenza Center) Republic of Korea In week 2 (7 to 13 January 2024), the overall weekly influenza-like illness (ILI) rate was 44.8 per 1,000 outpatient visits, which was lower than the rate recorded in the previous weeks (51.9 in week 1) (Figure 4). Figure 4: Weekly ILI incidence rate per 1,000 outpatient consultations, Republic of Korea, 2019 (from week 36- 52)-2024 (as of week 2) (Source: Korea Disease Control and Prevention Agency). Influenza Situation Update| 4 Bi-weekly Influenza Situation Update 31 January 2024 Sentinel influenza surveillance Japan In week 2 of 2024, the weekly number of cases reported by sentinel hospital sites in Japan slightly increased compared to the previous week. Overall, the weekly number of cases reportedremained relatively stable. (Figure 5). Figure 5: Weekly number of influenza cases reported per reporting sentinel hospital site, Japan 2014-2024 (Source: Japan National Institute of Infectious Diseases) Countries/areas in the tropical zone ILI and influenza activity is similar to the corresponding period from previous years in some of the countries and areas in the tropical zone. Hong Kong SAR (China) – ILI and hospital Surveillance The latest surveillance data showed a slightly decrease but remained elevated in the overall seasonal influenza activity. In week 3, the average consultation rate for influenza-like illness (ILI) among sentinel general outpatient clinics (GOPC) was 7.9 ILI cases per 1,000 consultations, which was lower than 9.0 recorded in the previous week (Figure 6). The average consultation rate for ILI among sentinel private medical practitioner (PMP) clinics was 55.8 ILI cases per 1,000 consultations, which was lower than 61.7 recorded in the previous week (Figure 7). Figure 6: ILI consultation rates at sentinel general outpatient clinics, Hong Kong SAR 2020-2024 Figure 7: ILI consultation rates at sentinel private medical practitioner clinics, Hong Kong SAR 2020-2024 (Source: Hong Kong Centre for Health Protection) (Source: Hong Kong Centre for Health Protection) Influenza Situation Update| 5 Bi-weekly Influenza Situation Update 31 January 2024 China (South) - ILI Surveillance During week 3, the percentage of outpatient or emergency visits for ILI (ILI%) at national sentinel hospitals in southern provinces was 7.7%, lower than the last week (8.7%), higher than the same week in 2021 -2023 (3.4%, 3.5% and 1.9%) (Figure 8). Figure 8: Percentage of visits due to ILI at national sentinel hospitals in Southern China, 2020-2024 (Source: China National Influenza Center) Singapore – Acute Respiratory Infection (ARI) Surveillance In week 3 (14 to 20 January), the average daily number of patients seeking treatment in the polyclinics for ARI is 2,607 (over 5.5 working days) (Figure 9). The proportion of patients with influenza-like illness (ILI) among the polyclinic attendances for ARI is 0.7%. The overall positivity rate for influenza among ILI samples (n=1,202) in the community was 29.3% in the past four weeks. Of the 190 specimens tested positive for influenza in December 2023, 111 were positive for Influenza A(H3N2) (58.4%), 50 were positive for Influenza A(pH1N1) (26.3%), and 29 were positive for Influenza B (15.3%) (Figure 10). Figure 9: Average daily polyclinic attendances for ARI in Singapore, 2023-2024 (Source: Singapore Ministry of Health) Figure 10: Monthly influenza surveillance for ARI in Singapore, 2018-2023 (Source: Singapore Ministry of Health) Influenza Situation Update| 6 Bi-weekly Influenza Situation Update 31 January 2024 Lao PDR During week 3 (15 to 21 January 2024), the National Center for Laboratory and Epidemiology received data from all sentinel sites in Lao PDR. The number of ILI cases presenting at sentinel sites slightly decreased compared to the previous week (Figure 11). There were 112 samples tested for influenza in week 3 of 2024, of which 12 positive: Influenza A/pdmH1N1 (n=1), Influenza A/H3 (n=2), and Influenza B-Victoria (n=9). Figure 11: Weekly number of ILI cases at sentinel sites (2019 to 2024) (Source: Lao National Center for Laboratory and Epidemiology) Cambodia In week 3 of 2024, the Ministry of Health received data from all seven sentinel sites in Cambodia. The number of ILI cases in Cambodia has slightly increased between week 2 (178 cases) and week 3 of 2024 (208 cases). The positivity rate for week 3 was 13% (Figure 12). Note: Starting from week 2 of 2024, the ILI surveillance has been updated as follow: a) Changed case definitions of ILI from >38oC (greater than 38) to ≥ 38oC (greater and equal to 38), b) Increasing number of samples per sentinel sites from 5 to 10 per week. Therefore, the number of cases and positivity might also increase. Figure 12: Number of ILI samples from sentinel sites and influenza positivity rate by the week, of 2022-2024, Cambodia (Source: Communicable Disease Control Department, Cambodia Ministry of Health) Influenza Situation Update| 7 Bi-weekly Influenza Situation Update 31 January 2024 Countries in the temperate zone of the southern hemisphere In the temperate zone of the southern hemisphere, influenza activity is reported during the influenza season, usually starting in May in Australia and New Zealand. Australia – Laboratory-confirmed influenza There is no update for this reporting period. In the year-to-date (1 January to 15 October 2023), there have been 251,095 notifications of laboratory-confirmed influenza reported to the National Notifiable Diseases Surveillance System in Australia. There were 6,037 laboratory-confirmed influenza notifications with a diagnosis date this fortnight (2 October to 15 October 2023), compared to 7,725 notifications in the previous fortnight. The number of notifications of laboratory confirmed influenza has continued to decrease since the peak in July. (Figure 13). Figure 13: Notifications of laboratory-confirmed influenza by month and week from 2016 to 2023 in Australia (Source: National Notifiable Diseases Surveillance System, Australian Department of Health) New Zealand – ILI Surveillance ndicators of influenza like illness in the community are currently lower than at the same point in 2023. During 2024 to the week ending 21 January 2024, the rate of ILI related Healthline calls and percentage of FluTracking participants with fever and cough have remained relatively stable (Figure 14). Figure 14: Weekly rates of general practice ILI consultations per 100,000 people in New Zealand in 2015-2024 (Source: New Zealand Institute of Environmental Science and Research) Influenza Situation Update| 8 Bi-weekly Influenza Situation Update 31 January 2024 Pacific Island Countries and Areas (PICs) - ILI Surveillance In week 3 (15 to 21 January), 18 out of 21 PICs reported ILI surveillance data. No reports are available for American Samoa, Guam, and Nauru. Fiji, CNM, and Samoa observed a slightly increased ILI trend compared to the past week. (Figure 15). 0 20 40 60 80 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 Cook Islands ILI Trend 2019 -2024 ( WK 3) ILI 2024 ILI 2019 ILI 2020 ILI 2021 ILI 2022 ILI 2023 0 500 1000 1500 2000 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 Fiji ILI Trend 2019 -2024 ( WK 3) ILI 2024 ILI 2019 ILI 2020 ILI 2021 ILI 2022 ILI 2023 0 200 400 600 800 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi week French Polynesia ILI trend 2019 - 2024 (WK 2) ILI 2024 ILI 2020 ILI 2021 ILI 2022 ILI 2019 ILI 2023 0 200 400 600 800 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi week FSM ILI trend 2019 - 2024 (WK2) ILI 2024 ILI 2020 ILI 2021 ILI 2019 ILI 2022 ILI 2023 0 500 1000 1500 2000 2500 3000 3500 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi week Kiribati ILI trend 2019-2024 (W3) ILI 2024 ILI 2020 ILI 2021 ILI 2019 ILI 2022 ILI 2023 0 50 100 150 200 250 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi week Marshall Islands ILI trend 2019 -2024 ( WK 2) ILI 2024 ILI 2020 ILI 2021 ILI 2019 ILI 2022 ILI 2023 Influenza Situation Update| 9 Bi-weekly Influenza Situation Update 31 January 2024 0 50 100 150 200 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es EPi week CNMI ILI Trend 2019 -20234 (WK 3) ILI 2024 ILI 2020 ILI 2021 ILI 2022 ILI 2019 ILI 2022 ILI 2023 0 100 200 300 400 500 600 700 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi week New Caledonia ILI Trend 2019 -2024 (WK 3) ILI 2024 ILI 2020 ILI 2021 ILI 2019 ILI 2022 ILI 2023 0 5 10 15 20 25 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi week Niue ILI Trend 2019 - 2024 (WK 44) ILI 2024 ILI 2020 ILI 2021 ILI 2019 ILI 2022 ILI 2023 0 50 100 150 200 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi week Palau ILI Trend 2019 - 2024 (WK 3) ILI 2024 ILI 2020 ILI 2021 ILI 2019 ILI 2022 ILI 2023 0 1 2 3 4 5 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi week Pitcairn Islands ILI Trend 2019 - 2024 (WK 3) ILI 2024 ILI 2019 ILI 2020 ILI 2021 ILI 2022 ILI 2023 0 1000 2000 3000 4000 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi week Samoa ILI Trend 2019 -2024 ( WK 3) ILI 2024 ILI 2019 ILI 2020 ILI 2021 ILI 2022 ILI 2023 Influenza Situation Update| 10 Bi-weekly Influenza Situation Update 31 January 2024 * Caution should be taken in interpreting these data as there may be changes in the number of sentinel sites reporting to the Pacific Syndromic Surveillance System. ** FSM: Federated States of Micronesia, CMNI: Commonwealth of Northern Mariana Islands Figure 15: Reported cases of influenza-like illness in Pacific Island Countries, 2019-2024 (Source: Pacific Syndromic Surveillance System Weekly Bulletin) Global influenza situation updates Virological update Global update 0 500 1000 1500 2000 2500 3000 3500 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi week Solomon Islands ILI Trend 2019 -2024 (WK50) ILI 2024 ILI 2019 ILI 2020 ILI 2021 ILI 2022 ILI 2023 0 10 20 30 40 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi week Tokelau ILI Trend 2019 -2023 (WK 41) ILI 2024 ILI 2019 ILI 2020 ILI 2021 ILI 2022 ILI 2023 Baseline 0 100 200 300 400 500 600 700 800 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi week Tonga ILI trend 2019 -2024 (WK 3) ILI 2024 ILI 2019 ILI 2020 ILI 2021 ILI 2022 ILI 2023 0 50 100 150 200 250 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 Tuvalu ILI trend 2019 -2024 (WK 2) ILI 2024 ILI 2019 ILI 2020 ILI 2021 ILI 2022 ILI 2023 0 50 100 150 200 250 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 Tuvalu ILI trend 2019 -2024 (WK 2) ILI 2024 ILI 2019 ILI 2020 ILI 2021 ILI 2022 ILI 2023 0 500 1000 1500 2000 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi week Vanuatu ILI Trend 2019 - 2023 (WK48) ILI 2024 ILI 2020 ILI 2021 ILI 2019 ILI 2022 ILI 2023 Influenza Situation Update| 11 Bi-weekly Influenza Situation Update 31 January 2024 Others: • Recommended composition of influenza virus vaccines for use in the 2023-2024 northern hemisphere influenza season Link • New recommended composition of influenza virus vaccines for use in the 2023 southern hemisphere influenza season Link • Recommended composition of influenza virus vaccines for use in the 2024 southern hemisphere influenza season Link • WHO Consultation on the Composition of Influenza Virus Vaccines for Use in the 2023 Southern Hemisphere Influenza Season 19-22 September 2022 Link • WHO issues updated influenza vaccines position paper Link WHO's YouTube Channel: film exploring a number of key aspects of the constant evolution of influenza viruses and associated impacts on public health. 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Dengue Situation Update 688 │ 1 Dengue Situation Update 688 4 January 2024 Update on the Dengue situation in the Western Pacific Region This report describes the epidemiology of dengue in the World Health Organization Western Pacific Region. Data are compiled from open sources (national indicator-based surveillance systems) with the exception of Cambodia, Lao People’s Democratic Republic, Viet Nam, and the Philippines, where data are provided by the WHO Country Offices. For the Pacific Island Countries, syndromic surveillance data are provided by the Division of Pacific Technical Support. Information is reported based on countries’ standard dengue case definitions, summary of these definitions and countries’ dengue surveillance systems - included as an annex to this report. Due to differences in surveillance methods and reporting practices, a comparison of trends between countries and areas is not possible, however, national trends can be observed over time. Northern Hemisphere Cambodia As of epidemiological week 47 of 2023, the National Dengue Surveillance System reported a total of 31,567 cases with 39 deaths (Case Fatality Rate (CFR) 0.12%) since 1 January 2023 (Figure 1), an increase by 169.3% (n=11,722) and 143.8% (n=16; Case Fatality Rate (CFR) : 0.16%) in cases and deaths respectively, as compared to cases and deaths reported in 2022 over the same period. Figure 1: Dengue cases reported weekly in 2023 vs Mean and Mean+2SD during 2015-2020 *excluding 2019 in Cambodia; Source: National Dengue Surveillance System (NDCP/CNM/MOH) Dengue Situation Update 688 │ 2 China There is no update for this reporting period. In October 2023, 5388 dengue cases and no deaths were reported in China. There were no deaths reported. There have been a total of 17,788 dengue cases and one death in the country from January 2023 to October 2023 (Figure 2). Figure 2: Dengue cases reported monthly from 2015-2023 (as of October) in China Source: National Health Commission and CDC, China Lao People’s Democratic Republic In epidemiological week 51 (18 December to 24 December 2023), 152 dengue cases and zero death were reported (Figure 3). The number of reported cases is lower than the numbers reported in epidemiological week 50 (230 cases with no deaths). The cumulative number of cases reported in 2023 (as of epidemiological week 51) is 31,997. This is a 9.8% increase compared to the 29,138 cases reported during the same period in 2022. There have now been 20 deaths reported in 2023. Figure 3: Dengue cases reported weekly from 2018-2023 in Lao PDR Source: National Centre for Laboratory and Epidemiology, Ministry of Health, Lao PDR Dengue Situation Update 688 │ 3 Malaysia During epidemiological week 51 (17 December to 23 December 2023), an decrease of 227 cases (7.2%) was reported with 2,913 cases as compared to 3,140 cases reported in the previous week (Figure 4). Four dengue-related death was reported in week 51. The cumulative number of dengue cases reported up to week 51 is 120,418 cases, which is an increase of 87.9% compared to 64,078 cases for the same period in 2022. As of epidemiological week 51, a total of 96 deaths have been reported, compared to 50 deaths for the same period in 2022. Figure 4: Dengue cases reported weekly from 2022, 2023, and median 2018-2022 in Malaysia Source: Department of Health, Malaysia Philippines During epidemiological Week 48 (26 November to 2 December 2023), there were 2,607 new dengue cases reported, a 41% decrease compared to the same period in 2022 (n=4,415 cases) (Figure 5). As of 2 December 2023, a total of 195,603 dengue cases have been reported. The number of cases is 23% lower compared to the same period in 2022 (n=252,700). From 1 January to 2 December 2023, there have been 657 deaths (CFR 0.34%) as compared to 894 deaths (CFR 0.35%;) reported in the same period in 2022. Figure 5: Dengue cases reported weekly from 2022 and 2023 in the Philippines Source: Department of Health, the Philippines (Note: there is a 3-4 week systematic delay in reporting and numbers should be interpreted with caution) N u m b er o f ca se s Dengue Situation Update 688 │ 4 Singapore In epidemiological week 50 (10 December to 16 December) and 51 (17 December to 23 December 2023), a total of 211 and 236 dengue cases were reported in Singapore, respectively. Cumulatively, a total of 9663 cases (Figure 6) have been reported as of 23 December 2023 . When compared with week 51 in 2022 (31,845 cases) , there has been a 69.6% decrease in cases reported in week 51 of this year. Preliminary results of all positive dengue samples serotyped in December 2023 (as of 23 December) showed DEN-1, DEN-2, DEN-3, and DEN-4 at 17.0%, 55.2%, 20.6%, and 7.3% respectively. Figure 6: Dengue cases reported weekly from 2018-2023 (as of 23 December) in Singapore Source: Communicable Diseases Division, Ministry of Health, Singapore (Note: Case numbers are derived from the MOH Singapore’s Weekly Infectious Bulletin Year Excelsheet as available from MOH | Weekly Infectious Diseases Bulletin) Viet Nam From 1 January to 17 December 2023 (epidemiological week 50), cumulatively 166,619 dengue cases including 42 deaths (CFR : 0.03%) were reported in Viet Nam. The number of cases and death decreased by 53.5% and 109 compared to the same period in 2022. During epidemiological week 50 (from 11 December to 17 December), 3,337 cases including no death were reported, which is a 8.6% decrease in cases compared to the previous week (3,650 cases). Of these cases, 2,531 were hospitalized, which is a 8.3% decrease compared to the previous week (2,759 hospitalizations) (Figure 7). Figure 7: Number of dengue hospital admissions and deaths by week in 2022 compared to 2023, as of week 50, 2023, Viet Nam Source: General Department of Preventive Medicine, Ministry of Health, Viet Nam Note hospitalizations include inpatients and outpatients The alert threshold is a 5-year mean plus 2 standard deviations Dengue Situation Update 688 │ 5 Southern Hemisphere Australia From 27 November to 10 December 2023, a total of 48 dengue cases were reported in Australia. As of 10 December 2023, the cumulative number of dengue cases is 1,023, a 170.6% increase this year compared to the the same period in 2022 (n=378 cases). The number of cases reported as of 10 December 2023 was higher than the reported number of cases for same month in the years 2020-2022 (Figure 8). Figure 8: Laboratory-confirmed dengue cases reported monthly from 2016-2023 in Australia Source: Department of Health, Australia Note: Graph was updated on 10 December 2023 Pacific Islands Countries New Caledonia There is no update for this reporting period. From 1 January to 30 September 2023, four confirmed dengue cases were reported in New Caledonia (Figure 9). This is higher compared to the same period in 2022 when a total of one dengue case was reported. Of the four confirmed dengue cases in 2023, two were imported cases. The serotype of the two imported cases were DENV-1 and DENV-2. Figure 9: Dengue cases reported by week from 2021 to 2023 in New Caledonia Source: Network of sentinel physicians, New Caledonia Dengue Situation Update 688 │ 6 Pacific Island Countries and Areas (PICs) – Dengue-like illness (DLI) Surveillance During epidemiological week 51 (ending 24 December 2023), five out of eighteen (5/18) Pacific Island Countries and Areas (PICs) with available surveillance data reported no or low numbers of DLI cases compared to past few weeks. Among them, most countries or areas reported similar or decreasing trend in DLI cases from week 50 to week 51. 0 100 200 300 400 500 600 700 800 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as e s Epi week Fiji DLI Trend - 2021 -2023 (W50) DLI 2023 DLI 2021 DLI 2022 Baseline 0 20 40 60 80 100 120 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 C as e s Epi week French Polynesia DLI Trend - 2021 -2023 (W49) DLI 2023 DLI 2021 DLI 2022 0 2 4 6 8 10 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 C as e s Epi week FSM DLI Trend - 2021 -2023 (W43) DLI 2023 DLI 2022 DLI 2021 0 2 4 6 8 10 12 14 16 18 20 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as e s Epi week Cook Islands DLI Trend - 2021 -2023 (W49) DLI 2023 DLI 2021 DLI 2022 0 2 4 6 8 10 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 ca se s Epi week Marshall Islands DLI Trend - 2021 -2023 (W49) DLI 2023 DLI 2021 DLI 2022 0 1 2 3 4 5 6 7 8 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 ca se s Epiweek Palau DLI Trend - 2021 -2023 (WK 51) DLI 2021 DLI 2022 DLI 2023 Dengue Situation Update 688 │ 7 0 2 4 6 8 10 12 14 16 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as e s Epi week Kiribati DLI Trend - 2021 -2023 (W49) DLI 2021 DLI 2022 DLI 2023 0 2 4 6 8 10 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as e s Epi week N Mariana Is DLI Trend - 2021 -2023 (W49) DLI 2021 DLI 2022 DLI 2023 0 1 2 3 4 5 6 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 ca se s Epi week New Caledonia DLI Trend - 2021 -2023 (W49) DLI 2023 DLI 2021 DLI 2022 0 5 10 15 20 25 30 35 40 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 ca se s Epi week Samoa DLI Trend - 2021 -2023 (WK51) DLI 2023 DLI 2021 DLI 2022 0 2 4 6 8 10 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 ca se s Epiweek Niue DLI Trend - 2021 -2023 (WK45) DLI 2021 DLI 2022 DLI 2023 0 2 4 6 8 10 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 ca se s Epi week Pitcairn Islands DLI Trend - 2021 -2023 (WK48) DLI 2021 DLI 2022 DLI 2023 Dengue Situation Update 688 │ 8 Figure 10. Reported cases of dengue-like illness in Pacific Islands Countries and Areas Source: WHO Division of Pacific Technical Support Note: Caution should be taken in interpreting these data as there may be changes in the number of sentinel sites reporting to the Pacific Syndromic Surveillance System (PSSS). Furthermore, the syndromic case definition of DLI may capture cases with non- dengue acute febrile illnesses (AFI) with similar clinical manifestations to dengue. This includes AFI such as chikungunya, influenza, hantavirus, leptospirosis, malaria, measles, paratyphoid and typhoid fevers, scrub typhus, yellow fever, zika, other diseases. The PSSS may also capture dengue cases under ‘prolonged fever’ surveillance. Alert threshold for DLI is twice the average number of cases seen in the previous 3 weeks. FSM: Federated States of Micronesia 0 10 20 30 40 50 60 70 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as e s Epi week Solomon Islands DLI Trend - 2021 -2023 (WK50) DLI 2023 DLI 2021 DLI 2022 0 2 4 6 8 10 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 C as e s Epiweek Tokelau DLI Trend - 2021 -2023 (WK 41) DLI 2021 DLI 2022 DLI 2023 0 1 2 3 4 5 6 7 8 9 10 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 C as e s EPI week Tuvalu DLI Trend - 2021 -2023 (WK49) DLI 2021 DLI 2022 DLI 2023 0 2 4 6 8 10 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as e s Epi week Tonga DLI Trend - 2021 -2023 (WK49) DLI 2023 DLI 2021 DLI 2022 0 5 10 15 20 25 30 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 ca se s Epi week Vanuatu DLI Trend - 2021 -2023 (W49) DLI 2023 DLI 2022 DLI 2021 0 2 4 6 8 10 12 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as e s EPI Week Wallis & Futuna DLI trend -2021 -2023 (WK51) DLI 2023 DLI 2021 DLI 2022 Dengue Situation Update 688 │ 9 Annex 1. Summary of dengue case definitions, laboratory sampling and testing methods used for surveillance in Member States as of 2023 Country Case definition Surveillance system Laboratory sampling and testing method Reference Clinically confirmed case Laboratory confirmation required Description Australia Fever, headache, arthralgia, myalgia, rash, nausea and vomiting Yes Dengue is a nationally notifiable disease and cases are monitored through the National Notifiable Diseases Surveillance System (NNDSS) indicator-based surveillance system. Both confirmed and probable cases are nationally notifiable. A confirmed case requires both laboratory definitive evidence and clinical evidence. A probable case requires either laboratory suggestive evidence and clinical evidence and epidemiological evidence, or clinical evidence and household epidemiological evidence. Laboratory definitive evidence: - Isolation of dengue virus, or - Detection of dengue virus by nucleic acid testing, or - Detection of NS1 antigen in the blood by EIA, or - IgG seroconversion or significant increase in antibody levelor fourfold or greater rise in titre to dengue virus (proof by neutralization or another specific test) Laboratory suggestive evidence: - Detection of NS1 antigen in blood by rapid antigen test, or - Detection of dengue virus-specific IgM in blood Epidemiological evidence: - Exposure between 3 – 14 days prior to onset either in a country with known dengue activity or in a dengue-receptive area in Australia where a locally-acquired or imported case has been documented with onset within a month. Household epidemiological evidence: - Living in the same house as a locally- acquired case in a dengue-receptive area of Australia within a month of onse in the 1 Dengue Situation Update 688 │ 10 case and at least one case in the chain of epidemiologically linked cases is laboratory confirmed. Cambodia Suspected dengue: very high fever at 39-40 degrees celcius for 2-7 days (usually 3-4 days), with 2 or more of the following signs: flushed face, headache, retro-orbital pain, myalgia/arthralgia, cutaneous rash, haemorrhagic signs (petechiae, positive tourniquet test), and leucopenia. Probable dengue: signs of suspected dengue plus laboratory test results (see right column)) or that the case occurred in an area where the dengue case has been confirmed. Yes National Dengue Control Program (NDCP) enhanced sentinel surveillance system Communicable Disease Control (CDC) syndromic surveillance system (CamEWARN). Health Management Information System (HMIS) collects data on confirmed cases and deaths. Data collected for Cambodia Laboratory Information System (CamLIS), comprised of 32 participating hospital laboratories where NS1 detection is conducted. Laboratory testing: Antibody HI>= 1/1280 or IgM/IgG positive by ELISA test in convalescence serum 2 China (i) more than two symptoms of acute onset fever, severe headache, orbital pain, myalgia, arthralgia, fatigue with a history of travel in a dengue endemic area within 15 days before symptom onset or cohabitation with an individual with confirmed dengue; or no travel history, but with a rash or positive tourniquet test AND leucopenia or thrombocytopenia or serum IgM positivity. No Reported to the Chinese Centre for Disease Control and Prevention (China CDC) through the Chinese National Notifiable Infectious Disease Reporting Information System (CNNDS). Laboratory confirmation is done by real-time RT-PCR, NS1 in acute-phase serum, or virus isolation from an acutely infected patient’s serum. WHO internal communication Lao People's Democratic Republic WHO dengue case classification (2009) † No National Surveillance System for Notifiable Selected Diseases, indicator-based surveillance system that consists of passive weekly reports of clinically suspected cases, on admission, from all health-care facilities across the country. 3 Malaysia WHO dengue case classification (2009) † Yes National Dengue Surveillance System, indicator-based surveillance system All suspected cases are to be tested by the following laboratory tests: Rapid Combo Test (RCT) (NS1, IgM, IgG), Dengue Antigen and Serology tests by ELISA, Dengue Viral RNA Detection (Real time RT-PCR), Viral Isolation 4 Philippines WHO dengue case classification (2009) † Yes Philippine Integrated Disease Surveillance and Response (PIDSR), indicator-based surveillance system. Reporting delays of 2-3 weeks, Confirmed dengue is a suspect case with positive (+) viral culture isolation and/or PCR. NS1 (+), IgM is used to identify probable dengue. 5, 6, 7 Dengue Situation Update 688 │ 11 making comparison of current weekly and cumulative figures with previous years difficult. Singapore (endemic) Fever, headache, backache, myalgia, rash, abdominal discomfort and thrombocytopenia and laboratory testing (see right column) No Dengue is a legally notifiable disease in Singapore and notifying the Ministry of Health should not be later than 24 hours from the time of diagnosis. Laboratory confirmation is done using standard diagnostic tests for the detection of dengue NS1 antigen, IgM and IgG, or RT-PCR. 8,9 Viet Nam (endemic) Acute onset of fever continuously lasting from 2-7 days AND at least 2 of the following: haemorrhagic manifestation /presentation; headache, loss of appetite, nausea, vomiting; rash; muscle pain, joint pain, orbital pain; lethargy; abdominal pain. No As per the MOH dengue surveillance guideline, in routine surveillance MAC-ELISA is conducted for at least 7% and virus isolation is conducted for at least 3% of clinical cases. In an outbreak, at least 5 to 10 suspected cases are tested. 10 Pacific Island Countries WHO dengue case classification (2009) † No Pacific Syndromic Surveillance System Confirmed case: Isolation of dengue virus or detection of dengue-specific antigen or antibodies in tissue, blood, CSF or other body fluid by an advanced laboratory test 11 Only the minimum criteria required for fulfilling a clinical dengue case definition are included here; additional signs and symptoms required for more severe forms are not listed. † A probable dengue case is defined as any case living in or travel to dengue endemic area with fever and two or more of the following: nausea, vomiting, rash, aches and pains, positive tourniquet test, leucopenia and any warning sign. A case with warning signs is defined as a clinically diagnosed case with any of the following: abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleed, lethargy, restlessness, liver enlargement > 2 cm and increase in haematocrit concurrent with rapid decrease in platelet count. Severe dengue is defined as severe plasma leakage leading to any of the following: shock, fluid accumulation with respiratory distress OR severe bleeding as evaluated by clinician OR severe organ involvement of liver (aspartate amino transferase or alanine amino transferase ≥ 1000), central nervous system (impaired consciousness) or heart and other organs.10 References: 1. Australian Government Department of Health AGDo. Dengue virus infection surveillance and case definition [updated 14 June 2022 and 1 January 2018 respectively] Available from: https://www.health.gov.au/diseases/dengue-virus-infection, and https://www.health.gov.au/sites/default/files/documents/2022/06/dengue-virus-infection-surveillance-case-definition.pdf 2. Cambodia Ministry of Health NCfP, Entomology and Malaria Control. National Guideline for Clinical Management of Dengue, 2018. 2018. Available from: https://niph.org.kh/niph/uploads/library/pdf/GL055_National_guideline_for_ClM_Dengue.pdf. 3. Khampapongpane B, Lewis HC, Ketmayoon P, Phonekeo D, Somoulay V, Khamsing A, et al. National dengue surveillance in the Lao People's Democratic Republic, 2006-2012: epidemiological and laboratory findings. Western Pac Surveill Response J. 2014;5(1):7-13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24734212. 4. Ministry of Health Malaysia DCD. Case definitions for infectious diseases in Malaysia. 2017. Available from: https://www.moh.gov.my/moh/resources/Penerbitan/Garis%20Panduan/Pengurusan%20KEsihatan%20&%20kawalan%20pykit/Case_Definition_Of_Infectious_Disease_3rd_Edition_2017.pdf 5. Secretary PDoHOot. Guidelines for the Nationwide Implementation of Dengue Rapid Diagnostic Test (RDT), Administrative order No.2016-0043. 2016(2016-0043). 6. Secretary PDoHOot. Revised Dengue Clinical Case Management Guidelines 2011, Administrative order No.2012-0006. 2012 22 March 2012. Report No. 7. Diseases SNCfI. Diseases and Conditions, Dengue 2020 [updated 14 September 2020. Available from: https://www.doh.gov.ph/Health-Advisory/Dengue. 8. National Centre for Infectious Diseases, Dengue. Available from: https://www.ncid.sg/Health-Professionals/Diseases-and-Conditions/Pages/Dengue.aspx Dengue Situation Update 688 │ 12 9. National Environment Agency. Surveillance and Epidemiology Programme [updated 21 April 2023]. Available from: https://www.nea.gov.sg/corporate-functions/resources/research/surveillance-and- epidemiology-programme#Ehi%20Diagnostics%20Unit 10. Viet Nam Ministry of Health VNMo. Circular 54/2015 / TT-BYT 2015 [updated 26 April 2016. Available from: https://syt.thuathienhue.gov.vn/?gd=27&cn=108&tc=3993. 11. Pacific Islands Outbreak Manual. Available from: https://www.pphsn.net/resources/outbreak-manual/ 12. WHO dengue outbreak toolbox. Available from: https://www.who.int/docs/default-source/outbreak-toolkit/updates-documents_july-5/dengue-outbreak-data-collection-toolbox---inis-3-july- 1.pdf?sfvrsn=ec3ffcf3_2
Dengue Situation Update 689 │ 1 Dengue Situation Update 689 18 January 2024 Update on the Dengue situation in the Western Pacific Region This report describes the epidemiology of dengue in the World Health Organization Western Pacific Region. Data are compiled from open sources (national indicator-based surveillance systems) with the exception of Cambodia, Lao People’s Democratic Republic, Viet Nam, and the Philippines, where data are provided by the WHO Country Offices. For the Pacific Island Countries, syndromic surveillance data are provided by the Division of Pacific Technical Support. Information is reported based on countries’ standard dengue case definitions, summary of these definitions and countries’ dengue surveillance systems - included as an annex to this report. Due to differences in surveillance methods and reporting practices, a comparison of trends between countries and areas is not possible, however, national trends can be observed over time. Northern Hemisphere Cambodia As of epidemiological week 52 of 2023, the National Dengue Surveillance System reported a total of 35,390 cases with 99 deaths (Case Fatality Rate (CFR) 0.28%) since 1 January 2023 (Figure 1), an increase by 172.5% (n=12,985) and 371.4% (n=21; Case Fatality Rate (CFR) : 0.16%) in cases and deaths respectively, as compared to cases and deaths reported in 2022 over the same period. Figure 1: Dengue cases reported weekly in 2023 vs Mean and Mean+2SD during 2015-2020 *excluding 2019 in Cambodia; Source: National Dengue Surveillance System (NDCP/CNM/MOH) Dengue Situation Update 689 │ 2 China In December 2023, 154 dengue cases and no deaths were reported in China. There have been a total of 19,627 dengue cases and one death in the country from January 2023 to December 2023 (Figure 2). Figure 2: Dengue cases reported monthly from 2015-2023 (as of October) in China Source: National Health Commission, CDC and National Disease Control and Prevention Administration, China Lao People’s Democratic Republic In epidemiological week 1 of 2024 (01 January to 07 January 2024), 65 dengue cases and zero deaths were reported (Figure 3). The number of reported cases is lower than the numbers reported in epidemiological week 52 (112 cases with no deaths), and higher than those in week 1 of 2023 (48 cases with no deaths). The cumulative number of cases reported in 2023 (as of epidemiological week 52) is 32,109. This is a 9.9% increase compared to the 29,210 cases reported during the same period in 2022. There have been 20 deaths reported in 2023. Dengue Situation Update 689 │ 3 Figure 3: Dengue cases reported weekly from 2018-2024 in Lao PDR Source: National Centre for Laboratory and Epidemiology, Ministry of Health, Lao PDR Malaysia During epidemiological week 1 of 2024 (31 December 2023 to 6 January 2024), an increase of 466 cases (17.2%) was reported with 3,181 cases as compared to 2,715 cases reported in the previous week (Figure 4). The cumulative number of dengue cases reported up to week 1 of 2024 is 3,181 cases, which is an increase of 43.4% compared to 2,219 cases for the same period in 2023. No dengue-related deaths were reported compared to 1 death for the same period in 2023. Figure 4: Dengue cases reported weekly from 2023, 2024 and median 2019-2023 in Malaysia Source: Department of Health, Malaysia N u m b er o f ca se s Dengue Situation Update 689 │ 4 Philippines There is no update for this reporting period. During epidemiological Week 48 (26 November to 2 December 2023), there were 2,607 new dengue cases reported, a 41% decrease compared to the same period in 2022 (n=4,415 cases) (Figure 5). As of 2 December 2023, a total of 195,603 dengue cases have been reported. The number of cases is 23% lower compared to the same period in 2022 (n=252,700). From 1 January to 2 December 2023, there have been 657 deaths (CFR 0.34%) as compared to 894 deaths (CFR 0.35%;) reported in the same period in 2022. Figure 5: Dengue cases reported weekly from 2022 and 2023 in the Philippines Source: Department of Health, the Philippines (Note: there is a 3-4 week systematic delay in reporting and numbers should be interpreted with caution) Singapore In epidemiological week 52 (24 December to 30 December), a total of 275 dengue cases were reported in Singapore. Cumulatively, a total of 9,938 cases (Figure 6) have been reported as of 30 December 2023. When compared with week 52 in 2022 (32,130 cases), there has been a 69.1% decrease in cases reported in week 52 of this year. Preliminary results of all positive dengue samples serotyped in December 2023 (as of 30 December) showed DEN-1, DEN-2, DEN-3, and DEN-4 at 17.8%, 56.5%, 17.8%, and 7.8% respectively. Figure 6: Dengue cases reported weekly from 2018-2023 (as of 30 December) in Singapore Source: Communicable Diseases Division, Ministry of Health, Singapore (Note: Case numbers are derived from the MOH Singapore’s Weekly Infectious Bulletin Year Excelsheet as available from MOH | Weekly Infectious Diseases Bulletin) Dengue Situation Update 689 │ 5 Viet Nam There is no update for this reporting period. From 1 January to 17 December 2023 (epidemiological week 50), cumulatively 166,619 dengue cases including 42 deaths (CFR: 0.03%) were reported in Viet Nam. The number of cases and death decreased by 53.5% and 109 compared to the same period in 2022. During epidemiological week 50 (from 11 December to 17 December), 3,337 cases including no death were reported, which is an 8.6% decrease in cases compared to the previous week (3,650 cases). Of these cases, 2,531 were hospitalized, which is an 8.3% decrease compared to the previous week (2,759 hospitalizations) (Figure 7). Figure 7: Number of dengue hospital admissions and deaths by week in 2022 compared to 2023, as of week 50, 2023, Viet Nam Source: General Department of Preventive Medicine, Ministry of Health, Viet Nam Note hospitalizations include inpatients and outpatients The alert threshold is a 5-year mean plus 2 standard deviations Southern Hemisphere Australia There is no update for this reporting period. From 27 November to 10 December 2023, a total of 48 dengue cases were reported in Australia. As of 10 December 2023, the cumulative number of dengue cases is 1,023, a 170.6% increase this year compared to the same period in 2022 (n=378 cases). The number of cases reported as of 10 December 2023 was higher than the reported number of cases for same month in the years 2020-2022 (Figure 8). Figure 8: Laboratory-confirmed dengue cases reported monthly from 2016-2023 in Australia Source: Department of Health, Australia Note: Graph was updated on 10 December 2023 Dengue Situation Update 689 │ 6 Pacific Islands Countries New Caledonia There is no update for this reporting period. From 1 January to 30 September 2023, four confirmed dengue cases were reported in New Caledonia (Figure 9). This is higher compared to the same period in 2022 when a total of one dengue case was reported. Of the four confirmed dengue cases in 2023, two were imported cases. The serotype of the two imported cases were DENV-1 and DENV-2. Figure 9: Dengue cases reported by week from 2021 to 2023 in New Caledonia Source: Network of sentinel physicians, New Caledonia Pacific Island Countries and Areas (PICs) – Dengue-like illness (DLI) Surveillance During epidemiological week 1 of 2024 (ending 07 January 2024), most Pacific Island Countries and Areas (PICs) with available surveillance data reported no numbers of DLI cases while Fiji reported lower numbers of DLI cases compared to the same period last year. Dengue Situation Update 689 │ 7 Dengue Situation Update 689 │ 8 Figure 10. Reported cases of dengue-like illness in Pacific Islands Countries and Areas Source: WHO Division of Pacific Technical Support Note: Caution should be taken in interpreting these data as there may be changes in the number of sentinel sites reporting to the Pacific Syndromic Surveillance System (PSSS). Furthermore, the syndromic case definition of DLI may capture cases with non- dengue acute febrile illnesses (AFI) with similar clinical manifestations to dengue. This includes AFI such as chikungunya, influenza, hantavirus, leptospirosis, malaria, measles, paratyphoid and typhoid fevers, scrub typhus, yellow fever, zika, other diseases. The PSSS may also capture dengue cases under ‘prolonged fever’ surveillance. Alert threshold for DLI is twice the average number of cases seen in the previous 3 weeks. FSM: Federated States of Micronesia Dengue Situation Update 689 │ 9 Annex 1. Summary of dengue case definitions, laboratory sampling and testing methods used for surveillance in Member States as of 2023 Country Case definition Surveillance system Laboratory sampling and testing method Reference Clinically confirmed case Laboratory confirmation required Description Australia Fever, headache, arthralgia, myalgia, rash, nausea and vomiting Yes Dengue is a nationally notifiable disease and cases are monitored through the National Notifiable Diseases Surveillance System (NNDSS) indicator-based surveillance system. Both confirmed and probable cases are nationally notifiable. A confirmed case requires both laboratory definitive evidence and clinical evidence. A probable case requires either laboratory suggestive evidence and clinical evidence and epidemiological evidence, or clinical evidence and household epidemiological evidence. Laboratory definitive evidence: - Isolation of dengue virus, or - Detection of dengue virus by nucleic acid testing, or - Detection of NS1 antigen in the blood by EIA, or - IgG seroconversion or significant increase in antibody levelor fourfold or greater rise in titre to dengue virus (proof by neutralization or another specific test) Laboratory suggestive evidence: - Detection of NS1 antigen in blood by rapid antigen test, or - Detection of dengue virus-specific IgM in blood Epidemiological evidence: - Exposure between 3 – 14 days prior to onset either in a country with known dengue activity or in a dengue-receptive area in Australia where a locally-acquired or imported case has been documented with onset within a month. Household epidemiological evidence: - Living in the same house as a locally- acquired case in a dengue-receptive area of Australia within a month of onse in the 1 Dengue Situation Update 689 │ 10 case and at least one case in the chain of epidemiologically linked cases is laboratory confirmed. Cambodia Suspected dengue: very high fever at 39-40 degrees celcius for 2-7 days (usually 3-4 days), with 2 or more of the following signs: flushed face, headache, retro-orbital pain, myalgia/arthralgia, cutaneous rash, haemorrhagic signs (petechiae, positive tourniquet test), and leucopenia. Probable dengue: signs of suspected dengue plus laboratory test results (see right column)) or that the case occurred in an area where the dengue case has been confirmed. Yes National Dengue Control Program (NDCP) enhanced sentinel surveillance system Communicable Disease Control (CDC) syndromic surveillance system (CamEWARN). Health Management Information System (HMIS) collects data on confirmed cases and deaths. Data collected for Cambodia Laboratory Information System (CamLIS), comprised of 32 participating hospital laboratories where NS1 detection is conducted. Laboratory testing: Antibody HI>= 1/1280 or IgM/IgG positive by ELISA test in convalescence serum 2 China (i) more than two symptoms of acute onset fever, severe headache, orbital pain, myalgia, arthralgia, fatigue with a history of travel in a dengue endemic area within 15 days before symptom onset or cohabitation with an individual with confirmed dengue; or no travel history, but with a rash or positive tourniquet test AND leucopenia or thrombocytopenia or serum IgM positivity. No Reported to the Chinese Centre for Disease Control and Prevention (China CDC) through the Chinese National Notifiable Infectious Disease Reporting Information System (CNNDS). Laboratory confirmation is done by real-time RT-PCR, NS1 in acute-phase serum, or virus isolation from an acutely infected patient’s serum. WHO internal communication Lao People's Democratic Republic WHO dengue case classification (2009) † No National Surveillance System for Notifiable Selected Diseases, indicator-based surveillance system that consists of passive weekly reports of clinically suspected cases, on admission, from all health-care facilities across the country. 3 Malaysia WHO dengue case classification (2009) † Yes National Dengue Surveillance System, indicator-based surveillance system All suspected cases are to be tested by the following laboratory tests: Rapid Combo Test (RCT) (NS1, IgM, IgG), Dengue Antigen and Serology tests by ELISA, Dengue Viral RNA Detection (Real time RT-PCR), Viral Isolation 4 Philippines WHO dengue case classification (2009) † Yes Philippine Integrated Disease Surveillance and Response (PIDSR), indicator-based surveillance system. Reporting delays of 2-3 weeks, Confirmed dengue is a suspect case with positive (+) viral culture isolation and/or PCR. NS1 (+), IgM is used to identify probable dengue. 5, 6, 7 Dengue Situation Update 689 │ 11 making comparison of current weekly and cumulative figures with previous years difficult. Singapore (endemic) Fever, headache, backache, myalgia, rash, abdominal discomfort and thrombocytopenia and laboratory testing (see right column) No Dengue is a legally notifiable disease in Singapore and notifying the Ministry of Health should not be later than 24 hours from the time of diagnosis. Laboratory confirmation is done using standard diagnostic tests for the detection of dengue NS1 antigen, IgM and IgG, or RT-PCR. 8,9 Viet Nam (endemic) Acute onset of fever continuously lasting from 2-7 days AND at least 2 of the following: haemorrhagic manifestation /presentation; headache, loss of appetite, nausea, vomiting; rash; muscle pain, joint pain, orbital pain; lethargy; abdominal pain. No As per the MOH dengue surveillance guideline, in routine surveillance MAC-ELISA is conducted for at least 7% and virus isolation is conducted for at least 3% of clinical cases. In an outbreak, at least 5 to 10 suspected cases are tested. 10 Pacific Island Countries WHO dengue case classification (2009) † No Pacific Syndromic Surveillance System Confirmed case: Isolation of dengue virus or detection of dengue-specific antigen or antibodies in tissue, blood, CSF or other body fluid by an advanced laboratory test 11 Only the minimum criteria required for fulfilling a clinical dengue case definition are included here; additional signs and symptoms required for more severe forms are not listed. † A probable dengue case is defined as any case living in or travel to dengue endemic area with fever and two or more of the following: nausea, vomiting, rash, aches and pains, positive tourniquet test, leucopenia and any warning sign. A case with warning signs is defined as a clinically diagnosed case with any of the following: abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleed, lethargy, restlessness, liver enlargement > 2 cm and increase in haematocrit concurrent with rapid decrease in platelet count. Severe dengue is defined as severe plasma leakage leading to any of the following: shock, fluid accumulation with respiratory distress OR severe bleeding as evaluated by clinician OR severe organ involvement of liver (aspartate amino transferase or alanine amino transferase ≥ 1000), central nervous system (impaired consciousness) or heart and other organs.10 References: 1. Australian Government Department of Health AGDo. Dengue virus infection surveillance and case definition [updated 14 June 2022 and 1 January 2018 respectively] Available from: https://www.health.gov.au/diseases/dengue-virus-infection, and https://www.health.gov.au/sites/default/files/documents/2022/06/dengue-virus-infection-surveillance-case-definition.pdf 2. Cambodia Ministry of Health NCfP, Entomology and Malaria Control. National Guideline for Clinical Management of Dengue, 2018. 2018. Available from: https://niph.org.kh/niph/uploads/library/pdf/GL055_National_guideline_for_ClM_Dengue.pdf. 3. Khampapongpane B, Lewis HC, Ketmayoon P, Phonekeo D, Somoulay V, Khamsing A, et al. National dengue surveillance in the Lao People's Democratic Republic, 2006-2012: epidemiological and laboratory findings. Western Pac Surveill Response J. 2014;5(1):7-13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24734212. 4. Ministry of Health Malaysia DCD. Case definitions for infectious diseases in Malaysia. 2017. Available from: https://www.moh.gov.my/moh/resources/Penerbitan/Garis%20Panduan/Pengurusan%20KEsihatan%20&%20kawalan%20pykit/Case_Definition_Of_Infectious_Disease_3rd_Edition_2017.pdf 5. Secretary PDoHOot. Guidelines for the Nationwide Implementation of Dengue Rapid Diagnostic Test (RDT), Administrative order No.2016-0043. 2016(2016-0043). 6. Secretary PDoHOot. Revised Dengue Clinical Case Management Guidelines 2011, Administrative order No.2012-0006. 2012 22 March 2012. Report No. 7. Diseases SNCfI. Diseases and Conditions, Dengue 2020 [updated 14 September 2020. Available from: https://www.doh.gov.ph/Health-Advisory/Dengue. 8. National Centre for Infectious Diseases, Dengue. Available from: https://www.ncid.sg/Health-Professionals/Diseases-and-Conditions/Pages/Dengue.aspx Dengue Situation Update 689 │ 12 9. National Environment Agency. Surveillance and Epidemiology Programme [updated 21 April 2023]. Available from: https://www.nea.gov.sg/corporate-functions/resources/research/surveillance-and- epidemiology-programme#Ehi%20Diagnostics%20Unit 10. Viet Nam Ministry of Health VNMo. Circular 54/2015 / TT-BYT 2015 [updated 26 April 2016. Available from: https://syt.thuathienhue.gov.vn/?gd=27&cn=108&tc=3993. 11. Pacific Islands Outbreak Manual. Available from: https://www.pphsn.net/resources/outbreak-manual/ 12. WHO dengue outbreak toolbox. Available from: https://www.who.int/docs/default-source/outbreak-toolkit/updates-documents_july-5/dengue-outbreak-data-collection-toolbox---inis-3-july- 1.pdf?sfvrsn=ec3ffcf3_2
Dengue Situation Update 690 │ 1 Dengue Situation Update 690 01 February 2024 Update on the Dengue situation in the Western Pacific Region This report describes the epidemiology of dengue in the World Health Organization Western Pacific Region. Data are compiled from open sources (national indicator-based surveillance systems) with the exception of Cambodia, Lao People’s Democratic Republic, Viet Nam, and the Philippines, where data are provided by the WHO Country Offices. For the Pacific Island Countries, syndromic surveillance data are provided by the Division of Pacific Technical Support. Information is reported based on countries’ standard dengue case definitions, summary of these definitions and countries’ dengue surveillance systems - included as an annex to this report. Due to differences in surveillance methods and reporting practices, a comparison of trends between countries and areas is not possible, however, national trends can be observed over time. Northern Hemisphere Cambodia As of epidemiological week 2 of 2024, the National Dengue Surveillance System reported a total of 1,078 cases with 3 deaths (Case Fatality Rate (CFR) 0.28%) since 1 January 2024 (Figure 1), an increase by 264.2% (n=296) in cases and by 3 deaths (n=0) respectively, as compared to cases and deaths reported in 2023 over the same period. Figure 1: Dengue cases reported weekly in 2024 vs endemic and epidemic alert lines in Cambodia; Source: National Dengue Surveillance System (NDCP/CNM/MOH) Dengue Situation Update 690 │ 2 China There is no update for this reporting period. In December 2023, 154 dengue cases and no deaths were reported in China. There have been a total of 19,627 dengue cases and one death in the country from January 2023 to December 2023 (Figure 2). Figure 2: Dengue cases reported monthly from 2015-2023 (as of October) in China Source: National Health Commission, CDC and National Disease Control and Prevention Administration, China Lao People’s Democratic Republic In epidemiological week 3 of 2024 (15 January to 21 January 2024), 223 dengue cases and zero deaths were reported (Figure 3). The number of reported cases is higher than the numbers reported in epidemiological week 2 (126 cases with no deaths), and higher than those in week 3 of 2023 (54 cases with no deaths). The cumulative number of cases reported in 2024 (as of epidemiological week 3) is 414. This is a 137.9% increase compared to the 174 cases reported during the same period in 2023. Dengue Situation Update 690 │ 3 Figure 3: Dengue cases reported weekly from 2018-2024 in Lao PDR Source: National Centre for Laboratory and Epidemiology, Ministry of Health, Lao PDR Malaysia During epidemiological week 3 of 2024 (14 January 2024 to 20 January 2024), an increase of 446 cases (12,65%) was reported with 3,971 cases as compared to 3,525 cases reported in the previous week (Figure 4). The cumulative number of dengue cases reported up to week 3 of 2024 is 10,677 cases, which is an increase of 51.3% compared to 7,058 cases for the same period in 2023. Two dengue-related deaths were reported up to week 3 of 2024 compared to 3 deaths for the same period in 2023. Figure 4: Dengue cases reported weekly from 2023, 2024 and median 2019-2023 in Malaysia Source: Department of Health, Malaysia Number of cases Dengue Situation Update 690 │ 4 Philippines There is no update for this reporting period. During epidemiological Week 48 (26 November to 2 December 2023), there were 2,607 new dengue cases reported, a 41% decrease compared to the same period in 2022 (n=4,415 cases) (Figure 5). As of 2 December 2023, a total of 195,603 dengue cases have been reported. The number of cases is 23% lower compared to the same period in 2022 (n=252,700). From 1 January to 2 December 2023, there have been 657 deaths (CFR 0.34%) as compared to 894 deaths (CFR 0.35%;) reported in the same period in 2022. Figure 5: Dengue cases reported weekly from 2022 and 2023 in the Philippines Source: Department of Health, the Philippines (Note: there is a 3-4 week systematic delay in reporting and numbers should be interpreted with caution) Singapore There is no update for this reporting period. In epidemiological week 52 (24 December to 30 December), a total of 275 dengue cases were reported in Singapore. Cumulatively, a total of 9,938 cases (Figure 6) have been reported as of 30 December 2023. When compared with week 52 in 2022 (32,130 cases), there has been a 69.1% decrease in cases reported in week 52 of this year. Preliminary results of all positive dengue samples serotyped in December 2023 (as of 30 December) showed DEN-1, DEN-2, DEN-3, and DEN-4 at 17.8%, 56.5%, 17.8%, and 7.8% respectively. Figure 6: Dengue cases reported weekly from 2018-2023 (as of 30 December) in Singapore Source: Communicable Diseases Division, Ministry of Health, Singapore (Note: Case numbers are derived from the MOH Singapore’s Weekly Infectious Bulletin Year Excelsheet as available from MOH | Weekly Infectious Diseases Bulletin) Dengue Situation Update 690 │ 5 Viet Nam From 1 January to 31 December 2023 (epidemiological week 52), cumulatively 172,000 dengue cases including 43 deaths (CFR: 0.025%) were reported in Viet Nam. Compared to the same period in 2022 (369,483 cases including 151 deaths), the number of cumulative cases decreased 53.8%, and the number of cumulative deaths decreased 72.4% (Figure 7). Figure 7: Number of dengue hospital admissions and deaths by week in 2022 compared to 2023, as of week 52, 2023, Viet Nam Source: General Department of Preventive Medicine, Ministry of Health, Viet Nam Note hospitalizations include inpatients and outpatients The alert threshold is a 5-year mean plus 2 standard deviations Southern Hemisphere Australia From 01 January to 07 January 2024, a total of 22 dengue cases were reported in Australia. From 08 January 2023 to 07 January 2024, the cumulative number of dengue cases is 1,090, which is 1.7 times higher than the same period’s 5 year rolling mean (n=653 cases). (Figure 8). Dengue Situation Update 690 │ 6 Figure 8: Laboratory-confirmed dengue cases reported monthly from 2016-2024 in Australia Source: Department of Health, Australia Note: Graph was updated on 7 January 2024 Pacific Islands Countries New Caledonia From 1 January to 31 December 2023, nine confirmed dengue cases were reported in New Caledonia (Figure 9). This is higher compared to the same period in 2022 when a total of three dengue case was reported. Of the nine confirmed dengue cases in 2023, six were imported cases. The serotype of the cases were DENV-1, DENV-2 and DENV-3. Figure 9: Dengue cases reported by week from 2021 to 2023 in New Caledonia Source: Network of sentinel physicians, New Caledonia Pacific Island Countries and Areas (PICs) – Dengue-like illness (DLI) Surveillance During epidemiological week 3 of 2024 (ending 21 January 2024), among Pacific Island Countries and Areas (PICs) with available surveillance data, Fiji, Palau, Samoa, Wallis & Futuna reported DLI cases.. Dengue Situation Update 690 │ 7 Dengue Situation Update 690 │ 8 Dengue Situation Update 690 │ 9 Figure 10. Reported cases of dengue-like illness in Pacific Islands Countries and Areas Source: WHO Division of Pacific Technical Support Note: Caution should be taken in interpreting these data as there may be changes in the number of sentinel sites reporting to the Pacific Syndromic Surveillance System (PSSS). Furthermore, the syndromic case definition of DLI may capture cases with non- dengue acute febrile illnesses (AFI) with similar clinical manifestations to dengue. This includes AFI such as chikungunya, influenza, hantavirus, leptospirosis, malaria, measles, paratyphoid and typhoid fevers, scrub typhus, yellow fever, zika, other diseases. The PSSS may also capture dengue cases under ‘prolonged fever’ surveillance. Alert threshold for DLI is twice the average number of cases seen in the previous 3 weeks. FSM: Federated States of Micronesia Dengue Situation Update 690 │ 10 Annex 1. Summary of dengue case definitions, laboratory sampling and testing methods used for surveillance in Member States as of 2023 Country Case definition Surveillance system Laboratory sampling and testing method Reference Clinically confirmed case Laboratory confirmation required Description Australia Fever, headache, arthralgia, myalgia, rash, nausea and vomiting Yes Dengue is a nationally notifiable disease and cases are monitored through the National Notifiable Diseases Surveillance System (NNDSS) indicator-based surveillance system. Both confirmed and probable cases are nationally notifiable. A confirmed case requires both laboratory definitive evidence and clinical evidence. A probable case requires either laboratory suggestive evidence and clinical evidence and epidemiological evidence, or clinical evidence and household epidemiological evidence. Laboratory definitive evidence: - Isolation of dengue virus, or - Detection of dengue virus by nucleic acid testing, or - Detection of NS1 antigen in the blood by EIA, or - IgG seroconversion or significant increase in antibody levelor fourfold or greater rise in titre to dengue virus (proof by neutralization or another specific test) Laboratory suggestive evidence: - Detection of NS1 antigen in blood by rapid antigen test, or - Detection of dengue virus-specific IgM in blood Epidemiological evidence: - Exposure between 3 – 14 days prior to onset either in a country with known dengue activity or in a dengue-receptive area in Australia where a locally-acquired or imported case has been documented with onset within a month. Household epidemiological evidence: - Living in the same house as a locally- acquired case in a dengue-receptive area of Australia within a month of onse in the 1 Dengue Situation Update 690 │ 11 case and at least one case in the chain of epidemiologically linked cases is laboratory confirmed. Cambodia Suspected dengue: very high fever at 39-40 degrees celcius for 2-7 days (usually 3-4 days), with 2 or more of the following signs: flushed face, headache, retro-orbital pain, myalgia/arthralgia, cutaneous rash, haemorrhagic signs (petechiae, positive tourniquet test), and leucopenia. Probable dengue: signs of suspected dengue plus laboratory test results (see right column)) or that the case occurred in an area where the dengue case has been confirmed. Yes National Dengue Control Program (NDCP) enhanced sentinel surveillance system Communicable Disease Control (CDC) syndromic surveillance system (CamEWARN). Health Management Information System (HMIS) collects data on confirmed cases and deaths. Data collected for Cambodia Laboratory Information System (CamLIS), comprised of 32 participating hospital laboratories where NS1 detection is conducted. Laboratory testing: Antibody HI>= 1/1280 or IgM/IgG positive by ELISA test in convalescence serum 2 China (i) more than two symptoms of acute onset fever, severe headache, orbital pain, myalgia, arthralgia, fatigue with a history of travel in a dengue endemic area within 15 days before symptom onset or cohabitation with an individual with confirmed dengue; or no travel history, but with a rash or positive tourniquet test AND leucopenia or thrombocytopenia or serum IgM positivity. No Reported to the Chinese Centre for Disease Control and Prevention (China CDC) through the Chinese National Notifiable Infectious Disease Reporting Information System (CNNDS). Laboratory confirmation is done by real-time RT-PCR, NS1 in acute-phase serum, or virus isolation from an acutely infected patient’s serum. WHO internal communication Lao People's Democratic Republic WHO dengue case classification (2009) † No National Surveillance System for Notifiable Selected Diseases, indicator-based surveillance system that consists of passive weekly reports of clinically suspected cases, on admission, from all health-care facilities across the country. 3 Malaysia WHO dengue case classification (2009) † Yes National Dengue Surveillance System, indicator-based surveillance system All suspected cases are to be tested by the following laboratory tests: Rapid Combo Test (RCT) (NS1, IgM, IgG), Dengue Antigen and Serology tests by ELISA, Dengue Viral RNA Detection (Real time RT-PCR), Viral Isolation 4 Philippines WHO dengue case classification (2009) † Yes Philippine Integrated Disease Surveillance and Response (PIDSR), indicator-based surveillance system. Reporting delays of 2-3 weeks, Confirmed dengue is a suspect case with positive (+) viral culture isolation and/or PCR. NS1 (+), IgM is used to identify probable dengue. 5, 6, 7 Dengue Situation Update 690 │ 12 making comparison of current weekly and cumulative figures with previous years difficult. Singapore (endemic) Fever, headache, backache, myalgia, rash, abdominal discomfort and thrombocytopenia and laboratory testing (see right column) No Dengue is a legally notifiable disease in Singapore and notifying the Ministry of Health should not be later than 24 hours from the time of diagnosis. Laboratory confirmation is done using standard diagnostic tests for the detection of dengue NS1 antigen, IgM and IgG, or RT-PCR. 8,9 Viet Nam (endemic) Acute onset of fever continuously lasting from 2-7 days AND at least 2 of the following: haemorrhagic manifestation /presentation; headache, loss of appetite, nausea, vomiting; rash; muscle pain, joint pain, orbital pain; lethargy; abdominal pain. No As per the MOH dengue surveillance guideline, in routine surveillance MAC-ELISA is conducted for at least 7% and virus isolation is conducted for at least 3% of clinical cases. In an outbreak, at least 5 to 10 suspected cases are tested. 10 Pacific Island Countries WHO dengue case classification (2009) † No Pacific Syndromic Surveillance System Confirmed case: Isolation of dengue virus or detection of dengue-specific antigen or antibodies in tissue, blood, CSF or other body fluid by an advanced laboratory test 11 Only the minimum criteria required for fulfilling a clinical dengue case definition are included here; additional signs and symptoms required for more severe forms are not listed. † A probable dengue case is defined as any case living in or travel to dengue endemic area with fever and two or more of the following: nausea, vomiting, rash, aches and pains, positive tourniquet test, leucopenia and any warning sign. A case with warning signs is defined as a clinically diagnosed case with any of the following: abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleed, lethargy, restlessness, liver enlargement > 2 cm and increase in haematocrit concurrent with rapid decrease in platelet count. Severe dengue is defined as severe plasma leakage leading to any of the following: shock, fluid accumulation with respiratory distress OR severe bleeding as evaluated by clinician OR severe organ involvement of liver (aspartate amino transferase or alanine amino transferase ≥ 1000), central nervous system (impaired consciousness) or heart and other organs.10 References: 1. Australian Government Department of Health AGDo. Dengue virus infection surveillance and case definition [updated 14 June 2022 and 1 January 2018 respectively] Available from: https://www.health.gov.au/diseases/dengue-virus-infection, and https://www.health.gov.au/sites/default/files/documents/2022/06/dengue-virus-infection-surveillance-case-definition.pdf 2. Cambodia Ministry of Health NCfP, Entomology and Malaria Control. National Guideline for Clinical Management of Dengue, 2018. 2018. Available from: https://niph.org.kh/niph/uploads/library/pdf/GL055_National_guideline_for_ClM_Dengue.pdf. 3. Khampapongpane B, Lewis HC, Ketmayoon P, Phonekeo D, Somoulay V, Khamsing A, et al. National dengue surveillance in the Lao People's Democratic Republic, 2006-2012: epidemiological and laboratory findings. Western Pac Surveill Response J. 2014;5(1):7-13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24734212. 4. Ministry of Health Malaysia DCD. Case definitions for infectious diseases in Malaysia. 2017. Available from: https://www.moh.gov.my/moh/resources/Penerbitan/Garis%20Panduan/Pengurusan%20KEsihatan%20&%20kawalan%20pykit/Case_Definition_Of_Infectious_Disease_3rd_Edition_2017.pdf 5. Secretary PDoHOot. Guidelines for the Nationwide Implementation of Dengue Rapid Diagnostic Test (RDT), Administrative order No.2016-0043. 2016(2016-0043). 6. Secretary PDoHOot. Revised Dengue Clinical Case Management Guidelines 2011, Administrative order No.2012-0006. 2012 22 March 2012. Report No. 7. Diseases SNCfI. Diseases and Conditions, Dengue 2020 [updated 14 September 2020. Available from: https://www.doh.gov.ph/Health-Advisory/Dengue. 8. National Centre for Infectious Diseases, Dengue. Available from: https://www.ncid.sg/Health-Professionals/Diseases-and-Conditions/Pages/Dengue.aspx Dengue Situation Update 690 │ 13 9. National Environment Agency. Surveillance and Epidemiology Programme [updated 21 April 2023]. Available from: https://www.nea.gov.sg/corporate-functions/resources/research/surveillance-and- epidemiology-programme#Ehi%20Diagnostics%20Unit 10. Viet Nam Ministry of Health VNMo. Circular 54/2015 / TT-BYT 2015 [updated 26 April 2016. Available from: https://syt.thuathienhue.gov.vn/?gd=27&cn=108&tc=3993. 11. Pacific Islands Outbreak Manual. Available from: https://www.pphsn.net/resources/outbreak-manual/ 12. WHO dengue outbreak toolbox. Available from: https://www.who.int/docs/default-source/outbreak-toolkit/updates-documents_july-5/dengue-outbreak-data-collection-toolbox---inis-3-july- 1.pdf?sfvrsn=ec3ffcf3_2
Dengue Situation Update 691 │ 1 Dengue Situation Update 691 15 February 2024 Update on the Dengue situation in the Western Pacific Region This report describes the epidemiology of dengue in the World Health Organization Western Pacific Region. Data are compiled from open sources (national indicator-based surveillance systems) with the exception of Cambodia, Lao People’s Democratic Republic, Viet Nam, and the Philippines, where data are provided by the WHO Country Offices. For the Pacific Island Countries, syndromic surveillance data are provided by the Division of Pacific Technical Support. Information is reported based on countries’ standard dengue case definitions, summary of these definitions and countries’ dengue surveillance systems - included as an annex to this report. Due to differences in surveillance methods and reporting practices, a comparison of trends between countries and areas is not possible, however, national trends can be observed over time. Northern Hemisphere Cambodia As of epidemiological week 4 of 2024, the National Dengue Surveillance System reported a total of 1,972 cases with 5 deaths (Case Fatality Rate (CFR) 0.25%) since 1 January 2024 (Figure 1), an increase by 307.4% (n=484) in cases and by 4 deaths (n=1) respectively, as compared to cases and deaths reported in 2023 over the same period. Figure 1: Dengue cases reported weekly in 2024 vs endemic and epidemic alert lines in Cambodia; Source: National Dengue Surveillance System (NDCP/CNM/MOH) Dengue Situation Update 691 │ 2 China There is no update for this reporting period. In December 2023, 154 dengue cases and no deaths were reported in China. There have been a total of 19,627 dengue cases and one death in the country from January 2023 to December 2023 (Figure 2). Figure 2: Dengue cases reported monthly from 2015-2023 (as of October) in China Source: National Health Commission, CDC and National Disease Control and Prevention Administration, China Lao People’s Democratic Republic In epidemiological week 5 of 2024 (29 January to 4 February 2024), 148 dengue cases and zero deaths were reported (Figure 3). The number of reported cases is lower than the numbers reported in epidemiological week 4 (170 cases with no deaths), and higher than those in week 5 of 2023 (51 cases with no deaths). The cumulative number of cases reported in 2024 (as of epidemiological week 3) is 732. This is a 170.1% increase compared to the 271 cases reported during the same period in 2023. Figure 3: Dengue cases reported weekly from 2018-2024 in Lao PDR Source: National Centre for Laboratory and Epidemiology, Ministry of Health, Lao PDR Dengue Situation Update 691 │ 3 Malaysia During epidemiological week 6 of 2024 (4 February 2024 to 10 February2024), a decrease of 338 cases (8.5%) was reported with 3,631 cases as compared to 3,969 cases reported in the previous week (Figure 4). The cumulative number of dengue cases reported up to week 6 of 2024 is 22,058 cases, which is an increase of 68.5% compared to 13,094 cases for the same period in 2023. 10 dengue-related deaths were reported up to week 6 of 2024 compared to 9 deaths for the same period in 2023. Figure 4: Dengue cases reported weekly from 2023, 2024 and median 2019-2023 in Malaysia Source: Department of Health, Malaysia Philippines There is no update for this reporting period. During epidemiological Week 48 (26 November to 2 December 2023), there were 2,607 new dengue cases reported, a 41% decrease compared to the same period in 2022 (n=4,415 cases) (Figure 5). As of 2 December 2023, a total of 195,603 dengue cases have been reported. The number of cases is 23% lower compared to the same period in 2022 (n=252,700). From 1 January to 2 December 2023, there have been 657 deaths (CFR 0.34%) as compared to 894 deaths (CFR 0.35%;) reported in the same period in 2022. Figure 5: Dengue cases reported weekly from 2022 and 2023 in the Philippines Source: Department of Health, the Philippines (Note: there is a 3-4 week systematic delay in reporting and numbers should be interpreted with caution) Number of cases Dengue Situation Update 691 │ 4 Singapore In epidemiological week 5 (28 January 2024 to 3 February 2024), a total of 487 dengue cases were reported in Singapore. Cumulatively, a total of 2,027 cases (Figure 6) have been reported as of 3 February 2024. When compared with week 5 in 2023 (1,239 cases), there has been a 63.6% increase in cases reported in week 5 of this year. Preliminary results of all positive dengue samples serotyped in January 2024 showed DEN-1, DEN-2, DEN-3, and DEN-4 at 21.3%, 62.7%, 11.6%, and 4.4% respectively. Figure 6: Dengue cases reported weekly from 2019-2024 (as of 7 February 2024) in Singapore Source: Communicable Diseases Division, Ministry of Health, Singapore (Note: Case numbers are derived from the MOH Singapore’s Weekly Infectious Bulletin Year Excelsheet as available from MOH | Weekly Infectious Diseases Bulletin) Viet Nam As of 14 January 2024 (epidemiological week 2), cumulatively 3,758 dengues cases including no deaths were reported in Viet Nam. Compared to the same period in 2023, the number of cumulative cases decreased 32.3%. (Figure 7). Figure 7: Number of dengue hospital admissions and deaths by week in 2022 compared to 2023, as of week 52, 2023, Viet Nam Source: General Department of Preventive Medicine, Ministry of Health, Viet Nam Note hospitalizations include inpatients and outpatients The alert threshold is a 5-year mean plus 2 standard deviations Graph was updated on 31 December 2023 Dengue Situation Update 691 │ 5 Southern Hemisphere Australia From 08 January to 21 January 2024, a total of 59 dengue cases were reported in Australia. From 22 January 2023 to 21 January 2024, the cumulative number of dengue cases is 1,117, which is 1.7 times higher than the same period’s 5 year rolling mean (n=645.6 cases). (Figure 8). Figure 8: Laboratory-confirmed dengue cases reported monthly from 2016-2024 in Australia Source: Department of Health, Australia Note: Graph was updated on 15 February 2024 Pacific Islands Countries New Caledonia There is no update for this reporting period. From 1 January to 31 December 2023, nine confirmed dengue cases were reported in New Caledonia (Figure 9). This is higher compared to the same period in 2022 when a total of three dengue case was reported. Of the nine confirmed dengue cases in 2023, six were imported cases. The serotype of the cases were DENV-1, DENV-2 and DENV-3. Figure 9: Dengue cases reported by week from 2021 to 2023 in New Caledonia Source: Network of sentinel physicians, New Caledonia Dengue Situation Update 691 │ 6 Pacific Island Countries and Areas (PICs) – Dengue-like illness (DLI) Surveillance During epidemiological week 5 of 2024 (ending 6 February 2024), Pacific Island Countries and Areas (PICs) with available surveillance data (16/18 PICs) reported no or low numbers of DLI cases. Among the PICs, Fiji, Samoa, Solomon Islands, Tokelau, Wallis & Futuna reported DLI cases. 0 5 10 15 20 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as e s Epi week Cook Islands DLI Trend - 2021 -2024 (W5) DLI 2004 DLI 2021 DLI 2022 DLI 2023 0 200 400 600 800 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as e s Epi week Fiji DLI Trend - 2021 -2024 (W5) DLI 2024 DLI 2021 DLI 2022 DLI 2023 Baseline 0 20 40 60 80 100 120 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 C as e s Epi week French Polynesia DLI Trend - 2021 -2024 (W2) DLI 2024 DLI 2021 DLI 2022 DLI 2023 0 2 4 6 8 10 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 C as e s Epi week FSM DLI Trend - 2021 -2024 (W5) DLI 2024 DLI 2022 0 5 10 15 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as e s Epi week Kiribati DLI Trend - 2021 -2024 (W5) DLI 2024 DLI 2021 DLI 2022 DLI 2023 0 1 2 3 4 5 6 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 ca se s Epi week New Caledonia DLI Trend - 2021 -2024 (W5) DLI 2024 DLI 2021 DLI 2022 DLI 2023 0 2 4 6 8 10 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 ca se s Epi week Pitcairn Islands DLI Trend - 2021 -2024 (W5) DLI 2024 DLI 2021 DLI 2022 DLI 2023 0 2 4 6 8 10 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 ca se s Epi week Marshall Islands DLI Trend - 2021 -2024 (W5) DLI 2024 DLI 2021 DLI 2022 DLI 2023 Dengue Situation Update 691 │ 7 0 5 10 15 20 25 30 35 40 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 ca se s Epi week Samoa DLI Trend - 2021 -2024(WK5) DLI 2024 DLI 2021 DLI 2022 DLI 2023 0 20 40 60 80 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as e s Epi week Solomon Islands DLI Trend - 2021 -2024 (WK5) DLI 2024 DLI 2021 DLI 2022 DLI 2023 0 2 4 6 8 10 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 C as e s EPI week Tuvalu DLI Trend - 2021 -2024 (W5) DLI 2004 DLI 2021 DLI 2022 DLI 2023 0 2 4 6 8 10 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as e s Epi week N Mariana Is DLI Trend - 2021 -2024(W5) DLI 2024 DLI 2021 DLI 2022 DLI 2023 0 2 4 6 8 10 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 ca se s Epiweek Niue DLI Trend - 2021 -2024 (W5) DLI 2024 DLI 2021 DLI 2022 DLI 2023 0 2 4 6 8 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 ca se s Epiweek Palau DLI Trend - 2021 -2024 (WK5) DLI 2024 DLI 2021 DLI 2022 DLI 2023 0 2 4 6 8 10 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as e s Epi week Tonga DLI Trend - 2021 -2024 (WK5) DLI 2024 DLI 2021 DLI 2022 DLI 2023 0 5 10 15 20 25 30 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 ca se s Epi week Vanuatu DLI Trend - 2021 -2023 (W48) DLI 2024 DLI 2022 DLI 2021 DLI 2023 Dengue Situation Update 691 │ 8 Figure 10. Reported cases of dengue-like illness in Pacific Islands Countries and Areas Source: WHO Division of Pacific Technical Support Note: Caution should be taken in interpreting these data as there may be changes in the number of sentinel sites reporting to the Pacific Syndromic Surveillance System (PSSS). Furthermore, the syndromic case definition of DLI may capture cases with non- dengue acute febrile illnesses (AFI) with similar clinical manifestations to dengue. This includes AFI such as chikungunya, influenza, hantavirus, leptospirosis, malaria, measles, paratyphoid and typhoid fevers, scrub typhus, yellow fever, zika, other diseases. The PSSS may also capture dengue cases under ‘prolonged fever’ surveillance. Alert threshold for DLI is twice the average number of cases seen in the previous 3 weeks. FSM: Federated States of Micronesia 0 2 4 6 8 10 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 C as e s Epiweek Tokelau DLI Trend - 2021 -2024 (W5) DLI 2024 DLI 2021 DLI 2022 DLI 2023 0 5 10 15 20 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as e s EPI Week Wallis & Futuna DLI trend -2021 -2024 (WK5) DLI 2024 DLI 2021 DLI 2022 DLI 2023 Dengue Situation Update 691 │ 9 Annex 1. Summary of dengue case definitions, laboratory sampling and testing methods used for surveillance in Member States as of 2023 Country Case definition Surveillance system Laboratory sampling and testing method Reference Clinically confirmed case Laboratory confirmation required Description Australia Fever, headache, arthralgia, myalgia, rash, nausea and vomiting Yes Dengue is a nationally notifiable disease and cases are monitored through the National Notifiable Diseases Surveillance System (NNDSS) indicator-based surveillance system. Both confirmed and probable cases are nationally notifiable. A confirmed case requires both laboratory definitive evidence and clinical evidence. A probable case requires either laboratory suggestive evidence and clinical evidence and epidemiological evidence, or clinical evidence and household epidemiological evidence. Laboratory definitive evidence: - Isolation of dengue virus, or - Detection of dengue virus by nucleic acid testing, or - Detection of NS1 antigen in the blood by EIA, or - IgG seroconversion or significant increase in antibody levelor fourfold or greater rise in titre to dengue virus (proof by neutralization or another specific test) Laboratory suggestive evidence: - Detection of NS1 antigen in blood by rapid antigen test, or - Detection of dengue virus-specific IgM in blood Epidemiological evidence: - Exposure between 3 – 14 days prior to onset either in a country with known dengue activity or in a dengue-receptive area in Australia where a locally-acquired or imported case has been documented with onset within a month. Household epidemiological evidence: - Living in the same house as a locally- acquired case in a dengue-receptive area of Australia within a month of onse in the 1 Dengue Situation Update 691 │ 10 case and at least one case in the chain of epidemiologically linked cases is laboratory confirmed. Cambodia Suspected dengue: very high fever at 39-40 degrees celcius for 2-7 days (usually 3-4 days), with 2 or more of the following signs: flushed face, headache, retro-orbital pain, myalgia/arthralgia, cutaneous rash, haemorrhagic signs (petechiae, positive tourniquet test), and leucopenia. Probable dengue: signs of suspected dengue plus laboratory test results (see right column)) or that the case occurred in an area where the dengue case has been confirmed. Yes National Dengue Control Program (NDCP) enhanced sentinel surveillance system Communicable Disease Control (CDC) syndromic surveillance system (CamEWARN). Health Management Information System (HMIS) collects data on confirmed cases and deaths. Data collected for Cambodia Laboratory Information System (CamLIS), comprised of 32 participating hospital laboratories where NS1 detection is conducted. Laboratory testing: Antibody HI>= 1/1280 or IgM/IgG positive by ELISA test in convalescence serum 2 China (i) more than two symptoms of acute onset fever, severe headache, orbital pain, myalgia, arthralgia, fatigue with a history of travel in a dengue endemic area within 15 days before symptom onset or cohabitation with an individual with confirmed dengue; or no travel history, but with a rash or positive tourniquet test AND leucopenia or thrombocytopenia or serum IgM positivity. No Reported to the Chinese Centre for Disease Control and Prevention (China CDC) through the Chinese National Notifiable Infectious Disease Reporting Information System (CNNDS). Laboratory confirmation is done by real-time RT-PCR, NS1 in acute-phase serum, or virus isolation from an acutely infected patient’s serum. WHO internal communication Lao People's Democratic Republic WHO dengue case classification (2009) † No National Surveillance System for Notifiable Selected Diseases, indicator-based surveillance system that consists of passive weekly reports of clinically suspected cases, on admission, from all health-care facilities across the country. 3 Malaysia WHO dengue case classification (2009) † Yes National Dengue Surveillance System, indicator-based surveillance system All suspected cases are to be tested by the following laboratory tests: Rapid Combo Test (RCT) (NS1, IgM, IgG), Dengue Antigen and Serology tests by ELISA, Dengue Viral RNA Detection (Real time RT-PCR), Viral Isolation 4 Philippines WHO dengue case classification (2009) † Yes Philippine Integrated Disease Surveillance and Response (PIDSR), indicator-based surveillance system. Reporting delays of 2-3 weeks, Confirmed dengue is a suspect case with positive (+) viral culture isolation and/or PCR. NS1 (+), IgM is used to identify probable dengue. 5, 6, 7 Dengue Situation Update 691 │ 11 making comparison of current weekly and cumulative figures with previous years difficult. Singapore (endemic) Fever, headache, backache, myalgia, rash, abdominal discomfort and thrombocytopenia and laboratory testing (see right column) No Dengue is a legally notifiable disease in Singapore and notifying the Ministry of Health should not be later than 24 hours from the time of diagnosis. Laboratory confirmation is done using standard diagnostic tests for the detection of dengue NS1 antigen, IgM and IgG, or RT-PCR. 8,9 Viet Nam (endemic) Acute onset of fever continuously lasting from 2-7 days AND at least 2 of the following: haemorrhagic manifestation /presentation; headache, loss of appetite, nausea, vomiting; rash; muscle pain, joint pain, orbital pain; lethargy; abdominal pain. No As per the MOH dengue surveillance guideline, in routine surveillance MAC-ELISA is conducted for at least 7% and virus isolation is conducted for at least 3% of clinical cases. In an outbreak, at least 5 to 10 suspected cases are tested. 10 Pacific Island Countries WHO dengue case classification (2009) † No Pacific Syndromic Surveillance System Confirmed case: Isolation of dengue virus or detection of dengue-specific antigen or antibodies in tissue, blood, CSF or other body fluid by an advanced laboratory test 11 Only the minimum criteria required for fulfilling a clinical dengue case definition are included here; additional signs and symptoms required for more severe forms are not listed. † A probable dengue case is defined as any case living in or travel to dengue endemic area with fever and two or more of the following: nausea, vomiting, rash, aches and pains, positive tourniquet test, leucopenia and any warning sign. A case with warning signs is defined as a clinically diagnosed case with any of the following: abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleed, lethargy, restlessness, liver enlargement > 2 cm and increase in haematocrit concurrent with rapid decrease in platelet count. Severe dengue is defined as severe plasma leakage leading to any of the following: shock, fluid accumulation with respiratory distress OR severe bleeding as evaluated by clinician OR severe organ involvement of liver (aspartate amino transferase or alanine amino transferase ≥ 1000), central nervous system (impaired consciousness) or heart and other organs.10 References: 1. Australian Government Department of Health AGDo. Dengue virus infection surveillance and case definition [updated 14 June 2022 and 1 January 2018 respectively] Available from: https://www.health.gov.au/diseases/dengue-virus-infection, and https://www.health.gov.au/sites/default/files/documents/2022/06/dengue-virus-infection-surveillance-case-definition.pdf 2. Cambodia Ministry of Health NCfP, Entomology and Malaria Control. National Guideline for Clinical Management of Dengue, 2018. 2018. Available from: https://niph.org.kh/niph/uploads/library/pdf/GL055_National_guideline_for_ClM_Dengue.pdf. 3. Khampapongpane B, Lewis HC, Ketmayoon P, Phonekeo D, Somoulay V, Khamsing A, et al. National dengue surveillance in the Lao People's Democratic Republic, 2006-2012: epidemiological and laboratory findings. Western Pac Surveill Response J. 2014;5(1):7-13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24734212. 4. Ministry of Health Malaysia DCD. Case definitions for infectious diseases in Malaysia. 2017. Available from: https://www.moh.gov.my/moh/resources/Penerbitan/Garis%20Panduan/Pengurusan%20KEsihatan%20&%20kawalan%20pykit/Case_Definition_Of_Infectious_Disease_3rd_Edition_2017.pdf 5. Secretary PDoHOot. Guidelines for the Nationwide Implementation of Dengue Rapid Diagnostic Test (RDT), Administrative order No.2016-0043. 2016(2016-0043). 6. Secretary PDoHOot. Revised Dengue Clinical Case Management Guidelines 2011, Administrative order No.2012-0006. 2012 22 March 2012. Report No. 7. Diseases SNCfI. Diseases and Conditions, Dengue 2020 [updated 14 September 2020. Available from: https://www.doh.gov.ph/Health-Advisory/Dengue. 8. National Centre for Infectious Diseases, Dengue. Available from: https://www.ncid.sg/Health-Professionals/Diseases-and-Conditions/Pages/Dengue.aspx Dengue Situation Update 691 │ 12 9. National Environment Agency. Surveillance and Epidemiology Programme [updated 21 April 2023]. Available from: https://www.nea.gov.sg/corporate-functions/resources/research/surveillance-and- epidemiology-programme#Ehi%20Diagnostics%20Unit 10. Viet Nam Ministry of Health VNMo. Circular 54/2015 / TT-BYT 2015 [updated 26 April 2016. Available from: https://syt.thuathienhue.gov.vn/?gd=27&cn=108&tc=3993. 11. Pacific Islands Outbreak Manual. Available from: https://www.pphsn.net/resources/outbreak-manual/ 12. WHO dengue outbreak toolbox. Available from: https://www.who.int/docs/default-source/outbreak-toolkit/updates-documents_july-5/dengue-outbreak-data-collection-toolbox---inis-3-july- 1.pdf?sfvrsn=ec3ffcf3_2
Dengue Situation Update 692 │ 1 Dengue Situation Update 693 14 March 2024 Update on the Dengue situation in the Western Pacific Region This report describes the epidemiology of dengue in the World Health Organization Western Pacific Region. Data are compiled from open sources (national indicator-based surveillance systems) with the exception of Cambodia, Lao People’s Democratic Republic, Viet Nam, and the Philippines, where data are provided by the WHO Country Offices. For the Pacific Island Countries, syndromic surveillance data are provided by the Division of Pacific Technical Support. Information is reported based on countries’ standard dengue case definitions, summary of these definitions and countries’ dengue surveillance systems - included as an annex to this report. Due to differences in surveillance methods and reporting practices, a comparison of trends between countries and areas is not possible, however, national trends can be observed over time. Northern Hemisphere Cambodia As of epidemiological week 9 of 2024, the National Dengue Surveillance System reported a total of 3,575 cases with 10 deaths (Case Fatality Rate (CFR) 0.28%) since 1 January 2024 (Figure 1), an increase by 267% (n=975) in cases and by 8 deaths (n=2) respectively, as compared to cases and deaths reported in 2023 over the same period. Figure 1: Dengue cases reported weekly in 2024 vs endemic and epidemic alert lines in Cambodia; Source: National Dengue Surveillance System (NDCP/CNM/MOH) Dengue Situation Update 692 │ 2 China There is no update for this reporting period. In December 2023, 154 dengue cases and no deaths were reported in China. There have been a total of 19,627 dengue cases and one death in the country from January 2023 to December 2023 (Figure 2). Figure 2: Dengue cases reported monthly from 2015-2023 (as of October) in China Source: National Health Commission, CDC and National Disease Control and Prevention Administration, China Lao People’s Democratic Republic There is no update for this reporting period. In epidemiological week 7 of 2024 (12 February to 18 February 2024), 129 dengue cases and zero deaths were reported (Figure 3). The number of reported cases is higher than the numbers reported in epidemiological week 6 (105 cases with no deaths), and higher than those in week 7 of 2023 (59 cases with no deaths). The cumulative number of cases reported in 2024 (as of epidemiological week 7) is 966. This is a 166.1% increase compared to the 363 cases reported during the same period in 2023. Figure 3: Dengue cases reported weekly from 2018-2024 in Lao PDR Source: National Centre for Laboratory and Epidemiology, Ministry of Health, Lao PDR Dengue Situation Update 692 │ 3 Malaysia There is no update for this reporting period. During epidemiological week 7 of 2024 (11 February 2024 to 17 February2024), a decrease of 148 cases (4.0%) was reported with 3,483 cases as compared to 3,631 cases reported in the previous week (Figure 4). The cumulative number of dengue cases reported up to week 7 of 2024 is 25,541 cases, which is an increase of 67.5% compared to 15,243 cases for the same period in 2023. 14 dengue-related deaths were reported up to week 7 of 2024 compared to 13 deaths for the same period in 2023. Figure 4: Dengue cases reported weekly from 2023, 2024 and median 2019-2023 in Malaysia Source: Department of Health, Malaysia Philippines There is no update for this reporting period. During epidemiological Week 48 (26 November to 2 December 2023), there were 2,607 new dengue cases reported, a 41% decrease compared to the same period in 2022 (n=4,415 cases) (Figure 5). As of 2 December 2023, a total of 195,603 dengue cases have been reported. The number of cases is 23% lower compared to the same period in 2022 (n=252,700). From 1 January to 2 December 2023, there have been 657 deaths (CFR 0.34%) as compared to 894 deaths (CFR 0.35%;) reported in the same period in 2022. Figure 5: Dengue cases reported weekly from 2022 and 2023 in the Philippines Source: Department of Health, the Philippines (Note: there is a 3-4 week systematic delay in reporting and numbers should be interpreted with caution) Number of cases Dengue Situation Update 692 │ 4 Singapore In epidemiological week 9 (25 February 2024 to 2 March 2024), a total of 372 dengue cases were reported in Singapore. Cumulatively, a total of 3,802 cases (Figure 6) have been reported as of 2 March 2024. When compared with week 9 in 2023 (1,855 cases), there has been a 105.0% increase in cases reported in week 9 of this year. Preliminary results of all positive dengue samples serotyped in February 2024 showed DEN- 1, DEN-2, DEN-3, and DEN-4 at 21.6%, 60.5%, 12.4%, and 5.5% respectively. Figure 6: Dengue cases reported weekly from 2019-2024 (as of 2 March 2024) in Singapore Source: Communicable Diseases Division, Ministry of Health, Singapore (Note: Case numbers are derived from the MOH Singapore’s weekly-infectious-disease-bulletin-year-2024_uploadas available from MOH | Weekly Infectious Diseases Bulletin) Viet Nam As of 3 March 2024 (epidemiological week 9), cumulatively 11,235 dengue cases, including no deaths, were reported in Viet Nam. Compared to the same period in 2023 (19,151 cases, including 4 deaths), the number of cumulative cases decreased by 41.3%, and the number of deaths decreased by 4 cases. (Figure 7). During week 9 (26 February to 3 March 2024), a total of 857 cases were reported nationwide; of those, 690 were hospitalized (80.5%). Compared to the previous week (934 cases, including 738 hospitalizations), the number of cases decreased by 8.2%, and the number of hospitalizations decreased by 6.5%. Figure 7: Number of dengue hospital admissions and deaths by week in 2023 compared to 2023, as of week 9, 2024, Viet Nam Source: General Department of Preventive Medicine, Ministry of Health, Viet Nam Note hospitalizations include inpatients and outpatients The alert threshold is a 5-year mean plus 2 standard deviations. Figure 7 was updated on 3 March 2024 Dengue Situation Update 692 │ 5 Southern Hemisphere Australia There is no update for this reporting period. From 08 January to 21 January 2024, a total of 59 dengue cases were reported in Australia. From 22 January 2023 to 21 January 2024, the cumulative number of dengue cases is 1,117, which is 1.7 times higher than the same period’s 5 year rolling mean (n=645.6 cases). (Figure 8). Figure 8: Laboratory-confirmed dengue cases reported monthly from 2016-2024 in Australia Source: Department of Health, Australia Note: Graph was updated on 15 February 2024 Pacific Islands Countries New Caledonia From 1 January to 29 February 2024, six confirmed dengue cases were reported in New Caledonia (Figure 9). This is higher compared to the same period in 2023, when a total of three dengue cases were reported. Of the six dengue cases in 2024, two were imported cases and two cases were probable cases. The serotypes of the cases were DENV-1 (3 cases), DENV-2 (1 case). Figure 9: Dengue cases reported by week from 2022 to 2024 in New Caledonia Source: Network of sentinel physicians, New Caledonia Dengue Situation Update 692 │ 6 Pacific Island Countries and Areas (PICs) – Dengue-like illness (DLI) Surveillance During epidemiological week 9 of 2024 (ending 3 March 2024), Pacific Island Countries and Areas (PICs) with available surveillance data (18/21 PICs) reported no or low numbers of DLI cases. Among the PICs, Cook Islands, Fiji, French Polynesia, Kiribati, Marshall Islands, Micronesia (Federated States of), New Caledonia, Niue, Northern Mariana Islands, Palau, Pitcairn Islands, Samoa, Solomon Islands, Tokelau, Tonga, Vanuatu, and Wallis and Futuna have reported DLI cases. The number of cases reported in Fiji, French Polynesia, Micronesia (Federated States of) and Palau in week 9 is higher than the number reported in week 8. Samoa in week 10 is higher than the number reported in week 9. 0 5 10 15 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epiweek Cook Islands DLI Trend -2024 2024 2023 5 years Median 0 200 400 600 800 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epiweek Fiji DLI Trend - WK9 2024 2023 5 Years Median 0 10 20 30 40 50 60 70 80 1 4 7 101316192225283134374043464952 C as es Epiweek French Polynesia -2024 (W9) 2024 2023 5 years Median 0 2 4 6 8 10 1 4 7 1013161922252831343740434649 C as es Epiweek FSM DLI Trend - 2024 2024 2023 5 Years Median 0 1 2 3 4 5 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epiweek Kiribati DLI Trend -2024 2023 2024 5 Years Median 0 2 4 6 8 10 12 14 16 18 1 4 7 101316192225283134374043464952 C as es Epiweek RMI DLI Trend -2024 2023 2024 5 Years Median Dengue Situation Update 692 │ 7 0 1 2 3 4 5 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epiweek CNMI DLI Trend -2024 2023 2024 5 Years Median 0 1 2 3 4 5 1 4 7 101316192225283134374043464952 C as e s Epiweek Niue DLI Trend -2024 2023 2024 5 Years Median 0 1 2 3 4 5 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 C as es Epiweek New Caledonia DLI Trend 2024 2024 2023 5 Years Median 0 5 10 15 20 25 30 1 4 7 101316192225283134374043464952 C as es Epiweek Palau DLI Trend (2024) 2024 2023 5 Years Median 0 1 2 3 4 5 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epiweek Pitcairn Islands DLI Trend 2024 2023 2024 5 Years Median 0 5 10 15 20 25 30 35 40 1 4 7 101316192225283134374043464952 C as es Epiweek Samoa DLI Trend -2014 2024 2023 5 Years Median Dengue Situation Update 692 │ 8 Figure 10. Reported cases of dengue-like illness in Pacific Islands Countries and Areas Source: WHO Division of Pacific Technical Support Note: Caution should be taken in interpreting these data as there may be changes in the number of sentinel sites reporting to the Pacific Syndromic Surveillance System (PSSS). Furthermore, the syndromic case definition of DLI may capture cases with non- dengue acute febrile illnesses (AFI) with similar clinical manifestations to dengue. This includes AFI such as chikungunya, influenza, hantavirus, leptospirosis, malaria, measles, paratyphoid and typhoid fevers, scrub typhus, yellow fever, zika, other diseases. The PSSS may also capture dengue cases under ‘prolonged fever’ surveillance. Alert threshold for DLI is twice the average number of cases seen in the previous 3 weeks. 0 5 10 15 20 25 30 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 C as es Epiweek Solomon Islands DLI 2024(W9) 2024 2023 5 Years Median 0 1 2 3 4 5 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epiweek Tokelau DLI Trend 2024 2024 2023 5 Years Median 0 2 4 6 8 10 12 14 1 4 7 101316192225283134374043464952 C as es Epiweek Tonga DLI Trend -2024 2023 2024 5 Years Median 0 5 10 15 20 25 1 4 7 101316192225283134374043464952 C as es Epiweek Vanuatu DLI Trend -2024 2024 2023 5 Years Median 0 5 10 15 20 1 4 7 101316192225283134374043464952 C as es Epiweek Wallis & Futuna 2024 2024 2023 5 Years Median Dengue Situation Update 692 │ 9 Annex 1. Summary of dengue case definitions, laboratory sampling and testing methods used for surveillance in Member States as of 2024 Country Case definition Surveillance system Laboratory sampling and testing method Reference Clinically confirmed case Laboratory confirmation required Description Australia Fever, headache, arthralgia, myalgia, rash, nausea and vomiting Yes Dengue is a nationally notifiable disease and cases are monitored through the National Notifiable Diseases Surveillance System (NNDSS) indicator-based surveillance system. Both confirmed and probable cases are nationally notifiable. A confirmed case requires both laboratory definitive evidence and clinical evidence. A probable case requires either laboratory suggestive evidence and clinical evidence and epidemiological evidence, or clinical evidence and household epidemiological evidence. Laboratory definitive evidence: - Isolation of dengue virus, or - Detection of dengue virus by nucleic acid testing, or - Detection of NS1 antigen in the blood by EIA, or - IgG seroconversion or significant increase in antibody levelor fourfold or greater rise in titre to dengue virus (proof by neutralization or another specific test) Laboratory suggestive evidence: - Detection of NS1 antigen in blood by rapid antigen test, or - Detection of dengue virus-specific IgM in blood Epidemiological evidence: - Exposure between 3 – 14 days prior to onset either in a country with known dengue activity or in a dengue-receptive area in Australia where a locally-acquired or imported case has been documented with onset within a month. Household epidemiological evidence: - Living in the same house as a locally- acquired case in a dengue-receptive area of Australia within a month of onse in the 1 Dengue Situation Update 692 │ 10 case and at least one case in the chain of epidemiologically linked cases is laboratory confirmed. Cambodia Suspected dengue: very high fever at 39-40 degrees celcius for 2-7 days (usually 3-4 days), with 2 or more of the following signs: flushed face, headache, retro-orbital pain, myalgia/arthralgia, cutaneous rash, haemorrhagic signs (petechiae, positive tourniquet test), and leucopenia. Probable dengue: signs of suspected dengue plus laboratory test results (see right column)) or that the case occurred in an area where the dengue case has been confirmed. Yes National Dengue Control Program (NDCP) enhanced sentinel surveillance system Communicable Disease Control (CDC) syndromic surveillance system (CamEWARN). Health Management Information System (HMIS) collects data on confirmed cases and deaths. Data collected for Cambodia Laboratory Information System (CamLIS), comprised of 32 participating hospital laboratories where NS1 detection is conducted. Laboratory testing: Antibody HI>= 1/1280 or IgM/IgG positive by ELISA test in convalescence serum 2 China (i) more than two symptoms of acute onset fever, severe headache, orbital pain, myalgia, arthralgia, fatigue with a history of travel in a dengue endemic area within 15 days before symptom onset or cohabitation with an individual with confirmed dengue; or no travel history, but with a rash or positive tourniquet test AND leucopenia or thrombocytopenia or serum IgM positivity. No Reported to the Chinese Centre for Disease Control and Prevention (China CDC) through the Chinese National Notifiable Infectious Disease Reporting Information System (CNNDS). Laboratory confirmation is done by real-time RT-PCR, NS1 in acute-phase serum, or virus isolation from an acutely infected patient’s serum. WHO internal communication Lao People's Democratic Republic WHO dengue case classification (2009) † No National Surveillance System for Notifiable Selected Diseases, indicator-based surveillance system that consists of passive weekly reports of clinically suspected cases, on admission, from all health-care facilities across the country. 3 Malaysia WHO dengue case classification (2009) † Yes National Dengue Surveillance System, indicator-based surveillance system All suspected cases are to be tested by the following laboratory tests: Rapid Combo Test (RCT) (NS1, IgM, IgG), Dengue Antigen and Serology tests by ELISA, Dengue Viral RNA Detection (Real time RT-PCR), Viral Isolation 4 Philippines WHO dengue case classification (2009) † Yes Philippine Integrated Disease Surveillance and Response (PIDSR), indicator-based surveillance system. Reporting delays of 2-3 weeks, Confirmed dengue is a suspect case with positive (+) viral culture isolation and/or PCR. NS1 (+), IgM is used to identify probable dengue. 5, 6, 7 Dengue Situation Update 692 │ 11 making comparison of current weekly and cumulative figures with previous years difficult. Singapore (endemic) Fever, headache, backache, myalgia, rash, abdominal discomfort and thrombocytopenia and laboratory testing (see right column) Yes Dengue is a legally notifiable disease in Singapore and notifying the Ministry of Health should not be later than 24 hours from the time of diagnosis. Laboratory confirmation is done using standard diagnostic tests for the detection of dengue NS1 antigen, IgM and IgG, or RT-PCR. 8,9 Viet Nam (endemic) Acute onset of fever continuously lasting from 2-7 days AND at least 2 of the following: haemorrhagic manifestation /presentation; headache, loss of appetite, nausea, vomiting; rash; muscle pain, joint pain, orbital pain; lethargy; abdominal pain. No As per the MOH dengue surveillance guideline, in routine surveillance MAC-ELISA is conducted for at least 7% and virus isolation is conducted for at least 3% of clinical cases. In an outbreak, at least 5 to 10 suspected cases are tested. 10 Pacific Island Countries WHO dengue case classification (2009) † No Pacific Syndromic Surveillance System Confirmed case: Isolation of dengue virus or detection of dengue-specific antigen or antibodies in tissue, blood, CSF or other body fluid by an advanced laboratory test 11 Only the minimum criteria required for fulfilling a clinical dengue case definition are included here; additional signs and symptoms required for more severe forms are not listed. † A probable dengue case is defined as any case living in or travel to dengue endemic area with fever and two or more of the following: nausea, vomiting, rash, aches and pains, positive tourniquet test, leucopenia and any warning sign. A case with warning signs is defined as a clinically diagnosed case with any of the following: abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleed, lethargy, restlessness, liver enlargement > 2 cm and increase in haematocrit concurrent with rapid decrease in platelet count. Severe dengue is defined as severe plasma leakage leading to any of the following: shock, fluid accumulation with respiratory distress OR severe bleeding as evaluated by clinician OR severe organ involvement of liver (aspartate amino transferase or alanine amino transferase ≥ 1000), central nervous system (impaired consciousness) or heart and other organs.10 References: 1. Australian Government Department of Health AGDo. Dengue virus infection surveillance and case definition [updated 14 June 2022 and 1 January 2018 respectively] Available from: https://www.health.gov.au/diseases/dengue-virus-infection, and https://www.health.gov.au/sites/default/files/documents/2022/06/dengue-virus-infection-surveillance-case-definition.pdf 2. Cambodia Ministry of Health NCfP, Entomology and Malaria Control. National Guideline for Clinical Management of Dengue, 2018. 2018. Available from: https://niph.org.kh/niph/uploads/library/pdf/GL055_National_guideline_for_ClM_Dengue.pdf. 3. Khampapongpane B, Lewis HC, Ketmayoon P, Phonekeo D, Somoulay V, Khamsing A, et al. National dengue surveillance in the Lao People's Democratic Republic, 2006-2012: epidemiological and laboratory findings. Western Pac Surveill Response J. 2014;5(1):7-13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24734212. 4. Ministry of Health Malaysia DCD. Case definitions for infectious diseases in Malaysia. 2017. Available from: https://www.moh.gov.my/moh/resources/Penerbitan/Garis%20Panduan/Pengurusan%20KEsihatan%20&%20kawalan%20pykit/Case_Definition_Of_Infectious_Disease_3rd_Edition_2017.pdf 5. Secretary PDoHOot. Guidelines for the Nationwide Implementation of Dengue Rapid Diagnostic Test (RDT), Administrative order No.2016-0043. 2016(2016-0043). 6. Secretary PDoHOot. Revised Dengue Clinical Case Management Guidelines 2011, Administrative order No.2012-0006. 2012 22 March 2012. Report No. 7. Diseases SNCfI. Diseases and Conditions, Dengue 2020 [updated 14 September 2020. Available from: https://www.doh.gov.ph/Health-Advisory/Dengue. 8. National Centre for Infectious Diseases, Dengue. Available from: https://www.ncid.sg/Health-Professionals/Diseases-and-Conditions/Pages/Dengue.aspx Dengue Situation Update 692 │ 12 9. National Environment Agency. Surveillance and Epidemiology Programme [updated 21 April 2023]. Available from: https://www.nea.gov.sg/corporate-functions/resources/research/surveillance-and- epidemiology-programme#Ehi%20Diagnostics%20Unit 10. Viet Nam Ministry of Health VNMo. Circular 54/2015 / TT-BYT 2015 [updated 26 April 2016. Available from: https://syt.thuathienhue.gov.vn/?gd=27&cn=108&tc=3993. 11. Pacific Islands Outbreak Manual. Available from: https://www.pphsn.net/resources/outbreak-manual/ 12. WHO dengue outbreak toolbox. Available from: https://www.who.int/docs/default-source/outbreak-toolkit/updates-documents_july-5/dengue-outbreak-data-collection-toolbox---inis-3-july- 1.pdf?sfvrsn=ec3ffcf3_2
Dengue Situation Update 694 │ 1 Dengue Situation Update 694 28 March 2024 Update on the Dengue situation in the Western Pacific Region This report describes the epidemiology of dengue in the World Health Organization Western Pacific Region. Data are compiled from open sources (national indicator-based surveillance systems) with the exception of Cambodia, Lao People’s Democratic Republic, Viet Nam, and the Philippines, where data are provided by the WHO Country Offices. For the Pacific Island Countries, syndromic surveillance data are provided by the Division of Pacific Technical Support. Information is reported based on countries’ standard dengue case definitions, summary of these definitions and countries’ dengue surveillance systems - included as an annex to this report. Due to differences in surveillance methods and reporting practices, a comparison of trends between countries and areas is not possible, however, national trends can be observed over time. Northern Hemisphere Cambodia As of epidemiological week 11 of 2024, the National Dengue Surveillance System reported a total of 4,113 cases with 13 deaths (Case Fatality Rate (CFR) 0.32%) since 1 January 2024 (Figure 1), This is almost 4 times the number reported in 2023 for the same period, with 1,177 cases and 3 deaths. Figure 1: Dengue cases reported weekly in 2024 vs endemic and epidemic alert lines in Cambodia; Source: National Dengue Surveillance System (NDCP/CNM/MOH) Dengue Situation Update 694 │ 2 China In February 2024, 42 dengue cases and no deaths were reported in China. There has been a total of 69 dengue cases and no death in the country from January 2024 to February 2024 (Figure 2). Figure 2: Dengue cases reported monthly from 2015-2024 (as of February) in China Source: National Disease Control and Prevention Administration, China Lao People’s Democratic Republic In epidemiological week 11 of 2024 (11 March to 17 March 2024), 170 dengue cases and zero deaths were reported (Figure 3). The number of reported cases is higher than the numbers reported in epidemiological week 10 (158 cases with no deaths), and higher than those in week 11 of 2023 (44 cases with no deaths). The cumulative number of cases reported in 2024 (as of epidemiological week 11) is 1,499. This is a 167.1% increase compared to the 542 cases reported during the same period in 2023. Figure 3: Dengue cases reported weekly from 2018-2024 in Lao PDR Source: National Centre for Laboratory and Epidemiology, Ministry of Health, Lao PDR Dengue Situation Update 694 │ 3 Malaysia There is no update for this reporting period. During epidemiological week 7 of 2024 (11 February 2024 to 17 February2024), a decrease of 148 cases (4.0%) was reported with 3,483 cases as compared to 3,631 cases reported in the previous week (Figure 4). The cumulative number of dengue cases reported up to week 7 of 2024 is 25,541 cases, which is an increase of 67.5% compared to 15,243 cases for the same period in 2023. 14 dengue-related deaths were reported up to week 7 of 2024 compared to 13 deaths for the same period in 2023. Figure 4: Dengue cases reported weekly from 2023, 2024 and median 2019-2023 in Malaysia Source: Department of Health, Malaysia Philippines There is no update for this reporting period. During epidemiological Week 48 (26 November to 2 December 2023), there were 2,607 new dengue cases reported, a 41% decrease compared to the same period in 2022 (n=4,415 cases) (Figure 5). As of 2 December 2023, a total of 195,603 dengue cases have been reported. The number of cases is 23% lower compared to the same period in 2022 (n=252,700). From 1 January to 2 December 2023, there have been 657 deaths (CFR 0.34%) as compared to 894 deaths (CFR 0.35%;) reported in the same period in 2022. Figure 5: Dengue cases reported weekly from 2022 and 2023 in the Philippines Source: Department of Health, the Philippines (Note: there is a 3-4 week systematic delay in reporting and numbers should be interpreted with caution) Number of cases Dengue Situation Update 694 │ 4 Singapore In epidemiological week 11 (10 March to 16 March 2024), a total of 331 dengue cases were reported in Singapore. Cumulatively, a total of 4,537 cases (Figure 6) have been reported as of 16 March 2024. When compared with week 11 in 2023 (2,123 cases), there has been a 105.0% increase in cases reported in week 11 of this year. Preliminary results of all positive dengue samples serotyped in February 2024 showed DEN-1, DEN-2, DEN-3, and DEN-4 at 23.0%, 59.8%, 11.7%, and 5.4% respectively. Figure 6: Dengue cases reported weekly from 2019-2024 (as of 16 March 2024) in Singapore Source: Communicable Diseases Division, Ministry of Health, Singapore (Note: Case numbers are derived from the MOH Singapore’s weekly-infectious-disease-bulletin-year-2024_uploadas available from MOH | Weekly Infectious Diseases Bulletin) Viet Nam As of 17 March 2024 (epidemiological week 11), cumulatively 12,937 dengue cases, including no deaths, were reported in Viet Nam. Compared to the same period in 2023 (22,093 cases, including 5 deaths), the number of cumulative cases decreased by 41.3%, and the number of deaths decreased by 5. (Figure 7). During week 11 (11 March to 17 March 2024), a total of 804 cases were reported nationwide; of those, 634 were hospitalized (78.8%). Compared to the previous week (842 cases, including 654 hospitalizations), the number of cases decreased by 4.5%, and the number of hospitalizations decreased by 3%. Dengue Situation Update 694 │ 5 Figure 7: Number of dengue hospital admissions and deaths by week in 2023 compared to 2023, as of week 11, 2024, Viet Nam Source: General Department of Preventive Medicine, Ministry of Health, Viet Nam Note hospitalizations include inpatients and outpatients The alert threshold is a 5-year mean plus 2 standard deviations. Figure 7 was updated on 17 March 2024 Southern Hemisphere Australia From 19 February to 3 March 2024, a total of 43 dengue cases were reported in Australia. From 4 March 2023 to 3 March 2024, the cumulative number of dengue cases is 1,166, which is 1.8 times higher than the same period’s 5 year rolling mean (n=641.6 cases). (Figure 8). Figure 8: Laboratory-confirmed dengue cases reported monthly from 2016-2024 in Australia Source: Department of Health, Australia Note: Graph was updated on 27 March 2024 Dengue Situation Update 694 │ 6 Pacific Islands Countries New Caledonia There is no update for this reporting period. From 1 January to 29 February 2024, six confirmed dengue cases were reported in New Caledonia (Figure 9). This is higher compared to the same period in 2023, when a total of three dengue cases were reported. Of the six dengue cases in 2024, two were imported cases and two cases were probable cases. The serotypes of the cases were DENV-1 (3 cases), DENV-2 (1 case). Figure 9: Dengue cases reported by week from 2022 to 2024 in New Caledonia Source: Network of sentinel physicians, New Caledonia Pacific Island Countries and Areas (PICs) – Dengue-like illness (DLI) Surveillance There is no update for this reporting period. During epidemiological week 9 of 2024 (ending 3 March 2024), Pacific Island Countries and Areas (PICs) with available surveillance data (18/21 PICs) reported no or low numbers of DLI cases. Among the PICs, Cook Islands, Fiji, French Polynesia, Kiribati, Marshall Islands, Micronesia (Federated States of), New Caledonia, Niue, Northern Mariana Islands, Palau, Pitcairn Islands, Samoa, Solomon Islands, Tokelau, Tonga, Vanuatu, and Wallis and Futuna have reported DLI cases. The number of cases reported in Fiji, French Polynesia, Micronesia (Federated States of) and Palau in week 9 is higher than the number reported in week 8. Samoa in week 10 is higher than the number reported in week 9. 0 5 10 15 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as e s Epiweek Cook Islands DLI Trend -2024 2024 2023 5 years Median 0 200 400 600 800 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epiweek Fiji DLI Trend - WK9 2024 2023 5 Years Median Dengue Situation Update 694 │ 7 0 10 20 30 40 50 60 70 80 1 4 7 101316192225283134374043464952 C as es Epiweek French Polynesia -2024 (W9) 2024 2023 5 years Median 0 2 4 6 8 10 1 4 7 1013161922252831343740434649 C as es Epiweek FSM DLI Trend - 2024 2024 2023 5 Years Median 0 1 2 3 4 5 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epiweek Kiribati DLI Trend -2024 2023 2024 5 Years Median 0 2 4 6 8 10 12 14 16 18 1 4 7 101316192225283134374043464952 C as es Epiweek RMI DLI Trend -2024 2023 2024 5 Years Median Dengue Situation Update 694 │ 8 0 1 2 3 4 5 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epiweek CNMI DLI Trend -2024 2023 2024 5 Years Median 0 1 2 3 4 5 1 4 7 101316192225283134374043464952 C as e s Epiweek Niue DLI Trend -2024 2023 2024 5 Years Median 0 1 2 3 4 5 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 C as es Epiweek New Caledonia DLI Trend 2024 2024 2023 5 Years Median 0 5 10 15 20 25 30 1 4 7 101316192225283134374043464952 C as es Epiweek Palau DLI Trend (2024) 2024 2023 5 Years Median 0 1 2 3 4 5 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epiweek Pitcairn Islands DLI Trend 2024 2023 2024 5 Years Median 0 5 10 15 20 25 30 35 40 1 4 7 101316192225283134374043464952 C as es Epiweek Samoa DLI Trend -2014 2024 2023 5 Years Median Dengue Situation Update 694 │ 9 Figure 10. Reported cases of dengue-like illness in Pacific Islands Countries and Areas Source: WHO Division of Pacific Technical Support Note: Caution should be taken in interpreting these data as there may be changes in the number of sentinel sites reporting to the Pacific Syndromic Surveillance System (PSSS). Furthermore, the syndromic case definition of DLI may capture cases with non- dengue acute febrile illnesses (AFI) with similar clinical manifestations to dengue. This includes AFI such as chikungunya, influenza, hantavirus, leptospirosis, malaria, measles, paratyphoid and typhoid fevers, scrub typhus, yellow fever, zika, other diseases. The PSSS may also capture dengue cases under ‘prolonged fever’ surveillance. Alert threshold for DLI is twice the average number of cases seen in the previous 3 weeks. 0 5 10 15 20 25 30 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 C as es Epiweek Solomon Islands DLI 2024(W9) 2024 2023 5 Years Median 0 1 2 3 4 5 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epiweek Tokelau DLI Trend 2024 2024 2023 5 Years Median 0 2 4 6 8 10 12 14 1 4 7 101316192225283134374043464952 C as es Epiweek Tonga DLI Trend -2024 2023 2024 5 Years Median 0 5 10 15 20 25 1 4 7 101316192225283134374043464952 C as es Epiweek Vanuatu DLI Trend -2024 2024 2023 5 Years Median 0 5 10 15 20 1 4 7 101316192225283134374043464952 C as es Epiweek Wallis & Futuna 2024 2024 2023 5 Years Median Dengue Situation Update 694 │ 10 Annex 1. Summary of dengue case definitions, laboratory sampling and testing methods used for surveillance in Member States as of 2024 Country Case definition Surveillance system Laboratory sampling and testing method Reference Clinically confirmed case Laboratory confirmation required Description Australia Fever, headache, arthralgia, myalgia, rash, nausea and vomiting Yes Dengue is a nationally notifiable disease and cases are monitored through the National Notifiable Diseases Surveillance System (NNDSS) indicator-based surveillance system. Both confirmed and probable cases are nationally notifiable. A confirmed case requires both laboratory definitive evidence and clinical evidence. A probable case requires either laboratory suggestive evidence and clinical evidence and epidemiological evidence, or clinical evidence and household epidemiological evidence. Laboratory definitive evidence: - Isolation of dengue virus, or - Detection of dengue virus by nucleic acid testing, or - Detection of NS1 antigen in the blood by EIA, or - IgG seroconversion or significant increase in antibody levelor fourfold or greater rise in titre to dengue virus (proof by neutralization or another specific test) Laboratory suggestive evidence: - Detection of NS1 antigen in blood by rapid antigen test, or - Detection of dengue virus-specific IgM in blood Epidemiological evidence: - Exposure between 3 – 14 days prior to onset either in a country with known dengue activity or in a dengue-receptive area in Australia where a locally-acquired or imported case has been documented with onset within a month. Household epidemiological evidence: - Living in the same house as a locally- acquired case in a dengue-receptive area of Australia within a month of onse in the 1 Dengue Situation Update 694 │ 11 case and at least one case in the chain of epidemiologically linked cases is laboratory confirmed. Cambodia Suspected dengue: very high fever at 39-40 degrees celcius for 2-7 days (usually 3-4 days), with 2 or more of the following signs: flushed face, headache, retro-orbital pain, myalgia/arthralgia, cutaneous rash, haemorrhagic signs (petechiae, positive tourniquet test), and leucopenia. Probable dengue: signs of suspected dengue plus laboratory test results (see right column)) or that the case occurred in an area where the dengue case has been confirmed. Yes National Dengue Control Program (NDCP) enhanced sentinel surveillance system Communicable Disease Control (CDC) syndromic surveillance system (CamEWARN). Health Management Information System (HMIS) collects data on confirmed cases and deaths. Data collected for Cambodia Laboratory Information System (CamLIS), comprised of 32 participating hospital laboratories where NS1 detection is conducted. Laboratory testing: Antibody HI>= 1/1280 or IgM/IgG positive by ELISA test in convalescence serum 2 China (i) more than two symptoms of acute onset fever, severe headache, orbital pain, myalgia, arthralgia, fatigue with a history of travel in a dengue endemic area within 15 days before symptom onset or cohabitation with an individual with confirmed dengue; or no travel history, but with a rash or positive tourniquet test AND leucopenia or thrombocytopenia or serum IgM positivity. No Reported to the Chinese Centre for Disease Control and Prevention (China CDC) through the Chinese National Notifiable Infectious Disease Reporting Information System (CNNDS). Laboratory confirmation is done by real-time RT-PCR, NS1 in acute-phase serum, or virus isolation from an acutely infected patient’s serum. WHO internal communication Lao People's Democratic Republic WHO dengue case classification (2009) † No National Surveillance System for Notifiable Selected Diseases, indicator-based surveillance system that consists of passive weekly reports of clinically suspected cases, on admission, from all health-care facilities across the country. 3 Malaysia WHO dengue case classification (2009) † Yes National Dengue Surveillance System, indicator-based surveillance system All suspected cases are to be tested by the following laboratory tests: Rapid Combo Test (RCT) (NS1, IgM, IgG), Dengue Antigen and Serology tests by ELISA, Dengue Viral RNA Detection (Real time RT-PCR), Viral Isolation 4 Philippines WHO dengue case classification (2009) † Yes Philippine Integrated Disease Surveillance and Response (PIDSR), indicator-based surveillance system. Reporting delays of 2-3 weeks, Confirmed dengue is a suspect case with positive (+) viral culture isolation and/or PCR. NS1 (+), IgM is used to identify probable dengue. 5, 6, 7 Dengue Situation Update 694 │ 12 making comparison of current weekly and cumulative figures with previous years difficult. Singapore (endemic) Fever, headache, backache, myalgia, rash, abdominal discomfort and thrombocytopenia and laboratory testing (see right column) Yes Dengue is a legally notifiable disease in Singapore and notifying the Ministry of Health should not be later than 24 hours from the time of diagnosis. Laboratory confirmation is done using standard diagnostic tests for the detection of dengue NS1 antigen, IgM and IgG, or RT-PCR. 8,9 Viet Nam (endemic) Acute onset of fever continuously lasting from 2-7 days AND at least 2 of the following: haemorrhagic manifestation /presentation; headache, loss of appetite, nausea, vomiting; rash; muscle pain, joint pain, orbital pain; lethargy; abdominal pain. No As per the MOH dengue surveillance guideline, in routine surveillance MAC-ELISA is conducted for at least 7% and virus isolation is conducted for at least 3% of clinical cases. In an outbreak, at least 5 to 10 suspected cases are tested. 10 Pacific Island Countries WHO dengue case classification (2009) † No Pacific Syndromic Surveillance System Confirmed case: Isolation of dengue virus or detection of dengue-specific antigen or antibodies in tissue, blood, CSF or other body fluid by an advanced laboratory test 11 Only the minimum criteria required for fulfilling a clinical dengue case definition are included here; additional signs and symptoms required for more severe forms are not listed. † A probable dengue case is defined as any case living in or travel to dengue endemic area with fever and two or more of the following: nausea, vomiting, rash, aches and pains, positive tourniquet test, leucopenia and any warning sign. A case with warning signs is defined as a clinically diagnosed case with any of the following: abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleed, lethargy, restlessness, liver enlargement > 2 cm and increase in haematocrit concurrent with rapid decrease in platelet count. Severe dengue is defined as severe plasma leakage leading to any of the following: shock, fluid accumulation with respiratory distress OR severe bleeding as evaluated by clinician OR severe organ involvement of liver (aspartate amino transferase or alanine amino transferase ≥ 1000), central nervous system (impaired consciousness) or heart and other organs.10 References: 1. Australian Government Department of Health AGDo. Dengue virus infection surveillance and case definition [updated 14 June 2022 and 1 January 2018 respectively] Available from: https://www.health.gov.au/diseases/dengue-virus-infection, and https://www.health.gov.au/sites/default/files/documents/2022/06/dengue-virus-infection-surveillance-case-definition.pdf 2. Cambodia Ministry of Health NCfP, Entomology and Malaria Control. National Guideline for Clinical Management of Dengue, 2018. 2018. Available from: https://niph.org.kh/niph/uploads/library/pdf/GL055_National_guideline_for_ClM_Dengue.pdf. 3. Khampapongpane B, Lewis HC, Ketmayoon P, Phonekeo D, Somoulay V, Khamsing A, et al. National dengue surveillance in the Lao People's Democratic Republic, 2006-2012: epidemiological and laboratory findings. Western Pac Surveill Response J. 2014;5(1):7-13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24734212. 4. Ministry of Health Malaysia DCD. Case definitions for infectious diseases in Malaysia. 2017. Available from: https://www.moh.gov.my/moh/resources/Penerbitan/Garis%20Panduan/Pengurusan%20KEsihatan%20&%20kawalan%20pykit/Case_Definition_Of_Infectious_Disease_3rd_Edition_2017.pdf 5. Secretary PDoHOot. Guidelines for the Nationwide Implementation of Dengue Rapid Diagnostic Test (RDT), Administrative order No.2016-0043. 2016(2016-0043). 6. Secretary PDoHOot. Revised Dengue Clinical Case Management Guidelines 2011, Administrative order No.2012-0006. 2012 22 March 2012. Report No. 7. Diseases SNCfI. Diseases and Conditions, Dengue 2020 [updated 14 September 2020. Available from: https://www.doh.gov.ph/Health-Advisory/Dengue. 8. National Centre for Infectious Diseases, Dengue. Available from: https://www.ncid.sg/Health-Professionals/Diseases-and-Conditions/Pages/Dengue.aspx Dengue Situation Update 694 │ 13 9. National Environment Agency. Surveillance and Epidemiology Programme [updated 21 April 2023]. Available from: https://www.nea.gov.sg/corporate-functions/resources/research/surveillance-and- epidemiology-programme#Ehi%20Diagnostics%20Unit 10. Viet Nam Ministry of Health VNMo. Circular 54/2015 / TT-BYT 2015 [updated 26 April 2016. Available from: https://syt.thuathienhue.gov.vn/?gd=27&cn=108&tc=3993. 11. Pacific Islands Outbreak Manual. Available from: https://www.pphsn.net/resources/outbreak-manual/ 12. WHO dengue outbreak toolbox. Available from: https://www.who.int/docs/default-source/outbreak-toolkit/updates-documents_july-5/dengue-outbreak-data-collection-toolbox---inis-3-july- 1.pdf?sfvrsn=ec3ffcf3_2
Dengue Situation Update 695 │ 1 Dengue Situation Update 695 11 April 2024 Update on the Dengue situation in the Western Pacific Region This report describes the epidemiology of dengue in the World Health Organization Western Pacific Region. Data are compiled from open sources (national indicator-based surveillance systems) with the exception of Cambodia, Lao People’s Democratic Republic, Viet Nam, and the Philippines, where data are provided by the WHO Country Offices. For the Pacific Island Countries, syndromic surveillance data are provided by the Division of Pacific Technical Support. Information is reported based on countries’ standard dengue case definitions, summary of these definitions and countries’ dengue surveillance systems - included as an annex to this report. Due to differences in surveillance methods and reporting practices, a comparison of trends between countries and areas is not possible, however, national trends can be observed over time. Northern Hemisphere Cambodia As of epidemiological week 13 of 2024, the National Dengue Surveillance System reported a total of 4,620 cases with 16 deaths (Case Fatality Rate (CFR) 0.35%) since 1 January 2024 (Figure 1), This is almost 4 times the number reported in 2023 for the same period, with 1,383 cases and 5 deaths. Figure 1: Dengue cases reported weekly in 2024 vs endemic and epidemic alert lines in Cambodia; Source: National Dengue Surveillance System (NDCP/CNM/MOH) Dengue Situation Update 695 │ 2 China There is no update for this reporting period. In February 2024, 42 dengue cases and no deaths were reported in China. There has been a total of 69 dengue cases and no death in the country from January 2024 to February 2024 (Figure 2). Figure 2: Dengue cases reported monthly from 2015-2024 (as of February) in China Source: National Disease Control and Prevention Administration, China Lao People’s Democratic Republic There is no update for this reporting period. In epidemiological week 11 of 2024 (11 March to 17 March 2024), 170 dengue cases and zero deaths were reported (Figure 3). The number of reported cases is higher than the numbers reported in epidemiological week 10 (158 cases with no deaths), and higher than those in week 11 of 2023 (44 cases with no deaths). The cumulative number of cases reported in 2024 (as of epidemiological week 11) is 1,499. This is a 167.1% increase compared to the 542 cases reported during the same period in 2023. Figure 3: Dengue cases reported weekly from 2018-2024 in Lao PDR Source: National Centre for Laboratory and Epidemiology, Ministry of Health, Lao PDR Dengue Situation Update 695 │ 3 Malaysia During epidemiological week 13 of 2024 (25 March 2024 to 31 March 2024), a decrease of 462 cases (15.0%) was reported with 2,579 cases as compared to 3,041 cases reported in the previous week (Figure 4). The cumulative number of dengue cases reported up to week 13 of 2024 is 44,144 cases, which is an increase of 54.4% compared to 28,587 cases for the same period in 2023. 31 dengue-related deaths were reported up to week 13 of 2024, compared to 18 deaths for the same period in 2023. Figure 4: Dengue cases reported weekly from 2023, 2024 and median 2019-2023 in Malaysia Source: Department of Health, Malaysia Philippines There is no update for this reporting period. During epidemiological Week 48 (26 November to 2 December 2023), there were 2,607 new dengue cases reported, a 41% decrease compared to the same period in 2022 (n=4 415 cases) (Figure 5). As of 2 December 2023, a total of 195,603 dengue cases have been reported. The number of cases is 23% lower compared to the same period in 2022 (n=252,700). From 1 January to 2 December 2023, there have been 657 deaths (CFR 0.34%) as compared to 894 deaths (CFR 0.35%;) reported in the same period in 2022. Figure 5: Dengue cases reported weekly from 2022 and 2023 in the Philippines Source: Department of Health, the Philippines (Note: there is a 3-4 week systematic delay in reporting and numbers should be interpreted with caution) Dengue Situation Update 695 │ 4 Singapore In epidemiological week 13 (24 March to 30 March 2024), a total of 349 dengue cases were reported in Singapore. Cumulatively, a total of 5,166 cases (Figure 6) have been reported as of 30 March 2024. When compared with week 13 in 2023 (2 359 cases), there has been a 119.0% increase in cases reported in week 13 of this year. Preliminary results of all positive dengue samples serotyped in March 2024 showed DEN- 1, DEN-2, DEN-3, and DEN-4 at 18.1%, 54.3%, 12.0%, and 15.6%, respectively. Figure 6: Dengue cases reported weekly from 2019-2024 (as of 16 March 2024) in Singapore Source: Communicable Diseases Division, Ministry of Health, Singapore (Note: Case numbers are derived from the MOH Singapore’s weekly-infectious-disease-bulletin-year-2024_uploadas available from MOH | Weekly Infectious Diseases Bulletin) Viet Nam As of 31 March 2024 (epidemiological week 13), cumulatively 14,542 dengue cases, including no deaths, were reported in Viet Nam. Compared to the same period in 2023 (25,044 cases, including 5 deaths), the number of cumulative cases decreased by 41.9%, and the number of deaths decreased by 5 (Figure 7). During week 13 (25 March to 31 March 2024), a total of 753 cases were reported nationwide; of those, 608 were hospitalized (80.7%). Compared to the previous week (805 cases, including 631 hospitalizations), the number of cases decreased by 6.5%, and the number of hospitalizations decreased by 3.6%. Dengue Situation Update 695 │ 5 Figure 7: Number of dengue hospital admissions and deaths by week in 2024 compared to 2023, as of week 13, 2024, Viet Nam Source: General Department of Preventive Medicine, Ministry of Health, Viet Nam Note hospitalizations include inpatients and outpatients The alert threshold is a 5-year mean plus 2 standard deviations. Figure 7 was updated on 17 March 2024 Southern Hemisphere Australia There is no update for this reporting period. From 19 February to 3 March 2024, a total of 43 dengue cases were reported in Australia. From 4 March 2023 to 3 March 2024, the cumulative number of dengue cases is 1,166, which is 1.8 times higher than the same period’s 5 year rolling mean (n=641.6 cases). (Figure 8). Figure 8: Laboratory-confirmed dengue cases reported monthly from 2016-2024 in Australia Source: Department of Health, Australia Note: Graph was updated on 27 March 2024 Dengue Situation Update 695 │ 6 Pacific Islands Countries New Caledonia There is no update for this reporting period. From 1 January to 29 February 2024, six confirmed dengue cases were reported in New Caledonia (Figure 9). This is higher compared to the same period in 2023, when a total of three dengue cases were reported. Of the six dengue cases in 2024, two were imported cases and two cases were probable cases. The serotypes of the cases were DENV-1 (3 cases), DENV-2 (1 case). Figure 9: Dengue cases reported by week from 2022 to 2024 in New Caledonia Source: Network of sentinel physicians, New Caledonia Pacific Island Countries and Areas (PICs) – Dengue-like illness (DLI) Surveillance During epidemiological week 14 of 2024 (ending 7 April 2024), Pacific Island Countries and Areas (PICs) with available surveillance data (17/21 PICs) reported low or similar numbers of DLI cases. Among the PICs, Cook Islands, Fiji, French Polynesia, Kiribati, Marshall Islands, Micronesia (Federated States of), New Caledonia, Niue, Northern Mariana Islands, Palau, Pitcairn Islands, Samoa, Solomon Islands, Tokelau, Tonga, Vanuatu, and Wallis and Futuna have reported DLI cases. The number of cases reported in Kiribati, Fiji, New Caledonia and Wallis and Futuna in week 14 is higher than the number reported in the previous week. Dengue Situation Update 695 │ 7 Dengue Situation Update 695 │ 8 Figure 10. Reported cases of dengue-like illness in Pacific Islands Countries and Areas Source: WHO Division of Pacific Technical Support Note: Caution should be taken in interpreting these data as there may be changes in the number of sentinel sites reporting to the Pacific Syndromic Surveillance System (PSSS). Furthermore, the syndromic case definition of DLI may capture cases with non- dengue acute febrile illnesses (AFI) with similar clinical manifestations to dengue. This includes AFI such as chikungunya, influenza, hantavirus, leptospirosis, malaria, measles, paratyphoid and typhoid fevers, scrub typhus, yellow fever, zika, other diseases. The PSSS may also capture dengue cases under ‘prolonged fever’ surveillance. Alert threshold for DLI is twice the average number of cases seen in the previous 3 weeks. Dengue Situation Update 695 │ 9 Annex 1. Summary of dengue case definitions, laboratory sampling and testing methods used for surveillance in Member States as of 2024 Country Case definition Surveillance system Laboratory sampling and testing method Reference Clinically confirmed case Laboratory confirmation required Description Australia Fever, headache, arthralgia, myalgia, rash, nausea and vomiting Yes Dengue is a nationally notifiable disease and cases are monitored through the National Notifiable Diseases Surveillance System (NNDSS) indicator-based surveillance system. Both confirmed and probable cases are nationally notifiable. A confirmed case requires both laboratory definitive evidence and clinical evidence. A probable case requires either laboratory suggestive evidence and clinical evidence and epidemiological evidence, or clinical evidence and household epidemiological evidence. Laboratory definitive evidence: - Isolation of dengue virus, or - Detection of dengue virus by nucleic acid testing, or - Detection of NS1 antigen in the blood by EIA, or - IgG seroconversion or significant increase in antibody levelor fourfold or greater rise in titre to dengue virus (proof by neutralization or another specific test) Laboratory suggestive evidence: - Detection of NS1 antigen in blood by rapid antigen test, or - Detection of dengue virus-specific IgM in blood Epidemiological evidence: - Exposure between 3 – 14 days prior to onset either in a country with known dengue activity or in a dengue-receptive area in Australia where a locally-acquired or imported case has been documented with onset within a month. Household epidemiological evidence: - Living in the same house as a locally- acquired case in a dengue-receptive area of Australia within a month of onse in the 1 Dengue Situation Update 695 │ 10 case and at least one case in the chain of epidemiologically linked cases is laboratory confirmed. Cambodia Suspected dengue: very high fever at 39-40 degrees celcius for 2-7 days (usually 3-4 days), with 2 or more of the following signs: flushed face, headache, retro-orbital pain, myalgia/arthralgia, cutaneous rash, haemorrhagic signs (petechiae, positive tourniquet test), and leucopenia. Probable dengue: signs of suspected dengue plus laboratory test results (see right column)) or that the case occurred in an area where the dengue case has been confirmed. Yes National Dengue Control Program (NDCP) enhanced sentinel surveillance system Communicable Disease Control (CDC) syndromic surveillance system (CamEWARN). Health Management Information System (HMIS) collects data on confirmed cases and deaths. Data collected for Cambodia Laboratory Information System (CamLIS), comprised of 32 participating hospital laboratories where NS1 detection is conducted. Laboratory testing: Antibody HI>= 1/1280 or IgM/IgG positive by ELISA test in convalescence serum 2 China (i) more than two symptoms of acute onset fever, severe headache, orbital pain, myalgia, arthralgia, fatigue with a history of travel in a dengue endemic area within 15 days before symptom onset or cohabitation with an individual with confirmed dengue; or no travel history, but with a rash or positive tourniquet test AND leucopenia or thrombocytopenia or serum IgM positivity. No Reported to the Chinese Centre for Disease Control and Prevention (China CDC) through the Chinese National Notifiable Infectious Disease Reporting Information System (CNNDS). Laboratory confirmation is done by real-time RT-PCR, NS1 in acute-phase serum, or virus isolation from an acutely infected patient’s serum. WHO internal communication Lao People's Democratic Republic WHO dengue case classification (2009) † No National Surveillance System for Notifiable Selected Diseases, indicator-based surveillance system that consists of passive weekly reports of clinically suspected cases, on admission, from all health-care facilities across the country. 3 Malaysia WHO dengue case classification (2009) † Yes National Dengue Surveillance System, indicator-based surveillance system All suspected cases are to be tested by the following laboratory tests: Rapid Combo Test (RCT) (NS1, IgM, IgG), Dengue Antigen and Serology tests by ELISA, Dengue Viral RNA Detection (Real time RT-PCR), Viral Isolation 4 Philippines WHO dengue case classification (2009) † Yes Philippine Integrated Disease Surveillance and Response (PIDSR), indicator-based surveillance system. Reporting delays of 2-3 weeks, Confirmed dengue is a suspect case with positive (+) viral culture isolation and/or PCR. NS1 (+), IgM is used to identify probable dengue. 5, 6, 7 Dengue Situation Update 695 │ 11 making comparison of current weekly and cumulative figures with previous years difficult. Singapore (endemic) Fever, headache, backache, myalgia, rash, abdominal discomfort and thrombocytopenia and laboratory testing (see right column) Yes Dengue is a legally notifiable disease in Singapore and notifying the Ministry of Health should not be later than 24 hours from the time of diagnosis. Laboratory confirmation is done using standard diagnostic tests for the detection of dengue NS1 antigen, IgM and IgG, or RT-PCR. 8,9 Viet Nam (endemic) Acute onset of fever continuously lasting from 2-7 days AND at least 2 of the following: haemorrhagic manifestation /presentation; headache, loss of appetite, nausea, vomiting; rash; muscle pain, joint pain, orbital pain; lethargy; abdominal pain. No As per the MOH dengue surveillance guideline, in routine surveillance MAC-ELISA is conducted for at least 7% and virus isolation is conducted for at least 3% of clinical cases. In an outbreak, at least 5 to 10 suspected cases are tested. 10 Pacific Island Countries WHO dengue case classification (2009) † No Pacific Syndromic Surveillance System Confirmed case: Isolation of dengue virus or detection of dengue-specific antigen or antibodies in tissue, blood, CSF or other body fluid by an advanced laboratory test 11 Only the minimum criteria required for fulfilling a clinical dengue case definition are included here; additional signs and symptoms required for more severe forms are not listed. † A probable dengue case is defined as any case living in or travel to dengue endemic area with fever and two or more of the following: nausea, vomiting, rash, aches and pains, positive tourniquet test, leucopenia and any warning sign. A case with warning signs is defined as a clinically diagnosed case with any of the following: abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleed, lethargy, restlessness, liver enlargement > 2 cm and increase in haematocrit concurrent with rapid decrease in platelet count. Severe dengue is defined as severe plasma leakage leading to any of the following: shock, fluid accumulation with respiratory distress OR severe bleeding as evaluated by clinician OR severe organ involvement of liver (aspartate amino transferase or alanine amino transferase ≥ 1000), central nervous system (impaired consciousness) or heart and other organs.10 References: 1. Australian Government Department of Health AGDo. Dengue virus infection surveillance and case definition [updated 14 June 2022 and 1 January 2018 respectively] Available from: https://www.health.gov.au/diseases/dengue-virus-infection, and https://www.health.gov.au/sites/default/files/documents/2022/06/dengue-virus-infection-surveillance-case-definition.pdf 2. Cambodia Ministry of Health NCfP, Entomology and Malaria Control. National Guideline for Clinical Management of Dengue, 2018. 2018. Available from: https://niph.org.kh/niph/uploads/library/pdf/GL055_National_guideline_for_ClM_Dengue.pdf. 3. Khampapongpane B, Lewis HC, Ketmayoon P, Phonekeo D, Somoulay V, Khamsing A, et al. National dengue surveillance in the Lao People's Democratic Republic, 2006-2012: epidemiological and laboratory findings. Western Pac Surveill Response J. 2014;5(1):7-13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24734212. 4. Ministry of Health Malaysia DCD. Case definitions for infectious diseases in Malaysia. 2017. Available from: https://www.moh.gov.my/moh/resources/Penerbitan/Garis%20Panduan/Pengurusan%20KEsihatan%20&%20kawalan%20pykit/Case_Definition_Of_Infectious_Disease_3rd_Edition_2017.pdf 5. Secretary PDoHOot. Guidelines for the Nationwide Implementation of Dengue Rapid Diagnostic Test (RDT), Administrative order No.2016-0043. 2016(2016-0043). 6. Secretary PDoHOot. Revised Dengue Clinical Case Management Guidelines 2011, Administrative order No.2012-0006. 2012 22 March 2012. Report No. 7. Diseases SNCfI. Diseases and Conditions, Dengue 2020 [updated 14 September 2020. Available from: https://www.doh.gov.ph/Health-Advisory/Dengue. 8. National Centre for Infectious Diseases, Dengue. Available from: https://www.ncid.sg/Health-Professionals/Diseases-and-Conditions/Pages/Dengue.aspx Dengue Situation Update 695 │ 12 9. National Environment Agency. Surveillance and Epidemiology Programme [updated 21 April 2023]. Available from: https://www.nea.gov.sg/corporate-functions/resources/research/surveillance-and- epidemiology-programme#Ehi%20Diagnostics%20Unit 10. Viet Nam Ministry of Health VNMo. Circular 54/2015 / TT-BYT 2015 [updated 26 April 2016. Available from: https://syt.thuathienhue.gov.vn/?gd=27&cn=108&tc=3993. 11. Pacific Islands Outbreak Manual. Available from: https://www.pphsn.net/resources/outbreak-manual/ 12. WHO dengue outbreak toolbox. Available from: https://www.who.int/docs/default-source/outbreak-toolkit/updates-documents_july-5/dengue-outbreak-data-collection-toolbox---inis-3-july- 1.pdf?sfvrsn=ec3ffcf3_2
Dengue Situation Update 696 │ 1 Dengue Situation Update 696 25 April 2024 Update on the Dengue situation in the Western Pacific Region This report describes the epidemiology of dengue in the World Health Organization Western Pacific Region. Data are compiled from open sources (national indicator-based surveillance systems) with the exception of Cambodia, Lao People’s Democratic Republic, Viet Nam, and the Philippines, where data are provided by the WHO Country Offices. For the Pacific Island Countries, syndromic surveillance data are provided by the Division of Pacific Technical Support. Information is reported based on countries’ standard dengue case definitions, summary of these definitions and countries’ dengue surveillance systems - included as an annex to this report. Due to differences in surveillance methods and reporting practices, a comparison of trends between countries and areas is not possible, however, national trends can be observed over time. Northern Hemisphere Cambodia As of epidemiological week 15 of 2024, the National Dengue Surveillance System reported a total of 5,062 cases with 17 deaths (Case Fatality Rate (CFR) 0.34%) since 1 January 2024 (Figure 1). This is almost 4 times the number reported in 2023 for the same period, with 1,671 cases and 4 deaths. Figure 1: Dengue cases reported weekly in 2024 vs endemic and epidemic alert lines in Cambodia; Source: National Dengue Surveillance System (NDCP/CNM/MOH) Dengue Situation Update 696 │ 2 China In March 2024, 38 dengue cases and no deaths were reported in China. There has been a total of 108 dengue cases and no death in the country since the beginning of 2024 (Figure 2). Figure 2: Dengue cases reported monthly from 2015-2024 (as of March) in China Source: National Disease Control and Prevention Administration, China Lao People’s Democratic Republic In epidemiological week 15 of 2024 (8 to 14 March 2024), 144 dengue cases and zero deaths were reported (Figure 3). The number of reported cases is lower than the numbers reported in epidemiological week 14 (190 cases with no deaths), and higher than those in week 15 of 2023 (85 cases with no deaths). The cumulative number of cases reported in 2024 (as of epidemiological week 15) is 2,043. This is a 222.3% increase compared to the 919 cases reported during the same period in 2023. Figure 3: Dengue cases reported weekly from 2018-2024 in Lao PDR Source: National Centre for Laboratory and Epidemiology, Ministry of Health, Lao PDR Dengue Situation Update 696 │ 3 Malaysia During epidemiological week 15 of 2024 (8 April to 14 April 2024), a decrease of 789 cases (32.0%) was reported with 1698 cases as compared to 2487 cases reported in the previous week (Figure 4). The cumulative number of dengue cases reported up to week 15 of 2024 is 48,329 cases, which is an increase of 45% compared to 33,325 cases for the same period in 2023. 35 dengue-related deaths were reported up to week 15 of 2024, compared to 21 deaths for the same period in 2023. Figure 4: Dengue cases reported weekly from 2023, 2024 and median 2019-2023 in Malaysia Source: Department of Health, Malaysia Philippines There is no update for this reporting period. During epidemiological Week 48 (26 November to 2 December 2023), there were 2,607 new dengue cases reported, a 41% decrease compared to the same period in 2022 (n=4 415 cases) (Figure 5). As of 2 December 2023, a total of 195,603 dengue cases have been reported. The number of cases is 23% lower compared to the same period in 2022 (n=252,700). From 1 January to 2 December 2023, there have been 657 deaths (CFR 0.34%) as compared to 894 deaths (CFR 0.35%;) reported in the same period in 2022. Figure 5: Dengue cases reported weekly from 2022 and 2023 in the Philippines Source: Department of Health, the Philippines (Note: there is a 3-4 week systematic delay in reporting and numbers should be interpreted with caution) Dengue Situation Update 696 │ 4 Singapore In epidemiological week 15 (7 to 13 April 2024), a total of 308 dengue cases were reported in Singapore. Cumulatively, a total of 5886 cases (Figure 6) have been reported as of 13 April 2024. When compared with week 15 in 2023 (2607 cases), there has been a 126% increase in cases reported in week 15 of this year. Preliminary results of all positive dengue samples serotyped in April 2024 showed DEN-1, DEN-2, DEN-3, and DEN-4 at 8.1%, 54.5%, 22.2% and 15.2%, respectively. Figure 6: Dengue cases reported weekly from 2019-2024 (as of 13 April 2024) in Singapore Source: Communicable Diseases Division, Ministry of Health, Singapore (Note: Case numbers are derived from the MOH Singapore’s weekly-infectious-disease-bulletin-year-2024_uploadas available from MOH | Weekly Infectious Diseases Bulletin) Viet Nam There is no update for this reporting period. As of 31 March 2024 (epidemiological week 13), cumulatively 14,542 dengue cases, including no deaths, were reported in Viet Nam. Compared to the same period in 2023 (25,044 cases, including 5 deaths), the number of cumulative cases decreased by 41.9%, and the number of deaths decreased by 5 (Figure 7). During week 13 (25 March to 31 March 2024), a total of 753 cases were reported nationwide; of those, 608 were hospitalized (80.7%). Compared to the previous week (805 cases, including 631 hospitalizations), the number of cases decreased by 6.5%, and the number of hospitalizations decreased by 3.6%. Dengue Situation Update 696 │ 5 Figure 7: Number of dengue hospital admissions and deaths by week in 2024 compared to 2023, as of week 13, 2024, Viet Nam Source: General Department of Preventive Medicine, Ministry of Health, Viet Nam Note hospitalizations include inpatients and outpatients The alert threshold is a 5-year mean plus 2 standard deviations. Figure 7 was updated on 17 March 2024 Southern Hemisphere Australia From 4 March to 31 March 2024, a total of 138 dengue cases were reported in Australia. From 1 April 2023 to 31 March 2024, the cumulative number of dengue cases is 1,225, which is 1.9 times higher than the same period’s 5 year rolling mean (n=647.4 cases). (Figure 8). Figure 8: Laboratory-confirmed dengue cases reported monthly from 2016-2024 in Australia Source: Department of Health, Australia Note: Graph was updated as of 31 March 2024 Dengue Situation Update 696 │ 6 Pacific Islands Countries New Caledonia There is no update for this reporting period. From 1 January to 29 February 2024, six confirmed dengue cases were reported in New Caledonia (Figure 9). This is higher compared to the same period in 2023, when a total of three dengue cases were reported. Of the six dengue cases in 2024, two were imported cases and two were probable cases. The serotypes of the cases were DENV-1 (3 cases), DENV-2 (1 case). Figure 9: Dengue cases reported by week from 2022 to 2024 in New Caledonia Source: Network of sentinel physicians, New Caledonia Pacific Island Countries and Areas (PICs) – Dengue-like illness (DLI) Surveillance During epidemiological week 15 of 2024 (ending 14 April 2024), Pacific Island Countries and Areas (PICs) with available surveillance data (18/21 PICs) reported similar numbers of DLI cases except some countries. Among the PICs, Cook Islands, Fiji, French Polynesia, Kiribati, Marshall Islands, Micronesia (Federated States of), New Caledonia, Niue, Northern Mariana Islands, Palau, Pitcairn Islands, Samoa, Solomon Islands, Tokelau, Tonga, Vanuatu, Tuvalu and Wallis and Futuna have reported DLI cases. The number of cases reported in Fiji, Micronesia (Federated States of), New Caledonia, Samoa and Wallis and Futuna in week 15 is higher than the number reported in the previous week. 0 5 10 15 1 4 7 1013 16 1922 25 2831 34 3740 43 4649 52 C as e s Epi Week Cook Islands DLI Trend - 2024 2024 2023 5 Years Median 0 200 400 600 800 1 4 7 101316192225283134374043464952 C as es Epi Week Fiji DLI Trend - 2024 2024 2023 5 Years Median Dengue Situation Update 696 │ 7 0 20 40 60 80 1 4 7 1013 16 1922 25 2831 34 3740 43 4649 52 C as es Epi Week French Polynesia DLI Trend - 2024 2024 2023 5 Years Median 0 5 10 15 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week FSM DLI Trend - 2024 2024 2023 5 Years Median 0 0.5 1 1.5 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week Kiribati DLI Trend - 2024 2024 2023 5 Years Median 0 5 10 15 20 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week RMI DLI Trend - 2024 2024 2023 5 Years Median 0 0.5 1 1.5 1 4 7 101316192225283134374043464952 C as es Epi Week CNMI DLI Trend - 2024 2024 2023 5 Years Median 0 0.2 0.4 0.6 0.8 1 1 4 7 101316192225283134374043464952 C as es Epi Week Niue DLI Trend - 2024 2024 2023 5 Years Median 0 1 2 3 4 5 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week New Caledonia DLI Trend - 2024 2024 2023 5 Years Median 0 5 10 15 20 25 1 4 7 1013 16 1922 25 2831 34 37 40 43 4649 52 C as es Epi Week Palau DLI Trend - 2024 2024 2023 5 Years Median Dengue Situation Update 696 │ 8 Figure 10. Reported cases of dengue-like illness in Pacific Islands Countries and Areas Source: WHO Division of Pacific Technical Support Note: Caution should be taken in interpreting these data as there may be changes in the number of sentinel sites reporting to the Pacific Syndromic Surveillance System (PSSS). Furthermore, the syndromic case definition of DLI may capture cases with non- dengue acute febrile illnesses (AFI) with similar clinical manifestations to dengue. This includes AFI such as chikungunya, influenza, hantavirus, leptospirosis, malaria, measles, paratyphoid and typhoid fevers, scrub typhus, yellow fever, zika, other diseases. The PSSS may also capture dengue cases under ‘prolonged fever’ surveillance. Alert threshold for DLI is twice the average number of cases seen in the previous 3 weeks. 0 0.2 0.4 0.6 0.8 1 1 4 7 101316192225283134374043464952 C as es Epi Week Pitcairn Islands DLI Trend - 2024 2024 2023 5 Years Median 0 20 40 60 80 100 1 4 7 101316192225283134374043464952 C as es Epi Week Samoa DLI Trend - 2024 2024 2023 5 Years Median 0 10 20 30 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week Solomon Islands DLI Trend - 2024 2024 2023 5 Years Median 0 0.5 1 1.5 2 2.5 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week Tokelau DLI Trend - 2024 2024 2023 5 Years Median 0 0.5 1 1.5 2 2.5 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week Tonga DLI Trend - 2024 2024 2023 5 Years Median 0 5 10 15 20 25 1 4 7 101316192225283134374043464952 C as es Epi Week Vanuatu DLI Trend - 2024 2024 2023 5 Years Median 0 1 2 3 4 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 C as es Epi Week Tuvalu DLI Trend - 2024 2024 2023 5 Years Median 0 5 10 15 20 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week Wallis & Futuna DLI Trend - 2024 2024 2023 5 Years Median Dengue Situation Update 695 │ 9 Annex 1. Summary of dengue case definitions, laboratory sampling and testing methods used for surveillance in Member States as of 2024 Country Case definition Surveillance system Laboratory sampling and testing method Reference Clinically confirmed case Laboratory confirmation required Description Australia Fever, headache, arthralgia, myalgia, rash, nausea and vomiting Yes Dengue is a nationally notifiable disease and cases are monitored through the National Notifiable Diseases Surveillance System (NNDSS) indicator-based surveillance system. Both confirmed and probable cases are nationally notifiable. A confirmed case requires both laboratory definitive evidence and clinical evidence. A probable case requires either laboratory suggestive evidence and clinical evidence and epidemiological evidence, or clinical evidence and household epidemiological evidence. Laboratory definitive evidence: - Isolation of dengue virus, or - Detection of dengue virus by nucleic acid testing, or - Detection of NS1 antigen in the blood by EIA, or - IgG seroconversion or significant increase in antibody levelor fourfold or greater rise in titre to dengue virus (proof by neutralization or another specific test) Laboratory suggestive evidence: - Detection of NS1 antigen in blood by rapid antigen test, or - Detection of dengue virus-specific IgM in blood Epidemiological evidence: - Exposure between 3 – 14 days prior to onset either in a country with known dengue activity or in a dengue-receptive area in Australia where a locally-acquired or imported case has been documented with onset within a month. Household epidemiological evidence: - Living in the same house as a locally- acquired case in a dengue-receptive area of Australia within a month of onse in the 1 Dengue Situation Update 695 │ 10 case and at least one case in the chain of epidemiologically linked cases is laboratory confirmed. Cambodia Suspected dengue: very high fever at 39-40 degrees celcius for 2-7 days (usually 3-4 days), with 2 or more of the following signs: flushed face, headache, retro-orbital pain, myalgia/arthralgia, cutaneous rash, haemorrhagic signs (petechiae, positive tourniquet test), and leucopenia. Probable dengue: signs of suspected dengue plus laboratory test results (see right column)) or that the case occurred in an area where the dengue case has been confirmed. Yes National Dengue Control Program (NDCP) enhanced sentinel surveillance system Communicable Disease Control (CDC) syndromic surveillance system (CamEWARN). Health Management Information System (HMIS) collects data on confirmed cases and deaths. Data collected for Cambodia Laboratory Information System (CamLIS), comprised of 32 participating hospital laboratories where NS1 detection is conducted. Laboratory testing: Antibody HI>= 1/1280 or IgM/IgG positive by ELISA test in convalescence serum 2 China (i) more than two symptoms of acute onset fever, severe headache, orbital pain, myalgia, arthralgia, fatigue with a history of travel in a dengue endemic area within 15 days before symptom onset or cohabitation with an individual with confirmed dengue; or no travel history, but with a rash or positive tourniquet test AND leucopenia or thrombocytopenia or serum IgM positivity. No Reported to the Chinese Centre for Disease Control and Prevention (China CDC) through the Chinese National Notifiable Infectious Disease Reporting Information System (CNNDS). Laboratory confirmation is done by real-time RT-PCR, NS1 in acute-phase serum, or virus isolation from an acutely infected patient’s serum. WHO internal communication Lao People's Democratic Republic WHO dengue case classification (2009) † No National Surveillance System for Notifiable Selected Diseases, indicator-based surveillance system that consists of passive weekly reports of clinically suspected cases, on admission, from all health-care facilities across the country. 3 Malaysia WHO dengue case classification (2009) † Yes National Dengue Surveillance System, indicator-based surveillance system All suspected cases are to be tested by the following laboratory tests: Rapid Combo Test (RCT) (NS1, IgM, IgG), Dengue Antigen and Serology tests by ELISA, Dengue Viral RNA Detection (Real time RT-PCR), Viral Isolation 4 Philippines WHO dengue case classification (2009) † Yes Philippine Integrated Disease Surveillance and Response (PIDSR), indicator-based surveillance system. Reporting delays of 2-3 weeks, Confirmed dengue is a suspect case with positive (+) viral culture isolation and/or PCR. NS1 (+), IgM is used to identify probable dengue. 5, 6, 7 Dengue Situation Update 695 │ 11 making comparison of current weekly and cumulative figures with previous years difficult. Singapore (endemic) Fever, headache, backache, myalgia, rash, abdominal discomfort and thrombocytopenia and laboratory testing (see right column) Yes Dengue is a legally notifiable disease in Singapore and notifying the Ministry of Health should not be later than 24 hours from the time of diagnosis. Laboratory confirmation is done using standard diagnostic tests for the detection of dengue NS1 antigen, IgM and IgG, or RT-PCR. 8,9 Viet Nam (endemic) Acute onset of fever continuously lasting from 2-7 days AND at least 2 of the following: haemorrhagic manifestation /presentation; headache, loss of appetite, nausea, vomiting; rash; muscle pain, joint pain, orbital pain; lethargy; abdominal pain. No As per the MOH dengue surveillance guideline, in routine surveillance MAC-ELISA is conducted for at least 7% and virus isolation is conducted for at least 3% of clinical cases. In an outbreak, at least 5 to 10 suspected cases are tested. 10 Pacific Island Countries WHO dengue case classification (2009) † No Pacific Syndromic Surveillance System Confirmed case: Isolation of dengue virus or detection of dengue-specific antigen or antibodies in tissue, blood, CSF or other body fluid by an advanced laboratory test 11 Only the minimum criteria required for fulfilling a clinical dengue case definition are included here; additional signs and symptoms required for more severe forms are not listed. † A probable dengue case is defined as any case living in or travel to dengue endemic area with fever and two or more of the following: nausea, vomiting, rash, aches and pains, positive tourniquet test, leucopenia and any warning sign. A case with warning signs is defined as a clinically diagnosed case with any of the following: abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleed, lethargy, restlessness, liver enlargement > 2 cm and increase in haematocrit concurrent with rapid decrease in platelet count. Severe dengue is defined as severe plasma leakage leading to any of the following: shock, fluid accumulation with respiratory distress OR severe bleeding as evaluated by clinician OR severe organ involvement of liver (aspartate amino transferase or alanine amino transferase ≥ 1000), central nervous system (impaired consciousness) or heart and other organs.10 References: 1. Australian Government Department of Health AGDo. Dengue virus infection surveillance and case definition [updated 14 June 2022 and 1 January 2018 respectively] Available from: https://www.health.gov.au/diseases/dengue-virus-infection, and https://www.health.gov.au/sites/default/files/documents/2022/06/dengue-virus-infection-surveillance-case-definition.pdf 2. Cambodia Ministry of Health NCfP, Entomology and Malaria Control. National Guideline for Clinical Management of Dengue, 2018. 2018. Available from: https://niph.org.kh/niph/uploads/library/pdf/GL055_National_guideline_for_ClM_Dengue.pdf. 3. Khampapongpane B, Lewis HC, Ketmayoon P, Phonekeo D, Somoulay V, Khamsing A, et al. National dengue surveillance in the Lao People's Democratic Republic, 2006-2012: epidemiological and laboratory findings. Western Pac Surveill Response J. 2014;5(1):7-13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24734212. 4. Ministry of Health Malaysia DCD. Case definitions for infectious diseases in Malaysia. 2017. Available from: https://www.moh.gov.my/moh/resources/Penerbitan/Garis%20Panduan/Pengurusan%20KEsihatan%20&%20kawalan%20pykit/Case_Definition_Of_Infectious_Disease_3rd_Edition_2017.pdf 5. Secretary PDoHOot. Guidelines for the Nationwide Implementation of Dengue Rapid Diagnostic Test (RDT), Administrative order No.2016-0043. 2016(2016-0043). 6. Secretary PDoHOot. Revised Dengue Clinical Case Management Guidelines 2011, Administrative order No.2012-0006. 2012 22 March 2012. Report No. 7. Diseases SNCfI. Diseases and Conditions, Dengue 2020 [updated 14 September 2020. Available from: https://www.doh.gov.ph/Health-Advisory/Dengue. 8. National Centre for Infectious Diseases, Dengue. Available from: https://www.ncid.sg/Health-Professionals/Diseases-and-Conditions/Pages/Dengue.aspx Dengue Situation Update 695 │ 12 9. National Environment Agency. Surveillance and Epidemiology Programme [updated 21 April 2023]. Available from: https://www.nea.gov.sg/corporate-functions/resources/research/surveillance-and- epidemiology-programme#Ehi%20Diagnostics%20Unit 10. Viet Nam Ministry of Health VNMo. Circular 54/2015 / TT-BYT 2015 [updated 26 April 2016. Available from: https://syt.thuathienhue.gov.vn/?gd=27&cn=108&tc=3993. 11. Pacific Islands Outbreak Manual. Available from: https://www.pphsn.net/resources/outbreak-manual/ 12. WHO dengue outbreak toolbox. Available from: https://www.who.int/docs/default-source/outbreak-toolkit/updates-documents_july-5/dengue-outbreak-data-collection-toolbox---inis-3-july- 1.pdf?sfvrsn=ec3ffcf3_2
Dengue Situation Update 697 │ 1 Dengue Situation Update 697 2 May 2024 Update on the Dengue situation in the Western Pacific Region This report describes the epidemiology of dengue in the World Health Organization Western Pacific Region. Data are compiled from open sources (national indicator-based surveillance systems) with the exception of Cambodia, Lao People’s Democratic Republic, Viet Nam, and the Philippines, where data are provided by the WHO Country Offices. For the Pacific Island Countries, syndromic surveillance data are provided by the Division of Pacific Technical Support. Information is reported based on countries’ standard dengue case definitions, summary of these definitions and countries’ dengue surveillance systems - included as an annex to this report. Due to differences in surveillance methods and reporting practices, a comparison of trends between countries and areas is not possible, however, national trends can be observed over time. Northern Hemisphere Cambodia There is no update for this reporting period. As of epidemiological week 15 of 2024, the National Dengue Surveillance System reported a total of 5 062 cases with 17 deaths (Case Fatality Rate (CFR) 0.34%) since 1 January 2024 (Figure 1). This is almost 4 times the number reported in 2023 for the same period, with 1 671 cases and 4 deaths. Figure 1: Dengue cases reported weekly in 2024 vs endemic and epidemic alert lines in Cambodia; Source: National Dengue Surveillance System (NDCP/CNM/MOH) Dengue Situation Update 697 │ 2 China There is no update for this reporting period. There has been a total of 108 dengue cases and no death in the country since the beginning of 2024 (Figure 2). Figure 2: Dengue cases reported monthly from 2015-2024 (as of March) in China Source: National Disease Control and Prevention Administration, China Lao People’s Democratic Republic In epidemiological week 16 of 2024 (15 to 20 April 2024), 1 127 dengue cases and zero deaths were reported (Figure 3). The number of reported cases is higher than the numbers reported in epidemiological week 15 (144 cases with no deaths), and lower than those in week 16 of 2023 (181 cases with no deaths). The cumulative number of cases reported in 2024 (as of epidemiological week 16) is 2 170. This is a 97.3% increase compared to the 1 100 cases reported during the same period in 2023. Figure 3: Dengue cases reported weekly from 2018-2024 in Lao PDR Source: National Centre for Laboratory and Epidemiology, Ministry of Health, Lao PDR Dengue Situation Update 697 │ 3 Malaysia During epidemiological week 16 of 2024 (14 April to 20 April 2024), an increase of 623 cases (37.0%) was reported with 2 321 cases as compared to 1 698 cases reported in the previous week (Figure 4). The cumulative number of dengue cases reported up to week 16 of 2024 is 50 650 cases, which is an increase of 44% compared to 35 202 cases for the same period in 2023. 39 dengue-related deaths were reported up to week 16 of 2024, compared to 22 deaths for the same period in 2023. Figure 4: Dengue cases reported weekly from 2023, 2024 and median 2019-2023 in Malaysia Source: Department of Health, Malaysia Philippines There is no update for this reporting period. During epidemiological Week 48 (26 November to 2 December 2023), there were 2 607 new dengue cases reported, a 41% decrease compared to the same period in 2022 (n=4 415 cases) (Figure 5). As of 2 December 2023, a total of 195 603 dengue cases have been reported. The number of cases is 23% lower compared to the same period in 2022 (n=252 700). From 1 January to 2 December 2023, there have been 657 deaths (CFR 0.34%) as compared to 894 deaths (CFR 0.35%;) reported in the same period in 2022. Figure 5: Dengue cases reported weekly from 2022 and 2023 in the Philippines Source: Department of Health, the Philippines (Note: there is a 3-4 week systematic delay in reporting and numbers should be interpreted with caution) Dengue Situation Update 697 │ 4 Singapore In epidemiological week 16 (14 to 20 April 2024), a total of 343 dengue cases were reported in Singapore. Cumulatively, a total of 6 232 cases (Figure 6) have been reported as of 20 April 2024. When compared with week 16 in 2023 (2 720 cases), there has been a 29% increase in cases reported in week 16 of this year. Preliminary results of all positive dengue samples serotyped in April 2024 showed DEN-1, DEN-2, DEN-3, and DEN-4 at 8.1%, 50.5%, 25.9% and 15.6%, respectively. Figure 6: Dengue cases reported weekly from 2019-2024 (as of 16 April 2024) in Singapore Source: Communicable Diseases Division, Ministry of Health, Singapore (Note: Case numbers are derived from the MOH Singapore’s weekly-infectious-disease-bulletin-year-2024_uploadas available from MOH | Weekly Infectious Diseases Bulletin) Viet Nam As of 21 April 2024 (epidemiological week 16), cumulatively 16 111 dengue cases, including 1 death, was reported in Viet Nam. Compared to the same period in 2023 (25 044 cases, including 5 deaths), the number of cumulative cases decreased by 1.7 times, and the number of deaths decreased by 5 (Figure 7). During week 16 (15 to 21 April 2024), a total of 654 cases were reported nationwide. Compared to the previous week, the number of cases decreased by 1.2 times. Figure 7: Number of dengue hospital admissions and deaths by week in 2024 compared to 2023, as of week 13, 2024, Viet Nam Source: General Department of Preventive Medicine, Ministry of Health, Viet Nam Note hospitalizations include inpatients and outpatients The alert threshold is a 5-year mean plus 2 standard deviations. Figure 7 was updated on 17 March 2024 Dengue Situation Update 697 │ 5 Southern Hemisphere Australia There is no update for this reporting period. From 4 to 31 March 2024, a total of 138 dengue cases were reported in Australia. From 1 April 2023 to 31 March 2024, the cumulative number of dengue cases is 1 225, which is 1.9 times higher than the same period’s 5 year rolling mean (n=647.4 cases). (Figure 8). Figure 8: Laboratory-confirmed dengue cases reported monthly from 2016-2024 in Australia Source: Department of Health, Australia Note: Graph was updated as of 31 March 2024 Pacific Islands Countries New Caledonia There is no update for this reporting period. From 1 January to 29 February 2024, six confirmed dengue cases were reported in New Caledonia (Figure 9). This is higher compared to the same period in 2023, when a total of three dengue cases were reported. Of the six dengue cases in 2024, two were imported cases and two were probable cases. The serotypes of the cases were DENV-1 (3 cases), DENV-2 (1 case). Figure 9: Dengue cases reported by week from 2022 to 2024 in New Caledonia Source: Network of sentinel physicians, New Caledonia Dengue Situation Update 697 │ 6 Pacific Island Countries and Areas (PICs) – Dengue-like illness (DLI) Surveillance During epidemiological week 16 of 2024 (ending 21 April 2024), Pacific Island Countries and Areas (PICs) with available surveillance data (18/21 PICs) reported similar numbers of DLI cases except some countries. Among the PICs, Cook Islands, Fiji, French Polynesia, Kiribati, Marshall Islands, Micronesia (Federated States of), New Caledonia, Niue, Northern Mariana Islands, Palau, Pitcairn Islands, Samoa, Solomon Islands, Tokelau, Tonga, Tuvalu, Vanuatu, and Wallis and Futuna have reported DLI cases. The number of cases reported in New Caledonia and Wallis and Futuna in week 16 is higher than the number reported in the previous week. Dengue Situation Update 697 │ 7 Figure 10. Reported cases of dengue-like illness in Pacific Islands Countries and Areas Source: WHO Division of Pacific Technical Support Dengue Situation Update 697 │ 8 Note: Caution should be taken in interpreting these data as there may be changes in the number of sentinel sites reporting to the Pacific Syndromic Surveillance System (PSSS). Furthermore, the syndromic case definition of DLI may capture cases with non- dengue acute febrile illnesses (AFI) with similar clinical manifestations to dengue. This includes AFI such as chikungunya, influenza, hantavirus, leptospirosis, malaria, measles, paratyphoid and typhoid fevers, scrub typhus, yellow fever, zika, other diseases. The PSSS may also capture dengue cases under ‘prolonged fever’ surveillance. Alert threshold for DLI is twice the average number of cases seen in the previous 3 weeks. Dengue Situation Update 697 │ 9 Annex 1. Summary of dengue case definitions, laboratory sampling and testing methods used for surveillance in Member States as of 2024 Country Case definition Surveillance system Laboratory sampling and testing method Reference Clinically confirmed case Laboratory confirmation required Description Australia Fever, headache, arthralgia, myalgia, rash, nausea and vomiting Yes Dengue is a nationally notifiable disease and cases are monitored through the National Notifiable Diseases Surveillance System (NNDSS) indicator-based surveillance system. Both confirmed and probable cases are nationally notifiable. A confirmed case requires both laboratory definitive evidence and clinical evidence. A probable case requires either laboratory suggestive evidence and clinical evidence and epidemiological evidence, or clinical evidence and household epidemiological evidence. Laboratory definitive evidence: - Isolation of dengue virus, or - Detection of dengue virus by nucleic acid testing, or - Detection of NS1 antigen in the blood by EIA, or - IgG seroconversion or significant increase in antibody levelor fourfold or greater rise in titre to dengue virus (proof by neutralization or another specific test) Laboratory suggestive evidence: - Detection of NS1 antigen in blood by rapid antigen test, or - Detection of dengue virus-specific IgM in blood Epidemiological evidence: - Exposure between 3 – 14 days prior to onset either in a country with known dengue activity or in a dengue-receptive area in Australia where a locally-acquired or imported case has been documented with onset within a month. Household epidemiological evidence: - Living in the same house as a locally- acquired case in a dengue-receptive area of Australia within a month of onse in the 1 Dengue Situation Update 697 │ 10 case and at least one case in the chain of epidemiologically linked cases is laboratory confirmed. Cambodia Suspected dengue: very high fever at 39-40 degrees celcius for 2-7 days (usually 3-4 days), with 2 or more of the following signs: flushed face, headache, retro-orbital pain, myalgia/arthralgia, cutaneous rash, haemorrhagic signs (petechiae, positive tourniquet test), and leucopenia. Probable dengue: signs of suspected dengue plus laboratory test results (see right column)) or that the case occurred in an area where the dengue case has been confirmed. Yes National Dengue Control Program (NDCP) enhanced sentinel surveillance system Communicable Disease Control (CDC) syndromic surveillance system (CamEWARN). Health Management Information System (HMIS) collects data on confirmed cases and deaths. Data collected for Cambodia Laboratory Information System (CamLIS), comprised of 32 participating hospital laboratories where NS1 detection is conducted. Laboratory testing: Antibody HI>= 1/1280 or IgM/IgG positive by ELISA test in convalescence serum 2 China (i) more than two symptoms of acute onset fever, severe headache, orbital pain, myalgia, arthralgia, fatigue with a history of travel in a dengue endemic area within 15 days before symptom onset or cohabitation with an individual with confirmed dengue; or no travel history, but with a rash or positive tourniquet test AND leucopenia or thrombocytopenia or serum IgM positivity. No Reported to the Chinese Centre for Disease Control and Prevention (China CDC) through the Chinese National Notifiable Infectious Disease Reporting Information System (CNNDS). Laboratory confirmation is done by real-time RT-PCR, NS1 in acute-phase serum, or virus isolation from an acutely infected patient’s serum. WHO internal communication Lao People's Democratic Republic WHO dengue case classification (2009) † No National Surveillance System for Notifiable Selected Diseases, indicator-based surveillance system that consists of passive weekly reports of clinically suspected cases, on admission, from all health-care facilities across the country. 3 Malaysia WHO dengue case classification (2009) † Yes National Dengue Surveillance System, indicator-based surveillance system All suspected cases are to be tested by the following laboratory tests: Rapid Combo Test (RCT) (NS1, IgM, IgG), Dengue Antigen and Serology tests by ELISA, Dengue Viral RNA Detection (Real time RT-PCR), Viral Isolation 4 Philippines WHO dengue case classification (2009) † Yes Philippine Integrated Disease Surveillance and Response (PIDSR), indicator-based surveillance system. Reporting delays of 2-3 weeks, Confirmed dengue is a suspect case with positive (+) viral culture isolation and/or PCR. NS1 (+), IgM is used to identify probable dengue. 5, 6, 7 Dengue Situation Update 697 │ 11 making comparison of current weekly and cumulative figures with previous years difficult. Singapore (endemic) Fever, headache, backache, myalgia, rash, abdominal discomfort and thrombocytopenia and laboratory testing (see right column) Yes Dengue is a legally notifiable disease in Singapore and notifying the Ministry of Health should not be later than 24 hours from the time of diagnosis. Laboratory confirmation is done using standard diagnostic tests for the detection of dengue NS1 antigen, IgM and IgG, or RT-PCR. 8,9 Viet Nam (endemic) Acute onset of fever continuously lasting from 2-7 days AND at least 2 of the following: haemorrhagic manifestation /presentation; headache, loss of appetite, nausea, vomiting; rash; muscle pain, joint pain, orbital pain; lethargy; abdominal pain. No As per the MOH dengue surveillance guideline, in routine surveillance MAC-ELISA is conducted for at least 7% and virus isolation is conducted for at least 3% of clinical cases. In an outbreak, at least 5 to 10 suspected cases are tested. 10 Pacific Island Countries WHO dengue case classification (2009) † No Pacific Syndromic Surveillance System Confirmed case: Isolation of dengue virus or detection of dengue-specific antigen or antibodies in tissue, blood, CSF or other body fluid by an advanced laboratory test 11 Only the minimum criteria required for fulfilling a clinical dengue case definition are included here; additional signs and symptoms required for more severe forms are not listed. † A probable dengue case is defined as any case living in or travel to dengue endemic area with fever and two or more of the following: nausea, vomiting, rash, aches and pains, positive tourniquet test, leucopenia and any warning sign. A case with warning signs is defined as a clinically diagnosed case with any of the following: abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleed, lethargy, restlessness, liver enlargement > 2 cm and increase in haematocrit concurrent with rapid decrease in platelet count. Severe dengue is defined as severe plasma leakage leading to any of the following: shock, fluid accumulation with respiratory distress OR severe bleeding as evaluated by clinician OR severe organ involvement of liver (aspartate amino transferase or alanine amino transferase ≥ 1000), central nervous system (impaired consciousness) or heart and other organs.10 References: 1. Australian Government Department of Health AGDo. Dengue virus infection surveillance and case definition [updated 14 June 2022 and 1 January 2018 respectively] Available from: https://www.health.gov.au/diseases/dengue-virus-infection, and https://www.health.gov.au/sites/default/files/documents/2022/06/dengue-virus-infection-surveillance-case-definition.pdf 2. Cambodia Ministry of Health NCfP, Entomology and Malaria Control. National Guideline for Clinical Management of Dengue, 2018. 2018. Available from: https://niph.org.kh/niph/uploads/library/pdf/GL055_National_guideline_for_ClM_Dengue.pdf. 3. Khampapongpane B, Lewis HC, Ketmayoon P, Phonekeo D, Somoulay V, Khamsing A, et al. National dengue surveillance in the Lao People's Democratic Republic, 2006-2012: epidemiological and laboratory findings. Western Pac Surveill Response J. 2014;5(1):7-13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24734212. 4. Ministry of Health Malaysia DCD. Case definitions for infectious diseases in Malaysia. 2017. Available from: https://www.moh.gov.my/moh/resources/Penerbitan/Garis%20Panduan/Pengurusan%20KEsihatan%20&%20kawalan%20pykit/Case_Definition_Of_Infectious_Disease_3rd_Edition_2017.pdf 5. Secretary PDoHOot. Guidelines for the Nationwide Implementation of Dengue Rapid Diagnostic Test (RDT), Administrative order No.2016-0043. 2016(2016-0043). 6. Secretary PDoHOot. Revised Dengue Clinical Case Management Guidelines 2011, Administrative order No.2012-0006. 2012 22 March 2012. Report No. 7. Diseases SNCfI. Diseases and Conditions, Dengue 2020 [updated 14 September 2020. Available from: https://www.doh.gov.ph/Health-Advisory/Dengue. 8. National Centre for Infectious Diseases, Dengue. Available from: https://www.ncid.sg/Health-Professionals/Diseases-and-Conditions/Pages/Dengue.aspx Dengue Situation Update 697 │ 12 9. National Environment Agency. Surveillance and Epidemiology Programme [updated 21 April 2023]. Available from: https://www.nea.gov.sg/corporate-functions/resources/research/surveillance-and- epidemiology-programme#Ehi%20Diagnostics%20Unit 10. Viet Nam Ministry of Health VNMo. Circular 54/2015 / TT-BYT 2015 [updated 26 April 2016. Available from: https://syt.thuathienhue.gov.vn/?gd=27&cn=108&tc=3993. 11. Pacific Islands Outbreak Manual. Available from: https://www.pphsn.net/resources/outbreak-manual/ 12. WHO dengue outbreak toolbox. Available from: https://www.who.int/docs/default-source/outbreak-toolkit/updates-documents_july-5/dengue-outbreak-data-collection-toolbox---inis-3-july- 1.pdf?sfvrsn=ec3ffcf3_2
Dengue Situation Update 698 │ 1 Dengue Situation Update 698 16 May 2024 Update on the Dengue situation in the Western Pacific Region This report describes the epidemiology of dengue in the World Health Organization Western Pacific Region. Data are compiled from open sources (national indicator-based surveillance systems) with the exception of Cambodia, Lao People’s Democratic Republic, Viet Nam, and the Philippines, where data are provided by the WHO Country Offices. For the Pacific Island Countries, syndromic surveillance data are provided by the Division of Pacific Technical Support. Information is reported based on countries’ standard dengue case definitions, summary of these definitions and countries’ dengue surveillance systems - included as an annex to this report. Due to differences in surveillance methods and reporting practices, a comparison of trends between countries and areas is not possible, however, national trends can be observed over time. Northern Hemisphere Cambodia As of epidemiological week 17 of 2024, the National Dengue Surveillance System reported a total of 5 351 cases with 19 deaths (Case Fatality Rate (CFR) 0.36%) since 1 January 2024 (Figure 1). This is more than double compared to the number reported in 2023 for the same period, with 2 000 cases and 4 deaths. Figure 1: Dengue cases reported weekly in 2024 vs endemic and epidemic alert lines in Cambodia; Source: National Dengue Surveillance System (NDCP/CNM/MOH) Dengue Situation Update 698 │ 2 China There is no update for this reporting period. There has been a total of 107 dengue cases and no death in the country since the beginning of 2024 (Figure 2). Figure 2: Dengue cases reported monthly from 2015-2024 (as of March) in China Source: National Disease Control and Prevention Administration, China Lao People’s Democratic Republic In epidemiological week 18 of 2024 (29 April to 5 May 2024), 154 dengue cases and zero deaths were reported (Figure 3). The number of reported cases is lower than the numbers reported in epidemiological week 17 (232 cases with no deaths), and lower than those in week 18 of 2023 (236 cases with no deaths). The cumulative number of cases reported in 2024 (as of epidemiological week 18) is 2 556. This is a 64.2% increase compared to the 1 557 cases reported during the same period in 2023. Figure 3: Dengue cases reported weekly from 2018-2024 in Lao PDR Source: National Centre for Laboratory and Epidemiology, Ministry of Health, Lao PDR Dengue Situation Update 698 │ 3 Malaysia During epidemiological week 18 of 2024 (28 April to 4 May 2024), a decrease of 242 cases (10.8%) was reported with 1 995 cases as compared to 2 237 cases reported in the previous week (Figure 4). The cumulative number of dengue cases reported up to week 18 of 2024 is 54 882 cases, which is an increase of 41% compared to 38 933 cases for the same period in 2023. 39 dengue-related deaths were reported up to week 18 of 2024, compared to 24 deaths for the same period in 2023. Figure 4: Dengue cases reported weekly from 2023, 2024 and median 2019-2023 in Malaysia Source: Department of Health, Malaysia Philippines There is no update for this reporting period. During epidemiological Week 48 (26 November to 2 December 2023), there were 2 607 new dengue cases reported, a 41% decrease compared to the same period in 2022 (n=4 415 cases) (Figure 5). As of 2 December 2023, a total of 195 603 dengue cases have been reported. The number of cases is 23% lower compared to the same period in 2022 (n=252 700). From 1 January to 2 December 2023, there have been 657 deaths (CFR 0.34%) as compared to 894 deaths (CFR 0.35%;) reported in the same period in 2022. Figure 5: Dengue cases reported weekly from 2022 and 2023 in the Philippines Source: Department of Health, the Philippines (Note: there is a 3-4 week systematic delay in reporting and numbers should be interpreted with caution) Dengue Situation Update 698 │ 4 Singapore In epidemiological week 18 (28 April to 4 May 2024), a total of 250 dengue cases were reported in Singapore. Cumulatively, a total of 6 816 cases (Figure 6) have been reported as of 4 May 2024. When compared with week 18 in 2023 (2 966 cases), there has been a 130% increase in cases reported in week 18 of this year. Preliminary results of all positive dengue samples serotyped in April 2024 showed DEN-1, DEN-2, DEN-3, and DEN-4 at 8.5%, 53.5%, 24.3% and 13.7%, respectively. Figure 6: Dengue cases reported weekly from 2019-2024 (as of 4 May 2024) in Singapore Source: Communicable Diseases Division, Ministry of Health, Singapore (Note: Case numbers are derived from the MOH Singapore’s weekly-infectious-disease-bulletin-year-2024_uploadas available from MOH | Weekly Infectious Diseases Bulletin) Viet Nam As of 12 May 2024 (epidemiological week 19), cumulatively 18 800 dengue cases, including two deaths, were reported in Viet Nam. Compared to the same period in 2023, the number of cumulative cases decreased by 1.6 times, and the number of deaths decreased by 6 (Figure 7). During week 19 (6 to 12 May 2024), a total of 620 cases were reported nationwide. Compared to the previous week, the number of cases decreased by 8%. Figure 7: Number of dengue hospital admissions and deaths by week in 2024 compared to 2023, as of week 19, 2024, Viet Nam Source: General Department of Preventive Medicine, Ministry of Health, Viet Nam Note hospitalizations include inpatients and outpatients The alert threshold is a 5-year mean plus 2 standard deviations. Dengue Situation Update 698 │ 5 Southern Hemisphere Australia In April 2024, a total of 272 dengue cases were reported in Australia. As of 30 April 2024, the cumulative number of dengue cases is 676, which is two times higher than the same period in 2023 (338 cases). (Figure 8). Figure 8: Laboratory-confirmed dengue cases reported monthly from 2016-2024 in Australia Source: Department of Health, Australia Note: Graph was updated as of 30 April 2024 Pacific Islands Countries New Caledonia There is no update for this reporting period. From 1 January to 29 February 2024, six confirmed dengue cases were reported in New Caledonia (Figure 9). This is higher compared to the same period in 2023, when a total of three dengue cases were reported. Of the six dengue cases in 2024, two were imported cases and two were probable cases. The serotypes of the cases were DENV-1 (3 cases), DENV-2 (1 case). Figure 9: Dengue cases reported by week from 2022 to 2024 in New Caledonia Source: Network of sentinel physicians, New Caledonia Dengue Situation Update 698 │ 6 Pacific Island Countries and Areas (PICs) – Dengue-like illness (DLI) Surveillance During epidemiological week 17 of 2024 (ending 28 April 2024), Pacific Island Countries and Areas (PICs) with available surveillance data (18/21 PICs) reported similar numbers of DLI cases except some countries. Among the PICs, Cook Islands, Fiji, French Polynesia, Kiribati, Marshall Islands, Micronesia (Federated States of), New Caledonia, Niue, Northern Mariana Islands, Palau, Pitcairn Islands, Samoa, Solomon Islands, Tokelau, Tonga, Tuvalu, Vanuatu, and Wallis and Futuna have reported DLI cases. The number of cases reported in Fiji, Kiribati, New Caledonia, Samoa and Solomon Islands in week 17 is higher than the number reported in the previous week. 0 5 10 15 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week Cook Islands DLI Trend - 2024 2024 2023 5 Years Median 0 200 400 600 800 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week Fiji DLI Trend - 2024 2024 2023 5 Years Median 0 20 40 60 80 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week French Polynesia DLI Trend - 2024 2024 2023 5 Years Median 0 20 40 60 80 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week Kiribati DLI Trend - 2024 2024 2023 5 Years Median 0 5 10 15 20 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week RMI DLI Trend - 2024 2024 2023 5 Years Median 0 5 10 15 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week FSM DLI Trend - 2024 2024 2023 5 Years Median 0 1 2 3 4 5 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week New Caledonia DLI Trend - 2024 2024 2023 5 Years Median 0 0.2 0.4 0.6 0.8 1 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week Niue DLI Trend - 2024 2024 2023 5 Years Median Dengue Situation Update 698 │ 7 0 0.5 1 1.5 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week CNMI DLI Trend - 2024 2024 2023 5 Years Median 0 5 10 15 20 25 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week Palau DLI Trend - 2024 2024 2023 5 Years Median 0 0.2 0.4 0.6 0.8 1 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week Pitcairn Islands DLI Trend - 2024 2024 2023 5 Years Median 0 20 40 60 80 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week Samoa DLI Trend - 2024 2024 2023 5 Years Median 0 10 20 30 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week Solomon Islands DLI Trend - 2024 2024 2023 5 Years Median 0 0.5 1 1.5 2 2.5 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week Tokelau DLI Trend - 2024 2024 2023 5 Years Median 0 0.5 1 1.5 2 2.5 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week Tonga DLI Trend - 2024 2024 2023 5 Years Median 0 1 2 3 4 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 C as es Epi Week Tuvalu DLI Trend - 2024 2024 2023 5 Years Median 0 5 10 15 20 25 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week Vanuatu DLI Trend - 2024 2024 2023 5 Years Median 0 5 10 15 20 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 C as es Epi Week Wallis & Futuna DLI Trend - 2024 2024 2023 5 Years Median Dengue Situation Update 698 │ 8 Figure 10. Reported cases of dengue-like illness in Pacific Islands Countries and Areas Source: WHO Division of Pacific Technical Support Note: Caution should be taken in interpreting these data as there may be changes in the number of sentinel sites reporting to the Pacific Syndromic Surveillance System (PSSS). Furthermore, the syndromic case definition of DLI may capture cases with non- dengue acute febrile illnesses (AFI) with similar clinical manifestations to dengue. This includes AFI such as chikungunya, influenza, hantavirus, leptospirosis, malaria, measles, paratyphoid and typhoid fevers, scrub typhus, yellow fever, zika, other diseases. The PSSS may also capture dengue cases under ‘prolonged fever’ surveillance. Alert threshold for DLI is twice the average number of cases seen in the previous 3 weeks. Dengue Situation Update 698 │ 9 Annex 1. Summary of dengue case definitions, laboratory sampling and testing methods used for surveillance in Member States as of 2024 Country Case definition Surveillance system Laboratory sampling and testing method Reference Clinically confirmed case Laboratory confirmation required Description Australia Fever, headache, arthralgia, myalgia, rash, nausea and vomiting Yes Dengue is a nationally notifiable disease and cases are monitored through the National Notifiable Diseases Surveillance System (NNDSS) indicator-based surveillance system. Both confirmed and probable cases are nationally notifiable. A confirmed case requires both laboratory definitive evidence and clinical evidence. A probable case requires either laboratory suggestive evidence and clinical evidence and epidemiological evidence, or clinical evidence and household epidemiological evidence. Laboratory definitive evidence: - Isolation of dengue virus, or - Detection of dengue virus by nucleic acid testing, or - Detection of NS1 antigen in the blood by EIA, or - IgG seroconversion or significant increase in antibody levelor fourfold or greater rise in titre to dengue virus (proof by neutralization or another specific test) - Detection of dengue virus-specific IgM in cerebrospinal fluid, in the absence of IgM to Murray valley encephalitis, West Nile virus/Kunjin, or Japanese encephalitis viruses. Laboratory suggestive evidence: - Detection of NS1 antigen in blood by rapid antigen test, or - Detection of dengue virus-specific IgM in blood Epidemiological evidence: - Exposure between 3 – 14 days prior to onset either in a country with known dengue activity or in a dengue-receptive area in Australia where a locally-acquired or imported case has been documented with onset within a month. 1 Dengue Situation Update 698 │ 10 Household epidemiological evidence: - Living in the same house as a locally- acquired case in a dengue-receptive area of Australia within a month of onse in the case and at least one case in the chain of epidemiologically linked cases is laboratory confirmed. Cambodia Suspected dengue: very high fever at 39-40 degrees celcius for 2-7 days (usually 3-4 days), with 2 or more of the following signs: flushed face, headache, retro-orbital pain, myalgia/arthralgia, cutaneous rash, haemorrhagic signs (petechiae, positive tourniquet test), and leucopenia. Probable dengue: signs of suspected dengue plus laboratory test results (see right column)) or that the case occurred in an area where the dengue case has been confirmed. Yes National Dengue Control Program (NDCP) enhanced sentinel surveillance system Communicable Disease Control (CDC) syndromic surveillance system (CamEWARN). Health Management Information System (HMIS) collects data on confirmed cases and deaths. Data collected for Cambodia Laboratory Information System (CamLIS), comprised of 32 participating hospital laboratories where NS1 detection is conducted. Laboratory testing: Antibody HI>= 1/1280 or IgM/IgG positive by ELISA test in convalescence serum 2 China 1) Typical dengue fever can be diagnosed with any of the following conditions: - General clinical symptoms of dengue fever, with an epidemiological history (having been to an area where dengue fever is prevalent within 14 days before onset), or living or working in an area where dengue fever cases have occurred within the past month, and with reduced white blood cell count and platelet count (below 100x10^9/L) - No epidemiological history, but with a rash, bleeding tendency, and positive IgG or IgM antibodies in a single serum sample. No Reported to the Chinese Centre for Disease Control and Prevention (China CDC) through the Chinese National Notifiable Infectious Disease Reporting Information System (CNNDS). A clinically diagnosed case with any of the of the following laboratory findings: - Isolation of the dengue virus from the serum, cerebrospinal fluid, blood cells, or tissues of an acute-phase patient - Detection of dengue virus gene sequence by RT-PCR or real-time fluorescent quantitative PCR - Detection of dengue virus NS1 antigen in serum from an acute-phase patient - A fourfold or greater increase in specific antibody titer in the convalescent phase compared to the acute phase. 3, WHO internal communication Dengue Situation Update 698 │ 11 2) Dengue Hemorrhagic Fever can be diagnosed when accompanied by any of the following clinical symptoms: - Bleeding tendency, significant bleeding manifestations (such as gastrointestinal bleeding or hemorrhage in the chest, abdomen, or cranium), hepatomegaly, and ascites; and - Laboratory findings including thrombocytopenia (platelet count below 100x10^9/L), hemoconcentration (an increase in hematocrit of more than 20% above normal levels or a decrease of more than 20% after fluid resuscitation), and hypoalbuminemia. 3) Dengue Shock Syndrome: Patients with dengue hemorrhagic fever presenting with cold and clammy skin, restlessness, rapid and weak pulse, low blood pressure with a narrow pulse pressure (less than 20mmHg or 2.7kPa), and reduced urine output. Lao People's Democratic Republic WHO dengue case classification (2009) † No National Surveillance System for Notifiable Selected Diseases, indicator-based surveillance system that consists of passive weekly reports of clinically suspected cases, on admission, from all health-care facilities across the country. 4 Malaysia WHO dengue case classification (2009) † Yes National Dengue Surveillance System, indicator-based surveillance system All suspected cases are to be tested by the following laboratory tests: Rapid Combo Test (RCT) (NS1, IgM, IgG), Dengue Antigen and Serology tests by ELISA, Dengue Viral RNA Detection (Real time RT-PCR), Viral Isolation 5 Philippines WHO dengue case classification (2009) † Yes Philippine Integrated Disease Surveillance and Response (PIDSR), indicator-based surveillance system. Reporting delays of 2-3 weeks, making comparison of current weekly and cumulative figures with previous years difficult. Confirmed dengue is a suspect case with positive (+) viral culture isolation and/or PCR. NS1 (+), IgM is used to identify probable dengue. 6, 7, 8 Dengue Situation Update 698 │ 12 Singapore (endemic) Fever, headache, backache, myalgia, rash, abdominal discomfort and thrombocytopenia and laboratory testing (see right column) Yes Dengue is a legally notifiable disease in Singapore and notifying the Ministry of Health should not be later than 24 hours from the time of diagnosis. Laboratory confirmation is done using standard diagnostic tests for the detection of dengue NS1 antigen, IgM and IgG, or RT-PCR. 9, 10 Viet Nam (endemic) Acute onset of fever continuously lasting from 2-7 days AND at least 2 of the following: haemorrhagic manifestation /presentation; headache, loss of appetite, nausea, vomiting; rash; muscle pain, joint pain, orbital pain; lethargy; abdominal pain. No As per the MOH dengue surveillance guideline, in routine surveillance MAC-ELISA is conducted for at least 7% and virus isolation is conducted for at least 3% of clinical cases. In an outbreak, at least 5 to 10 suspected cases are tested. 11 Pacific Island Countries WHO dengue case classification (2009) † No Pacific Syndromic Surveillance System Confirmed case: Isolation of dengue virus or detection of dengue-specific antigen or antibodies in tissue, blood, CSF or other body fluid by an advanced laboratory test 12 Only the minimum criteria required for fulfilling a clinical dengue case definition are included here; additional signs and symptoms required for more severe forms are not listed. † A probable dengue case is defined as any case living in or travel to dengue endemic area with fever and two or more of the following: nausea, vomiting, rash, aches and pains, positive tourniquet test, leucopenia and any warning sign. A case with warning signs is defined as a clinically diagnosed case with any of the following: abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleed, lethargy, restlessness, liver enlargement > 2 cm and increase in haematocrit concurrent with rapid decrease in platelet count. Severe dengue is defined as severe plasma leakage leading to any of the following: shock, fluid accumulation with respiratory distress OR severe bleeding as evaluated by clinician OR severe organ involvement of liver (aspartate amino transferase or alanine amino transferase ≥ 1000), central nervous system (impaired consciousness) or heart and other organs.10 References: 1. Australian Government Department of Health AGDo. Dengue virus infection surveillance and case definition [updated 14 June 2022 and 1 January 2018 respectively] Available from: https://www.health.gov.au/diseases/dengue-virus-infection, and https://www.health.gov.au/sites/default/files/documents/2022/06/dengue-virus-infection-surveillance-case-definition.pdf 2. Cambodia Ministry of Health NCfP, Entomology and Malaria Control. National Guideline for Clinical Management of Dengue, 2018. 2018. Available from: https://niph.org.kh/niph/uploads/library/pdf/GL055_National_guideline_for_ClM_Dengue.pdf. 3. China CDC. Dengue surveillance guideline. Available from: https://www.chinacdc.cn/jkzt/crb/zl/dgr/jszl_2235/201810/P020181010391462131548.pdf 4. Khampapongpane B, Lewis HC, Ketmayoon P, Phonekeo D, Somoulay V, Khamsing A, et al. National dengue surveillance in the Lao People's Democratic Republic, 2006-2012: epidemiological and laboratory findings. Western Pac Surveill Response J. 2014;5(1):7-13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24734212. 5. Ministry of Health Malaysia DCD. Case definitions for infectious diseases in Malaysia. 2017. Available from: https://www.moh.gov.my/moh/resources/Penerbitan/Garis%20Panduan/Pengurusan%20KEsihatan%20&%20kawalan%20pykit/Case_Definition_Of_Infectious_Disease_3rd_Edition_2017.pdf 6. Secretary PDoHOot. Guidelines for the Nationwide Implementation of Dengue Rapid Diagnostic Test (RDT), Administrative order No.2016-0043. 2016(2016-0043). 7. Secretary PDoHOot. Revised Dengue Clinical Case Management Guidelines 2011, Administrative order No.2012-0006. 2012 22 March 2012. Report No. 8. Diseases SNCfI. Diseases and Conditions, Dengue 2020 [updated 14 September 2020. Available from: https://www.doh.gov.ph/Health-Advisory/Dengue. 9. National Centre for Infectious Diseases, Dengue. Available from: https://www.ncid.sg/Health-Professionals/Diseases-and-Conditions/Pages/Dengue.aspx 10. National Environment Agency. Surveillance and Epidemiology Programme [updated 21 April 2023]. Available from: https://www.nea.gov.sg/corporate-functions/resources/research/surveillance-and- epidemiology-programme#Ehi%20Diagnostics%20Unit Dengue Situation Update 698 │ 13 11. Viet Nam Ministry of Health VNMo. Circular 54/2015 / TT-BYT 2015 [updated 26 April 2016. Available from: https://syt.thuathienhue.gov.vn/?gd=27&cn=108&tc=3993. 12. Pacific Islands Outbreak Manual. Available from: https://www.pphsn.net/resources/outbreak-manual/ 13. WHO dengue outbreak toolbox. Available from: https://www.who.int/docs/default-source/outbreak-toolkit/updates-documents_july-5/dengue-outbreak-data-collection-toolbox---inis-3-july- 1.pdf?sfvrsn=ec3ffcf3_2
Dengue Situation Update 700 │ 1 Dengue Situation Update 700 13 June 2024 Update on the Dengue situation in the Western Pacific Region This report describes the epidemiology of dengue in the World Health Organization Western Pacific Region. Data are compiled from open sources (national indicator-based surveillance systems) with the exception of Cambodia, Lao People’s Democratic Republic, Viet Nam, and the Philippines, where data are provided by the WHO Country Offices. For the Pacific Island Countries, syndromic surveillance data are provided by the Division of Pacific Technical Support. Information is reported based on countries’ standard dengue case definitions, summary of these definitions and countries’ dengue surveillance systems - included as an annex to this report. Due to differences in surveillance methods and reporting practices, a comparison of trends between countries and areas is not possible, however, national trends can be observed over time. Northern Hemisphere Cambodia As of epidemiological week 22 of 2024, the National Dengue Surveillance System reported a total of 5 927 cases with 22 deaths (Case Fatality Rate (CFR) 0.37%) since 1 January 2024 (Figure 1). This is almost double compared to the number reported in 2023 for the same period, with 3 463 cases and 5 deaths. Figure 1: Dengue cases reported weekly in 2024 vs endemic and epidemic alert lines in Cambodia; Source: National Dengue Surveillance System (NDCP/CNM/MOH) Dengue Situation Update 700 │ 2 China In April 2024, 58 dengue cases and no deaths were reported in China. There has been a total of 165 dengue cases and no death in the country since the beginning of 2024 (Figure 2). Figure 2: Dengue cases reported monthly from 2015-2024 (as of April) in China Source: National Disease Control and Prevention Administration, China Lao People’s Democratic Republic In epidemiological week 22 of 2024 (27 May to 2 June 2024), 175 dengue cases and zero deaths were reported (Figure 3). The number of reported cases is higher than the numbers reported in epidemiological week 21 (159 cases with no deaths), and lower than those in week 22 of 2023 (589 cases with no deaths). The cumulative number of cases reported in 2024 (as of epidemiological week 22) is 3 259. This is a 4.9% increase compared to the 3 106 cases reported during the same period in 2023. Figure 3: Dengue cases reported weekly from 2018-2024 in Lao PDR Source: National Centre for Laboratory and Epidemiology, Ministry of Health, Lao PDR Dengue Situation Update 700 │ 3 Malaysia During epidemiological week 21 of 2024 (2 to 8 June 2024), a decrease of 35 cases (1.4%) was reported with 2 426 cases as compared to 2 461 cases reported in the previous week (Figure 4). The cumulative number of dengue cases reported up to week 21 of 2024 is 62 107 cases, which is an increase of 34.3% compared to 46 257 cases for the same period in 2023. 46 dengue-related deaths were reported up to week 21 of 2024, compared to 31 deaths for the same period in 2023. Figure 4: Dengue cases reported weekly from 2023, 2024 and median 2019-2023 in Malaysia Source: Department of Health, Malaysia Philippines There is no update for this reporting period. During epidemiological Week 48 (26 November to 2 December 2023), there were 2 607 new dengue cases reported, a 41% decrease compared to the same period in 2022 (n=4 415 cases) (Figure 5). As of 2 December 2023, a total of 195 603 dengue cases have been reported. The number of cases is 23% lower compared to the same period in 2022 (n=252 700). From 1 January to 2 December 2023, there have been 657 deaths (CFR 0.34%) as compared to 894 deaths (CFR 0.35%;) reported in the same period in 2022. Figure 5: Dengue cases reported weekly from 2022 and 2023 in the Philippines Source: Department of Health, the Philippines (Note: there is a 3-4 week systematic delay in reporting and numbers should be interpreted with caution) Dengue Situation Update 700 │ 4 Singapore In epidemiological week 22 (26 May to 1 June 2024), a total of 313 dengue cases were reported in Singapore. Cumulatively, a total of 8 033 cases (Figure 6) have been reported as of 1 June 2024. When compared to the same period in 2023 (3 431 cases), there has been a 134% increase in cases reported in 2024. Preliminary results of all positive dengue samples serotyped in May 2024 showed DEN-1, DEN-2, DEN-3, and DEN-4 at 6.0%, 44.7%, 35.0% and 14.3% respectively. Figure 6: Dengue cases reported weekly from 2019-2024 (as of 1 June 2024) in Singapore Source: Communicable Diseases Division, Ministry of Health, Singapore (Note: Case numbers are derived from the MOH Singapore’s weekly-infectious-disease-bulletin-year-2024_upload as available from MOH | Weekly Infectious Diseases Bulletin) Viet Nam As of 26 May 2024, there were 23 614 dengue cases including three deaths cumulatively reported in Viet Nam. Compared to the same period in 2023 (36 284 cases including 8 deaths), the number of cumulative cases decreased by 35%, and the number of deaths decreased by five cases . During week 23 (3 to 9 June 2024), a total of 1 272 cases and no deaths were reported nationwide. Of these cases, 964 (75.8%) were hospitalised. Compared to the previous week, the number of cases increased by 7.4% and the number of hospitalisations increased by 4.6% (Figure 7). Figure 7: Number of dengue hospital admissions and deaths by week in 2024 compared to 2023, as of week 23, 2024, Viet Nam Source: General Department of Preventive Medicine, Ministry of Health, Viet Nam Note hospitalizations include inpatients and outpatients The alert threshold is a 5-year mean plus 2 standard deviations. Dengue Situation Update 700 │ 5 Southern Hemisphere Australia In May 2024, a total of 273 dengue cases were reported in Australia. As of 31 May 2024, the cumulative number of dengue cases is 1 020, which is more than two times higher than the same period in 2023 (422 cases). (Figure 8). Figure 8: Laboratory-confirmed dengue cases reported monthly from 2016-2024 in Australia Source: Department of Health, Australia Note: Graph was updated as of 31 May 2024 Pacific Islands Countries New Caledonia There is no update for this reporting period. From 1 January to 29 February 2024, six confirmed dengue cases were reported in New Caledonia (Figure 9). This is higher compared to the same period in 2023, when a total of three dengue cases were reported. Of the six dengue cases in 2024, two were imported cases and two were probable cases. The serotypes of the cases were DENV-1 (3 cases), DENV-2 (1 case). Figure 9: Dengue cases reported by week from 2022 to 2024 in New Caledonia Source: Network of sentinel physicians, New Caledonia Dengue Situation Update 700 │ 6 Pacific Island Countries and Areas (PICs) – Dengue-like illness (DLI) Surveillance In epidemiological week 22 of 2024 (ending 2 June 2024), among the PICs with available surveillance data (18/21 PICs), an upward trend of DLI cases was reported in Fiji, Samoa and Tonga. The remaining PICs reported either no or low numbers of DLI cases or provided no updates (Figure 10). Dengue Situation Update 700 │ 7 Dengue Situation Update 700 │ 8 Figure 10. Reported cases of dengue-like illness in Pacific Islands Countries and Areas Source: WHO Division of Pacific Technical Support Note: Caution should be taken in interpreting these data as there may be changes in the number of sentinel sites reporting to the Pacific Syndromic Surveillance System (PSSS). Furthermore, the syndromic case definition of DLI may capture cases with non- dengue acute febrile illnesses (AFI) with similar clinical manifestations to dengue. This includes AFI such as chikungunya, influenza, hantavirus, leptospirosis, malaria, measles, paratyphoid and typhoid fevers, scrub typhus, yellow fever, zika, other diseases. The PSSS may also capture dengue cases under ‘prolonged fever’ surveillance. Alert threshold for DLI is twice the average number of cases seen in the previous 3 weeks. Dengue Situation Update 699 │ 9 Annex 1. Summary of dengue case definitions, laboratory sampling and testing methods used for surveillance in Member States as of 2024 Country Case definition Surveillance system Laboratory sampling and testing method Reference Clinically confirmed case Laboratory confirmation required Description Australia Fever, headache, arthralgia, myalgia, rash, nausea and vomiting Yes Dengue is a nationally notifiable disease and cases are monitored through the National Notifiable Diseases Surveillance System (NNDSS) indicator-based surveillance system. Both confirmed and probable cases are nationally notifiable. A confirmed case requires both laboratory definitive evidence and clinical evidence. A probable case requires either laboratory suggestive evidence and clinical evidence and epidemiological evidence, or clinical evidence and household epidemiological evidence. Laboratory definitive evidence: - Isolation of dengue virus, or - Detection of dengue virus by nucleic acid testing, or - Detection of NS1 antigen in the blood by EIA, or - IgG seroconversion or significant increase in antibody levelor fourfold or greater rise in titre to dengue virus (proof by neutralization or another specific test) - Detection of dengue virus-specific IgM in cerebrospinal fluid, in the absence of IgM to Murray valley encephalitis, West Nile virus/Kunjin, or Japanese encephalitis viruses. Laboratory suggestive evidence: - Detection of NS1 antigen in blood by rapid antigen test, or - Detection of dengue virus-specific IgM in blood Epidemiological evidence: - Exposure between 3 – 14 days prior to onset either in a country with known dengue activity or in a dengue-receptive area in Australia where a locally-acquired or imported case has been documented with onset within a month. 1 Dengue Situation Update 699 │ 10 Household epidemiological evidence: - Living in the same house as a locally- acquired case in a dengue-receptive area of Australia within a month of onse in the case and at least one case in the chain of epidemiologically linked cases is laboratory confirmed. Cambodia Suspected dengue: very high fever at 39-40 degrees celcius for 2-7 days (usually 3-4 days), with 2 or more of the following signs: flushed face, headache, retro-orbital pain, myalgia/arthralgia, cutaneous rash, haemorrhagic signs (petechiae, positive tourniquet test), and leucopenia. Probable dengue: signs of suspected dengue plus laboratory test results (see right column)) or that the case occurred in an area where the dengue case has been confirmed. Yes National Dengue Control Program (NDCP) enhanced sentinel surveillance system Communicable Disease Control (CDC) syndromic surveillance system (CamEWARN). Health Management Information System (HMIS) collects data on confirmed cases and deaths. Data collected for Cambodia Laboratory Information System (CamLIS), comprised of 32 participating hospital laboratories where NS1 detection is conducted. Laboratory testing: Antibody HI>= 1/1280 or IgM/IgG positive by ELISA test in convalescence serum 2 China 1) Typical dengue fever can be diagnosed with any of the following conditions: - General clinical symptoms of dengue fever, with an epidemiological history (having been to an area where dengue fever is prevalent within 14 days before onset), or living or working in an area where dengue fever cases have occurred within the past month, and with reduced white blood cell count and platelet count (below 100x10^9/L) - No epidemiological history, but with a rash, bleeding tendency, and positive IgG or IgM antibodies in a single serum sample. No Reported to the Chinese Centre for Disease Control and Prevention (China CDC) through the Chinese National Notifiable Infectious Disease Reporting Information System (CNNDS). A clinically diagnosed case with any of the of the following laboratory findings: - Isolation of the dengue virus from the serum, cerebrospinal fluid, blood cells, or tissues of an acute-phase patient - Detection of dengue virus gene sequence by RT-PCR or real-time fluorescent quantitative PCR - Detection of dengue virus NS1 antigen in serum from an acute-phase patient - A fourfold or greater increase in specific antibody titer in the convalescent phase compared to the acute phase. 3, WHO internal communication Dengue Situation Update 699 │ 11 2) Dengue Hemorrhagic Fever can be diagnosed when accompanied by any of the following clinical symptoms: - Bleeding tendency, significant bleeding manifestations (such as gastrointestinal bleeding or hemorrhage in the chest, abdomen, or cranium), hepatomegaly, and ascites; and - Laboratory findings including thrombocytopenia (platelet count below 100x10^9/L), hemoconcentration (an increase in hematocrit of more than 20% above normal levels or a decrease of more than 20% after fluid resuscitation), and hypoalbuminemia. 3) Dengue Shock Syndrome: Patients with dengue hemorrhagic fever presenting with cold and clammy skin, restlessness, rapid and weak pulse, low blood pressure with a narrow pulse pressure (less than 20mmHg or 2.7kPa), and reduced urine output. Lao People's Democratic Republic WHO dengue case classification (2009) † No National Surveillance System for Notifiable Selected Diseases, indicator-based surveillance system that consists of passive weekly reports of clinically suspected cases, on admission, from all health-care facilities across the country. 4 Malaysia WHO dengue case classification (2009) † Yes National Dengue Surveillance System, indicator-based surveillance system All suspected cases are to be tested by the following laboratory tests: Rapid Combo Test (RCT) (NS1, IgM, IgG), Dengue Antigen and Serology tests by ELISA, Dengue Viral RNA Detection (Real time RT-PCR), Viral Isolation 5 Philippines WHO dengue case classification (2009) † Yes Philippine Integrated Disease Surveillance and Response (PIDSR), indicator-based surveillance system. Reporting delays of 2-3 weeks, making comparison of current weekly and cumulative figures with previous years difficult. Confirmed dengue is a suspect case with positive (+) viral culture isolation and/or PCR. NS1 (+), IgM is used to identify probable dengue. 6, 7, 8 Dengue Situation Update 699 │ 12 Singapore (endemic) Fever, headache, backache, myalgia, rash, abdominal discomfort and thrombocytopenia and laboratory testing (see right column) Yes Dengue is a legally notifiable disease in Singapore and notifying the Ministry of Health should not be later than 24 hours from the time of diagnosis. Laboratory confirmation is done using standard diagnostic tests for the detection of dengue NS1 antigen, IgM and IgG, or RT-PCR. 9, 10 Viet Nam (endemic) Acute onset of fever continuously lasting from 2-7 days AND at least 2 of the following: haemorrhagic manifestation /presentation; headache, loss of appetite, nausea, vomiting; rash; muscle pain, joint pain, orbital pain; lethargy; abdominal pain. No As per the MOH dengue surveillance guideline, in routine surveillance MAC-ELISA is conducted for at least 7% and virus isolation is conducted for at least 3% of clinical cases. In an outbreak, at least 5 to 10 suspected cases are tested. 11 Pacific Island Countries WHO dengue case classification (2009) † No Pacific Syndromic Surveillance System Confirmed case: Isolation of dengue virus or detection of dengue-specific antigen or antibodies in tissue, blood, CSF or other body fluid by an advanced laboratory test 12 Only the minimum criteria required for fulfilling a clinical dengue case definition are included here; additional signs and symptoms required for more severe forms are not listed. † A probable dengue case is defined as any case living in or travel to dengue endemic area with fever and two or more of the following: nausea, vomiting, rash, aches and pains, positive tourniquet test, leucopenia and any warning sign. A case with warning signs is defined as a clinically diagnosed case with any of the following: abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleed, lethargy, restlessness, liver enlargement > 2 cm and increase in haematocrit concurrent with rapid decrease in platelet count. Severe dengue is defined as severe plasma leakage leading to any of the following: shock, fluid accumulation with respiratory distress OR severe bleeding as evaluated by clinician OR severe organ involvement of liver (aspartate amino transferase or alanine amino transferase ≥ 1000), central nervous system (impaired consciousness) or heart and other organs.10 References: 1. Australian Government Department of Health AGDo. Dengue virus infection surveillance and case definition [updated 14 June 2022 and 1 January 2018 respectively] Available from: https://www.health.gov.au/diseases/dengue-virus-infection, and https://www.health.gov.au/sites/default/files/documents/2022/06/dengue-virus-infection-surveillance-case-definition.pdf 2. Cambodia Ministry of Health NCfP, Entomology and Malaria Control. National Guideline for Clinical Management of Dengue, 2018. 2018. Available from: https://niph.org.kh/niph/uploads/library/pdf/GL055_National_guideline_for_ClM_Dengue.pdf. 3. China CDC. Dengue surveillance guideline. Available from: https://www.chinacdc.cn/jkzt/crb/zl/dgr/jszl_2235/201810/P020181010391462131548.pdf 4. Khampapongpane B, Lewis HC, Ketmayoon P, Phonekeo D, Somoulay V, Khamsing A, et al. National dengue surveillance in the Lao People's Democratic Republic, 2006-2012: epidemiological and laboratory findings. Western Pac Surveill Response J. 2014;5(1):7-13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24734212. 5. Ministry of Health Malaysia DCD. Case definitions for infectious diseases in Malaysia. 2017. Available from: https://www.moh.gov.my/moh/resources/Penerbitan/Garis%20Panduan/Pengurusan%20KEsihatan%20&%20kawalan%20pykit/Case_Definition_Of_Infectious_Disease_3rd_Edition_2017.pdf 6. Secretary PDoHOot. Guidelines for the Nationwide Implementation of Dengue Rapid Diagnostic Test (RDT), Administrative order No.2016-0043. 2016(2016-0043). 7. Secretary PDoHOot. Revised Dengue Clinical Case Management Guidelines 2011, Administrative order No.2012-0006. 2012 22 March 2012. Report No. 8. Diseases SNCfI. Diseases and Conditions, Dengue 2020 [updated 14 September 2020. Available from: https://www.doh.gov.ph/Health-Advisory/Dengue. 9. National Centre for Infectious Diseases, Dengue. Available from: https://www.ncid.sg/Health-Professionals/Diseases-and-Conditions/Pages/Dengue.aspx 10. National Environment Agency. Surveillance and Epidemiology Programme [updated 21 April 2023]. Available from: https://www.nea.gov.sg/corporate-functions/resources/research/surveillance-and- epidemiology-programme#Ehi%20Diagnostics%20Unit Dengue Situation Update 699 │ 13 11. Viet Nam Ministry of Health VNMo. Circular 54/2015 / TT-BYT 2015 [updated 26 April 2016. Available from: https://syt.thuathienhue.gov.vn/?gd=27&cn=108&tc=3993. 12. Pacific Islands Outbreak Manual. Available from: https://www.pphsn.net/resources/outbreak-manual/ 13. WHO dengue outbreak toolbox. Available from: https://www.who.int/docs/default-source/outbreak-toolkit/updates-documents_july-5/dengue-outbreak-data-collection-toolbox---inis-3-july- 1.pdf?sfvrsn=ec3ffcf3_2
Dengue Situation Update 701 │ 1 Dengue Situation Update 701 27 June 2024 Update on the Dengue situation in the Western Pacific Region This report describes the epidemiology of dengue in the World Health Organization Western Pacific Region. Data are compiled from open sources (national indicator-based surveillance systems) with the exception of Cambodia, Lao People’s Democratic Republic, Viet Nam, and the Philippines, where data are provided by the WHO Country Offices. For the Pacific Island Countries, syndromic surveillance data are provided by the Division of Pacific Technical Support. Information is reported based on countries’ standard dengue case definitions, summary of these definitions and countries’ dengue surveillance systems - included as an annex to this report. Due to differences in surveillance methods and reporting practices, a comparison of trends between countries and areas is not possible, however, national trends can be observed over time. Northern Hemisphere Cambodia As of epidemiological week 24 of 2024, the National Dengue Surveillance System reported a total of 6 280 cases with 23 deaths (Case Fatality Rate (CFR) 0.37%) since 1 January 2024 (Figure 1). This is higher compared to the number reported in 2023 for the same period, with 4 730 cases and 9 deaths. Figure 1: Dengue cases reported weekly in 2024 vs endemic and epidemic alert lines in Cambodia; Source: National Dengue Surveillance System (NDCP/CNM/MOH) Dengue Situation Update 701 │ 2 China There is no update for this reporting period. There has been a total of 165 dengue cases and no death in the country since the beginning of 2024 (Figure 2). Figure 2: Dengue cases reported monthly from 2015-2024 (as of April) in China Source: National Disease Control and Prevention Administration, China Lao People’s Democratic Republic In epidemiological week 24 of 2024 (10 to 16 June 2024), 336 dengue cases and zero deaths were reported (Figure 3). The number of reported cases is higher than the numbers reported in epidemiological week 23 (302 cases with no deaths), and lower than those in week 24 of 2023 (671 cases with no deaths). The cumulative number of cases reported in 2024 (as of epidemiological week 24) is 3 897. This is a 10.5% decrease compared to the 4 355 cases reported during the same period in 2023. Figure 3: Dengue cases reported weekly from 2018-2024 in Lao PDR Source: National Centre for Laboratory and Epidemiology, Ministry of Health, Lao PDR Dengue Situation Update 701 │ 3 Malaysia During epidemiological week 24 of 2024 (9 to 15 June 2024), an increase of 392 cases (15.6%) was reported with 2 900 cases as compared to 2 508 cases reported in the previous week (Figure 4). The cumulative number of dengue cases reported up to week 24 of 2024 is 70 037 cases, which is an increase of 29.3% compared to 54 139 cases for the same period in 2023. 53 dengue-related deaths were reported up to week 24 of 2024, compared to 39 deaths for the same period in 2023. Figure 4: Dengue cases reported weekly from 2023, 2024 and median 2019-2023 in Malaysia Source: Department of Health, Malaysia Philippines There is no update for this reporting period. During epidemiological Week 48 (26 November to 2 December 2023), there were 2 607 new dengue cases reported, a 41% decrease compared to the same period in 2022 (n=4 415 cases) (Figure 5). As of 2 December 2023, a total of 195 603 dengue cases have been reported. The number of cases is 23% lower compared to the same period in 2022 (n=252 700). From 1 January to 2 December 2023, there have been 657 deaths (CFR 0.34%) as compared to 894 deaths (CFR 0.35%;) reported in the same period in 2022. Figure 5: Dengue cases reported weekly from 2022 and 2023 in the Philippines Source: Department of Health, the Philippines (Note: there is a 3-4 week systematic delay in reporting and numbers should be interpreted with caution) Dengue Situation Update 701 │ 4 Singapore In epidemiological week 24 (9 to 15 June 2024), a total of 306 dengue cases were reported in Singapore. Cumulatively, a total of 8 671 cases (Figure 6) have been reported as of 15 June 2024. When compared to the same period in 2023 (3 863 cases), there has been a 124% increase in cases reported in 2024. Preliminary results of all positive dengue samples serotyped in June 2024 showed DEN-1, DEN-2, DEN-3 and DEN-4 at 7.2%, 43.0%, 45.2% and 4.5% respectively. Figure 6: Dengue cases reported weekly from 2019-2024 (as of 15 June 2024) in Singapore Source: Communicable Diseases Division, Ministry of Health, Singapore (Note: Case numbers are derived from the MOH Singapore’s weekly-infectious-disease-bulletin-year-2024_upload as available from MOH | Weekly Infectious Diseases Bulletin) Viet Nam In epidemiological week 24 (10 to 16 June 2024), approximately 1 500 cases and no deaths were reported in Viet Nam. Cumulatively, approximately 25 000 dengue cases including three deaths have been reported as of 16 June 2024. Compared to the same period in 2023, the number of cumulative cases decreased by 32%, and the number of deaths decreased by six cases. Dengue Situation Update 701 │ 5 Southern Hemisphere Australia There is no update for this reporting period. In May 2024, a total of 273 dengue cases were reported in Australia. As of 31 May 2024, the cumulative number of dengue cases is 1 020, which is more than two times higher than the same period in 2023 (422 cases). (Figure 7). Figure 7: Laboratory-confirmed dengue cases reported monthly from 2016-2024 in Australia Source: Department of Health, Australia Note: Graph was updated as of 31 May 2024 Pacific Islands Countries New Caledonia There is no update for this reporting period. From 1 January to 29 February 2024, six confirmed dengue cases were reported in New Caledonia (Figure 8). This is higher compared to the same period in 2023, when a total of three dengue cases were reported. Of the six dengue cases in 2024, two were imported cases and two were probable cases. The serotypes of the cases were DENV-1 (3 cases), DENV-2 (1 case). Figure 8: Dengue cases reported by week from 2022 to 2024 in New Caledonia Source: Network of sentinel physicians, New Caledonia Dengue Situation Update 701 │ 6 Pacific Island Countries and Areas (PICs) – Dengue-like illness (DLI) Surveillance Among the PICs with available surveillance data (18/21 PICs), an upward trend of DLI cases was reported in Solomon Islands in week 24 (ending 16 June), and a downward trend of DLI cases was reported in Samoa in week 25 of 2024 (ending 23 June). The remaining PICs reported either no or low numbers of DLI cases or provided no updates (Figure 9). Dengue Situation Update 701 │ 7 Dengue Situation Update 701 │ 8 Figure 9. Reported cases of dengue-like illness in Pacific Islands Countries and Areas Source: WHO Division of Pacific Technical Support Note: Caution should be taken in interpreting these data as there may be changes in the number of sentinel sites reporting to the Pacific Syndromic Surveillance System (PSSS). Furthermore, the syndromic case definition of DLI may capture cases with non- dengue acute febrile illnesses (AFI) with similar clinical manifestations to dengue. This includes AFI such as chikungunya, influenza, hantavirus, leptospirosis, malaria, measles, paratyphoid and typhoid fevers, scrub typhus, yellow fever, zika, other diseases. The PSSS may also capture dengue cases under ‘prolonged fever’ surveillance. Alert threshold for DLI is twice the average number of cases seen in the previous 3 weeks. Dengue Situation Update 701 │ 9 Annex 1. Summary of dengue case definitions, laboratory sampling and testing methods used for surveillance in Member States as of 2024 Country Case definition Surveillance system Laboratory sampling and testing method Reference Clinically confirmed case Laboratory confirmation required Description Australia Fever, headache, arthralgia, myalgia, rash, nausea and vomiting Yes Dengue is a nationally notifiable disease and cases are monitored through the National Notifiable Diseases Surveillance System (NNDSS) indicator-based surveillance system. Both confirmed and probable cases are nationally notifiable. A confirmed case requires both laboratory definitive evidence and clinical evidence. A probable case requires either laboratory suggestive evidence and clinical evidence and epidemiological evidence, or clinical evidence and household epidemiological evidence. Laboratory definitive evidence: - Isolation of dengue virus, or - Detection of dengue virus by nucleic acid testing, or - Detection of NS1 antigen in the blood by EIA, or - IgG seroconversion or significant increase in antibody levelor fourfold or greater rise in titre to dengue virus (proof by neutralization or another specific test) - Detection of dengue virus-specific IgM in cerebrospinal fluid, in the absence of IgM to Murray valley encephalitis, West Nile virus/Kunjin, or Japanese encephalitis viruses. Laboratory suggestive evidence: - Detection of NS1 antigen in blood by rapid antigen test, or - Detection of dengue virus-specific IgM in blood Epidemiological evidence: - Exposure between 3 – 14 days prior to onset either in a country with known dengue activity or in a dengue-receptive area in Australia where a locally-acquired or imported case has been documented with onset within a month. 1 Dengue Situation Update 701 │ 10 Household epidemiological evidence: - Living in the same house as a locally- acquired case in a dengue-receptive area of Australia within a month of onse in the case and at least one case in the chain of epidemiologically linked cases is laboratory confirmed. Cambodia Suspected dengue: very high fever at 39-40 degrees celcius for 2-7 days (usually 3-4 days), with 2 or more of the following signs: flushed face, headache, retro-orbital pain, myalgia/arthralgia, cutaneous rash, haemorrhagic signs (petechiae, positive tourniquet test), and leucopenia. Probable dengue: signs of suspected dengue plus laboratory test results (see right column)) or that the case occurred in an area where the dengue case has been confirmed. Yes National Dengue Control Program (NDCP) enhanced sentinel surveillance system Communicable Disease Control (CDC) syndromic surveillance system (CamEWARN). Health Management Information System (HMIS) collects data on confirmed cases and deaths. Data collected for Cambodia Laboratory Information System (CamLIS), comprised of 32 participating hospital laboratories where NS1 detection is conducted. Laboratory testing: Antibody HI>= 1/1280 or IgM/IgG positive by ELISA test in convalescence serum 2 China 1) Typical dengue fever can be diagnosed with any of the following conditions: - General clinical symptoms of dengue fever, with an epidemiological history (having been to an area where dengue fever is prevalent within 14 days before onset), or living or working in an area where dengue fever cases have occurred within the past month, and with reduced white blood cell count and platelet count (below 100x10^9/L) - No epidemiological history, but with a rash, bleeding tendency, and positive IgG or IgM antibodies in a single serum sample. No Reported to the Chinese Centre for Disease Control and Prevention (China CDC) through the Chinese National Notifiable Infectious Disease Reporting Information System (CNNDS). A clinically diagnosed case with any of the of the following laboratory findings: - Isolation of the dengue virus from the serum, cerebrospinal fluid, blood cells, or tissues of an acute-phase patient - Detection of dengue virus gene sequence by RT-PCR or real-time fluorescent quantitative PCR - Detection of dengue virus NS1 antigen in serum from an acute-phase patient - A fourfold or greater increase in specific antibody titer in the convalescent phase compared to the acute phase. 3, WHO internal communication Dengue Situation Update 701 │ 11 2) Dengue Hemorrhagic Fever can be diagnosed when accompanied by any of the following clinical symptoms: - Bleeding tendency, significant bleeding manifestations (such as gastrointestinal bleeding or hemorrhage in the chest, abdomen, or cranium), hepatomegaly, and ascites; and - Laboratory findings including thrombocytopenia (platelet count below 100x10^9/L), hemoconcentration (an increase in hematocrit of more than 20% above normal levels or a decrease of more than 20% after fluid resuscitation), and hypoalbuminemia. 3) Dengue Shock Syndrome: Patients with dengue hemorrhagic fever presenting with cold and clammy skin, restlessness, rapid and weak pulse, low blood pressure with a narrow pulse pressure (less than 20mmHg or 2.7kPa), and reduced urine output. Lao People's Democratic Republic WHO dengue case classification (2009) † No National Surveillance System for Notifiable Selected Diseases, indicator-based surveillance system that consists of passive weekly reports of clinically suspected cases, on admission, from all health-care facilities across the country. 4 Malaysia WHO dengue case classification (2009) † Yes National Dengue Surveillance System, indicator-based surveillance system All suspected cases are to be tested by the following laboratory tests: Rapid Combo Test (RCT) (NS1, IgM, IgG), Dengue Antigen and Serology tests by ELISA, Dengue Viral RNA Detection (Real time RT-PCR), Viral Isolation 5 Philippines WHO dengue case classification (2009) † Yes Philippine Integrated Disease Surveillance and Response (PIDSR), indicator-based surveillance system. Reporting delays of 2-3 weeks, making comparison of current weekly and cumulative figures with previous years difficult. Confirmed dengue is a suspect case with positive (+) viral culture isolation and/or PCR. NS1 (+), IgM is used to identify probable dengue. 6, 7, 8 Dengue Situation Update 701 │ 12 Singapore (endemic) Fever, headache, backache, myalgia, rash, abdominal discomfort and thrombocytopenia and laboratory testing (see right column) Yes Dengue is a legally notifiable disease in Singapore and notifying the Ministry of Health should not be later than 24 hours from the time of diagnosis. Laboratory confirmation is done using standard diagnostic tests for the detection of dengue NS1 antigen, IgM and IgG, or RT-PCR. 9, 10 Viet Nam (endemic) Acute onset of fever continuously lasting from 2-7 days AND at least 2 of the following: haemorrhagic manifestation /presentation; headache, loss of appetite, nausea, vomiting; rash; muscle pain, joint pain, orbital pain; lethargy; abdominal pain. No As per the MOH dengue surveillance guideline, in routine surveillance MAC-ELISA is conducted for at least 7% and virus isolation is conducted for at least 3% of clinical cases. In an outbreak, at least 5 to 10 suspected cases are tested. 11 Pacific Island Countries WHO dengue case classification (2009) † No Pacific Syndromic Surveillance System Confirmed case: Isolation of dengue virus or detection of dengue-specific antigen or antibodies in tissue, blood, CSF or other body fluid by an advanced laboratory test 12 Only the minimum criteria required for fulfilling a clinical dengue case definition are included here; additional signs and symptoms required for more severe forms are not listed. † A probable dengue case is defined as any case living in or travel to dengue endemic area with fever and two or more of the following: nausea, vomiting, rash, aches and pains, positive tourniquet test, leucopenia and any warning sign. A case with warning signs is defined as a clinically diagnosed case with any of the following: abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleed, lethargy, restlessness, liver enlargement > 2 cm and increase in haematocrit concurrent with rapid decrease in platelet count. Severe dengue is defined as severe plasma leakage leading to any of the following: shock, fluid accumulation with respiratory distress OR severe bleeding as evaluated by clinician OR severe organ involvement of liver (aspartate amino transferase or alanine amino transferase ≥ 1000), central nervous system (impaired consciousness) or heart and other organs.10 References: 1. Australian Government Department of Health AGDo. Dengue virus infection surveillance and case definition [updated 14 June 2022 and 1 January 2018 respectively] Available from: https://www.health.gov.au/diseases/dengue-virus-infection, and https://www.health.gov.au/sites/default/files/documents/2022/06/dengue-virus-infection-surveillance-case-definition.pdf 2. Cambodia Ministry of Health NCfP, Entomology and Malaria Control. National Guideline for Clinical Management of Dengue, 2018. 2018. Available from: https://niph.org.kh/niph/uploads/library/pdf/GL055_National_guideline_for_ClM_Dengue.pdf. 3. China CDC. Dengue surveillance guideline. Available from: https://www.chinacdc.cn/jkzt/crb/zl/dgr/jszl_2235/201810/P020181010391462131548.pdf 4. Khampapongpane B, Lewis HC, Ketmayoon P, Phonekeo D, Somoulay V, Khamsing A, et al. National dengue surveillance in the Lao People's Democratic Republic, 2006-2012: epidemiological and laboratory findings. Western Pac Surveill Response J. 2014;5(1):7-13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24734212. 5. Ministry of Health Malaysia DCD. Case definitions for infectious diseases in Malaysia. 2017. Available from: https://www.moh.gov.my/moh/resources/Penerbitan/Garis%20Panduan/Pengurusan%20KEsihatan%20&%20kawalan%20pykit/Case_Definition_Of_Infectious_Disease_3rd_Edition_2017.pdf 6. Secretary PDoHOot. Guidelines for the Nationwide Implementation of Dengue Rapid Diagnostic Test (RDT), Administrative order No.2016-0043. 2016(2016-0043). 7. Secretary PDoHOot. Revised Dengue Clinical Case Management Guidelines 2011, Administrative order No.2012-0006. 2012 22 March 2012. Report No. 8. Diseases SNCfI. Diseases and Conditions, Dengue 2020 [updated 14 September 2020. Available from: https://www.doh.gov.ph/Health-Advisory/Dengue. 9. National Centre for Infectious Diseases, Dengue. Available from: https://www.ncid.sg/Health-Professionals/Diseases-and-Conditions/Pages/Dengue.aspx 10. National Environment Agency. Surveillance and Epidemiology Programme [updated 21 April 2023]. Available from: https://www.nea.gov.sg/corporate-functions/resources/research/surveillance-and- epidemiology-programme#Ehi%20Diagnostics%20Unit Dengue Situation Update 701 │ 13 11. Viet Nam Ministry of Health VNMo. Circular 54/2015 / TT-BYT 2015 [updated 26 April 2016. Available from: https://syt.thuathienhue.gov.vn/?gd=27&cn=108&tc=3993. 12. Pacific Islands Outbreak Manual. Available from: https://www.pphsn.net/resources/outbreak-manual/ 13. WHO dengue outbreak toolbox. Available from: https://www.who.int/docs/default-source/outbreak-toolkit/updates-documents_july-5/dengue-outbreak-data-collection-toolbox---inis-3-july- 1.pdf?sfvrsn=ec3ffcf3_2
Dengue Situation Update 702 │ 1 Dengue Situation Update 702 11 July 2024 Update on the Dengue situation in the Western Pacific Region This report describes the epidemiology of dengue in the World Health Organization Western Pacific Region. Data are compiled from open sources (national indicator-based surveillance systems) with the exception of Cambodia, Lao People’s Democratic Republic, Viet Nam, and the Philippines, where data are provided by the WHO Country Offices. For the Pacific Island Countries, syndromic surveillance data are provided by the Division of Pacific Technical Support. Information is reported based on countries’ standard dengue case definitions, summary of these definitions and countries’ dengue surveillance systems - included as an annex to this report. Due to differences in surveillance methods and reporting practices, a comparison of trends between countries and areas is not possible, however, national trends can be observed over time. Northern Hemisphere Cambodia As of epidemiological week 26 of 2024, the National Dengue Surveillance System reported a total of 6 742 cases with 23 deaths (Case Fatality Rate (CFR) 0.34%) since 1 January 2024 (Figure 1). This is higher compared to the number reported in 2023 for the same period, with 6 688 cases and 14 deaths. Figure 1: Dengue cases reported weekly in 2024 vs endemic and epidemic alert lines in Cambodia; Source: National Dengue Surveillance System (NDCP/CNM/MOH) Dengue Situation Update 702 │ 2 China There has been a total of 274 dengue cases and no death reported since the beginning of 2024 (Figure 2). Figure 2: Dengue cases reported monthly from 2015-2024 (as of May) in China Source: National Disease Control and Prevention Administration, China Lao People’s Democratic Republic In epidemiological week 26 of 2024 (24 to 30 June 2024), 605 dengue cases and zero deaths were reported (Figure 3). The number of reported cases is higher than the numbers reported in epidemiological week 25 (443 cases with no deaths), and lower than those in week 26 of 2023 (1 281 cases with three deaths). The cumulative number of cases reported in 2024 (as of epidemiological week 26) is 4 945. This is a 25.0% decrease compared to the 6 591 cases reported during the same period in 2023. Figure 3: Dengue cases reported weekly from 2018-2024 in Lao PDR Source: National Centre for Laboratory and Epidemiology, Ministry of Health, Lao PDR Dengue Situation Update 702 │ 3 Malaysia During epidemiological week 26 of 2024 (23 to 29 June 2024), an increase of 350 cases (14.4%) was reported with 2 788 cases as compared to 2 438 cases reported in the previous week (Figure 4). The cumulative number of dengue cases reported up to week 26 of 2024 is 75 263 cases, which is an increase of 27.4% compared to 59 057 cases for the same period in 2023. 60 dengue-related deaths were reported up to week 26 of 2024, compared to 40 deaths for the same period in 2023. Figure 4: Dengue cases reported weekly from 2023, 2024 and median 2019-2023 in Malaysia Source: Department of Health, Malaysia Philippines There is no update for this reporting period. During epidemiological Week 48 (26 November to 2 December 2023), there were 2 607 new dengue cases reported, a 41% decrease compared to the same period in 2022 (n=4 415 cases) (Figure 5). As of 2 December 2023, a total of 195 603 dengue cases have been reported. The number of cases is 23% lower compared to the same period in 2022 (n=252 700). From 1 January to 2 December 2023, there have been 657 deaths (CFR 0.34%) as compared to 894 deaths (CFR 0.35%;) reported in the same period in 2022. Figure 5: Dengue cases reported weekly from 2022 and 2023 in the Philippines Source: Department of Health, the Philippines (Note: there is a 3-4 week systematic delay in reporting and numbers should be interpreted with caution) Dengue Situation Update 702 │ 4 Singapore In epidemiological week 26 (23 to 29 June 2024), a total of 292 dengue cases were reported in Singapore. Cumulatively, a total of 9 257 cases (Figure 6) have been reported as of 29 June 2024. When compared to the same period in 2023 (4 349 cases), there has been a 123% increase in cases reported in 2024. Preliminary results of all positive dengue samples serotyped in June 2024 showed DEN-1, DEN-2, DEN-3 and DEN-4 at 8.3%, 52.8%, 33.5% and 5.4% respectively. Figure 6: Dengue cases reported weekly from 2019-2024 (as of 29 June 2024) in Singapore Source: Communicable Diseases Division, Ministry of Health, Singapore (Note: Case numbers are derived from the MOH Singapore’s weekly-infectious-disease-bulletin-year-2024_upload as available from MOH | Weekly Infectious Diseases Bulletin) Viet Nam There is no update for this reporting period. In epidemiological week 24 (10 to 16 June 2024), approximately 1 500 cases and no deaths were reported in Viet Nam. Cumulatively, approximately 25 000 dengue cases including three deaths have been reported as of 16 June 2024. Compared to the same period in 2023, the number of cumulative cases decreased by 32%, and the number of deaths decreased by six cases. Dengue Situation Update 702 │ 5 Southern Hemisphere Australia In June 2024, a total of 195 dengue cases were reported in Australia. As of 30 June 2024, the cumulative number of dengue cases is 1 282, which is more than 2.5 times higher than the same period in 2023 (496 cases). (Figure 7). Figure 7: Laboratory-confirmed dengue cases reported monthly from 2016-2024 in Australia Source: Department of Health, Australia Note: Graph was updated as of 30 June 2024 Pacific Islands Countries New Caledonia From 1 January to 30 June 2024, eight confirmed dengue cases were reported in New Caledonia (Figure 8). This is higher compared to the same period in 2023, when a total of five dengue cases were reported. Of the eight dengue cases in 2024, two were locally acquired confirmed cases, and the serotypes of the cases were DENV-1 and DENV-2, respectively. There is no ongoing epidemic. Figure 8: Dengue cases reported by month from 2022 to 2024 in New Caledonia Source: Network of sentinel physicians, New Caledonia Dengue Situation Update 702 │ 6 Pacific Island Countries and Areas (PICs) – Dengue-like illness (DLI) Surveillance Among the PICs with available surveillance data (18/21 PICs), an upward trend of DLI cases was reported in Vanuatu in week 26 (ending 30 June), and a downward trend of DLI cases was reported in Fiji (week 26) and Samoa (week 27). The remaining PICs reported either no or low numbers of DLI cases or provided no updates (Figure 9). Dengue Situation Update 702 │ 7 Dengue Situation Update 702 │ 8 Figure 9. Reported cases of dengue-like illness in Pacific Islands Countries and Areas Source: WHO Division of Pacific Technical Support Note: Caution should be taken in interpreting these data as there may be changes in the number of sentinel sites reporting to the Pacific Syndromic Surveillance System (PSSS). Furthermore, the syndromic case definition of DLI may capture cases with non- dengue acute febrile illnesses (AFI) with similar clinical manifestations to dengue. This includes AFI such as chikungunya, influenza, hantavirus, leptospirosis, malaria, measles, paratyphoid and typhoid fevers, scrub typhus, yellow fever, zika, other diseases. The PSSS may also capture dengue cases under ‘prolonged fever’ surveillance. Alert threshold for DLI is twice the average number of cases seen in the previous 3 weeks. Dengue Situation Update 702 │ 9 Annex 1. Summary of dengue case definitions, laboratory sampling and testing methods used for surveillance in Member States as of 2024 Country Case definition Surveillance system Laboratory sampling and testing method Reference Clinically confirmed case Laboratory confirmation required Description Australia Fever, headache, arthralgia, myalgia, rash, nausea and vomiting Yes Dengue is a nationally notifiable disease and cases are monitored through the National Notifiable Diseases Surveillance System (NNDSS) indicator-based surveillance system. Both confirmed and probable cases are nationally notifiable. A confirmed case requires both laboratory definitive evidence and clinical evidence. A probable case requires either laboratory suggestive evidence and clinical evidence and epidemiological evidence, or clinical evidence and household epidemiological evidence. Laboratory definitive evidence: - Isolation of dengue virus, or - Detection of dengue virus by nucleic acid testing, or - Detection of NS1 antigen in the blood by EIA, or - IgG seroconversion or significant increase in antibody levelor fourfold or greater rise in titre to dengue virus (proof by neutralization or another specific test) - Detection of dengue virus-specific IgM in cerebrospinal fluid, in the absence of IgM to Murray valley encephalitis, West Nile virus/Kunjin, or Japanese encephalitis viruses. Laboratory suggestive evidence: - Detection of NS1 antigen in blood by rapid antigen test, or - Detection of dengue virus-specific IgM in blood Epidemiological evidence: - Exposure between 3 – 14 days prior to onset either in a country with known dengue activity or in a dengue-receptive area in Australia where a locally-acquired or imported case has been documented with onset within a month. 1 Dengue Situation Update 702 │ 10 Household epidemiological evidence: - Living in the same house as a locally- acquired case in a dengue-receptive area of Australia within a month of onse in the case and at least one case in the chain of epidemiologically linked cases is laboratory confirmed. Cambodia Suspected dengue: very high fever at 39-40 degrees celcius for 2-7 days (usually 3-4 days), with 2 or more of the following signs: flushed face, headache, retro-orbital pain, myalgia/arthralgia, cutaneous rash, haemorrhagic signs (petechiae, positive tourniquet test), and leucopenia. Probable dengue: signs of suspected dengue plus laboratory test results (see right column)) or that the case occurred in an area where the dengue case has been confirmed. Yes National Dengue Control Program (NDCP) enhanced sentinel surveillance system Communicable Disease Control (CDC) syndromic surveillance system (CamEWARN). Health Management Information System (HMIS) collects data on confirmed cases and deaths. Data collected for Cambodia Laboratory Information System (CamLIS), comprised of 32 participating hospital laboratories where NS1 detection is conducted. Laboratory testing: Antibody HI>= 1/1280 or IgM/IgG positive by ELISA test in convalescence serum 2 China 1) Typical dengue fever can be diagnosed with any of the following conditions: - General clinical symptoms of dengue fever, with an epidemiological history (having been to an area where dengue fever is prevalent within 14 days before onset), or living or working in an area where dengue fever cases have occurred within the past month, and with reduced white blood cell count and platelet count (below 100x10^9/L) - No epidemiological history, but with a rash, bleeding tendency, and positive IgG or IgM antibodies in a single serum sample. No Reported to the Chinese Centre for Disease Control and Prevention (China CDC) through the Chinese National Notifiable Infectious Disease Reporting Information System (CNNDS). A clinically diagnosed case with any of the of the following laboratory findings: - Isolation of the dengue virus from the serum, cerebrospinal fluid, blood cells, or tissues of an acute-phase patient - Detection of dengue virus gene sequence by RT-PCR or real-time fluorescent quantitative PCR - Detection of dengue virus NS1 antigen in serum from an acute-phase patient - A fourfold or greater increase in specific antibody titer in the convalescent phase compared to the acute phase. 3, WHO internal communication Dengue Situation Update 702 │ 11 2) Dengue Hemorrhagic Fever can be diagnosed when accompanied by any of the following clinical symptoms: - Bleeding tendency, significant bleeding manifestations (such as gastrointestinal bleeding or hemorrhage in the chest, abdomen, or cranium), hepatomegaly, and ascites; and - Laboratory findings including thrombocytopenia (platelet count below 100x10^9/L), hemoconcentration (an increase in hematocrit of more than 20% above normal levels or a decrease of more than 20% after fluid resuscitation), and hypoalbuminemia. 3) Dengue Shock Syndrome: Patients with dengue hemorrhagic fever presenting with cold and clammy skin, restlessness, rapid and weak pulse, low blood pressure with a narrow pulse pressure (less than 20mmHg or 2.7kPa), and reduced urine output. Lao People's Democratic Republic WHO dengue case classification (2009) † No National Surveillance System for Notifiable Selected Diseases, indicator-based surveillance system that consists of passive weekly reports of clinically suspected cases, on admission, from all health-care facilities across the country. 4 Malaysia WHO dengue case classification (2009) † Yes National Dengue Surveillance System, indicator-based surveillance system All suspected cases are to be tested by the following laboratory tests: Rapid Combo Test (RCT) (NS1, IgM, IgG), Dengue Antigen and Serology tests by ELISA, Dengue Viral RNA Detection (Real time RT-PCR), Viral Isolation 5 Philippines WHO dengue case classification (2009) † Yes Philippine Integrated Disease Surveillance and Response (PIDSR), indicator-based surveillance system. Reporting delays of 2-3 weeks, making comparison of current weekly and cumulative figures with previous years difficult. Confirmed dengue is a suspect case with positive (+) viral culture isolation and/or PCR. NS1 (+), IgM is used to identify probable dengue. 6, 7, 8 Dengue Situation Update 702 │ 12 Singapore (endemic) Fever, headache, backache, myalgia, rash, abdominal discomfort and thrombocytopenia and laboratory testing (see right column) Yes Dengue is a legally notifiable disease in Singapore and notifying the Ministry of Health should not be later than 24 hours from the time of diagnosis. Laboratory confirmation is done using standard diagnostic tests for the detection of dengue NS1 antigen, IgM and IgG, or RT-PCR. 9, 10 Viet Nam (endemic) Acute onset of fever continuously lasting from 2-7 days AND at least 2 of the following: haemorrhagic manifestation /presentation; headache, loss of appetite, nausea, vomiting; rash; muscle pain, joint pain, orbital pain; lethargy; abdominal pain. No As per the MOH dengue surveillance guideline, in routine surveillance MAC-ELISA is conducted for at least 7% and virus isolation is conducted for at least 3% of clinical cases. In an outbreak, at least 5 to 10 suspected cases are tested. 11 Pacific Island Countries WHO dengue case classification (2009) † No Pacific Syndromic Surveillance System Confirmed case: Isolation of dengue virus or detection of dengue-specific antigen or antibodies in tissue, blood, CSF or other body fluid by an advanced laboratory test 12 Only the minimum criteria required for fulfilling a clinical dengue case definition are included here; additional signs and symptoms required for more severe forms are not listed. † A probable dengue case is defined as any case living in or travel to dengue endemic area with fever and two or more of the following: nausea, vomiting, rash, aches and pains, positive tourniquet test, leucopenia and any warning sign. A case with warning signs is defined as a clinically diagnosed case with any of the following: abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleed, lethargy, restlessness, liver enlargement > 2 cm and increase in haematocrit concurrent with rapid decrease in platelet count. Severe dengue is defined as severe plasma leakage leading to any of the following: shock, fluid accumulation with respiratory distress OR severe bleeding as evaluated by clinician OR severe organ involvement of liver (aspartate amino transferase or alanine amino transferase ≥ 1000), central nervous system (impaired consciousness) or heart and other organs.10 References: 1. Australian Government Department of Health AGDo. Dengue virus infection surveillance and case definition [updated 14 June 2022 and 1 January 2018 respectively] Available from: https://www.health.gov.au/diseases/dengue-virus-infection, and https://www.health.gov.au/sites/default/files/documents/2022/06/dengue-virus-infection-surveillance-case-definition.pdf 2. Cambodia Ministry of Health NCfP, Entomology and Malaria Control. National Guideline for Clinical Management of Dengue, 2018. 2018. Available from: https://niph.org.kh/niph/uploads/library/pdf/GL055_National_guideline_for_ClM_Dengue.pdf. 3. China CDC. Dengue surveillance guideline. Available from: https://www.chinacdc.cn/jkzt/crb/zl/dgr/jszl_2235/201810/P020181010391462131548.pdf 4. Khampapongpane B, Lewis HC, Ketmayoon P, Phonekeo D, Somoulay V, Khamsing A, et al. National dengue surveillance in the Lao People's Democratic Republic, 2006-2012: epidemiological and laboratory findings. Western Pac Surveill Response J. 2014;5(1):7-13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24734212. 5. Ministry of Health Malaysia DCD. Case definitions for infectious diseases in Malaysia. 2017. Available from: https://www.moh.gov.my/moh/resources/Penerbitan/Garis%20Panduan/Pengurusan%20KEsihatan%20&%20kawalan%20pykit/Case_Definition_Of_Infectious_Disease_3rd_Edition_2017.pdf 6. Secretary PDoHOot. Guidelines for the Nationwide Implementation of Dengue Rapid Diagnostic Test (RDT), Administrative order No.2016-0043. 2016(2016-0043). 7. Secretary PDoHOot. Revised Dengue Clinical Case Management Guidelines 2011, Administrative order No.2012-0006. 2012 22 March 2012. Report No. 8. Diseases SNCfI. Diseases and Conditions, Dengue 2020 [updated 14 September 2020. Available from: https://www.doh.gov.ph/Health-Advisory/Dengue. 9. National Centre for Infectious Diseases, Dengue. Available from: https://www.ncid.sg/Health-Professionals/Diseases-and-Conditions/Pages/Dengue.aspx 10. National Environment Agency. Surveillance and Epidemiology Programme [updated 21 April 2023]. Available from: https://www.nea.gov.sg/corporate-functions/resources/research/surveillance-and- epidemiology-programme#Ehi%20Diagnostics%20Unit Dengue Situation Update 702 │ 13 11. Viet Nam Ministry of Health VNMo. Circular 54/2015 / TT-BYT 2015 [updated 26 April 2016. Available from: https://syt.thuathienhue.gov.vn/?gd=27&cn=108&tc=3993. 12. Pacific Islands Outbreak Manual. Available from: https://www.pphsn.net/resources/outbreak-manual/ 13. WHO dengue outbreak toolbox. Available from: https://www.who.int/docs/default-source/outbreak-toolkit/updates-documents_july-5/dengue-outbreak-data-collection-toolbox---inis-3-july- 1.pdf?sfvrsn=ec3ffcf3_2
Dengue Situation Update 703 │ 1 Dengue Situation Update 703 25 July 2024 Update on the Dengue situation in the Western Pacific Region This report describes the epidemiology of dengue in the World Health Organization Western Pacific Region. Data are compiled from open sources (national indicator-based surveillance systems) with the exception of Cambodia, Lao People’s Democratic Republic, Viet Nam, and the Philippines, where data are provided by the WHO Country Offices. For the Pacific Island Countries, syndromic surveillance data are provided by the Division of Pacific Technical Support. Information is reported based on countries’ standard dengue case definitions, summary of these definitions and countries’ dengue surveillance systems - included as an annex to this report. Due to differences in surveillance methods and reporting practices, a comparison of trends between countries and areas is not possible, however, national trends can be observed over time. Northern Hemisphere Cambodia As of epidemiological week 27 of 2024, the National Dengue Surveillance System reported a total of 7 058 cases with 24 deaths (Case Fatality Rate (CFR) 0.34%) since 1 January 2024 (Figure 1). This is lower compared to the number reported in 2023 for the same period, with 7 838 cases and 18 deaths. Figure 1: Dengue cases reported weekly in 2024 vs endemic and epidemic alert lines in Cambodia; Source: National Dengue Surveillance System (NDCP/CNM/MOH) Dengue Situation Update 703 │ 2 China There is no update for this reporting period. There has been a total of 274 dengue cases and no death reported since the beginning of 2024 (Figure 2). Figure 2: Dengue cases reported monthly from 2015-2024 (as of May) in China Source: National Disease Control and Prevention Administration, China Lao People’s Democratic Republic In epidemiological week 28 of 2024 (8 to 14 July 2024), 890 dengue cases and zero deaths were reported (Figure 3). The number of reported cases is higher than the numbers reported in epidemiological week 27 (818 cases with three deaths), and lower than those in week 28 of 2023 (2 037 cases with one death). The cumulative number of cases reported in 2024 (as of epidemiological week 26) is 6 653. This is a 34.9% decrease compared to the 10 212 cases reported during the same period in 2023. Figure 3: Dengue cases reported weekly from 2018-2024 in Lao PDR Source: National Centre for Laboratory and Epidemiology, Ministry of Health, Lao PDR Dengue Situation Update 703 │ 3 Malaysia During epidemiological week 28 of 2024 (7 to 13 July 2024), a decrease of 432 cases (14.4%) was reported with 2 373 cases as compared to 2 805 cases reported in the previous week (Figure 4). The cumulative number of dengue cases reported up to week 28 of 2024 is 80 441 cases, which is an increase of 25.8% compared to 63 966 cases for the same period in 2023. 65 dengue-related deaths were reported up to week 28 of 2024, compared to 45 deaths for the same period in 2023. Figure 4: Dengue cases reported weekly from 2023, 2024 and median 2019-2023 in Malaysia Source: Department of Health, Malaysia Philippines There is no update for this reporting period. During epidemiological Week 48 (26 November to 2 December 2023), there were 2 607 new dengue cases reported, a 41% decrease compared to the same period in 2022 (n=4 415 cases) (Figure 5). As of 2 December 2023, a total of 195 603 dengue cases have been reported. The number of cases is 23% lower compared to the same period in 2022 (n=252 700). From 1 January to 2 December 2023, there have been 657 deaths (CFR 0.34%) as compared to 894 deaths (CFR 0.35%;) reported in the same period in 2022. Figure 5: Dengue cases reported weekly from 2022 and 2023 in the Philippines Source: Department of Health, the Philippines (Note: there is a 3-4 week systematic delay in reporting and numbers should be interpreted with caution) Dengue Situation Update 703 │ 4 Singapore In epidemiological week 28 (7 to 13 July 2024), a total of 291 dengue cases were reported in Singapore. Cumulatively, a total of 9 874 cases (Figure 6) have been reported as of 13 July 2024. When compared to the same period in 2023 (4 792 cases), there has been a 106% increase in cases reported in 2024. Preliminary results of all positive dengue samples serotyped in June 2024 showed DEN-1, DEN-2, DEN-3 and DEN-4 at 8.5%, 52.2%, 33.2% and 6.1% respectively. Figure 6: Dengue cases reported weekly from 2019-2024 (as of 13 July 2024) in Singapore Source: Communicable Diseases Division, Ministry of Health, Singapore (Note: Case numbers are derived from the MOH Singapore’s weekly-infectious-disease-bulletin-year-2024_upload as available from MOH | Weekly Infectious Diseases Bulletin) Viet Nam In epidemiological week 29 (15 to 21 July 2024), a total of 2 957 cases and no deaths were reported in Viet Nam, a decrease by 2.9% compared to 3 044 cases in the previous week. Cumulatively, 39 940 dengue cases including three deaths have been reported as of 21 July 2024. Compared to the same period in 2023, the number of cumulative cases decreased by 30.4%, and the number of deaths decreased by eight cases. Figure 7: Number of dengue hospital admissions and deaths by week in 2024 compared to 2023, as of week 29, 2024, Viet Nam Source: General Department of Preventive Medicine, Ministry of Health, Viet Nam Note hospitalizations include inpatients and outpatients The alert threshold is a 5-year mean plus 2 standard deviations. Dengue Situation Update 703 │ 5 Southern Hemisphere Australia In June 2024, a total of 232 dengue cases were reported in Australia. As of 30 June 2024, the cumulative number of dengue cases is 1 336, which is more than 2.5 times higher than the same period in 2023 (496 cases). (Figure 7). Figure 7: Laboratory-confirmed dengue cases reported monthly from 2016-2024 in Australia Source: Department of Health, Australia Note: Graph was updated as of 30 June 2024 Pacific Islands Countries New Caledonia There is no update for this reporting period. From 1 January to 30 June 2024, eight confirmed dengue cases were reported in New Caledonia (Figure 8). This is higher compared to the same period in 2023, when a total of five dengue cases were reported. Of the eight dengue cases in 2024, two were locally acquired confirmed cases, and the serotypes of the cases were DENV-1 and DENV-2, respectively. There is no ongoing epidemic. Figure 8: Dengue cases reported by month from 2022 to 2024 in New Caledonia Source: Network of sentinel physicians, New Caledonia Dengue Situation Update 703 │ 6 Pacific Island Countries and Areas (PICs) – Dengue-like illness (DLI) Surveillance Among the PICs with available surveillance data (18/21 PICs), an upward trend of DLI cases was reported in French Polynesia in week 28 (ending 14 July), and a downward trend of DLI cases was reported in Fiji, Samoa and Vanuatu. The remaining PICs reported either no or low numbers of DLI cases or provided no updates (Figure 9). Dengue Situation Update 703 │ 7 Dengue Situation Update 703 │ 8 Figure 9. Reported cases of dengue-like illness in Pacific Islands Countries and Areas Source: WHO Division of Pacific Technical Support Note: Caution should be taken in interpreting these data as there may be changes in the number of sentinel sites reporting to the Pacific Syndromic Surveillance System (PSSS). Furthermore, the syndromic case definition of DLI may capture cases with non- dengue acute febrile illnesses (AFI) with similar clinical manifestations to dengue. This includes AFI such as chikungunya, influenza, hantavirus, leptospirosis, malaria, measles, paratyphoid and typhoid fevers, scrub typhus, yellow fever, zika, other diseases. The PSSS may also capture dengue cases under ‘prolonged fever’ surveillance. Alert threshold for DLI is twice the average number of cases seen in the previous 3 weeks. Dengue Situation Update 703 │ 9 Annex 1. Summary of dengue case definitions, laboratory sampling and testing methods used for surveillance in Member States Country Case definition Surveillance system Laboratory sampling and testing method Reference Clinically confirmed case Laboratory confirmation required Description Australia Fever, headache, arthralgia, myalgia, rash, nausea and vomiting Yes Dengue is a nationally notifiable disease and cases are monitored through the National Notifiable Diseases Surveillance System (NNDSS) indicator-based surveillance system. Both confirmed and probable cases are nationally notifiable. A confirmed case requires both laboratory definitive evidence and clinical evidence. A probable case requires either laboratory suggestive evidence and clinical evidence and epidemiological evidence, or clinical evidence and household epidemiological evidence. Laboratory definitive evidence: - Isolation of dengue virus, or - Detection of dengue virus by nucleic acid testing, or - Detection of NS1 antigen in the blood by EIA, or - IgG seroconversion or significant increase in antibody levelor fourfold or greater rise in titre to dengue virus (proof by neutralization or another specific test) - Detection of dengue virus-specific IgM in cerebrospinal fluid, in the absence of IgM to Murray valley encephalitis, West Nile virus/Kunjin, or Japanese encephalitis viruses. Laboratory suggestive evidence: - Detection of NS1 antigen in blood by rapid antigen test, or - Detection of dengue virus-specific IgM in blood Epidemiological evidence: - Exposure between 3 – 14 days prior to onset either in a country with known dengue activity or in a dengue-receptive area in Australia where a locally-acquired or imported case has been documented with onset within a month. 1 Dengue Situation Update 703 │ 10 Household epidemiological evidence: - Living in the same house as a locally- acquired case in a dengue-receptive area of Australia within a month of onse in the case and at least one case in the chain of epidemiologically linked cases is laboratory confirmed. Cambodia Suspected dengue: very high fever at 39-40 degrees celcius for 2-7 days (usually 3-4 days), with 2 or more of the following signs: flushed face, headache, retro-orbital pain, myalgia/arthralgia, cutaneous rash, haemorrhagic signs (petechiae, positive tourniquet test), and leucopenia. Probable dengue: signs of suspected dengue plus laboratory test results (see right column)) or that the case occurred in an area where the dengue case has been confirmed. Yes National Dengue Control Program (NDCP) enhanced sentinel surveillance system Communicable Disease Control (CDC) syndromic surveillance system (CamEWARN). Health Management Information System (HMIS) collects data on confirmed cases and deaths. Data collected for Cambodia Laboratory Information System (CamLIS), comprised of 32 participating hospital laboratories where NS1 detection is conducted. Laboratory testing: Antibody HI>= 1/1280 or IgM/IgG positive by ELISA test in convalescence serum 2 China 1) Typical dengue fever can be diagnosed with any of the following conditions: - General clinical symptoms of dengue fever, with an epidemiological history (having been to an area where dengue fever is prevalent within 14 days before onset), or living or working in an area where dengue fever cases have occurred within the past month, and with reduced white blood cell count and platelet count (below 100x10^9/L) - No epidemiological history, but with a rash, bleeding tendency, and positive IgG or IgM antibodies in a single serum sample. No Reported to the Chinese Centre for Disease Control and Prevention (China CDC) through the Chinese National Notifiable Infectious Disease Reporting Information System (CNNDS). A clinically diagnosed case with any of the of the following laboratory findings: - Isolation of the dengue virus from the serum, cerebrospinal fluid, blood cells, or tissues of an acute-phase patient - Detection of dengue virus gene sequence by RT-PCR or real-time fluorescent quantitative PCR - Detection of dengue virus NS1 antigen in serum from an acute-phase patient - A fourfold or greater increase in specific antibody titer in the convalescent phase compared to the acute phase. 3, WHO internal communication Dengue Situation Update 703 │ 11 2) Dengue Hemorrhagic Fever can be diagnosed when accompanied by any of the following clinical symptoms: - Bleeding tendency, significant bleeding manifestations (such as gastrointestinal bleeding or hemorrhage in the chest, abdomen, or cranium), hepatomegaly, and ascites; and - Laboratory findings including thrombocytopenia (platelet count below 100x10^9/L), hemoconcentration (an increase in hematocrit of more than 20% above normal levels or a decrease of more than 20% after fluid resuscitation), and hypoalbuminemia. 3) Dengue Shock Syndrome: Patients with dengue hemorrhagic fever presenting with cold and clammy skin, restlessness, rapid and weak pulse, low blood pressure with a narrow pulse pressure (less than 20mmHg or 2.7kPa), and reduced urine output. Lao People's Democratic Republic WHO dengue case classification (2009) † No National Surveillance System for Notifiable Selected Diseases, indicator-based surveillance system that consists of passive weekly reports of clinically suspected cases, on admission, from all health-care facilities across the country. 4 Malaysia WHO dengue case classification (2009) † Yes National Dengue Surveillance System, indicator-based surveillance system All suspected cases are to be tested by the following laboratory tests: Rapid Combo Test (RCT) (NS1, IgM, IgG), Dengue Antigen and Serology tests by ELISA, Dengue Viral RNA Detection (Real time RT-PCR), Viral Isolation 5 Philippines WHO dengue case classification (2009) † Yes Philippine Integrated Disease Surveillance and Response (PIDSR), indicator-based surveillance system. Reporting delays of 2-3 weeks, making comparison of current weekly and cumulative figures with previous years difficult. Confirmed dengue is a suspect case with positive (+) viral culture isolation and/or PCR. NS1 (+), IgM is used to identify probable dengue. 6, 7, 8 Dengue Situation Update 703 │ 12 Singapore (endemic) Fever, headache, backache, myalgia, rash, abdominal discomfort and thrombocytopenia and laboratory testing (see right column) Yes Dengue is a legally notifiable disease in Singapore and notifying the Ministry of Health should not be later than 24 hours from the time of diagnosis. Laboratory confirmation is done using standard diagnostic tests for the detection of dengue NS1 antigen, IgM and IgG, or RT-PCR. 9, 10 Viet Nam (endemic) Acute onset of fever continuously lasting from 2-7 days AND at least 2 of the following: haemorrhagic manifestation /presentation; headache, loss of appetite, nausea, vomiting; rash; muscle pain, joint pain, orbital pain; lethargy; abdominal pain. No As per the MOH dengue surveillance guideline, in routine surveillance MAC-ELISA is conducted for at least 7% and virus isolation is conducted for at least 3% of clinical cases. In an outbreak, at least 5 to 10 suspected cases are tested. 11 Pacific Island Countries WHO dengue case classification (2009) † No Pacific Syndromic Surveillance System Confirmed case: Isolation of dengue virus or detection of dengue-specific antigen or antibodies in tissue, blood, CSF or other body fluid by an advanced laboratory test 12 Only the minimum criteria required for fulfilling a clinical dengue case definition are included here; additional signs and symptoms required for more severe forms are not listed. † A probable dengue case is defined as any case living in or travel to dengue endemic area with fever and two or more of the following: nausea, vomiting, rash, aches and pains, positive tourniquet test, leucopenia and any warning sign. A case with warning signs is defined as a clinically diagnosed case with any of the following: abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleed, lethargy, restlessness, liver enlargement > 2 cm and increase in haematocrit concurrent with rapid decrease in platelet count. Severe dengue is defined as severe plasma leakage leading to any of the following: shock, fluid accumulation with respiratory distress OR severe bleeding as evaluated by clinician OR severe organ involvement of liver (aspartate amino transferase or alanine amino transferase ≥ 1000), central nervous system (impaired consciousness) or heart and other organs.10 References: 1. Australian Government Department of Health AGDo. Dengue virus infection surveillance and case definition [updated 14 June 2022 and 1 January 2018 respectively] Available from: https://www.health.gov.au/diseases/dengue-virus-infection, and https://www.health.gov.au/sites/default/files/documents/2022/06/dengue-virus-infection-surveillance-case-definition.pdf 2. Cambodia Ministry of Health NCfP, Entomology and Malaria Control. National Guideline for Clinical Management of Dengue, 2018. 2018. Available from: https://niph.org.kh/niph/uploads/library/pdf/GL055_National_guideline_for_ClM_Dengue.pdf. 3. China CDC. Dengue surveillance guideline. Available from: https://www.chinacdc.cn/jkzt/crb/zl/dgr/jszl_2235/201810/P020181010391462131548.pdf 4. Khampapongpane B, Lewis HC, Ketmayoon P, Phonekeo D, Somoulay V, Khamsing A, et al. National dengue surveillance in the Lao People's Democratic Republic, 2006-2012: epidemiological and laboratory findings. Western Pac Surveill Response J. 2014;5(1):7-13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24734212. 5. Ministry of Health Malaysia DCD. Case definitions for infectious diseases in Malaysia. 2017. Available from: https://www.moh.gov.my/moh/resources/Penerbitan/Garis%20Panduan/Pengurusan%20KEsihatan%20&%20kawalan%20pykit/Case_Definition_Of_Infectious_Disease_3rd_Edition_2017.pdf 6. Secretary PDoHOot. Guidelines for the Nationwide Implementation of Dengue Rapid Diagnostic Test (RDT), Administrative order No.2016-0043. 2016(2016-0043). 7. Secretary PDoHOot. Revised Dengue Clinical Case Management Guidelines 2011, Administrative order No.2012-0006. 2012 22 March 2012. Report No. 8. Diseases SNCfI. Diseases and Conditions, Dengue 2020 [updated 14 September 2020. Available from: https://www.doh.gov.ph/Health-Advisory/Dengue. 9. National Centre for Infectious Diseases, Dengue. Available from: https://www.ncid.sg/Health-Professionals/Diseases-and-Conditions/Pages/Dengue.aspx 10. National Environment Agency. Surveillance and Epidemiology Programme [updated 21 April 2023]. Available from: https://www.nea.gov.sg/corporate-functions/resources/research/surveillance-and- epidemiology-programme#Ehi%20Diagnostics%20Unit Dengue Situation Update 703 │ 13 11. Viet Nam Ministry of Health VNMo. Circular 54/2015 / TT-BYT 2015 [updated 26 April 2016. Available from: https://syt.thuathienhue.gov.vn/?gd=27&cn=108&tc=3993. 12. Pacific Islands Outbreak Manual. Available from: https://www.pphsn.net/resources/outbreak-manual/ 13. WHO dengue outbreak toolbox. Available from: https://www.who.int/docs/default-source/outbreak-toolkit/updates-documents_july-5/dengue-outbreak-data-collection-toolbox---inis-3-july- 1.pdf?sfvrsn=ec3ffcf3_2
Dengue Situation Update 704 │ 1 Dengue Situation Update 704 8 August 2024 Update on the Dengue situation in the Western Pacific Region This report describes the epidemiology of dengue in the World Health Organization Western Pacific Region. Data are compiled from open sources (national indicator-based surveillance systems) with the exception of Cambodia, Lao People’s Democratic Republic, Viet Nam, and the Philippines, where data are provided by the WHO Country Offices. For the Pacific Island Countries, syndromic surveillance data are provided by the Division of Pacific Technical Support. Information is reported based on countries’ standard dengue case definitions, summary of these definitions and countries’ dengue surveillance systems - included as an annex to this report. Due to differences in surveillance methods and reporting practices, a comparison of trends between countries and areas is not possible, however, national trends can be observed over time. Northern Hemisphere Cambodia As of epidemiological week 30 of 2024, the National Dengue Surveillance System reported a total of 8 497 cases with 25 deaths (Case Fatality Rate (CFR) 0.29%) since 1 January 2024 (Figure 1). This is lower compared to the number reported in 2023 for the same period, with 11 833 cases and 32 deaths. Figure 1: Dengue cases reported weekly in 2024 vs endemic and epidemic alert lines in Cambodia; Source: National Dengue Surveillance System (NDCP/CNM/MOH) Dengue Situation Update 704│ 2 China There has been a total of 404 dengue cases and no death reported since the beginning of 2024 (Figure 2). Figure 2: Dengue cases reported monthly from 2015-2024 (as of May) in China Source: National Disease Control and Prevention Administration, China Lao People’s Democratic Republic In epidemiological week 30 of 2024 (22 to 28 July 2024), 990 dengue cases and two deaths were reported (Figure 3). The number of reported cases is higher than the numbers reported in epidemiological week 29 (914 cases with no death), and lower than those in week 30 of 2023 (2 189 cases with no death). The cumulative number of cases reported in 2024 (as of epidemiological week 30) is 8 557. This is a 40.7% decrease compared to the 14 436 cases reported during the same period in 2023. Figure 3: Dengue cases reported weekly from 2018-2024 in Lao PDR Source: National Centre for Laboratory and Epidemiology, Ministry of Health, Lao PDR Dengue Situation Update 704│ 3 Malaysia During epidemiological week 29 of 2024 (14 to 20 July 2024), an increase of 317 cases (13.4%) was reported with 2 690 cases as compared to 2 373 cases reported in the previous week (Figure 4). The cumulative number of dengue cases reported up to week 29 of 2024 is 83 131 cases, which is an increase of 25.5% compared to 66 224 cases for the same period in 2023. 69 dengue-related deaths were reported up to week 29 of 2024, compared to 47 deaths for the same period in 2023. Figure 4: Dengue cases reported weekly from 2023, 2024 and median 2019-2023 in Malaysia Source: Department of Health, Malaysia Philippines There is no update for this reporting period. During epidemiological Week 48 (26 November to 2 December 2023), there were 2 607 new dengue cases reported, a 41% decrease compared to the same period in 2022 (n=4 415 cases) (Figure 5). As of 2 December 2023, a total of 195 603 dengue cases have been reported. The number of cases is 23% lower compared to the same period in 2022 (n=252 700). From 1 January to 2 December 2023, there have been 657 deaths (CFR 0.34%) as compared to 894 deaths (CFR 0.35%;) reported in the same period in 2022. Figure 5: Dengue cases reported weekly from 2022 and 2023 in the Philippines Source: Department of Health, the Philippines (Note: there is a 3-4 week systematic delay in reporting and numbers should be interpreted with caution) Dengue Situation Update 704│ 4 Singapore In epidemiological week 30 (21 to 27 July 2024), a total of 311 dengue cases were reported in Singapore. Cumulatively, a total of 10 421 cases (Figure 6) have been reported as of 27 July 2024. When compared to the same period in 2023 (5 206 cases), there has been a 100% increase in cases reported in 2024. Preliminary results of all positive dengue samples serotyped in July 2024 showed DEN-1, DEN-2, DEN-3 and DEN-4 at 6.6%, 59.2%, 23.9% and 10.2% respectively. Figure 6: Dengue cases reported weekly from 2019-2024 (as of 27 July 2024) in Singapore Source: Communicable Diseases Division, Ministry of Health, Singapore (Note: Case numbers are derived from the MOH Singapore’s weekly-infectious-disease-bulletin-year-2024_upload as available from MOH | Weekly Infectious Diseases Bulletin) Viet Nam In epidemiological week 31 (29 July to 4 August 2024), a total of 2 147 cases and no deaths were reported in Viet Nam, a decrease by 38.6% compared to 3 498 cases in the previous week. Cumulatively, 49 187 dengue cases including five deaths have been reported as of 4 August 2024. Compared to the same period in 2023, the number of cumulative cases decreased by 15.4%, and the number of deaths decreased by 11 cases. Figure 7: Number of dengue hospital admissions and deaths by week in 2024 compared to 2023, as of week 31, 2024, Viet Nam Source: General Department of Preventive Medicine, Ministry of Health, Viet Nam Note hospitalizations include inpatients and outpatients The alert threshold is a 5-year mean plus 2 standard deviations. Southern Hemisphere Dengue Situation Update 704│ 5 Australia In July 2024, a total of 154 dengue cases were reported in Australia. As of 31 July 2024, the cumulative number of dengue cases is 1 493, which is about 2.5 times higher than the same period in 2023 (601 cases). (Figure 7). Figure 7: Laboratory-confirmed dengue cases reported monthly from 2016-2024 in Australia Source: Department of Health, Australia Note: Graph was updated as of 31 July 2024 Pacific Islands Countries New Caledonia There is no update for this reporting period. From 1 January to 30 June 2024, eight confirmed dengue cases were reported in New Caledonia (Figure 8). This is higher compared to the same period in 2023, when a total of five dengue cases were reported. Of the eight dengue cases in 2024, two were locally acquired confirmed cases, and the serotypes of the cases were DENV-1 and DENV-2, respectively. There is no ongoing epidemic. Figure 8: Dengue cases reported by month from 2022 to 2024 in New Caledonia Source: Network of sentinel physicians, New Caledonia Pacific Island Countries and Areas (PICs) – Dengue-like illness (DLI) Surveillance Among the PICs with available surveillance data (18/21 PICs), an upward trend of DLI cases was reported in Fiji, Northern Mariana Islands, Solomon Islands, Wallis and Futuna in week 29 (ending 21 July), and a Dengue Situation Update 704│ 6 downward trend of DLI cases was reported in Samoa and Vanuatu. The remaining PICs reported either no or low numbers of DLI cases or provided no updates (Figure 9). Dengue Situation Update 704│ 7 Dengue Situation Update 704│ 8 Figure 9. Reported cases of dengue-like illness in Pacific Islands Countries and Areas Source: WHO Division of Pacific Technical Support Note: Caution should be taken in interpreting these data as there may be changes in the number of sentinel sites reporting to the Pacific Syndromic Surveillance System (PSSS). Furthermore, the syndromic case definition of DLI may capture cases with non- dengue acute febrile illnesses (AFI) with similar clinical manifestations to dengue. This includes AFI such as chikungunya, influenza, hantavirus, leptospirosis, malaria, measles, paratyphoid and typhoid fevers, scrub typhus, yellow fever, zika, other diseases. The PSSS may also capture dengue cases under ‘prolonged fever’ surveillance. Alert threshold for DLI is twice the average number of cases seen in the previous 3 weeks. Dengue Situation Update 704│ 9 Annex 1. Summary of dengue case definitions, laboratory sampling and testing methods used for surveillance in Member States Country Case definition Surveillance system Laboratory sampling and testing method Reference Clinically confirmed case Laboratory confirmation required Description Australia Fever, headache, arthralgia, myalgia, rash, nausea and vomiting Yes Dengue is a nationally notifiable disease and cases are monitored through the National Notifiable Diseases Surveillance System (NNDSS) indicator-based surveillance system. Both confirmed and probable cases are nationally notifiable. A confirmed case requires both laboratory definitive evidence and clinical evidence. A probable case requires either laboratory suggestive evidence and clinical evidence and epidemiological evidence, or clinical evidence and household epidemiological evidence. Laboratory definitive evidence: - Isolation of dengue virus, or - Detection of dengue virus by nucleic acid testing, or - Detection of NS1 antigen in the blood by EIA, or - IgG seroconversion or significant increase in antibody levelor fourfold or greater rise in titre to dengue virus (proof by neutralization or another specific test) - Detection of dengue virus-specific IgM in cerebrospinal fluid, in the absence of IgM to Murray valley encephalitis, West Nile virus/Kunjin, or Japanese encephalitis viruses. Laboratory suggestive evidence: - Detection of NS1 antigen in blood by rapid antigen test, or - Detection of dengue virus-specific IgM in blood Epidemiological evidence: - Exposure between 3 – 14 days prior to onset either in a country with known dengue activity or in a dengue-receptive area in Australia where a locally-acquired or imported case has been documented with onset within a month. 1 Dengue Situation Update 704│ 10 Household epidemiological evidence: - Living in the same house as a locally- acquired case in a dengue-receptive area of Australia within a month of onse in the case and at least one case in the chain of epidemiologically linked cases is laboratory confirmed. Cambodia Suspected dengue: very high fever at 39-40 degrees celcius for 2-7 days (usually 3-4 days), with 2 or more of the following signs: flushed face, headache, retro-orbital pain, myalgia/arthralgia, cutaneous rash, haemorrhagic signs (petechiae, positive tourniquet test), and leucopenia. Probable dengue: signs of suspected dengue plus laboratory test results (see right column)) or that the case occurred in an area where the dengue case has been confirmed. Yes National Dengue Control Program (NDCP) enhanced sentinel surveillance system Communicable Disease Control (CDC) syndromic surveillance system (CamEWARN). Health Management Information System (HMIS) collects data on confirmed cases and deaths. Data collected for Cambodia Laboratory Information System (CamLIS), comprised of 32 participating hospital laboratories where NS1 detection is conducted. Laboratory testing: Antibody HI>= 1/1280 or IgM/IgG positive by ELISA test in convalescence serum 2 China 1) Typical dengue fever can be diagnosed with any of the following conditions: - General clinical symptoms of dengue fever, with an epidemiological history (having been to an area where dengue fever is prevalent within 14 days before onset), or living or working in an area where dengue fever cases have occurred within the past month, and with reduced white blood cell count and platelet count (below 100x10^9/L) - No epidemiological history, but with a rash, bleeding tendency, and positive IgG or IgM antibodies in a single serum sample. No Reported to the Chinese Centre for Disease Control and Prevention (China CDC) through the Chinese National Notifiable Infectious Disease Reporting Information System (CNNDS). A clinically diagnosed case with any of the of the following laboratory findings: - Isolation of the dengue virus from the serum, cerebrospinal fluid, blood cells, or tissues of an acute-phase patient - Detection of dengue virus gene sequence by RT-PCR or real-time fluorescent quantitative PCR - Detection of dengue virus NS1 antigen in serum from an acute-phase patient - A fourfold or greater increase in specific antibody titer in the convalescent phase compared to the acute phase. 3, WHO internal communication Dengue Situation Update 704│ 11 2) Dengue Hemorrhagic Fever can be diagnosed when accompanied by any of the following clinical symptoms: - Bleeding tendency, significant bleeding manifestations (such as gastrointestinal bleeding or hemorrhage in the chest, abdomen, or cranium), hepatomegaly, and ascites; and - Laboratory findings including thrombocytopenia (platelet count below 100x10^9/L), hemoconcentration (an increase in hematocrit of more than 20% above normal levels or a decrease of more than 20% after fluid resuscitation), and hypoalbuminemia. 3) Dengue Shock Syndrome: Patients with dengue hemorrhagic fever presenting with cold and clammy skin, restlessness, rapid and weak pulse, low blood pressure with a narrow pulse pressure (less than 20mmHg or 2.7kPa), and reduced urine output. Lao People's Democratic Republic WHO dengue case classification (2009) † No National Surveillance System for Notifiable Selected Diseases, indicator-based surveillance system that consists of passive weekly reports of clinically suspected cases, on admission, from all health-care facilities across the country. 4 Malaysia WHO dengue case classification (2009) † Yes National Dengue Surveillance System, indicator-based surveillance system All suspected cases are to be tested by the following laboratory tests: Rapid Combo Test (RCT) (NS1, IgM, IgG), Dengue Antigen and Serology tests by ELISA, Dengue Viral RNA Detection (Real time RT-PCR), Viral Isolation 5 Philippines WHO dengue case classification (2009) † Yes Philippine Integrated Disease Surveillance and Response (PIDSR), indicator-based surveillance system. Reporting delays of 2-3 weeks, making comparison of current weekly and cumulative figures with previous years difficult. Confirmed dengue is a suspect case with positive (+) viral culture isolation and/or PCR. NS1 (+), IgM is used to identify probable dengue. 6, 7, 8 Dengue Situation Update 704│ 12 Singapore (endemic) Fever, headache, backache, myalgia, rash, abdominal discomfort and thrombocytopenia and laboratory testing (see right column) Yes Dengue is a legally notifiable disease in Singapore and notifying the Ministry of Health should not be later than 24 hours from the time of diagnosis. Laboratory confirmation is done using standard diagnostic tests for the detection of dengue NS1 antigen, IgM and IgG, or RT-PCR. 9, 10 Viet Nam (endemic) Acute onset of fever continuously lasting from 2-7 days AND at least 2 of the following: haemorrhagic manifestation /presentation; headache, loss of appetite, nausea, vomiting; rash; muscle pain, joint pain, orbital pain; lethargy; abdominal pain. No As per the MOH dengue surveillance guideline, in routine surveillance MAC-ELISA is conducted for at least 7% and virus isolation is conducted for at least 3% of clinical cases. In an outbreak, at least 5 to 10 suspected cases are tested. 11 Pacific Island Countries WHO dengue case classification (2009) † No Pacific Syndromic Surveillance System Confirmed case: Isolation of dengue virus or detection of dengue-specific antigen or antibodies in tissue, blood, CSF or other body fluid by an advanced laboratory test 12 Only the minimum criteria required for fulfilling a clinical dengue case definition are included here; additional signs and symptoms required for more severe forms are not listed. † A probable dengue case is defined as any case living in or travel to dengue endemic area with fever and two or more of the following: nausea, vomiting, rash, aches and pains, positive tourniquet test, leucopenia and any warning sign. A case with warning signs is defined as a clinically diagnosed case with any of the following: abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleed, lethargy, restlessness, liver enlargement > 2 cm and increase in haematocrit concurrent with rapid decrease in platelet count. Severe dengue is defined as severe plasma leakage leading to any of the following: shock, fluid accumulation with respiratory distress OR severe bleeding as evaluated by clinician OR severe organ involvement of liver (aspartate amino transferase or alanine amino transferase ≥ 1000), central nervous system (impaired consciousness) or heart and other organs.10 References: 1. Australian Government Department of Health AGDo. Dengue virus infection surveillance and case definition [updated 14 June 2022 and 1 January 2018 respectively] Available from: https://www.health.gov.au/diseases/dengue-virus-infection, and https://www.health.gov.au/sites/default/files/documents/2022/06/dengue-virus-infection-surveillance-case-definition.pdf 2. Cambodia Ministry of Health NCfP, Entomology and Malaria Control. National Guideline for Clinical Management of Dengue, 2018. 2018. Available from: https://niph.org.kh/niph/uploads/library/pdf/GL055_National_guideline_for_ClM_Dengue.pdf. 3. China CDC. Dengue surveillance guideline. Available from: https://www.chinacdc.cn/jkzt/crb/zl/dgr/jszl_2235/201810/P020181010391462131548.pdf 4. Khampapongpane B, Lewis HC, Ketmayoon P, Phonekeo D, Somoulay V, Khamsing A, et al. National dengue surveillance in the Lao People's Democratic Republic, 2006-2012: epidemiological and laboratory findings. Western Pac Surveill Response J. 2014;5(1):7-13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24734212. 5. Ministry of Health Malaysia DCD. Case definitions for infectious diseases in Malaysia. 2017. Available from: https://www.moh.gov.my/moh/resources/Penerbitan/Garis%20Panduan/Pengurusan%20KEsihatan%20&%20kawalan%20pykit/Case_Definition_Of_Infectious_Disease_3rd_Edition_2017.pdf 6. Secretary PDoHOot. Guidelines for the Nationwide Implementation of Dengue Rapid Diagnostic Test (RDT), Administrative order No.2016-0043. 2016(2016-0043). 7. Secretary PDoHOot. Revised Dengue Clinical Case Management Guidelines 2011, Administrative order No.2012-0006. 2012 22 March 2012. Report No. 8. Diseases SNCfI. Diseases and Conditions, Dengue 2020 [updated 14 September 2020. Available from: https://www.doh.gov.ph/Health-Advisory/Dengue. 9. National Centre for Infectious Diseases, Dengue. Available from: https://www.ncid.sg/Health-Professionals/Diseases-and-Conditions/Pages/Dengue.aspx 10. National Environment Agency. Surveillance and Epidemiology Programme [updated 21 April 2023]. Available from: https://www.nea.gov.sg/corporate-functions/resources/research/surveillance-and- epidemiology-programme#Ehi%20Diagnostics%20Unit Dengue Situation Update 704│ 13 11. Viet Nam Ministry of Health VNMo. Circular 54/2015 / TT-BYT 2015 [updated 26 April 2016. Available from: https://syt.thuathienhue.gov.vn/?gd=27&cn=108&tc=3993. 12. Pacific Islands Outbreak Manual. Available from: https://www.pphsn.net/resources/outbreak-manual/ 13. WHO dengue outbreak toolbox. Available from: https://www.who.int/docs/default-source/outbreak-toolkit/updates-documents_july-5/dengue-outbreak-data-collection-toolbox---inis-3-july- 1.pdf?sfvrsn=ec3ffcf3_2
Dengue Situation Update 705 │ 1 Dengue Situation Update 705 22 August 2024 Update on the Dengue situation in the Western Pacific Region This report describes the epidemiology of dengue in the World Health Organization Western Pacific Region. Data are compiled from open sources (national indicator-based surveillance systems) with the exception of Cambodia, Lao People’s Democratic Republic, Viet Nam, and the Philippines, where data are provided by the WHO Country Offices. For the Pacific Island Countries, syndromic surveillance data are provided by the Division of Pacific Technical Support. Information is reported based on countries’ standard dengue case definitions, summary of these definitions and countries’ dengue surveillance systems - included as an annex to this report. Due to differences in surveillance methods and reporting practices, a comparison of trends between countries and areas is not possible, however, national trends can be observed over time. Northern Hemisphere Cambodia As of epidemiological week 32 of 2024, the National Dengue Surveillance System reported a total of 9 755 cases with 30 deaths (Case Fatality Rate (CFR) 0.31%) since 1 January 2024 (Figure 1). This is lower compared to the number reported in 2023 for the same period, with 14 722 cases and 41 deaths. Figure 1: Dengue cases reported weekly in 2024 vs endemic and epidemic alert lines in Cambodia; Source: National Dengue Surveillance System (NDCP/CNM/MOH) Dengue Situation Update 705│ 2 China There has been a total of 404 dengue cases and no death reported since the beginning of 2024 (Figure 2). Figure 2: Dengue cases reported monthly from 2015-2024 (as of June) in China Source: National Disease Control and Prevention Administration, China Lao People’s Democratic Republic In epidemiological week 32 of 2024 (5 to 11 August 2024), 924 dengue cases and no deaths were reported (Figure 3). The number of reported cases is higher than the numbers reported in epidemiological week 31 (895 cases with no death), and lower than those in week 32 of 2023 (1 705 cases with two death). The cumulative number of cases reported in 2024 (as of epidemiological week 32) is 10 376. This is a 42.73% decrease compared to the 18 118 cases reported during the same period in 2023. Figure 3: Dengue cases reported weekly from 2018-2024 in Lao PDR Source: National Centre for Laboratory and Epidemiology, Ministry of Health, Lao PDR Malaysia During epidemiological week 32 of 2024 (4-10 August 2024), a decrease of 237 cases (10.4%) was reported with 2 278 as compared to 2 515 cases reported in the previous week (Figure 4). The cumulative number Dengue Situation Update 705│ 3 of dengue cases reported up to week 32 of 2024 is 90 533 cases, which is an increase of 22.87% compared to 73 680 cases for the same period in 2023. 80 dengue-related deaths were reported up to week 32 of 2024, increased compared to 53 deaths for the same period in 2023. Figure 4: Dengue cases reported weekly from 2023, 2024 and median 2019-2023 in Malaysia Source: Department of Health, Malaysia Philippines There is no update for this reporting period. During epidemiological Week 48 (26 November to 2 December 2023), there were 2 607 new dengue cases reported, a 41% decrease compared to the same period in 2022 (n=4 415 cases) (Figure 5). As of 2 December 2023, a total of 195 603 dengue cases have been reported. The number of cases is 23% lower compared to the same period in 2022 (n=252 700). From 1 January to 2 December 2023, there have been 657 deaths (CFR 0.34%) as compared to 894 deaths (CFR 0.35%;) reported in the same period in 2022. Figure 5: Dengue cases reported weekly from 2022 and 2023 in the Philippines Source: Department of Health, the Philippines (Note: there is a 3-4 week systematic delay in reporting and numbers should be interpreted with caution) Singapore In epidemiological week 32 (4 to 10 August 2024), a total of 218 dengue cases were reported in Singapore. Cumulatively, a total of 10 913 cases (Figure 6) have been reported as of 10 August 2024. When compared to the same period in 2023 (5 564 cases), there has been 96.13% increase in cases reported in 2024. Preliminary results of all positive dengue samples serotyped in August 2024 showed DEN-1, DEN-2, DEN- 3 and DEN-4 at 0.0%, 62.0%, 36.0% and 2.0% respectively. Dengue Situation Update 705│ 4 Figure 6: Dengue cases reported weekly from 2019-2024 (as of 10 Aug 2024) in Singapore Source: Communicable Diseases Division, Ministry of Health, Singapore (Note: Case numbers are derived from the MOH Singapore’s weekly-infectious-disease-bulletin-year-2024_upload as available from MOH | Weekly Infectious Diseases Bulletin) Viet Nam In epidemiological week 33 (12 to 18 August 2024), a total of 3 147 cases and 2 deaths were reported in Viet Nam, an increase by 3.18% compared to 3 050 cases in the previous week. Cumulatively, 57 858 dengue cases including nine deaths have been reported as of 18 August 2024. Compared to the same period in 2023, the number of cumulative cases decreased by 44%, and the number of deaths decreased by 7cases. Figure 7: Number of dengue hospital admissions and deaths by week in 2024 compared to 2023, as of week 33, 2024, Viet Nam Source: General Department of Preventive Medicine, Ministry of Health, Viet Nam Note hospitalizations include inpatients and outpatients The alert threshold is a 5-year mean plus 2 standard deviations. Southern Hemisphere Australia In August 2024, a total of 30 dengue cases were reported in Australia. As of 10 August 2024, the cumulative number of dengue cases is 1 557, which is about 2.2 times higher than the same period in 2023 (714 cases). (Figure 7). Dengue Situation Update 705│ 5 Figure 7: Laboratory-confirmed dengue cases reported monthly from 2016-2024 in Australia Source: Department of Health, Australia Note: Graph was updated as of 20 August 2024 Pacific Islands Countries New Caledonia There is no update for this reporting period. From 1 January to 30 June 2024, eight confirmed dengue cases were reported in New Caledonia (Figure 8). This is higher compared to the same period in 2023, when a total of five dengue cases were reported. Of the eight dengue cases in 2024, two were locally acquired confirmed cases, and the serotypes of the cases were DENV-1 and DENV-2, respectively. There is no ongoing epidemic. Figure 8: Dengue cases reported by month from 2022 to 2024 in New Caledonia Source: Network of sentinel physicians, New Caledonia Pacific Island Countries and Areas (PICs) – Dengue-like illness (DLI) Surveillance Among the PICs with available surveillance data (18/21 PICs), an upward trend of DLI cases was reported in Fiji, Vanuatu and Wallis and Futuna in week 31 (ending 12 August), and a downward trend of DLI cases was reported in Samoa and Solomon Islands. The remaining PICs reported either no or low numbers of DLI cases or provided no updates (Figure 9). Dengue Situation Update 705│ 6 Dengue Situation Update 705│ 7 Figure 9. Reported cases of dengue-like illness in Pacific Islands Countries and Areas Source: WHO Division of Pacific Technical Support Note: Caution should be taken in interpreting these data as there may be changes in the number of sentinel sites reporting to the Pacific Syndromic Surveillance System (PSSS). Furthermore, the syndromic case definition of DLI may capture cases with non- dengue acute febrile illnesses (AFI) with similar clinical manifestations to dengue. This includes AFI such as chikungunya, influenza, hantavirus, leptospirosis, malaria, measles, paratyphoid and typhoid fevers, scrub typhus, yellow fever, zika, other diseases. The PSSS may also capture dengue cases under ‘prolonged fever’ surveillance. Alert threshold for DLI is twice the average number of cases seen in the previous 3 weeks. Dengue Situation Update 705│ 8 Annex 1. Summary of dengue case definitions, laboratory sampling and testing methods used for surveillance in Member States Country Case definition Surveillance system Laboratory sampling and testing method Reference Clinically confirmed case Laboratory confirmation required Description Australia Fever, headache, arthralgia, myalgia, rash, nausea and vomiting Yes Dengue is a nationally notifiable disease and cases are monitored through the National Notifiable Diseases Surveillance System (NNDSS) indicator-based surveillance system. Both confirmed and probable cases are nationally notifiable. A confirmed case requires both laboratory definitive evidence and clinical evidence. A probable case requires either laboratory suggestive evidence and clinical evidence and epidemiological evidence, or clinical evidence and household epidemiological evidence. Laboratory definitive evidence: - Isolation of dengue virus, or - Detection of dengue virus by nucleic acid testing, or - Detection of NS1 antigen in the blood by EIA, or - IgG seroconversion or significant increase in antibody levelor fourfold or greater rise in titre to dengue virus (proof by neutralization or another specific test) - Detection of dengue virus-specific IgM in cerebrospinal fluid, in the absence of IgM to Murray valley encephalitis, West Nile virus/Kunjin, or Japanese encephalitis viruses. Laboratory suggestive evidence: - Detection of NS1 antigen in blood by rapid antigen test, or - Detection of dengue virus-specific IgM in blood Epidemiological evidence: - Exposure between 3 – 14 days prior to onset either in a country with known dengue activity or in a dengue-receptive area in Australia where a locally-acquired or imported case has been documented with onset within a month. 1 Dengue Situation Update 705│ 9 Household epidemiological evidence: - Living in the same house as a locally- acquired case in a dengue-receptive area of Australia within a month of onse in the case and at least one case in the chain of epidemiologically linked cases is laboratory confirmed. Cambodia Suspected dengue: very high fever at 39-40 degrees celcius for 2-7 days (usually 3-4 days), with 2 or more of the following signs: flushed face, headache, retro-orbital pain, myalgia/arthralgia, cutaneous rash, haemorrhagic signs (petechiae, positive tourniquet test), and leucopenia. Probable dengue: signs of suspected dengue plus laboratory test results (see right column)) or that the case occurred in an area where the dengue case has been confirmed. Yes National Dengue Control Program (NDCP) enhanced sentinel surveillance system Communicable Disease Control (CDC) syndromic surveillance system (CamEWARN). Health Management Information System (HMIS) collects data on confirmed cases and deaths. Data collected for Cambodia Laboratory Information System (CamLIS), comprised of 32 participating hospital laboratories where NS1 detection is conducted. Laboratory testing: Antibody HI>= 1/1280 or IgM/IgG positive by ELISA test in convalescence serum 2 China 1) Typical dengue fever can be diagnosed with any of the following conditions: - General clinical symptoms of dengue fever, with an epidemiological history (having been to an area where dengue fever is prevalent within 14 days before onset), or living or working in an area where dengue fever cases have occurred within the past month, and with reduced white blood cell count and platelet count (below 100x10^9/L) - No epidemiological history, but with a rash, bleeding tendency, and positive IgG or IgM antibodies in a single serum sample. 2) Dengue Hemorrhagic Fever can be diagnosed when accompanied by any of the following clinical symptoms: - Bleeding tendency, significant bleeding manifestations (such as gastrointestinal bleeding or hemorrhage in the chest, abdomen, or cranium), hepatomegaly, and ascites; and No Reported to the Chinese Centre for Disease Control and Prevention (China CDC) through the Chinese National Notifiable Infectious Disease Reporting Information System (CNNDS). A clinically diagnosed case with any of the of the following laboratory findings: - Isolation of the dengue virus from the serum, cerebrospinal fluid, blood cells, or tissues of an acute-phase patient - Detection of dengue virus gene sequence by RT-PCR or real-time fluorescent quantitative PCR - Detection of dengue virus NS1 antigen in serum from an acute-phase patient - A fourfold or greater increase in specific antibody titer in the convalescent phase compared to the acute phase. 3, WHO internal communication Dengue Situation Update 705│ 10 - Laboratory findings including thrombocytopenia (platelet count below 100x10^9/L), hemoconcentration (an increase in hematocrit of more than 20% above normal levels or a decrease of more than 20% after fluid resuscitation), and hypoalbuminemia. 3) Dengue Shock Syndrome: Patients with dengue hemorrhagic fever presenting with cold and clammy skin, restlessness, rapid and weak pulse, low blood pressure with a narrow pulse pressure (less than 20mmHg or 2.7kPa), and reduced urine output. Lao People's Democratic Republic WHO dengue case classification (2009) † No National Surveillance System for Notifiable Selected Diseases, indicator-based surveillance system that consists of passive weekly reports of clinically suspected cases, on admission, from all health-care facilities across the country. 4 Malaysia WHO dengue case classification (2009) † Yes National Dengue Surveillance System, indicator-based surveillance system All suspected cases are to be tested by the following laboratory tests: Rapid Combo Test (RCT) (NS1, IgM, IgG), Dengue Antigen and Serology tests by ELISA, Dengue Viral RNA Detection (Real time RT-PCR), Viral Isolation 5 Philippines WHO dengue case classification (2009) † Yes Philippine Integrated Disease Surveillance and Response (PIDSR), indicator-based surveillance system. Reporting delays of 2-3 weeks, making comparison of current weekly and cumulative figures with previous years difficult. Confirmed dengue is a suspect case with positive (+) viral culture isolation and/or PCR. NS1 (+), IgM is used to identify probable dengue. 6, 7, 8 Singapore (endemic) Fever, headache, backache, myalgia, rash, abdominal discomfort and thrombocytopenia and laboratory testing (see right column) Yes Dengue is a legally notifiable disease in Singapore and notifying the Ministry of Health should not be later than 24 hours from the time of diagnosis. Laboratory confirmation is done using standard diagnostic tests for the detection of dengue NS1 antigen, IgM and IgG, or RT-PCR. 9, 10 Viet Nam (endemic) Acute onset of fever continuously lasting from 2-7 days AND at least 2 of the following: haemorrhagic manifestation /presentation; headache, loss of appetite, nausea, vomiting; rash; muscle pain, joint pain, orbital pain; lethargy; abdominal pain. No As per the MOH dengue surveillance guideline, in routine surveillance MAC-ELISA is conducted for at least 7% and virus isolation is conducted for at least 3% of clinical cases. In an outbreak, at least 5 to 10 suspected cases are tested. 11 Dengue Situation Update 705│ 11 Pacific Island Countries WHO dengue case classification (2009) † No Pacific Syndromic Surveillance System Confirmed case: Isolation of dengue virus or detection of dengue-specific antigen or antibodies in tissue, blood, CSF or other body fluid by an advanced laboratory test 12 Only the minimum criteria required for fulfilling a clinical dengue case definition are included here; additional signs and symptoms required for more severe forms are not listed. † A probable dengue case is defined as any case living in or travel to dengue endemic area with fever and two or more of the following: nausea, vomiting, rash, aches and pains, positive tourniquet test, leucopenia and any warning sign. A case with warning signs is defined as a clinically diagnosed case with any of the following: abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleed, lethargy, restlessness, liver enlargement > 2 cm and increase in haematocrit concurrent with rapid decrease in platelet count. Severe dengue is defined as severe plasma leakage leading to any of the following: shock, fluid accumulation with respiratory distress OR severe bleeding as evaluated by clinician OR severe organ involvement of liver (aspartate amino transferase or alanine amino transferase ≥ 1000), central nervous system (impaired consciousness) or heart and other organs.10 References: 1. Australian Government Department of Health AGDo. Dengue virus infection surveillance and case definition [updated 14 June 2022 and 1 January 2018 respectively] Available from: https://www.health.gov.au/diseases/dengue-virus-infection, and https://www.health.gov.au/sites/default/files/documents/2022/06/dengue-virus-infection-surveillance-case-definition.pdf 2. Cambodia Ministry of Health NCfP, Entomology and Malaria Control. National Guideline for Clinical Management of Dengue, 2018. 2018. Available from: https://niph.org.kh/niph/uploads/library/pdf/GL055_National_guideline_for_ClM_Dengue.pdf. 3. China CDC. Dengue surveillance guideline. Available from: https://www.chinacdc.cn/jkzt/crb/zl/dgr/jszl_2235/201810/P020181010391462131548.pdf 4. Khampapongpane B, Lewis HC, Ketmayoon P, Phonekeo D, Somoulay V, Khamsing A, et al. National dengue surveillance in the Lao People's Democratic Republic, 2006-2012: epidemiological and laboratory findings. Western Pac Surveill Response J. 2014;5(1):7-13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24734212. 5. Ministry of Health Malaysia DCD. Case definitions for infectious diseases in Malaysia. 2017. Available from: https://www.moh.gov.my/moh/resources/Penerbitan/Garis%20Panduan/Pengurusan%20KEsihatan%20&%20kawalan%20pykit/Case_Definition_Of_Infectious_Disease_3rd_Edition_2017.pdf 6. Secretary PDoHOot. Guidelines for the Nationwide Implementation of Dengue Rapid Diagnostic Test (RDT), Administrative order No.2016-0043. 2016(2016-0043). 7. Secretary PDoHOot. Revised Dengue Clinical Case Management Guidelines 2011, Administrative order No.2012-0006. 2012 22 March 2012. Report No. 8. Diseases SNCfI. Diseases and Conditions, Dengue 2020 [updated 14 September 2020. Available from: https://www.doh.gov.ph/Health-Advisory/Dengue. 9. National Centre for Infectious Diseases, Dengue. Available from: https://www.ncid.sg/Health-Professionals/Diseases-and-Conditions/Pages/Dengue.aspx 10. National Environment Agency. Surveillance and Epidemiology Programme [updated 21 April 2023]. Available from: https://www.nea.gov.sg/corporate-functions/resources/research/surveillance-and- epidemiology-programme#Ehi%20Diagnostics%20Unit 11. Viet Nam Ministry of Health VNMo. Circular 54/2015 / TT-BYT 2015 [updated 26 April 2016. Available from: https://syt.thuathienhue.gov.vn/?gd=27&cn=108&tc=3993. 12. Pacific Islands Outbreak Manual. Available from: https://www.pphsn.net/resources/outbreak-manual/ 13. WHO dengue outbreak toolbox. Available from: https://www.who.int/docs/default-source/outbreak-toolkit/updates-documents_july-5/dengue-outbreak-data-collection-toolbox---inis-3-july- 1.pdf?sfvrsn=ec3ffcf3_2
Dengue Situation Update 706 │ 1 Dengue Situation Update 706 5 September 2024 Update on the Dengue situation in the Western Pacific Region This report describes the epidemiology of dengue in the World Health Organization Western Pacific Region. Data are compiled from open sources (national indicator-based surveillance systems) with the exception of Cambodia, Lao People’s Democratic Republic, Viet Nam, and the Philippines, where data are provided by the WHO Country Offices. For the Pacific Island Countries, syndromic surveillance data are provided by the Division of Pacific Technical Support. Information is reported based on countries’ standard dengue case definitions, summary of these definitions and countries’ dengue surveillance systems - included as an annex to this report. Due to differences in surveillance methods and reporting practices, a comparison of trends between countries and areas is not possible, however, national trends can be observed over time. Northern Hemisphere Cambodia There is no update for this reporting period. As of epidemiological week32 of 2024, the National Dengue Surveillance System reported a total of 9 755 cases with 30 deaths (Case Fatality Rate (CFR) 0.31%) since 1 January 2024 (Figure 1). This is lower compared to the number reported in 2023 for the same period, with 14 722 cases and 41 deaths. Figure 1: Dengue cases reported weekly in 2024 vs endemic and epidemic alert lines in Cambodia; Source: National Dengue Surveillance System (NDCP/CNM/MOH) Dengue Situation Update 706│ 2 China There has been a total of 958 dengue cases and no death reported since the beginning of 2024 (Figure 2). Figure 2: Dengue cases reported monthly from 2015-2024 (as of July) in China Source: National Disease Control and Prevention Administration, China Lao People’s Democratic Republic In epidemiological week 34 of 2024 (19 to 25 August 2024), 940 dengue cases and one death were reported (Figure 3). The number of reported cases is lower than the numbers reported in epidemiological week 33 (1000 cases with no death), and lower than those in week 34 of 2023 (1 428 cases with no death). The cumulative number of cases reported in 2024 (as of epidemiological week 34) is 12 316. This is a 41.74% decrease compared to the 21 140 cases reported during the same period in 2023. Figure 3: Dengue cases reported weekly from 2018-2024 in Lao PDR Source: National Centre for Laboratory and Epidemiology, Ministry of Health, Lao PDR Malaysia During epidemiological week 34 of 2024 (18-24 August 2024), a decrease of 314 cases (13.69%) was reported with 1 980 as compared to 2 294 cases reported in the previous week (Figure 4). The cumulative number of dengue cases reported up to week 34 of 2024 is 94 807 cases, which is an increase of 21.12% Dengue Situation Update 706│ 3 compared to 78 277 cases for the same period in 2023. 84 dengue-related deaths were reported up to week 34 of 2024, increased compared to 55 deaths for the same period in 2023. Figure 4: Dengue cases reported weekly from 2023, 2024 and median 2019-2023 in Malaysia Source: Department of Health, Malaysia Philippines There is no update for this reporting period. During epidemiological Week 48 (26 November to 2 December 2023), there were 2 607 new dengue cases reported, a 41% decrease compared to the same period in 2022 (n=4 415 cases) (Figure 5). As of 2 December 2023, a total of 195 603 dengue cases have been reported. The number of cases is 23% lower compared to the same period in 2022 (n=252 700). From 1 January to 2 December 2023, there have been 657 deaths (CFR 0.34%) as compared to 894 deaths (CFR 0.35%;) reported in the same period in 2022. Figure 5: Dengue cases reported weekly from 2022 and 2023 in the Philippines Source: Department of Health, the Philippines (Note: there is a 3-4 week systematic delay in reporting and numbers should be interpreted with caution) Dengue Situation Update 706│ 4 Singapore In epidemiological week 34 (18 to 24 August 2024), a total of 186 dengue cases were reported in Singapore. Cumulatively, a total of 11 315 cases (Figure 6) have been reported as of 24 August 2024. When compared to the same period in 2023 (5 955 cases), there has been 90% increase in cases reported in 2024. Preliminary results of all positive dengue samples serotyped in August 2024 showed DEN-1, DEN-2, DEN- 3 and DEN-4 at 2.5%, 62.3%, 32.8% and 2.5% respectively. Figure 6: Dengue cases reported weekly from 2019-2024 (as of 24 Aug 2024) in Singapore Source: Communicable Diseases Division, Ministry of Health, Singapore (Note: Case numbers are derived from the MOH Singapore’s weekly-infectious-disease-bulletin-year-2024_upload as available from MOH | Weekly Infectious Diseases Bulletin) Viet Nam In epidemiological week 35 (26 August to 1 September 2024), a total of 3 700 cases and no death were reported in Viet Nam, an increase by 5.6% compared to 3 494 cases in the previous week. Cumulatively, 67 748 dengue cases including ten deaths have been reported as of 1 September 2024. Compared to the same period in 2023, the number of cumulative cases decreased by 11.2%, and the number of deaths decreased by 56.5%. Figure 7: Number of dengue hospital admissions and deaths by week in 2024 compared to 2023, as of week 35, 2024, Viet Nam Source: General Department of Preventive Medicine, Ministry of Health, Viet Nam Note hospitalizations include inpatients and outpatients The alert threshold is a 5-year mean plus 2 standard deviations. Dengue Situation Update 706│ 5 Southern Hemisphere Australia In August 2024, a total of 95 dengue cases were reported in Australia. As of 31 August 2024, the cumulative number of dengue cases is 1 645, which is about 1.3 times higher than the same period in 2023 (714 cases). (Figure 7). Figure 7: Laboratory-confirmed dengue cases reported monthly from 2016-2024 in Australia Source: Department of Health, Australia Note: Graph was updated as of 31 August 2024 Pacific Islands Countries New Caledonia There is no update for this reporting period. From 1 January to 30 June 2024, eight confirmed dengue cases were reported in New Caledonia (Figure 8). This is higher compared to the same period in 2023, when a total of five dengue cases were reported. Of the eight dengue cases in 2024, two were locally acquired confirmed cases, and the serotypes of the cases were DENV-1 and DENV-2, respectively. There is no ongoing epidemic. Figure 8: Dengue cases reported by month from 2022 to 2024 in New Caledonia Source: Network of sentinel physicians, New Caledonia Dengue Situation Update 706│ 6 Pacific Island Countries and Areas (PICs) – Dengue-like illness (DLI) Surveillance Among the PICs with available surveillance data (18/21 PICs), an upward trend of DLI cases was reported in Fiji and Vanuatu in week 33 (ending 26 August), and a downward trend of DLI cases was reported in Solomon Islands. The remaining PICs reported either no or low numbers of DLI cases or provided no updates (Figure 9). Dengue Situation Update 706│ 7 Figure 9. Reported cases of dengue-like illness in Pacific Islands Countries and Areas Source: WHO Division of Pacific Technical Support Note: Caution should be taken in interpreting these data as there may be changes in the number of sentinel sites reporting to the Pacific Syndromic Surveillance System (PSSS). Furthermore, the syndromic case definition of DLI may capture cases with non- dengue acute febrile illnesses (AFI) with similar clinical manifestations to dengue. This includes AFI such as chikungunya, influenza, hantavirus, leptospirosis, malaria, measles, paratyphoid and typhoid fevers, scrub typhus, yellow fever, zika, other diseases. The PSSS may also capture dengue cases under ‘prolonged fever’ surveillance. Alert threshold for DLI is twice the average number of cases seen in the previous 3 weeks. Dengue Situation Update 705│ 8 Annex 1. Summary of dengue case definitions, laboratory sampling and testing methods used for surveillance in Member States Country Case definition Surveillance system Laboratory sampling and testing method Reference Clinically confirmed case Laboratory confirmation required Description Australia Fever, headache, arthralgia, myalgia, rash, nausea and vomiting Yes Dengue is a nationally notifiable disease and cases are monitored through the National Notifiable Diseases Surveillance System (NNDSS) indicator-based surveillance system. Both confirmed and probable cases are nationally notifiable. A confirmed case requires both laboratory definitive evidence and clinical evidence. A probable case requires either laboratory suggestive evidence and clinical evidence and epidemiological evidence, or clinical evidence and household epidemiological evidence. Laboratory definitive evidence: - Isolation of dengue virus, or - Detection of dengue virus by nucleic acid testing, or - Detection of NS1 antigen in the blood by EIA, or - IgG seroconversion or significant increase in antibody levelor fourfold or greater rise in titre to dengue virus (proof by neutralization or another specific test) - Detection of dengue virus-specific IgM in cerebrospinal fluid, in the absence of IgM to Murray valley encephalitis, West Nile virus/Kunjin, or Japanese encephalitis viruses. Laboratory suggestive evidence: - Detection of NS1 antigen in blood by rapid antigen test, or - Detection of dengue virus-specific IgM in blood Epidemiological evidence: - Exposure between 3 – 14 days prior to onset either in a country with known dengue activity or in a dengue- receptive area in Australia where a locally-acquired or imported case has been documented with onset within a month. Household epidemiological evidence: - Living in the same house as a locally-acquired case in a dengue-receptive area of Australia within a month of onse in the case and at least one case in the chain of epidemiologically linked cases is laboratory confirmed. 1 Dengue Situation Update 705│ 9 Cambodia Suspected dengue: very high fever at 39-40 degrees celcius for 2-7 days (usually 3-4 days), with 2 or more of the following signs: flushed face, headache, retro-orbital pain, myalgia/arthralgia, cutaneous rash, haemorrhagic signs (petechiae, positive tourniquet test), and leucopenia. Probable dengue: signs of suspected dengue plus laboratory test results (see right column)) or that the case occurred in an area where the dengue case has been confirmed. Yes National Dengue Control Program (NDCP) enhanced sentinel surveillance system Communicable Disease Control (CDC) syndromic surveillance system (CamEWARN). Health Management Information System (HMIS) collects data on confirmed cases and deaths. Data collected for Cambodia Laboratory Information System (CamLIS), comprised of 32 participating hospital laboratories where NS1 detection is conducted. Laboratory testing: Antibody HI>= 1/1280 or IgM/IgG positive by ELISA test in convalescence serum 2 China 1) Typical dengue fever can be diagnosed with any of the following conditions: - General clinical symptoms of dengue fever, with an epidemiological history (having been to an area where dengue fever is prevalent within 14 days before onset), or living or working in an area where dengue fever cases have occurred within the past month, and with reduced white blood cell count and platelet count (below 100x10^9/L) - No epidemiological history, but with a rash, bleeding tendency, and positive IgG or IgM antibodies in a single serum sample. 2) Dengue Hemorrhagic Fever can be diagnosed when accompanied by any of the following clinical symptoms: - Bleeding tendency, significant bleeding manifestations (such as gastrointestinal bleeding or hemorrhage in the chest, abdomen, or cranium), hepatomegaly, and ascites; and No Reported to the Chinese Centre for Disease Control and Prevention (China CDC) through the Chinese National Notifiable Infectious Disease Reporting Information System (CNNDS). A clinically diagnosed case with any of the of the following laboratory findings: - Isolation of the dengue virus from the serum, cerebrospinal fluid, blood cells, or tissues of an acute- phase patient - Detection of dengue virus gene sequence by RT-PCR or real-time fluorescent quantitative PCR - Detection of dengue virus NS1 antigen in serum from an acute-phase patient - A fourfold or greater increase in specific antibody titer in the convalescent phase compared to the acute phase. 3, WHO internal communication Dengue Situation Update 705│ 10 - Laboratory findings including thrombocytopenia (platelet count below 100x10^9/L), hemoconcentration (an increase in hematocrit of more than 20% above normal levels or a decrease of more than 20% after fluid resuscitation), and hypoalbuminemia. 3) Dengue Shock Syndrome: Patients with dengue hemorrhagic fever presenting with cold and clammy skin, restlessness, rapid and weak pulse, low blood pressure with a narrow pulse pressure (less than 20mmHg or 2.7kPa), and reduced urine output. Lao People's Democratic Republic WHO dengue case classification (2009) † No National Surveillance System for Notifiable Selected Diseases, indicator-based surveillance system that consists of passive weekly reports of clinically suspected cases, on admission, from all health-care facilities across the country. 4 Malaysia WHO dengue case classification (2009) † Yes National Dengue Surveillance System, indicator-based surveillance system All suspected cases are to be tested by the following laboratory tests: Rapid Combo Test (RCT) (NS1, IgM, IgG), Dengue Antigen and Serology tests by ELISA, Dengue Viral RNA Detection (Real time RT-PCR), Viral Isolation 5 Philippines WHO dengue case classification (2009) † Yes Philippine Integrated Disease Surveillance and Response (PIDSR), indicator-based surveillance system. Reporting delays of 2-3 weeks, making comparison of current weekly and cumulative figures with previous years difficult. Confirmed dengue is a suspect case with positive (+) viral culture isolation and/or PCR. NS1 (+), IgM is used to identify probable dengue. 6, 7, 8 Singapore (endemic) Fever, headache, backache, myalgia, rash, abdominal discomfort and thrombocytopenia and laboratory testing (see right column) Yes Dengue is a legally notifiable disease in Singapore and notifying the Ministry of Health should not be later than 24 hours from the time of diagnosis. Laboratory confirmation is done using standard diagnostic tests for the detection of dengue NS1 antigen, IgM and IgG, or RT-PCR. 9, 10 Dengue Situation Update 705│ 11 Viet Nam (endemic) Acute onset of fever continuously lasting from 2-7 days AND at least 2 of the following: haemorrhagic manifestation /presentation; headache, loss of appetite, nausea, vomiting; rash; muscle pain, joint pain, orbital pain; lethargy; abdominal pain. No As per the MOH dengue surveillance guideline, in routine surveillance MAC-ELISA is conducted for at least 7% and virus isolation is conducted for at least 3% of clinical cases. In an outbreak, at least 5 to 10 suspected cases are tested. 11 Pacific Island Countries WHO dengue case classification (2009) † No Pacific Syndromic Surveillance System Confirmed case: Isolation of dengue virus or detection of dengue-specific antigen or antibodies in tissue, blood, CSF or other body fluid by an advanced laboratory test 12 Only the minimum criteria required for fulfilling a clinical dengue case definition are included here; additional signs and symptoms required for more severe forms are not listed. † A probable dengue case is defined as any case living in or travel to dengue endemic area with fever and two or more of the following: nausea, vomiting, rash, aches and pains, positive tourniquet test, leucopenia and any warning sign. A case with warning signs is defined as a clinically diagnosed case with any of the following: abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleed, lethargy, restlessness, liver enlargement > 2 cm and increase in haematocrit concurrent with rapid decrease in platelet count. Severe dengue is defined as severe plasma leakage leading to any of the following: shock, fluid accumulation with respiratory distress OR severe bleeding as evaluated by clinician OR severe organ involvement of liver (aspartate amino transferase or alanine amino transferase ≥ 1000), central nervous system (impaired consciousness) or heart and other organs.10 References: 1. Australian Government Department of Health AGDo. Dengue virus infection surveillance and case definition [updated 14 June 2022 and 1 January 2018 respectively] Available from: https://www.health.gov.au/diseases/dengue-virus-infection, and https://www.health.gov.au/sites/default/files/documents/2022/06/dengue-virus-infection-surveillance-case-definition.pdf 2. Cambodia Ministry of Health NCfP, Entomology and Malaria Control. National Guideline for Clinical Management of Dengue, 2018. 2018. Available from: https://niph.org.kh/niph/uploads/library/pdf/GL055_National_guideline_for_ClM_Dengue.pdf. 3. China CDC. Dengue surveillance guideline. Available from: https://www.chinacdc.cn/jkzt/crb/zl/dgr/jszl_2235/201810/P020181010391462131548.pdf 4. Khampapongpane B, Lewis HC, Ketmayoon P, Phonekeo D, Somoulay V, Khamsing A, et al. National dengue surveillance in the Lao People's Democratic Republic, 2006-2012: epidemiological and laboratory findings. Western Pac Surveill Response J. 2014;5(1):7-13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24734212. 5. Ministry of Health Malaysia DCD. Case definitions for infectious diseases in Malaysia. 2017. Available from: https://www.moh.gov.my/moh/resources/Penerbitan/Garis%20Panduan/Pengurusan%20KEsihatan%20&%20kawalan%20pykit/Case_Definition_Of_Infectious_Disease_3rd_Edition_2017.pdf 6. Secretary PDoHOot. Guidelines for the Nationwide Implementation of Dengue Rapid Diagnostic Test (RDT), Administrative order No.2016-0043. 2016(2016-0043). 7. Secretary PDoHOot. Revised Dengue Clinical Case Management Guidelines 2011, Administrative order No.2012-0006. 2012 22 March 2012. Report No. 8. Diseases SNCfI. Diseases and Conditions, Dengue 2020 [updated 14 September 2020. Available from: https://www.doh.gov.ph/Health-Advisory/Dengue. 9. National Centre for Infectious Diseases, Dengue. Available from: https://www.ncid.sg/Health-Professionals/Diseases-and-Conditions/Pages/Dengue.aspx 10. National Environment Agency. Surveillance and Epidemiology Programme [updated 21 April 2023]. Available from: https://www.nea.gov.sg/corporate-functions/resources/research/surveillance-and- epidemiology-programme#Ehi%20Diagnostics%20Unit 11. Viet Nam Ministry of Health VNMo. Circular 54/2015 / TT-BYT 2015 [updated 26 April 2016. Available from: https://syt.thuathienhue.gov.vn/?gd=27&cn=108&tc=3993. 12. Pacific Islands Outbreak Manual. Available from: https://www.pphsn.net/resources/outbreak-manual/ 13. WHO dengue outbreak toolbox. Available from: https://www.who.int/docs/default-source/outbreak-toolkit/updates-documents_july-5/dengue-outbreak-data-collection-toolbox---inis-3-july- 1.pdf?sfvrsn=ec3ffcf3_2
Dengue Situation Update 707 │ 1 Dengue Situation Update 707 19 September 2024 Update on the Dengue situation in the Western Pacific Region This report describes the epidemiology of dengue in the World Health Organization Western Pacific Region. Data are compiled from open sources (national indicator-based surveillance systems) with the exception of Cambodia, Lao People’s Democratic Republic, Viet Nam, and the Philippines, where data are provided by the WHO Country Offices. For the Pacific Island Countries, syndromic surveillance data are provided by the Division of Pacific Technical Support. Information is reported based on countries’ standard dengue case definitions, summary of these definitions and countries’ dengue surveillance systems - included as an annex to this report. Due to differences in surveillance methods and reporting practices, a comparison of trends between countries and areas is not possible, however, national trends can be observed over time. Northern Hemisphere Cambodia As of epidemiological week 36 of 2024, the National Dengue Surveillance System reported a total of 12 689 cases with 36 deaths (Case Fatality Rate (CFR) 0.28%) since 1 January 2024 (Figure 1). This is lower compared to the number reported in 2023 for the same period, with 20 343 cases and 59 deaths. Figure 1: Dengue cases reported weekly in 2024 vs endemic and epidemic alert lines in Cambodia; Source: National Dengue Surveillance System (NDCP/CNM/MOH) Dengue Situation Update 707│ 2 China In August 2024, a total of 1 801 of dengue cases were reported in China. The number of reported cases is higher than the number reported in July 2024 (554 cases). There has been a total of 2 759 dengue cases and no death reported since the beginning of 2024 (Figure 2). Figure 2: Dengue cases reported monthly from 2015-2024 (as of August) in China Source: National Disease Control and Prevention Administration, China Lao People’s Democratic Republic In epidemiological week 36 of 2024 (2 to 8 September 2024), 758 dengue cases and no death were reported (Figure 3). The number of reported cases is higher than the numbers reported in epidemiological week 35 (728 cases with no death), and lower than those in week 36 of 2023 (1 016 cases with one death). The cumulative number of cases reported in 2024 (as of epidemiological week 36) is 13 802. This is a 40.9% decrease compared to the 23 356 cases reported during the same period in 2023. Figure 3: Dengue cases reported weekly from 2018-2024 in Lao PDR Source: National Centre for Laboratory and Epidemiology, Ministry of Health, Lao PDR Dengue Situation Update 707│ 3 Malaysia During epidemiological week 36 of 2024 (1-7 September 2024), an increase of 105 cases (5.95%) was reported with 1 870 as compared to 1 765 cases reported in the previous week (Figure 4). The cumulative number of dengue cases reported up to week 36 of 2024 is 98 442 cases, which is an increase of 19.34% compared to 82 485 cases for the same period in 2023. 89 dengue-related deaths were reported up to week 36 of 2024, increased compared to 59 deaths for the same period in 2023. Figure 4: Dengue cases reported weekly from 2023, 2024 and median 2019-2023 in Malaysia Source: Department of Health, Malaysia Singapore In epidemiological week 36 (1 to 7 September 2024), a total of 190 dengue cases were reported in Singapore. Cumulatively, a total of 11 683 cases (Figure 6) have been reported as of 7 September 2024. When compared to the same period in 2023 (6 428 cases), there has been 81.75% increase in cases reported in 2024. Preliminary results of all positive dengue samples serotyped in August 2024 showed DEN-1, DEN-2, DEN-3 and DEN-4 at 3%, 64.2%, 27.3% and 5.5% respectively. Figure 6: Dengue cases reported weekly from 2019-2024 (as of 7 September 2024) in Singapore Source: Communicable Diseases Division, Ministry of Health, Singapore (Note: Case numbers are derived from the MOH Singapore’s weekly-infectious-disease-bulletin-year-2024_upload as available from MOH | Weekly Infectious Diseases Bulletin) Dengue Situation Update 707│ 4 Viet Nam In epidemiological week 36 (2 to 8 September 2024), a total of 3 825 cases and no death were reported in Viet Nam, an increase by 3.7% compared to 3 689 cases in the previous week. Cumulatively, 71 300 dengue cases including 11 deaths have been reported as of 8 September 2024. Compared to the same period in 2023, the number of cumulative cases decreased by 12.4%, and the number of deaths decreased by 56%. Figure 7: Number of dengue hospital admissions and deaths by week in 2024 compared to 2023, as of week 36, 2024, Viet Nam Source: General Department of Preventive Medicine, Ministry of Health, Viet Nam Note hospitalizations include inpatients and outpatients The alert threshold is a 5-year mean plus 2 standard deviations. Southern Hemisphere Australia From 1 to 18 September 2024, a total of 40 dengue cases were reported in Australia. As of 31 August 2024, the cumulative number of dengue cases is 1 690, which is about 1.4 times higher than the same period in 2023 (714 cases) (Figure 7). Figure 7: Laboratory-confirmed dengue cases reported monthly from 2016-2024 in Australia Source: Department of Health, Australia Note: Graph was updated as of 18 September 2024 Dengue Situation Update 707│ 5 Pacific Islands Countries New Caledonia There is no update for this reporting period. From 1 January to 1 September 2024, eight confirmed dengue cases were reported in New Caledonia (Figure 8). This is higher compared to the same period in 2023, when a total of five dengue cases were reported. Of the eight dengue cases in 2024, two were locally acquired confirmed cases, and the serotypes of the cases were DENV-1 and DENV-2, respectively. There is no ongoing epidemic. Figure 8: Dengue cases reported by month from 1/ 1/ 2022 to 1/ 9/ 2024 in New Caledonia Source: Network of sentinel physicians, New Caledonia Pacific Island Countries and Areas (PICs) – Dengue-like illness (DLI) Surveillance Among the PICs with available surveillance data (18/21 PICs), an upward trend of DLI cases was reported in Micronesia (Federated States of) and Vanuatu in week 35 (ending 9 September), and a downward trend of DLI cases was reported in Fiji, Samoa, Solomon Islands and Wallis & Futuna. The remaining PICs reported either no or low numbers of DLI cases or provided no updates (Figure 9). Dengue Situation Update 707│ 6 Dengue Situation Update 707│ 7 Figure 9. Reported cases of dengue-like illness in Pacific Islands Countries and Areas Source: WHO Division of Pacific Technical Support Note: Caution should be taken in interpreting these data as there may be changes in the number of sentinel sites reporting to the Pacific Syndromic Surveillance System (PSSS). Furthermore, the syndromic case definition of DLI may capture cases with non- dengue acute febrile illnesses (AFI) with similar clinical manifestations to dengue. This includes AFI such as chikungunya, influenza, hantavirus, leptospirosis, malaria, measles, paratyphoid and typhoid fevers, scrub typhus, yellow fever, zika, other diseases. The PSSS may also capture dengue cases under ‘prolonged fever’ surveillance. Alert threshold for DLI is twice the average number of cases seen in the previous 3 weeks. Dengue Situation Update 705│ 8 Annex 1. Summary of dengue case definitions, laboratory sampling and testing methods used for surveillance in Member States Country Case definition Surveillance system Laboratory sampling and testing method Reference Clinically confirmed case Laboratory confirmation required Description Australia Fever, headache, arthralgia, myalgia, rash, nausea and vomiting Yes Dengue is a nationally notifiable disease and cases are monitored through the National Notifiable Diseases Surveillance System (NNDSS) indicator-based surveillance system. Both confirmed and probable cases are nationally notifiable. A confirmed case requires both laboratory definitive evidence and clinical evidence. A probable case requires either laboratory suggestive evidence and clinical evidence and epidemiological evidence, or clinical evidence and household epidemiological evidence. Laboratory definitive evidence: - Isolation of dengue virus, or - Detection of dengue virus by nucleic acid testing, or - Detection of NS1 antigen in the blood by EIA, or - IgG seroconversion or significant increase in antibody levelor fourfold or greater rise in titre to dengue virus (proof by neutralization or another specific test) - Detection of dengue virus-specific IgM in cerebrospinal fluid, in the absence of IgM to Murray valley encephalitis, West Nile virus/Kunjin, or Japanese encephalitis viruses. Laboratory suggestive evidence: - Detection of NS1 antigen in blood by rapid antigen test, or - Detection of dengue virus-specific IgM in blood Epidemiological evidence: - Exposure between 3 – 14 days prior to onset either in a country with known dengue activity or in a dengue-receptive area in Australia where a locally-acquired or imported case has been documented with onset within a month. 1 Dengue Situation Update 705│ 9 Household epidemiological evidence: - Living in the same house as a locally- acquired case in a dengue-receptive area of Australia within a month of onse in the case and at least one case in the chain of epidemiologically linked cases is laboratory confirmed. Cambodia Suspected dengue: very high fever at 39-40 degrees celcius for 2-7 days (usually 3-4 days), with 2 or more of the following signs: flushed face, headache, retro-orbital pain, myalgia/arthralgia, cutaneous rash, haemorrhagic signs (petechiae, positive tourniquet test), and leucopenia. Probable dengue: signs of suspected dengue plus laboratory test results (see right column)) or that the case occurred in an area where the dengue case has been confirmed. Yes National Dengue Control Program (NDCP) enhanced sentinel surveillance system Communicable Disease Control (CDC) syndromic surveillance system (CamEWARN). Health Management Information System (HMIS) collects data on confirmed cases and deaths. Data collected for Cambodia Laboratory Information System (CamLIS), comprised of 32 participating hospital laboratories where NS1 detection is conducted. Laboratory testing: Antibody HI>= 1/1280 or IgM/IgG positive by ELISA test in convalescence serum 2 China 1) Typical dengue fever can be diagnosed with any of the following conditions: - General clinical symptoms of dengue fever, with an epidemiological history (having been to an area where dengue fever is prevalent within 14 days before onset), or living or working in an area where dengue fever cases have occurred within the past month, and with reduced white blood cell count and platelet count (below 100x10^9/L) - No epidemiological history, but with a rash, bleeding tendency, and positive IgG or IgM antibodies in a single serum sample. No Reported to the Chinese Centre for Disease Control and Prevention (China CDC) through the Chinese National Notifiable Infectious Disease Reporting Information System (CNNDS). A clinically diagnosed case with any of the of the following laboratory findings: - Isolation of the dengue virus from the serum, cerebrospinal fluid, blood cells, or tissues of an acute-phase patient - Detection of dengue virus gene sequence by RT-PCR or real-time fluorescent quantitative PCR - Detection of dengue virus NS1 antigen in serum from an acute-phase patient - A fourfold or greater increase in specific antibody titer in the convalescent phase compared to the acute phase. 3, WHO internal communication Dengue Situation Update 705│ 10 2) Dengue Hemorrhagic Fever can be diagnosed when accompanied by any of the following clinical symptoms: - Bleeding tendency, significant bleeding manifestations (such as gastrointestinal bleeding or hemorrhage in the chest, abdomen, or cranium), hepatomegaly, and ascites; and - Laboratory findings including thrombocytopenia (platelet count below 100x10^9/L), hemoconcentration (an increase in hematocrit of more than 20% above normal levels or a decrease of more than 20% after fluid resuscitation), and hypoalbuminemia. 3) Dengue Shock Syndrome: Patients with dengue hemorrhagic fever presenting with cold and clammy skin, restlessness, rapid and weak pulse, low blood pressure with a narrow pulse pressure (less than 20mmHg or 2.7kPa), and reduced urine output. Lao People's Democratic Republic WHO dengue case classification (2009) † No National Surveillance System for Notifiable Selected Diseases, indicator-based surveillance system that consists of passive weekly reports of clinically suspected cases, on admission, from all health-care facilities across the country. 4 Malaysia WHO dengue case classification (2009) † Yes National Dengue Surveillance System, indicator-based surveillance system All suspected cases are to be tested by the following laboratory tests: Rapid Combo Test (RCT) (NS1, IgM, IgG), Dengue Antigen and Serology tests by ELISA, Dengue Viral RNA Detection (Real time RT-PCR), Viral Isolation 5 Philippines WHO dengue case classification (2009) † Yes Philippine Integrated Disease Surveillance and Response (PIDSR), indicator-based surveillance system. Reporting delays of 2-3 weeks, making comparison of current weekly and cumulative figures with previous years difficult. Confirmed dengue is a suspect case with positive (+) viral culture isolation and/or PCR. NS1 (+), IgM is used to identify probable dengue. 6, 7, 8 Dengue Situation Update 705│ 11 Singapore (endemic) Fever, headache, backache, myalgia, rash, abdominal discomfort and thrombocytopenia and laboratory testing (see right column) Yes Dengue is a legally notifiable disease in Singapore and notifying the Ministry of Health should not be later than 24 hours from the time of diagnosis. Laboratory confirmation is done using standard diagnostic tests for the detection of dengue NS1 antigen, IgM and IgG, or RT-PCR. 9, 10 Viet Nam (endemic) Acute onset of fever continuously lasting from 2-7 days AND at least 2 of the following: haemorrhagic manifestation /presentation; headache, loss of appetite, nausea, vomiting; rash; muscle pain, joint pain, orbital pain; lethargy; abdominal pain. No As per the MOH dengue surveillance guideline, in routine surveillance MAC-ELISA is conducted for at least 7% and virus isolation is conducted for at least 3% of clinical cases. In an outbreak, at least 5 to 10 suspected cases are tested. 11 Pacific Island Countries WHO dengue case classification (2009) † No Pacific Syndromic Surveillance System Confirmed case: Isolation of dengue virus or detection of dengue-specific antigen or antibodies in tissue, blood, CSF or other body fluid by an advanced laboratory test 12 Only the minimum criteria required for fulfilling a clinical dengue case definition are included here; additional signs and symptoms required for more severe forms are not listed. † A probable dengue case is defined as any case living in or travel to dengue endemic area with fever and two or more of the following: nausea, vomiting, rash, aches and pains, positive tourniquet test, leucopenia and any warning sign. A case with warning signs is defined as a clinically diagnosed case with any of the following: abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleed, lethargy, restlessness, liver enlargement > 2 cm and increase in haematocrit concurrent with rapid decrease in platelet count. Severe dengue is defined as severe plasma leakage leading to any of the following: shock, fluid accumulation with respiratory distress OR severe bleeding as evaluated by clinician OR severe organ involvement of liver (aspartate amino transferase or alanine amino transferase ≥ 1000), central nervous system (impaired consciousness) or heart and other organs.10 References: 1. Australian Government Department of Health AGDo. Dengue virus infection surveillance and case definition [updated 14 June 2022 and 1 January 2018 respectively] Available from: https://www.health.gov.au/diseases/dengue-virus-infection, and https://www.health.gov.au/sites/default/files/documents/2022/06/dengue-virus-infection-surveillance-case-definition.pdf 2. Cambodia Ministry of Health NCfP, Entomology and Malaria Control. National Guideline for Clinical Management of Dengue, 2018. 2018. Available from: https://niph.org.kh/niph/uploads/library/pdf/GL055_National_guideline_for_ClM_Dengue.pdf. 3. China CDC. Dengue surveillance guideline. Available from: https://www.chinacdc.cn/jkzt/crb/zl/dgr/jszl_2235/201810/P020181010391462131548.pdf 4. Khampapongpane B, Lewis HC, Ketmayoon P, Phonekeo D, Somoulay V, Khamsing A, et al. National dengue surveillance in the Lao People's Democratic Republic, 2006-2012: epidemiological and laboratory findings. Western Pac Surveill Response J. 2014;5(1):7-13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24734212. 5. Ministry of Health Malaysia DCD. Case definitions for infectious diseases in Malaysia. 2017. Available from: https://www.moh.gov.my/moh/resources/Penerbitan/Garis%20Panduan/Pengurusan%20KEsihatan%20&%20kawalan%20pykit/Case_Definition_Of_Infectious_Disease_3rd_Edition_2017.pdf 6. Secretary PDoHOot. Guidelines for the Nationwide Implementation of Dengue Rapid Diagnostic Test (RDT), Administrative order No.2016-0043. 2016(2016-0043). 7. Secretary PDoHOot. Revised Dengue Clinical Case Management Guidelines 2011, Administrative order No.2012-0006. 2012 22 March 2012. Report No. 8. Diseases SNCfI. Diseases and Conditions, Dengue 2020 [updated 14 September 2020. Available from: https://www.doh.gov.ph/Health-Advisory/Dengue. 9. National Centre for Infectious Diseases, Dengue. Available from: https://www.ncid.sg/Health-Professionals/Diseases-and-Conditions/Pages/Dengue.aspx 10. National Environment Agency. Surveillance and Epidemiology Programme [updated 21 April 2023]. Available from: https://www.nea.gov.sg/corporate-functions/resources/research/surveillance-and- epidemiology-programme#Ehi%20Diagnostics%20Unit Dengue Situation Update 705│ 12 11. Viet Nam Ministry of Health VNMo. Circular 54/2015 / TT-BYT 2015 [updated 26 April 2016. Available from: https://syt.thuathienhue.gov.vn/?gd=27&cn=108&tc=3993. 12. Pacific Islands Outbreak Manual. Available from: https://www.pphsn.net/resources/outbreak-manual/ 13. WHO dengue outbreak toolbox. Available from: https://www.who.int/docs/default-source/outbreak-toolkit/updates-documents_july-5/dengue-outbreak-data-collection-toolbox---inis-3-july- 1.pdf?sfvrsn=ec3ffcf3_2
Dengue Situation Update 708│ 1 Dengue Situation Update 708 3 October 2024 Update on the Dengue situation in the Western Pacific Region This report describes the epidemiology of dengue in the World Health Organization Western Pacific Region. Data are compiled from open sources (national indicator-based surveillance systems) with the exception of Cambodia, Lao People’s Democratic Republic, Viet Nam, and the Philippines, where data are provided by the WHO Country Offices. For the Pacific Island Countries, syndromic surveillance data are provided by the Division of Pacific Technical Support. Information is reported based on countries’ standard dengue case definitions, summary of these definitions and countries’ dengue surveillance systems - included as an annex to this report. Due to differences in surveillance methods and reporting practices, a comparison of trends between countries and areas is not possible, however, national trends can be observed over time. Northern Hemisphere Cambodia As of epidemiological week 38 of 2024, the National Dengue Surveillance System reported a total of 13 752 cases with 37 deaths (Case Fatality Rate (CFR) 0.27%) since 1 January 2024 (Figure 1). This is lower compared to the number reported in 2023 for the same period, with 22 850 cases and 61 deaths. Figure 1: Dengue cases reported weekly in 2024 vs endemic and epidemic alert lines in Cambodia; Source: National Dengue Surveillance System (NDCP/CNM/MOH) Dengue Situation Update 708 │ 2 China There is no update for this reporting period. In August 2024, a total of 1 801 of dengue cases were reported in China. The number of reported cases is higher than the number reported in July 2024 (554 cases). There has been a total of 2 759 dengue cases and no death reported since the beginning of 2024 (Figure 2). Figure 2: Dengue cases reported monthly from 2015-2024 (as of August) in China Source: National Disease Control and Prevention Administration, China Lao People’s Democratic Republic In epidemiological week 38 of 2024 (16 to 22 September 2024), 744 dengue cases and no death were reported (Figure 3). The number of reported cases is higher than the numbers reported in epidemiological week 37 (544 cases with no death), and lower than those in week 38 of 2023 (999 cases with no death). The cumulative number of cases reported in 2024 (as of epidemiological week 38) is 15 090. This is a 40.95% decrease compared to the 25 555 cases reported during the same period in 2023. Figure 3: Dengue cases reported weekly from 2018-2024 in Lao PDR Source: National Centre for Laboratory and Epidemiology, Ministry of Health, Lao PDR Dengue Situation Update 708 │ 3 Malaysia During epidemiological week 38 of 2024 (15-21 September 2024), a decrease of 280 cases (15.6%) was reported with 1 514 as compared to 1 794 cases reported in the previous week (Figure 4). The cumulative number of dengue cases reported up to week 38 of 2024 is 101 750 cases, which is an increase of 16.7% compared to 87 175 cases for the same period in 2023. 91 dengue-related deaths were reported up to week 38 of 2024, increased compared to 62 deaths for the same period in 2023. Figure 4: Dengue cases reported weekly from 2023, 2024 and median 2019-2023 in Malaysia Source: Department of Health, Malaysia Singapore In epidemiological week 38 (15 to 21 September 2024), a total of 182 dengue cases, with no dengue haemorrhagic fever, were reported in Singapore. Cumulatively, a total of 12 067 cases (Figure 6) have been reported as of 21 September 2024. When compared to the same period in 2023 (7 060 cases), there has been 70.9% increase in cases reported in 2024. Preliminary results of all positive dengue samples serotyped in September 2024 showed DEN-1, DEN-2, DEN-3 and DEN-4 at 10%, 45%, 37.3% and 7.7% respectively. Figure 6: Dengue cases reported weekly from 2019-2024 (as of 21 September 2024) in Singapore Source: Communicable Diseases Division, Ministry of Health, Singapore (Note: Case numbers are derived from the MOH Singapore’s weekly-infectious-disease-bulletin-year-2024_upload as available from MOH | Weekly Infectious Diseases Bulletin) Dengue Situation Update 708 │ 4 Viet Nam In epidemiological week 38 (16 to 22 September 2024), a total of 3 377 cases and no death were reported in Viet Nam, an increase by 3.7% compared to 2 808 cases in the previous week. Cumulatively, 76 838 dengue cases including 12 deaths have been reported as of 22 September 2024. Compared to the same period in 2023, the number of cumulative cases decreased by 18.5%, and the number of deaths decreased by 53.8%. Figure 7: Number of dengue hospital admissions and deaths by week in 2024 compared to 2023, as of week 38, 2024, Viet Nam Source: General Department of Preventive Medicine, Ministry of Health, Viet Nam Note hospitalizations include inpatients and outpatients The alert threshold is a 5-year mean plus 2 standard deviations. Southern Hemisphere Australia From 1 to 30 September 2024, a total of 89 dengue cases were reported in Australia. As of 30 August 2024, the cumulative number of dengue cases is 1 788, which is about 1.2 times higher than the same period in 2023 (823 cases) (Figure 7). Figure 7: Laboratory-confirmed dengue cases reported monthly from 2016-2024 in Australia Source: Department of Health, Australia Note: Graph was updated as of 30 September 2024 Dengue Situation Update 708 │ 5 Pacific Islands Countries New Caledonia There is no update for this reporting period. From 1 January to 1 September 2024, eight confirmed dengue cases were reported in New Caledonia (Figure 8). This is higher compared to the same period in 2023, when a total of five dengue cases were reported. Of the eight dengue cases in 2024, two were locally acquired confirmed cases, and the serotypes of the cases were DENV-1 and DENV-2, respectively. There is no ongoing epidemic. Figure 8: Dengue cases reported by month from 1/ 1/ 2022 to 1/ 9/ 2024 in New Caledonia Source: Network of sentinel physicians, New Caledonia Pacific Island Countries and Areas (PICs) – Dengue-like illness (DLI) Surveillance Among the PICs with available surveillance data (18/21 PICs), an upward trend of DLI cases was reported in Fiji, French Polynesia and Solomon Islands in week 36 (ending 23 September), and a downward trend of DLI cases was reported in Micronesia, Federated States of (FSM). The remaining PICs reported either no or low numbers of DLI cases or provided no updates (Figure 9). Dengue Situation Update 708 │ 6 Dengue Situation Update 708 │ 7 Figure 9. Reported cases of dengue-like illness in Pacific Islands Countries and Areas Source: WHO Division of Pacific Technical Support Note: Caution should be taken in interpreting these data as there may be changes in the number of sentinel sites reporting to the Pacific Syndromic Surveillance System (PSSS). Furthermore, the syndromic case definition of DLI may capture cases with non- dengue acute febrile illnesses (AFI) with similar clinical manifestations to dengue. This includes AFI such as chikungunya, influenza, hantavirus, leptospirosis, malaria, measles, paratyphoid and typhoid fevers, scrub typhus, yellow fever, zika, other diseases. The PSSS may also capture dengue cases under ‘prolonged fever’ surveillance. Alert threshold for DLI is twice the average number of cases seen in the previous 3 weeks. Dengue Situation Update 705│ 8 Annex 1. Summary of dengue case definitions, laboratory sampling and testing methods used for surveillance in Member States Country Case definition Surveillance system Laboratory sampling and testing method Reference Clinically confirmed case Laboratory confirmation required Description Australia Fever, headache, arthralgia, myalgia, rash, nausea and vomiting Yes Dengue is a nationally notifiable disease and cases are monitored through the National Notifiable Diseases Surveillance System (NNDSS) indicator-based surveillance system. Both confirmed and probable cases are nationally notifiable. A confirmed case requires both laboratory definitive evidence and clinical evidence. A probable case requires either laboratory suggestive evidence and clinical evidence and epidemiological evidence, or clinical evidence and household epidemiological evidence. Laboratory definitive evidence: - Isolation of dengue virus, or - Detection of dengue virus by nucleic acid testing, or - Detection of NS1 antigen in the blood by EIA, or - IgG seroconversion or significant increase in antibody levelor fourfold or greater rise in titre to dengue virus (proof by neutralization or another specific test) - Detection of dengue virus-specific IgM in cerebrospinal fluid, in the absence of IgM to Murray valley encephalitis, West Nile virus/Kunjin, or Japanese encephalitis viruses. Laboratory suggestive evidence: - Detection of NS1 antigen in blood by rapid antigen test, or - Detection of dengue virus-specific IgM in blood Epidemiological evidence: - Exposure between 3 – 14 days prior to onset either in a country with known dengue activity or in a dengue-receptive area in Australia where a locally-acquired or imported case has been documented with onset within a month. 1 Dengue Situation Update 705│ 9 Household epidemiological evidence: - Living in the same house as a locally- acquired case in a dengue-receptive area of Australia within a month of onse in the case and at least one case in the chain of epidemiologically linked cases is laboratory confirmed. Cambodia Suspected dengue: very high fever at 39-40 degrees celcius for 2-7 days (usually 3-4 days), with 2 or more of the following signs: flushed face, headache, retro-orbital pain, myalgia/arthralgia, cutaneous rash, haemorrhagic signs (petechiae, positive tourniquet test), and leucopenia. Probable dengue: signs of suspected dengue plus laboratory test results (see right column)) or that the case occurred in an area where the dengue case has been confirmed. Yes National Dengue Control Program (NDCP) enhanced sentinel surveillance system Communicable Disease Control (CDC) syndromic surveillance system (CamEWARN). Health Management Information System (HMIS) collects data on confirmed cases and deaths. Data collected for Cambodia Laboratory Information System (CamLIS), comprised of 32 participating hospital laboratories where NS1 detection is conducted. Laboratory testing: Antibody HI>= 1/1280 or IgM/IgG positive by ELISA test in convalescence serum 2 China 1) Typical dengue fever can be diagnosed with any of the following conditions: - General clinical symptoms of dengue fever, with an epidemiological history (having been to an area where dengue fever is prevalent within 14 days before onset), or living or working in an area where dengue fever cases have occurred within the past month, and with reduced white blood cell count and platelet count (below 100x10^9/L) - No epidemiological history, but with a rash, bleeding tendency, and positive IgG or IgM antibodies in a single serum sample. 2) Dengue Hemorrhagic Fever can be diagnosed when accompanied by any of the following clinical symptoms: No Reported to the Chinese Centre for Disease Control and Prevention (China CDC) through the Chinese National Notifiable Infectious Disease Reporting Information System (CNNDS). A clinically diagnosed case with any of the of the following laboratory findings: - Isolation of the dengue virus from the serum, cerebrospinal fluid, blood cells, or tissues of an acute-phase patient - Detection of dengue virus gene sequence by RT-PCR or real-time fluorescent quantitative PCR - Detection of dengue virus NS1 antigen in serum from an acute-phase patient - A fourfold or greater increase in specific antibody titer in the convalescent phase compared to the acute phase. 3, WHO internal communication Dengue Situation Update 705│ 10 - Bleeding tendency, significant bleeding manifestations (such as gastrointestinal bleeding or hemorrhage in the chest, abdomen, or cranium), hepatomegaly, and ascites; and - Laboratory findings including thrombocytopenia (platelet count below 100x10^9/L), hemoconcentration (an increase in hematocrit of more than 20% above normal levels or a decrease of more than 20% after fluid resuscitation), and hypoalbuminemia. 3) Dengue Shock Syndrome: Patients with dengue hemorrhagic fever presenting with cold and clammy skin, restlessness, rapid and weak pulse, low blood pressure with a narrow pulse pressure (less than 20mmHg or 2.7kPa), and reduced urine output. Lao People's Democratic Republic WHO dengue case classification (2009) † No National Surveillance System for Notifiable Selected Diseases, indicator-based surveillance system that consists of passive weekly reports of clinically suspected cases, on admission, from all health-care facilities across the country. 4 Malaysia WHO dengue case classification (2009) † Yes National Dengue Surveillance System, indicator-based surveillance system All suspected cases are to be tested by the following laboratory tests: Rapid Combo Test (RCT) (NS1, IgM, IgG), Dengue Antigen and Serology tests by ELISA, Dengue Viral RNA Detection (Real time RT-PCR), Viral Isolation 5 Philippines WHO dengue case classification (2009) † Yes Philippine Integrated Disease Surveillance and Response (PIDSR), indicator-based surveillance system. Reporting delays of 2-3 weeks, making comparison of current weekly and cumulative figures with previous years difficult. Confirmed dengue is a suspect case with positive (+) viral culture isolation and/or PCR. NS1 (+), IgM is used to identify probable dengue. 6, 7, 8 Singapore (endemic) Fever, headache, backache, myalgia, rash, abdominal discomfort and thrombocytopenia and laboratory testing (see right column) Yes Dengue is a legally notifiable disease in Singapore and notifying the Ministry of Health should not be later than 24 hours from the time of diagnosis. Laboratory confirmation is done using standard diagnostic tests for the detection of dengue NS1 antigen, IgM and IgG, or RT-PCR. 9, 10 Dengue Situation Update 705│ 11 Viet Nam (endemic) Acute onset of fever continuously lasting from 2-7 days AND at least 2 of the following: haemorrhagic manifestation /presentation; headache, loss of appetite, nausea, vomiting; rash; muscle pain, joint pain, orbital pain; lethargy; abdominal pain. No As per the MOH dengue surveillance guideline, in routine surveillance MAC-ELISA is conducted for at least 7% and virus isolation is conducted for at least 3% of clinical cases. In an outbreak, at least 5 to 10 suspected cases are tested. 11 Pacific Island Countries WHO dengue case classification (2009) † No Pacific Syndromic Surveillance System Confirmed case: Isolation of dengue virus or detection of dengue-specific antigen or antibodies in tissue, blood, CSF or other body fluid by an advanced laboratory test 12 Only the minimum criteria required for fulfilling a clinical dengue case definition are included here; additional signs and symptoms required for more severe forms are not listed. † A probable dengue case is defined as any case living in or travel to dengue endemic area with fever and two or more of the following: nausea, vomiting, rash, aches and pains, positive tourniquet test, leucopenia and any warning sign. A case with warning signs is defined as a clinically diagnosed case with any of the following: abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleed, lethargy, restlessness, liver enlargement > 2 cm and increase in haematocrit concurrent with rapid decrease in platelet count. Severe dengue is defined as severe plasma leakage leading to any of the following: shock, fluid accumulation with respiratory distress OR severe bleeding as evaluated by clinician OR severe organ involvement of liver (aspartate amino transferase or alanine amino transferase ≥ 1000), central nervous system (impaired consciousness) or heart and other organs.10 References: 1. Australian Government Department of Health AGDo. Dengue virus infection surveillance and case definition [updated 14 June 2022 and 1 January 2018 respectively] Available from: https://www.health.gov.au/diseases/dengue-virus-infection, and https://www.health.gov.au/sites/default/files/documents/2022/06/dengue-virus-infection-surveillance-case-definition.pdf 2. Cambodia Ministry of Health NCfP, Entomology and Malaria Control. National Guideline for Clinical Management of Dengue, 2018. 2018. Available from: https://niph.org.kh/niph/uploads/library/pdf/GL055_National_guideline_for_ClM_Dengue.pdf. 3. China CDC. Dengue surveillance guideline. Available from: https://www.chinacdc.cn/jkzt/crb/zl/dgr/jszl_2235/201810/P020181010391462131548.pdf 4. Khampapongpane B, Lewis HC, Ketmayoon P, Phonekeo D, Somoulay V, Khamsing A, et al. National dengue surveillance in the Lao People's Democratic Republic, 2006-2012: epidemiological and laboratory findings. Western Pac Surveill Response J. 2014;5(1):7-13. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24734212. 5. Ministry of Health Malaysia DCD. Case definitions for infectious diseases in Malaysia. 2017. Available from: https://www.moh.gov.my/moh/resources/Penerbitan/Garis%20Panduan/Pengurusan%20KEsihatan%20&%20kawalan%20pykit/Case_Definition_Of_Infectious_Disease_3rd_Edition_2017.pdf 6. Secretary PDoHOot. Guidelines for the Nationwide Implementation of Dengue Rapid Diagnostic Test (RDT), Administrative order No.2016-0043. 2016(2016-0043). 7. Secretary PDoHOot. Revised Dengue Clinical Case Management Guidelines 2011, Administrative order No.2012-0006. 2012 22 March 2012. Report No. 8. Diseases SNCfI. Diseases and Conditions, Dengue 2020 [updated 14 September 2020. Available from: https://www.doh.gov.ph/Health-Advisory/Dengue. 9. National Centre for Infectious Diseases, Dengue. Available from: https://www.ncid.sg/Health-Professionals/Diseases-and-Conditions/Pages/Dengue.aspx 10. National Environment Agency. Surveillance and Epidemiology Programme [updated 21 April 2023]. Available from: https://www.nea.gov.sg/corporate-functions/resources/research/surveillance-and- epidemiology-programme#Ehi%20Diagnostics%20Unit 11. Viet Nam Ministry of Health VNMo. Circular 54/2015 / TT-BYT 2015 [updated 26 April 2016. Available from: https://syt.thuathienhue.gov.vn/?gd=27&cn=108&tc=3993. 12. Pacific Islands Outbreak Manual. Available from: https://www.pphsn.net/resources/outbreak-manual/ 13. WHO dengue outbreak toolbox. Available from: https://www.who.int/docs/default-source/outbreak-toolkit/updates-documents_july-5/dengue-outbreak-data-collection-toolbox---inis-3-july- 1.pdf?sfvrsn=ec3ffcf3_2