Dengue Control through Schoolchildren in Thailand By
Dr Yongyuth Wangroongsarb Vector-Borne Disease Control Programme, Department of Communicable Disease Control, Ministry of Public Health Nonthaburi 11000, Thailand Fax 66-2-965-9007
Abstract Dengue haemorrhagic fever (DHF) was first recognized in Thailand in 1949. Although the morbidity from DHF seems to have stabilized over the past few years, the mortality and case fatality rates have been dramatically brought down. However, DHF remains a crucial public health problem, particularly for young children who are the most affected. After several trials on dengue control, a national dengue control programme was started through the schoolchildren approach in 1992. With a target of reducing DHF morbidity among schoolchildren from 447.8/100 000 to 240/100 000 by 1996, and to 160/100 000 by 2001, the project had achieved the goal of morbidity reduction to 219.2/100 000 pop. by 1996. The project was also evaluated from 96 school samples nationwide during September-November 1994. It was found that 93.7% of the schools sampled had been involved in the project. 62.5% of the provinces and 64.3% of the districts surveyed showed decreasing morbidity rates among both schoolchildren and all other age groups. The majority of both health and education staff had positive attitudes to the objectives and strategies of the project. However, the main constraints were low frequency and non-regularity of the teaching and learning process, lack of consistent supervision from health staff, poor communication and coordination between different organizational personnel and, lastly, insufficiency and irregular and delayed supplies for school support. These weaknesses have been vigorously overcome during the past 2-3 years in order to improve the project implementation.
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Introduction Dengue haemorrhagic fever, a severe form of classical dengue, is one of the tropical diseases transmitted by Aedes mosquito. The disease has worldwide distribution, but is more prevalent in the regions of south-east Asia, western and eastern Pacific islands, the Caribbean and Latin America(1,2). It is also stated that DHF is a new, emerging or re-emerging infectious disease, which is threatening people living in many regions(3,4). In Thailand, for almost 50 years after the first recognition of the disease in 1949, DHF has spread across the country. It is considered an endemic disease in certain areas(5). With the availability now of better medical and health care facilities to communities, there has been a sharp decrease in the death and case fatality rates during the past few decades; however, the morbidity rate seems to remain rather stable.
Epidemiological situation Morbidity and mortality After DHF was first recognized in 1949 at Bangkok, more than 1500 cases were reported during 1950-1957(1,6). Later in 1958, there was an outbreak of DHF in Bangkok and other surrounding provinces(1,7,8). Since then, the number of reported cases has been gradually increasing over time, from 2158 cases in 1958 to 7663 cases in 1965. During 19581967, the disease occurrence was confined only to Bangkok and other big cities, but later in 1978, the disease spread across the country in urban areas and then to rural areas with a larger number of cases – 12 547 in 1978 to 80 076 in 1985. In 1987, the cases touched a high of 174 285, which was the largest number ever recorded(7). Since 1990, the number of the reported cases has been declining every year, approximately 40 000-60 000 cases a year (Fig.1).
Figure 1. Trend of DHF morbidity and mortality rates in Thailand, 1958-1997
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Table 1. Morbidity, mortality and case fatality rates of DHF in Thailand, 1958-1996. Year 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997* Cases 2158 2706 160 1851 561 5947 2215 7663 5816 2060 6430 8670 2767 11540 23782 8280 8160 17767 9616 38768 12547 11478 43328 25670 22250 30025 69101 80076 27837 17428 5 26926 74391 92005 43511 41125 67017 51688 60330 37929 43107 Deaths 300 296 21 65 36 308 173 385 137 65 71 109 47 299 685 315 328 438 361 756 308 127 403 257 159 229 496 542 236 1,007 179 290 414 137 136 222 140 183 116 81 Morbidity Mortality Rate Rate (/100,000) (/100,000) 8.87 10.92 0.62 6.99 2.05 20.88 7.49 25.06 18.47 6.34 19.16 25.11 7.61 30.88 61.81 20.92 20.05 42.43 22.43 88.28 27.93 24.92 91.96 54.06 45.89 60.71 137.12 154.94 52.88 325.13 49.37 133.95 163.43 76.79 71.16 114.88 87.47 101.46 63.09 71.71 1.23 1.19 0.08 0.25 0.13 1.08 0.59 1.26 0.44 0.20 0.21 0.32 0.13 0.80 1.78 0.80 0.81 1.05 0.84 1.72 0.68 0.28 0.85 0.54 0.33 0.46 0.98 1.05 0.45 1.88 0.33 0.52 0.74 0.24 0.24 0.38 0.24 0.31 0.19 0.13 CFR (%) 13.90 10.94 13.13 3.51 6.42 5.18 7.81 5.02 2.36 3.16 1.10 1.26 1.70 2.59 2.88 3.80 4.02 2.47 3.75 1.95 2.45 1.11 0.93 1.00 0.71 0.76 0.72 0.68 0.85 0.58 0.66 0.39 0.45 0.31 0.33 0.33 0.27 0.30 0.31 0.19
number of deaths due to DHF has fluctuated during the past few decades, the mortality rate seems to be on the decrease during the same period – from 1.19/100 000 in 1959 to 0.19/100 000 in 1996. Similar is the trend in the case fatality rate – down from 13.9% in 1958 to 0.31% in 1996 (Table 1). This seems to be due to improvements in medical care and services as well as better accessibility to medical services and health facilities of people in communities. Nevertheless, the case fatality rate in the past few years seems to be rather stable.
Seasonal variation DF/DHF occurs mostly in the rainy season (from May to October) which coincides with the reopening of schools for new sessions(1,9). The peak of the disease outbreak usually is reached in June and July (see Fig. 2). It is noticed that manmade containers are the most potential Aedes breeding places commonly found in the rainy season, and shortage of water supply at some periods of time had resulted in a significant increase in the number of water containers even though piped water supply was available(10). Moreover, schools and households in villages, with high disease prevalence, had a higher number of water containers that resulted in more vector populations(11).
Age distribution DHF cases are mostly found in the age group 5-9 years. Annually, the number of cases in the age group of 5-14 years accounts for 70-75% of total reported cases (Fig. 3). The average morbidity rate during the past five years (1987-1991)
* data as of Oct 2, 1997 Source: Division of Epidemiology, Ministry of Public Health, Thailand.
In 1958, 300 persons died of DHF (1.23 deaths/100 000). Although the
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Figure 2. Seasonal variation of DHF in Thailand, 1987-1996. Reported DHF cases distributed by month, Thailand. (medians of 1987-1991 and 1992-1996)
Figure 3. Age group distribution of DHF cases in Thailand, 1986-1996 Proportional percentage of DHF cases by specific age-groups. (means of 1986-1989, 1990-1993 and 1994-1996)
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among the 5-14-year-old children was extremely high – 447.8 cases/100 000 a year. This number is about 3-4 times (7,9) higher than that of all age groups . It has been noticed that the age distribution of the disease has shifted to the higher age group during the past decade, from 09 years to 5-14 years (Fig. 3).
Conventional methods of dengue prevention and control Currently, the dengue programme is an integrated programme which has a community-based prevention and control approach. It is now recognized that without community participation, dengue control is neither achieveable nor sustainable(13,14). Several models of dengue control through the community participation approach have been studied during the past decades(15,16). Health volunteers like village health volunteers, village leaders, village councils, monks, teachers, elderly women and other local prime movers in villages were encouraged to participate in the programme. Periodic clean-up campaigns were organized by health personnel to effect vector source reduction and other environmental modifications. Social mobilization by utilizing the mass media, community talks and public relations, and various other strategies were used to initiate and encourage communities to participate in the search, elimination and destruction of the aquatic foci which were potential larval breeding sites. Incentives and rewards were also provided to volunteers and community members to promote their participation and to help them develop health education and health communication. However, these model 56
also did not prove viable due to inconsistency and non-sustainability of their participation in dengue control activities. This could have been due to the reason that the suitability of the community participation approach was dependent on various socioeconomic, cultural and political features in the community. A small and well-organized community, which is culturally and economically more homo-genous, is more suitable for community initiative than the rapidly growing, socially complex and multicultural urban communities(17). It is well recognized that dengue control activities must be integrated with other health sectors and the community. Dengue control in primary schools is another development model which uses primary school children as volunteers for vector control in schools and communities. This school-based approach seems to be working success-fully in Thailand after five years of programme implementation.
Dengue control through schoolchildren According to epidemiological analysis, the disease victims are young school children aged below 15 years. They are mostly primary school children (grades 1-6) and secondary schoolchildren (grades 7-9). The peak of the disease usually occurs in June and July, the same period as the schools commence. Actually, the disease is transmitted by Aedes mosquitoes which are day-time biting vectors. Thus, it is argued that the disease transmission might be happening in school areas(5,7,9,18). Several research studies on model development of DHF prevention by the community-based approach focusing on Dengue Bulletin – Vol 21, 1997
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primary schools had been conducted in (15.19,20) . In these studies, several provinces schoolchildren were educated about dengue, its transmission and prevention. They were initiated and encouraged as health volunteers to participate in vector survey and vector control in their schools while local health workers technically supervized and promptly supported them with supplies. The outcome of this strategic approach, in terms of disease prevention, was satisfactorily successful as compared with other conventional approaches. Aedes larval indices were reduced by 60-80% in comparison with the results obtained from conventional models(15,19). It was also found that schoolchildren were more effective than village volunteers, particularly in urban communities(19). These studies substantially encouraged the Ministry of Public Health to revise the control strategies. Finally, in cooperation with the Ministry of Education, the Ministry of Public Health decided to establish a joint project for national dengue campaign in primary schools, which started in 1992.
and 160/100 000 by 2001(18). Additionally, another target is to reduce the disease transmission by reducing the container index (C.I.) in schools to as low as 10%(9).
Strategies According to the project, the interventions to be applied are:
Providing health education to all primary schoolchildren by integrating the “dengue message” into the current curriculum of the national primary education programme. Producing and publishing manuals and guidelines related to dengue infection and its control for the teaching staff in order to use them as teaching aids. Producing some additional reading books related to dengue for each level of schoolchildren. Producing several types of health education materials such as posters, pamphlets and audiovisual aids to support the schools involved in the project for educating schoolchildren. Organizing both health and education staff at local level in every province and district to carry on the project, orientating them about the project and urging the local health staff to supervise all schools involved in the project. Distributing and disseminating all health-related materials and other supplies to all schools involved in the project. 57
Purposes and targets The main purpose of the project is to educate schoolchildren about dengue and its transmission as well as about the methods for its prevention. Schoolchildren are also encouraged to participate in vector control activities by eliminating Aedes breeding places within their school and household areas(18). The target of the joint project is to reduce the DHF morbidity rate among schoolchildren to 240/100 000 by 1996
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All primary schoolchildren are expected to participate in vector control by elimi-nating Aedes breeding places within their schools and household areas. Some senior students would be trained and encouraged to act as health volunteers in order to advocate health education in their communities as well.
Project implementation The project has been implemented through the joint management of both health and educational organizations. It is eventually run by a number of joint committees (organizational staff of both departments) from central to peripheral levels. Generally, the committee may be divided into two bodies – a steering committee and a technical coordination and operation committee. The steering committee is an executive committee principally comprised of health professionals and under the chairmanship of the Health Minister. This committee is responsible for administrative and management issues of the joint project, including resource allocation and adjustment(18). The technical coordination and operation committee is responsible for project implementation in terms of technical support, monitoring and supervision, including management of logistics and supplies. The technical committee may be categorized into two levels, central and peripheral levels. At the central level, there are several sub-committees. Most of them are mainly dominated by education professionals. The technical committee and subcommittees are responsible for coordinat-
ing the work of both health and education organizational staff to establish a national curriculum for primary education by integrating health information and dengue message into the current curriculum, producing guidelines and manuals for teaching staff and additional reading books for schoolchildren, and preparing health educational aids and materials to supply to all schools involved in the project. In addition, they are also responsible for monitoring and evaluating the project implementation(18). At the peripheral level, from province to district, there are joint committees at each level. These joint committees are a kind of working groups or task forces mainly responsible for project operation. The working groups or committees at either provincial or district levels are, in fact, composed of both local health and education professionals, including some local politicians and other local officers. These committees are carrying out project activities in all schools involved by orientating both local health and education personnel about the dengue control programme, organizing staff from both sectors for the project; technically supervising the schools involved; managing and disseminating supplies to schools, and monitoring and evaluating project activities and outcomes. The work plans or plans of action at provincial and district levels are organized and prepared by the committees at those levels. Work plans at the provincial level are submitted to the steering committee at the central level for approval and budget allocation(18). According to the plan, monitoring of activities and project evaluations were to be done on a regular basis in order to provide feedback to the Health Ministry Dengue Bulletin – Vol 21, 1997
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and other stakeholders about the success and shortcomings of the control programme.
Division of Environmental Health, Municipality Division of Education, Municipality
Responsible and contributing agencies Because of the joint nature of the project, the contributing agencies include both health and education department staff. They are categorized into several levels as follows:
At district level
District Health Office District Primary Education Office Division of Environmental Health, Municipality Division of Education, Municipality
At central level Ministry of Public Health
Vector-borne Programme
Disease
Control
Budgeting and funding support The project has been implemented with financial support from the Central (national government) budget, which has been proposed under a budgetline of the Vector-Borne Disease Control Programme under the CDC Department, Ministry of Public Health. The expenditure for the project during 1992-1997 was about Baht 62.07 million or US$ 2.483 million (25 Baht = 1US$), which was expended mainly for supplies, including chemicals, for school support.
Department of Communicable Disease Control (Department of CDC) Division of School Department of Health Health,
Division of Epidemiology under the Office of Permanent Secretary
Ministry of Education
Office of the National Primary Education Commission Department of Curriculum Instruction Development and
Department of Teacher Education
Stakeholders and their concerns In this project, there are several levels of stakeholders. At each level, each stakeholder has its own concerns that are different from one another. They are dependent on what roles and responsibilities each stakeholder actually has (Table 2). Besides the CDC department, other stakeholders contributing to the 59
At provincial level
Provincial Health Office Provincial Primary Education Office
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project are the joint committees at both central and peripheral levels as well as the provincial primary education commission and provincial health authorities. At the Central level, the steering committee plays a vital and important role in administration and project management, including resource allocation. Its concerns therefore include justification of resource allocation as well as cost-effectiveness of the project. The technical coordination and operation committees mainly concern themselves with achieving successful organization of the project, effectiveness of its manage-ment and consistency and quality of its performance. At the peripheral level, the provincial joint committees are mainly responsible for technical support and management during project implementation. The success of the project partly depends on their performance. So, their concerns are to ensure effectiveness of resource management and quality assurance of health improvement among school children. The district joint committees are principally operational task forces or working groups that directly contribute to project operation. They deal with day-today problems and come up with solutions. Thus, the qualitative attributes of the project are dependent on their enthusiastic involvement and active participation. Their concerns are the outcome of disease control among schoolchildren, technical coordination between staff of both departments and problem-solving during project implementation. Table 2. Some examples of the stakeholders of the dengue control project and their concerns Stakeholders Concerns
1. Department of Communicable Disease Control (CDC), Ministry of Public Health
1. Goal achievement of the project in terms of morbidity reduction 2. Attitudes of both organizational staff/personnel 3. Sustainability of such a strategic approach 4. Effectiveness of project management
2. Joint Committees A. Central level 1. Steering committee 1. Justification of resource allocation 2. Cost-effectiveness of the project 3. Effectiveness of project management 1. Achievement of health education by integrating health information into current curriculum 2. Achievement of organizing the project 3. Effectiveness of project management 4. Consistency and quality of performance 1. Effectiveness of resource management 2. Quality assurance of health improvement among schoolchildren 1. Effectiveness of the project in terms of disease control 2. Technical coordination between both organizational staff 3. Problem-solving concerns 1. Effectiveness of disease prevention in the schools 2. Effectiveness and efficiency of resource reallocation 3. Effective management of logistic supplies 1. Effectiveness of health education in the schools 2. Effectiveness of resource reallocation 3. The development of knowledge, attitude and practice of those schoolchildren in health care activities
2. Technical coordination and operation committees
B. Peripheral level 1. Provincial joint committees
2. District joint committees
3. Provincial health authorities
4. Provincial primary education commission
Finally, the provincial primary education commission and the provincial health authorities are important stakeholders in the project. They have the authority to
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organize manpower and allocate financial resources to each school in the areas they are responsible for. They are concerned with ensuring effectiveness of disease control measures and resource reallocation, achievement of the education programme as well as effective management of supplies for school support.
Project evaluation Since the project was started in 1992, it might be too premature to expect the project to make an impact in terms of disease prevention. From the standpoint of a stakeholder like the CDC Department, its first priority is achievement of project goals in terms of morbidity reduction and sustain-ability of the schoolchildren approach if the outcome is successful. As part of project evaluation, a crosssectional survey was conducted during September-November 1994. In this study, 96 schools across the country were sampled and 371 personnel were interviewed. It revealed that 93.7% of the schools sampled were involved in the project. Two-three years after the start of the project, 62.5% of the provinces and 64.3% of the districts surveyed had reported reduced morbidity rates of DHF among both schoolchildren and all other age groups(21). The majority of health and education staff held a positive attitude to the objectives and strategies of the project as well as its approach(22). However, 76.7% of the schools involved received programme orientation. Larval control activities were taught by 80% of the teachers and were performed by 94.4% of
the students(23). About two-thirds of the teachers admitted that breeding-site reduction was the most appropriate and effective control measure. However, the main constraints were low frequency and non-regularity of the teaching and learning process, lack of consistent supervision, poor communication and coordination between different organizational staff and health and education personnel and, lastly, insufficient and irregular supplies to schools such as educational materials and chemical larvicides(24). These shortcomings have been overcome during the past 2-3 years which have helped greatly to improve project implementation. It is hoped that intersectoral cooperation between the health and education departments, in close collaboration with the community, will be able to reduce the danger of DF/DHF as a major public health problem in Thailand in the near future.
References 1. Thongcharoen P and Jatanasen S. Epidemiology of dengue and dengue haemorrhagic fever. In: Thongcharoen P, editor. Monograph on dengue/dengue haemorrhagic fever. World Health Organization, Regional Office for SouthEast Asia, New Delhi 1993, 1-8. 2. Division of Control of Tropical Diseases and Division of Communicable Diseases, World Health Organization. Preventing dengue and dengue haemorrhagic fever: A fact sheet for municipal and community leaders. World Health Organization, Geneva, 1996. 3. World Health Organization. Emerging infectious diseases; World Health Day 1977. Information kit. World Health Organization, Geneva, 1977. 4. World Health Organization, South-East Asia Region. Emerging infectious diseases in SouthEast Asia Region, New Delhi, 1977.
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Dengue Control through Schoolchildren in Thailand 5. Wangroongsarb Y. Development and approaches for controlling dengue/dengue haemorrhagic fever in Thailand. Strategy for prevention and control of dengue/dengue haemorrhagic fever in South-East Asia Region. Presented in Regional Consultative Meeting, Oct 10-13, 1995, SEARO, New Delhi, 1995. 6. Ong-ard Charoensuk. Epidemiology of dengue haemorrhagic fever in Thailand. Division of Epidemiology, Bangkok, 1995. 7. Division of General Communicable Diseases, Department of Communicable Disease Control. Dengue haemorrhagic fever. Kuru-sabha, Bangkok, 1993. 8. Division of General Communicable Diseases, Department of Communicable Disease Control. Technical guidelines for vector-borne disease control implementation, Bangkok, 1992. 9. Division of General Communicable Diseases, Department of Communicable Disease Control. Master Plan for Vector-Borne Disease Control: 1992-1996. Bangkok, The Division, 1992. 10. Swaddiwudhipong W, Chaovakiratipong C, Koonchote S et al. Effect of health education on community participation in control of dengue haemorrhagic fever in an urban area of Thailand. South-East Asian J Trop Med Pub Hlth 1992, 23(2):200-6. 11. Strickman D, Innis B, Nisalak A, Kittayapong P. Prevalence of antibody to dengue virus in children and its relationship to distribution of mosquito vector larvae in a rural Thai community. South-East Asian J Trop Med Pub Hlth 1990, 21(4):710-1. 12. Jatanasen S. Environmental management and health education in Aedes aegypti control in Thailand. Bull Wld Hlth Org 1967, 36(4):636-8. 13. Ashton J and Seymour H. The new public health: The Liverpool experience. Milton Keynes: Open University Press, 1988. 14. The Healthy Cities Inter-Sectoral Committee. The Liverpool Declaration on the Right to Health. The UK Healthy Cities Conference March 28-30, 1988. Liverpool, United Kingdom, 1988. 15. Manasthitpong N, Srisawat P, Nilapan S and Burapangkul C. A comparative study on Aedes aegypti control models in Chaiyapoom province. Com Dis J 1991, 17(3):200-6. 16. MacDonald MB. Fighting a new disease: Issues in community mobilization for controlling DHF in displaced persons camps along the Thai-Cambodian border. South-East Asian J Trop Med Pub Hlth 1990, 21(4):681-2. 17. Pan American Health Organization. Dengue and dengue haemorrhagic fever in the Americas: Guidelines for prevention and control. WHO/PAHO, Washington, D.C., 1994. 18. Department of Communicable Disease Control, Ministry of Public Health (Thailand). National joint project between Health and Education ministries for dengue control among primary schools. Bangkok: The Division of General Communicable Diseases, 1992. 19. Phanthumachinda B, Phan-Urai P, Samutrapongse W and Charosensook O. Studies on community participation in Aedes aegypti control at Phanus Nikhom district, Chonburi province, Thailand. Mosq Borne Dis Bull 1985, 2(3):1-8. 20. Phanthumachinda B, Samutrapongse W, PhanUrai P, Boonabuncha S and Matcum B. Approaches for community participation in Aedes aegypti control, Phanus Nikhom district, Chonburi province. Dengue Newsletter, WHO/SEARO 1987,13:55-61. 21. Wangroongsarb Y. Programme evaluation of dengue control among primary schoolchildren. Com Dis J 1995, 21(4):222-8. 22. Wangroongsarb Y. Assessment of attitude of health and education personnel towards dengue control programme among primary schoolchildren. Com Dis J 1996, 22(3):247-58. 23. Wangroongsarb Y. Evaluation of the effectiveness of school practice in dengue control programme in primary schools. Com Dis J 1997 23(3):401-10. 24. Wangroongsarb Y. Evaluation of the programme management of dengue control programme in primary schools. In Press.
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16,000
Median 1987-91 14,000 12,000 10,000 8,000 6,000 4,000 2,000 0 J F M A M J J A S O N D
Median 1992-96
50.00 45.00 40.00 35.00 30.00 25.00 20.00 15.00 10.00 5.00 0.00 0-4 y 5-9 y 10-14 y
Mean 1986-89 Mean 1990-93 Mean 1994-96
15+ y
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1,000.00 Morbidity CFR 100.00 Mortality
16 14 12 10 8 %
10.00 /100,000 1.00
6 4 2
0.10
0.01
0
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