EPIDEMIOLOGICAL REVIEW OF
IN THE WHO WESTERN PACIFIC REGION
2.000
World Health Organization Regional Office for the Western Pacific Manila, Philippines WHO!WPRQ LIBRARY MANILA, PlULIPPlNES
Prepareo b-:g LeJ'lYDS;-9 Elimination Unit
WHO Western Pacific Region In coHaboration witb Dr P.S. Rao1 WHO consu[tmtt1
December
2.001
ACKNOWLEDGEMENTS
We would like to thank aJlleprosy programme managers, and statisticians from all the countries and areas of the Western Pacific Region for providing appropriate data for this document.
© World Health Organization 2002 Publications of the World Health Organization enjoy copyright protection in accordance with the provisions of Protocol 2 of the Universal Copyright Convention. All rights reserved.
The designations employed and the presentation of the material in this report do not imply the expression of any opinion whatsoever on the part of the Secretariat ofthe World Health Organization concerning the legal status of any country, territory, city or area or its authorities, or concerning the delimitation of its frontiers or boundaries. Where the designation "country or area" appears, it covers countries, territories, cities or areas.
Updated information on leprosy in the Western Pacific Region is available on the web site: http\\www.wpro.who.int
ii
CONTENTS
Acknowledgements Abbreviations 1 2
[i
iv
Summary Introduction Regional achievements Epidemiological situation Programme activities Problems and difficulties Future priorities and activities
5 6
3 4 5
7 13
6 7
16 17 20
Annex: Annual statistic form 2000: Leprosy
FIGURES AND TABLES Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Leprosy situation in the Western Pacific Region, end of2000 Leprosy prevalence rates and multidrug therapy coverage in the Western Pacific Region, 1988-2000 Distribution of the number of registered cases and the prevalence rates per 10 000 in eight countries ofthe Western Pacific Region, 2000 Distribution of new cases of leprosy detected in 2000 New case detection rate in 2000 Leprosy new case detection rate per 100 000, Western Pacific Region, 1988-2000 Trend in prevalence rate in countries that are yet to achieve elimination Trend in prevalence rate after elimination in some large countries Trend in new case detection rate after elimination in some large countries Trend of prevalence rate after elimination in some small countries Latest notification ofleprosy cases and monitoring indicators by country, 2000 Trend in the prevalence and new case detection, Western Pacific Region, 1988-2000 Table 3
4 6 7 9 10
11 17 18 18 18
Table 1 Table 2
3
8 12
Proportion ofMB, disability grade 2 and children below 15 years among new cases, 1994-2000
iii
,....
LEPROSY: EPIDEMIOLOGICAL REVIEW IN THE WHO WESTERN PACIFIC REGION 1.000
ABBREVIATIONS
LEC LEM MB MDT NGO PIC
Leprosy elimination campaign Leprosy elimination monitoring Multibacillary Multidrug therapy Nongovernmental organization Pacifrc Island Countries
PB P/D ROM SAPEL SMHF WHO WPR
Paucibacillazy Prevalence/detection ratio Rifampicin-Ofloxacin-Minocycline Special Action Project for Elimination of Leprosy Sasakawa Memorial Health Foundation World Health Organization Western Pacific Region
iv
Leprosy has been eliminated as a public health problem in 35
1 SUMMARY
countries/areas of the Western Pacific Region, representing 99. 99% of the regional population. Eight countries have reported
This Epidemiological Review of Leprosy 2000 is based on the information collected from 37 countries/areas of the Western Pacific Region and other sources. A total of36 countries/areas have sent annual leprosy data for 2000. Only Wallis and Futuna with a population of 14 000, zero prevalence and no new cases in the last few years has not sent a report. Leprosy has been eliminated as a public health problem in 35 countries/ areas of the Region, representing 99.99% of the regional population. Eight countries have reported zero prevalence and new case detection. The disease is, however, still a public health problem in the Marshall Islands and the Federated States of Micronesia. There were 12 731 registered cases at the end of 2000 compared to 14 199 at the end of 1999. The prevalence rate decreased from 0.09 per 10 000 in 1999 to 0.07 in 2000, adecreaseof22%. ThePeople'sRepublic of China (henceforth, China), Malaysia, Papua New Guinea and the Philippines were the countries that most contributed to this reduction. There were only three countries with more than 1000 registered cases. There were 8360 new cases reported in 2000, with a new case detection rate of0.49 per 100 000 population compared to 9498 reported in 1999, with a detection rate of0.57- a reduction of 14%. Papua New Guinea, the Philippines and VietNam have contributed most to this reduction. An increase in new cases was observed in the Lao People's Democratic Republic and the Federated States of Micronesia. Among the new cases, 75.4% weremultibacillary, 7.7% were children below 15 years and 12.4% were with visible disability at the time of detection. The prevalence and detection rates showed signs of further convergence compared to 1999. The prevalence/detection (P/D) ratio was 1.5, indicating administration of shorter treatment regimens for single lesion and for multibacillary patients and good compliance to treatment. During the year, four leprosy elimination campaigns (LEC) and two Special Action Projects for Elimination of Leprosy (SAPEL) were completed in addition to selected screening of the population in the Federated States of Micronesia, Kiribati and the Marshall Islands that resulted in detection of 303 new cases. A post elimination leprosy
zero prevalence and new case detection.
1
LEPROSY: EPIDEMIOLOGICAL REVIEW IN THE WHO WESTERN PACIFIC REGION 2.000
surveillance system has been implemented in selected provinces in Cambodia as a pilot project. The prevalence rate has declined continuously and consistently since 1988 by 95%, whereas the new case detection rate has remained stable with small variation between years. However, in 1998 there was a marked reduction of 23% compared to 1997 and a further 11% and 14% decline in 1999 and 2000, respectively. A significant declining trend of new case detection rate has set in and this might lead to interruption of transmission and freedom from leprosy in the longrun. The countries that achieved the elimination goal in recent years as well as years ago, especially large countries, have registered a progressive decline in prevalence and case detection rates after reaching elimination. Future activities will be focused in the two countries that did not reach the elimination target. In addition, efforts will be made to achieve elimination at sub-national level in large countries that have already reached the elimination at national level. Extending field testing ofleprosy surveillance system and independent evaluation of programme achievements will be the major concerns during the post-elimination phase in the Region.
2
LEPROSY: EPIDEMIOLOGICAL REVIEW IN THE WHO WESTERN PACIFIC REGION 2.000
Table 1: Latest notification of leprosy cases and monitoring indicators by country, 2000 Population Prevalence New case detection
x 1000 American Samoa Australia 62 19 100 338 12 017 1 295 000 19 845 232 155 6797 126 920 85 47 274 5311 444 23 264 81 51 115 2533 12 209 3839 2 19 4825 76 348 0.051 159 3263 459
---N ~o .----~ R ~~~ ~--~~ N ~ o . ----R =a t~ e----M ~~ ~~D~~~~~ c ~ h~ ffd ~. ~ .
x 10000 10 0 0 582 3646 0
x100 2 4 G
ooo
Cases cured
P/0**..
Ratio 5.0 0
% 100 75
% 0 0
%
1.61 0
3.23 0.02 0 6.22 0.12 0
50 0
3 0 0 761 2026 0
·· !Biunei D$!$alili:n Cam. bodia Chlria Cook Islands Fiji French Polynesia Guam Hong Kong, China Japan Kiribati Republic of Korea
0 0.46 0.03
0 66.67
0 8 .2
0 10.4 3.6
0
747 1603
0.8 2.3 0
82.28 21.1 0 66.67 20 80
0 0.08
·0 g
0 0 0 0
0 11 .1 20 20
7 16
1.07 2 .16 3.23 0.16 0.01 22.35 0.07 5 .72 0 .23
5 9
0.8 3.2
0.69 0.32 0.65 0
5
5 36 0 8
5 11 12 19
3 12 0 16 0 292 0 48 0 97 3 3.3 0.7 0.6 0 1.4 1.3 0 0
54.55 50 36.84
0 0
0 0 26.3
3.3 0
0.9A
5.3
0.4 0.9 1.6
535 286
0. 11 0.54 0.02
35 304
65.71 28.6 70;07 15.8
0 6.6
Lao PDA Macao, China Malaysia N. Mariana Islands Marshall Islands Micronesia FS Mongolia Nauru New Caledonia New Zealand Niue Palau Papua New Guinea Philippines Pitcairn Islands Samoa Singapore Solomon Islands Tokelau Tonga Tuvalu Vanuatu VietNam Wallis and Futuna (99) Summary
0 62.32 100 31.96 52.22
0 5.3 0
0 10.6 0
631
0.27 1.23 12.55 4.96
207
0 .89 3.7 190.20 78.26 0 41 .67 3.35 0.08 0
10 64 57 0 7 9 0 0
3 97 90 0
33 0 0
28.9
105 0
0 5.83
0 40
0 40
5 7
0
7 16 0 0
0.43 0
57.14 28.6 66.67 0 0
0 0 0
3 0 6
0 3.16
0 0
6 371 4320 0 4
31 .58 7.01 4.43 0
83.33 49.11 87.8
0 26.3 6.3
0.77 0.57 0 0.25
338 3379 0
4.4 7.2
403 3785 0
1.1 1.3 0
0 100 40
0 100
0 0
5 5
3.14 0.14 1.96 0 0 0
0 21 0 0
0.8 6
30 8 0
0.09 0.17
0
0
9 0 0
77.78 11.1
0 0
0.9 0
0 0
0 0 0 66.67
0 0
100 10 200 76 325 14 1 706 434
0 0
0 0
2 0
0 0 1.7
0 0.2S 0.27 0 0.07
0 3
0 0
5 2077 0 12 731
1.50 1.89 0
0 6.9 0 7.7 1743 0
1446
60.86 20.7 0 0
1.4 0
8360
0.49
75.36 12.4
9365
1.5
* Proportion of multibacillary cases. ** Proportion of cases with grade 2 disability among new cases. *** Proportion of children younger than 15 years among new cases. **** Ratio between prevalent cases at the end of the year and the number of new cases detected during the year. ***** Figures in ( ) mean year of latest data.
3
World Health Organization Regional Office for the Western Pacific STB and Leprosy Elimination Focus Mot1golle
FIGURE 1: People's ~epubllc ot China
Macao Lao People's Democratic Republic
I
Leprosy Situation in the Western Pacific Region End of 2000 Northern Mariana Is. Ph•llpptnos ~
l / I
.
~
Republic of Marshall Is.
'~'
~ • Palau
Federated States of Micronesia
Nauru
...
Kiribati
American Samoa
...
..
• French Polynesia
LEGEND 0- 0.49 cases per 10 000 (26 countries) • • • 0.5- 0.99 cases per 10 000 (5 countries) 10 or less cases (American Samoa. Nauru, Northern Mariana Islands and Palau) 1 or more cases per 10 000 (2 countries) The designation on this map do not Imply the expression of any opinion on the part of the Regional Director concerning the legal status of any country or territory or the delimitation of Its frontiers. PIC group of islands not to scale. NOTE: Shaded areas are outside the WHO Region for the
Western Pacific.
In the Western Pacific Region, multidrug therapy implementation began in
2 INTRODUCTION
1985. It reached 10% coverage in 1988 and almost 100% by 1994. Elimination of leprosy at the regional level was
The WHO Western Pacific Region (WPR) comprises 37 countries and areas 1 with a population of approximately 1706 million*. The Region contains very large countries such as China and Japan representing, respectively, 76% and 8% of the total regional population and very small countries of which 30 comprise only 3% of the total population. Eight countries have populations of more than 10 million and six have a population of between 1 million and 10 million. Of the remaining 23 countries with a population ofless than 1 million, six have a population of more than 200 000 and 17 have a population ofless than 200 000 of which eight have 20 000 or less. Countries are scattered in the north, west, central and south Pacific. The development of multi drug therapy (MDT) for the treatment ofleprosy in the early 1980s represented an important step in combating the disease. The MDT implementation started in control programmes in 1982-1985 and was used worldwide by 1990. The reduction in prevalence achieved during this first phase was so impressive that elimination ofleprosy as a public health problem - considered to be a prevalence rate of less than one case per 10 000 population -became an attainable target. Based on this, the Forty-Fourth World Health Assembly, held in 1991, adopted a resolution aiming for global elimination of the disease by the year 2000. In the Western Pacific Region, MDT implementation began in 1985. It reached 10% coverage in 1988 and almost 100% by 1994 (Figure 2). Elimination ofleprosy at the regional level was achieved in 1991. By the end of 1995, 21 countries of the Region had already reached the elimination target. Today only two small countries of the 37 in the Region have not yet reached this elimination target.
achieved in 1991.
1
Throughout the text, the word "country" will be used to indicate either country or area.
*As furnished by countries in their annual reports for 2000 and UN estimates where countries not furnished.
5
Achievements as of the end of 2000 include a 14% reduction in new case
3 REGIONAL (as
ACHIEVEMENTS
detection of leprosy from 1999 and 41%from 1997, and the lowest new case detection rate in the last 13 years.
of tbe eni) of .2000)
• Prevalence and MDT coverage • 12 731 registered cases- prevalence rate of0.07 per 10 000 • 95% reduction in the prevalence rate in the last 13 years • MDT coverage 10% in 1988,70% in 1990 and 100% in 1994 • Prevalence decreased as the MDT coverage increased (Figure 2) • New case detection • 8360 new cases- detection rate of0.49 per 100 000, the lowest detection rate in the last 13 years • 14% reduction from 1999 and 41% from 1997 Elimination targets • Regional elimination achieved in 1991 • 35 out of3 7 countries achieved elimination • 99.99% of the regional population lives in countries where leprosy has been eliminated • Elimination sustained in countries that reached earlier elimination Special projects, 2000 (leprosy elimination campaigns, Special Action Projects for the Elimination of Leprosy and mass screening) • 9 special projects completed during 2000 covering 3.4 million population • 303 new cases detected, representing 3.6% of the new cases detected during 2000 1.6 1.4 0 0 0 0
•
•
Figure 2: Leprosy prevalence rates and multidrug therapy coverage in the Western Pacific Region, 1988-2000
100 90 Q)
1.2 0
. 80 70
Prevalence rate -a- MDT coverage
-
OJ Q) ()
~ 0
>
.... c C.:p Q)
60 0.8 50
>.
a> ro (6""3
~
a. Q)
.... a. 0 Q) a. 0.6 () c Q)
0
~
-ro > c.. ~
0.4 0.2 0
40 :E OJ 30 2 20 E ::l 10 +---+---+---r---r---~--~~--~-------+---+---+0 "0
~
:::;-:
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 Year
6
4
EPIDEMIOLOGICAL SITUATION
Table 1 summarizes the latest available data on leprosy by country, as of the end of 2000. Out of 37 countries, 36 sent data using the annual statistic form (Annex 1) and/or the format communicated by WHO Headquarters. Only Wallis and Futuna with a population of about 14 000 has not sent data. PREVALENCE AND ELIMINATION SITUATION
Leprosy prevalence decreasedfrom 14 224 in 1999 to 12 731 in 2000 and the prevalence rate dropped from 0.09 to 0. 07 during the same period, representing a decrease of 22%. China, Malaysia, Papua New Guinea, and the Philippines contributed mostly to this latest reduction in the prevalence rate.
• Prevalence Prevalence is defined as the number of registered cases for chemotherapy at the end of a year and the corresponding rate is expressed per 10 000 population. Elimination of leprosy as public health problem is considered achieved when the prevalence rate is less than 1 per 10 000 at the national level. Cambodia
Leprosy prevalence decreased from 14 224 in 1999 to 12 731 in 2000 and the prevalence rate dropped from 0.09 to 0.07 during the same period, representing a decrease of 22%. China, Malaysia, Papua New Guinea, and the Philippines contributed mostly to this latest reduction in the prevalence rate. Only three countries have more than 1000 registered cases. The Philippines with 4320 has the largest number of registered cases, followed by China (3646) and VietNam (2077).
I
·-
China Nauru Marshall Islands Micronesia FS Papua New Guinea Philippines VietNam
1 -
• -. 0 5 10 15 Prevalence rate per 10 000 population
15
10
5
Registered cases ('OOOs)
Figure 3: Distribution of the number of registered cases and the prevalence rates per 10 000 in eight countries of the Western Pacific Region, 2000
When comparing rates, however, it becomes obvious that some small countries (the Marshall Islands, the Federated States ofMicronesia and Nauru) also have a serious leprosy problem (Figure 3). Prevalence has shown a continuous decline since 1988 (Figure 2; Table 2). The prevalence rate has fallen from 1.49 in 1988 to 0.07 in 2000, a more than 95% reduction in 13 years. The decrease was especially marked from 1988 to 1991, years in which MDT coverage also rapidly increased.
7
LEPROSY: EPIDEMIOLOGICAL REVIEW IN THE WHO WESTERN PACifiC REGION 2.000
TABLE 2: Trends in prevalence and new case detection, Western Pacific Region, 1988-2000 Regional Year Population 'OOOs
Registered cases Number Rate per 10000
Newly deteced cases Number Rate per 100 000
1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000
1 446 939 1 468 180 1 497 093 1 515 579 1 537 199 1 560 521 1 580 357 1 610 291 1 628 600 1 634 465 1 652 781 1 672 418 1 706 434
215 000 197 648 152 739 75504 67 591 55977 39 911 30812 26576 23648 19 800 14199 12 731
(1.49) (1.35) (1.02) (0.49) (0.44) (0.36) (0.25) (0.19) (0.16) (0.15) (0.12) (0.09) (0.07)
10 282 11 768 13 294 15164 13 610 11 052 12 730 11 941 13 027 13 544 10 648 9498 8360
(0.71) (0.80) (0.89) (1 .00) (0.89) (0.71) (0.81) (0.74) (0.80) (0.83) (0.64) (0.57) (0.49)
With the introduction of single dose treatment for single lesion and oneyear duration for multibacillary (MB), the duration of the disease has been reduced to between one day and 12 months . As a result, the prevalence is converging with detection.
• Elimination Elimination at regional level was achieved in 1991 . During 2000, Kiribati, Papua New Guinea and Samoa achieved elimination. This brings to 35 the number of countries that have attained elimination. The two countries that are yet to achieve elimination by the end of 2000 are the Marshall Islands and the Federated States of Micronesia. Four countries with a small population that have 10 or fewer registered cases are considered to have achieved elimination. To date, 99.99% of the regional population lives in countries that have eliminated the disease. 35 countries achieved elimination, representing 99.7% of the Regional population American Samoa*; Australia; Brunei Darussalam; Cambodia; China ; Cook Islands; Fiji; French Polynesia; Guam; Hong Kong, China ; Japan; Kiribati; the Republic of Korea; the Lao People's Democratic Republic; Malaysia; Macao, China; the Commonwealth of the Northern Mariana Islands*; Mongolia; Nauru*; New Caledonia; New Zealand; Niue; Palau*; Papua New Guinea ; the Philippines; the Pitcairn Islands; Samoa; Singapore; Solomon Is; Tokelau; Tonga; Tuvalu; Vanuatu; Viet Nam; and Wallis and Futuna * 10 or less cases
Two countries did not achieve elimination The Marshall Islands and the Federated States of Micronesia
8
LEPROSY: EPIDEMIOLOGICAL REVIEW IN THE WHO WESTERN PACIFIC REGION 2000
NEW CASE DETECTION There were 8360 new cases detected in 2000 corresponding to a new case detection rate of 0.49 per 100 000 population, compared to 9498 new cases detected in 1999 with a rate of0.57 (Table 2 ). Five countries contributed to 89% of all new cases detected. The highest proportion of 41% of all new cases was detected in the Philippines (Figure 4). The new case detection rate varied from 0 to 190.2 per 100 000 in 2000. Five countries have reported a case detection rate of more than 10/100 000 with the highest in the Marshall Islands. Another 14 countries reported a case detection rate between 1 and 10/100 000. Of the remaining 18 countries, nine reported a case detection rate ofbetween 0.01 and 0.99/100 000 and eight reported that no new cases were detected, with one country not reporting (Figure 5). The 2000 new case detection rate is the lowest reported during the last 13 years and shows a decline of 14% since 1999. (Figure 6; Table 2). The reduction was mostly due to decreases in numbers of new cases in Papua New Guinea (375), the Philippines (357) and VietNam (349). The new case detection rate has varied from 0.71 in 1988 to 0.49 per 10 000 in 2000, reaching a peak of 1 in 1991. The rate has generally remained stable in the last 13 years with only small variations between years. An exception was the marked reduction of 23% in 1998, with a further reduction of 11% in 1999 and 14% in 2000 (Figure 6). This represents a reduction of 41% from 1997. New case detection includes patients that showed the onset of the disease during 2000 (incident cases) as well as in previous years (backlog cases that remained undetected). The exact proportion of the backlog cases among new cases is not known. Case detection is also influenced by the intensity of programme activities, service coverage and reporting system as well as sensitivity and specificity of the diagnosis. Therefore, the Others Papua New Guinea 10% 4% Cambodia 9% China 19% VietNam 17% Figure 4: Distribution of new cases of leprosy detected in 2000
Philippines 41%
9
LEPROSY: EPIDEMIOLOGICAL REVIEW IN THE WHO WESTERN PACIFIC REGION 2000
Figure 5: New case detection rate in 2000 Marshall Islands Micronesia FS Nauru Palau ~iribati
19(. 2 78.2 41.67 31 58
Papua New Guinea Cambodia
c701 6.22 5.72 4.43
22.35
Lao PDR . Philippines .
New Caledonia . 3.35 N. Mariana Islands . 3.27 Guam . 3.23 American Samoa 1 3.23 Samoa • 3.14 French Polynesia • 2.16 Solomon Islands . 1.96 VietNam . 1.89 Vanuatu 1 1.5 Fiji Malaysia 1.07 0.89
WPR average 0.49 Macao, China Hong Kong, China Singapore China New Zealand Republic of Korea Australia Japan 0
0.23 0.16 0.15 0.12 0.08 0.07 0.02 0.01 20 40 60 80 100 Rate/10 000 Note: No cases were detected in Brunei Darussalam, Cook Islands, Mongolia, Niue, Pitcairn Islands, Tokelau, Tonga and Tuvalu
.·
120
140
160
180
200
10
LEPROSY: EPIDEMIOLOGICAL :REVIEW IN THE WHO WESTERN PACIFIC :REGION 2000
Rate per 100 000 1.2
0.8 0.6 0.4
[~
~~
r-t.
.n.
~
-a-
~
Figure 6: Leprosy new case detection rate per 100 000, Western Pacific Region, 1988-2000
--~
0.2 0
1988 1989
1990 1991
1992
1993
1994
1995
1996
1997
1998
1999 2000
Year
detection rate may not represent the true incidence and the degree of transmission of infection in the community. However, linear regression analysis of data from 1988 to 2000 revealed a significant declining trend in the new case detection rate. This might lead to interruption of transmission and freedom from leprosy in the long run. OTHER INFORMATION AND INDICATORS A total of 9365 cases completed treatment in 2000. On average, the ratio between prevalence and detection was 1.5 and remained stable compared to 1999. One-year fixed duration MDT for MB cases was introduced in 1997-1998, so the ratio should be about 1 and not exceed 1.5 for the countries that introduced the one-year policy. The ratio was very high in the Republic of Korea (15.3); Singapore (6.0); American Samoa (5 .0); Hong Kong, China (3 .3); the Commonwealth of the Northern Mariana Islands (3.3); French Polynesia (3 .2); and Malaysia (3 .0) (Table 1). This indicates that, in these countries, patients are treated for longer than necessary, registers are not updated or the patients are irregular in taking their treatment, or a combination of these factors. Only Cambodia, Fiji, Kiribati, the Lao People's Democratic Republic, the Marshall Islands, the Federated States of Micronesia, Samoa and Solomon Islands reported a ratio of less than 1, while the ratio for the majority of the other countries was between 1 and 2. This analysis indicates that one-year fixed duration MDT for MB has not yet been fully implemented. Among new cases, the proportion of MB (75%), disability grade 22 (12.4%) and those involving children younger than 15 years (7.7%) 2
Disability grade 2: Hands and feet present visible deformity or damage present; eyes: present severe visual impairment (vision worse than 6/60; inability to count fingers at 6 metres), lagophthalmos, iridocyclitis and corneal opacities.
11
r LEPROSY: EPIDEMIOLOGICAL REVIEW IN THE WHO WESTERN PACIFIC REGION 2000
showed a marginal change from 1999. The proportion of MB cases among new cases has averaged 71%, reaching a peak of 80% in 1994. Visible disability, expressed as grade 2, represented on average 14% and showed little variation. The percentage of new cases involving children younger than 15 years was, on an average, 7% compared to a range of3% to 9% between 1994 and 2000 (Table 3). Table3: Proportion of MB, disability grade 2 and children below
15 years among the new cases, 1994-2000
Year
New cases* No.
Multi bacillary No.
" "Di~ability grade 2 No.
Children <15 No.
%
%
%
1994 1995 1996 1997 1998 1999
2000 Total
10 697 11 906 13 070 13 583 10 587 9482 8360 77685
8545 8027 8650 9385 7216 6714 q300 54 837
80 67 66 69 68 71 75 71
1232 1822 1637
12 15 13 15
2064 1'51 8 1172 1036 10481
14 12 12 14
372 582 11 32 1076 887 882 647 5578
3 5 7 8 8 9 8 7
*
The numbers are those reported by the countries in the year considered and countries that did not report are not included.
12
In 2000, the WHO RegionalOL(lceforthe Western Pacific focused its
5
PROGRAMME ACTIVITIES
efforts on assisting the five countries that did not achieve elimination the previous y ear and the two countries that reached
STRENGTIIENING NATIONAL PROGRAMMES IN CAMBODIA, THE KIRIBATI1 THE MARSHALL ISLANDS, FEDERATED STATES OF MICRONESIA, PAPUA NEW GUINEA1 THE PHILIPPINES AND SAMOA
elimination in 1998.
These seven countries were provided with technical assistance to strengthen programme capability in planning and implementing special projects. They were the countries that most benefited from special projects, especially, Cambodia and the Philippines, which achieved elimination during 1998. SPECIAL PROJECTS
Leprosy elimination campaigns and Special Action Projects for the Elimination of Leprosy In 2000, the WHO Regional Office for the Western Pacific focused its efforts on assisting the five countries that did not achieve elimination the previous year and the two countries that reached elimination in 1998. These countries with the assistance of WHO and nongovernmental organizations (NGOs), and through their own resources developed and implemented leprosy elimination campaigns (LECs) and Special Action Projects for Elimination of Leprosy (SAPELs). During 2000, six special projects were completed of which two were SAPELs, three LECs and one LEC-like project (rapid survey of high endemic pockets). The projects covered a population of about 3.4 million, detected 260 new cases, giving a detection rate of7.76 per 100 000 and representing 3.1% of the detected cases in 2000. The high detection rate confirms that these special projects were both needed and successful. The Philippines implemented three such projects, Cambodia two and Papua New Guinea one. The first such projects were conducted in 1996 and by 2000, 76 projects had been completed, covering a population of36.8 million and detecting 4844 new cases. The figures represented 9% of the cumulative new cases detected during these five years. The countries that most benefited from these projects were Cambodia and the Philippines, giving coverage of97% and 26%, respectively, of their total populations.
•
13
LEPROSY: EPIDEMIOLOGICAL REVIEW IN THE WHO WESTERN PACIFIC REGION 2000
• Other special projects The Federated States ofMicronesia, Kiribati and the Marshall Islands, which had high prevalence rates, implemented special projects to accelerate and achieve elimination by the year 2000. • The Federated States of Micronesia A two-year project was implemented to screen twice the whole population to detect cases and treat those detected. Preventive therapy, consisting of ROM' combination for adults and rifampicin alone for children younger than 15, was also administered twice to all healthy people during screening. Preventive therapy coverage of the population was 87% with one dose and 54% with two doses. As a result of the project, 288 new cases were detected in 1996, 123 in 1997 and 39 in 1998, representing a more than 85% reduction in new cases from 1996 to 1998. Screening of some high endemic villages was carried out in 2000. During screening, 13 70 people were examined and four new cases were detected. There was an increase in the number of new cases detected during 1999 and 2000 compared to 1998. However, the prevalence rate declined marginally compared to 1999. • Kiribati The country is implementing a project similar to that of the Federated States of Micronesia, with mass screening and administration of preventive therapy to selected populations. So far, the project has detected 150 new cases, of which 135 were found in the first round. Mass screening and administration of preventive therapy continued during the second round in 1999 and detected 24 new cases. Screening of the population in high endemic villages was carried out in 2000, covering 11 263 persons with detection of six new cases. The country reached elimination by the end of2000 with a prevalence rate of0.94/10 000. • The Marshall Islands The project of whole population screening and preventive therapy to the contacts of past and present cases of leprosy that was started in 1998 had been completed by April 2000. Some 222 new cases of leprosy were detected and treated during the survey. There was a perceptible fall in prevalence and new case detection rate at the end of 2000 to 12.55/ 10 000 and 190.2/100 000, respectively, from 17.84 and 227.45 in 1999. COLLABORATION WITH OTHER PARTNERS
- - - - - --
Continuous collaboration has been maintained with the Sasakawa Memorial Health Foundation (SMHF), which funded most of the activities 2
Rifampicin-ofloxacin-minocycline.
14
LEPROSY: EPIDEMIOLOGICAL REVIEW IN THE WHO WESTERN PACIFIC REGION 1.000
developed in the Federated States of Micronesia and Papua New Guinea. A partnership programme has been developed with the Pacific Leprosy Foundation to assist South Pacific countries, especially Kiribati, Samoa, Solomon Islands, Tonga and Vanuatu. Coordination meetings with governments and NGOs for leprosy elimination were held in Cambodia, the Lao People's Democratic Republic, Papua New Guinea and the Philippines. FOLLOW-UP ON THE CONCLUSIONS OF THE INTER-COUNTRY WORKSHOP ON THE ELIMINATION OF LEPROSY1 1998 An intercountry workshop on the elimination ofleprosy in the Western Pacific Region was held at the WHO Regional Office for the Western Pacific in Manila, the Philippines, from 8 to 11 June 1998.
As a follow-up to the conclusions of the workshop, in addition to others, a document on the post-elimination leprosy surveillance system was prepared in 1999. A pilot project was started in selected provinces, implementing the surveillance system in Cambodia during 2000. National governments were encouraged and supported in planning and implementation of special projects both in countries that reached elimination and those yet to reach elimination. Similarly, all the countries and areas were advised and assisted to conduct national campaigns to improve leprosy awareness in the communities and health staff at various levels.
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The epidemiology of the disease itself is still a problem because, to date,
6 PROBLEMS AND DIFFICULTIES
there is no effective way to measure the level of infection and the incidence of the disease in the community. This is
In some countries, accessibility is restricted because of poor communications and vast distances (small islands countries, for instance). In others (such as the Philippines and Papua New Guinea) some places are not accessible because of security concerns. Therefore, patients living in difficult-to-reach areas now represent an important proportion of the total caseload and it will be harder to detect these patients. Few countries (Hong Kong, China; the Republic of Korea; Malaysia; and Singapore) still have a prevalence and detection ratio higher than 2, indicating that patients are treated longer than necessary and that they are inflating the prevalence. Also, it shows that implementation of the 12-month duration regimen for MB is progressing slowly in certain areas. The epidemiology of the disease itself is still a problem because, to date, there is no effective way to measure the level of infection and the incidence of the disease in the community. This is complicated by the process of self-healing of many single lesions as well as the tendency for the patients to hide the disease because of the social stigma.
complicated by the process of self-healing of many single lesions as well as the tendency for the patients to hide the disease because of the social stigma.
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LECs targeting areas of high prevalence within large countries to detect
7
FUTURE PRIORITIES AND ACTIVITIES
"hidden" cases and/or SAPELs targeting difficult-to-reach areas/ populations will be carried out in order to achieve sub-national elimination.
COUNTRIES IN WHICH LEPROSY HAS NOT BEEN ELIMINATED (O.OIOfo OF THE REGIONAL POPULATION) The trend of prevalence for the last seven years in the Marshall Islands and the Federated States of Micronesia was declining after an initial rise due to special projects implementation (Figure 7). The Federated States of Micronesia and the Marshall Islands showed similar epidemiological leprosy patterns. They also started similar projects with mass screening and administration of preventive treatment to achieve elimination. The two countries have completed these special projects and they will be closely monitored on their progress towards elimination. COUNTRIES THAT ACHIEVED ELIMINATION AT THE NATIONAL LEVEL LECs targeting areas of high prevalence within large countries to detect "hidden" cases and/or SAPELs targeting difficult-to-reach areas/ populations will be carried out in order to achieve sub-national elimination (Cambodia, the Lao People's Democratic Republic, Papua New Guinea, the Philippines and VietNam,).
•
Post elimination trends of prevalence and new cases detection Figure 7: Trend in prevalence rate in countries that are yet to reach elimination
The prevalence and new cases detection trends in countries with a relatively large population size indicate a consistent and continuous decline (Figures 8 and 9).
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LEPROSY: EPIDEMIOLOGICAL REVIEW IN THE WHO WESTERN PACIHC REGION 2000
However, there were wide fluctuations in countries with a small population, sometimes even crossing over the elimination level, especially in countries with a population ofless than 500 000 (Figure 10). These trends will be closely monitored and appropriate action will be initiated where necessary. POST-ELIMINATION STRATEGY
•
Strengthening surveillance
At the current low level of prevalence and case detection in the Region, it is likely that the capability to diagnose and manage leprosy cases of the health staff of the ongoing control programme will deteriorate. Also the present information system on leprosy needs to be revised and integrated with general health information system. Thus, in this changed situation, a cost-effective post-elimination surveillance system needs to be established in the Region. A document was developed in the Regional Office on a post elimination leprosy surveillance system that is based on the establishment of referral 1
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Figure 8: Trend in prevalence rate after elimination in some large countries
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Figure 9: Trend in new case detection rate after elimination in some large countries
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18
LEPROSY: EPIDEMIOLOGICAL REVIEW IN THE WHO WESTERN PACIFIC REGION 2000
centres, notification of individual cases, organizing leprosy awareness campaigns and periodic evaluation during 1999. The system has been implemented in selected provinces of Cambodia as a pilot project in 2000. Based on the results, the system will be gradually expanded for wider coverage.
• Validation of leprosy elimination At present, a country is considered to have achieved elimination based on the statistical information provided by the national government without further validation. The completeness and correctness of the statistical information in most countries is in general not satisfactory because of the inherent wealmesses in the operation ofhealth information systems. It is noticed, especially in large countries, that prevalence rates were well above 1 per I 0 000 at the sub-national level when elimination is achieved at national level. Whether criteria other than reaching elimination at national level are required for large countries needs to be examined carefully. Although exercises such as independent Leprosy Elimination Monitoring (LEM) might help to evaluate programme performance, it would not indicate decisively that the prevalence in the community is same as reported. There are also no specific and sensitive laboratory tools to measure the levels ofleprosy infection in the community to understand the dynamics of transmission and to correlate with prevalence. The cross-sectional surveys could measure the prevalence, but the sample sizes required for estimated prevalence of less than 1 per 10 000 population with clustering of cases will be huge and not practicable. While searching for tools and methods for validating leprosy elimination more scientifically, identification and implementation of measures to improve the surveillance and health information systems for more valid and reliable data appears to be the priority. RESOURCE REQUIREMENTS
To carry out the leprosy strategic plan for the period 2000-2003, US$2.2 million are required, with US$600 000 in each of the first two years and US$500 000 in each of the next two. Further, the assistance provided by NGOs to national governments should be kept at current levels until a cost-effective surveillance system is established and the high pockets ofleprosy are eliminated.
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ANNEX WHO: WESTERN PACIFIC REGION P.O. Box 2932 Manila 1000 PHILIPPINES Tel: (632) 528 80 01 Fax: (632) 521 10 36 ANNUAL STATISTIC FORM 2000: LEPROSY
COUNTRY _____________________ CASES DETECTED
POPULATION ------------------- - -
Single lesion
PB
/10 000
%
%
/10 000
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