MASS CHEMOTHERAPY MAY NOT BE MASS CHEMOTHERAPY MAY NOT BE AN EFFECTIVE STRATEGY FOR AN EFFECTIVE STRATEGY FOR

SCHISTOSOMIASIS CONTROL IN THE SCHISTOSOMIASIS CONTROL IN THE PHILIPPINESPHILIPPINES

VL TalloVL Tallo¹¹, PPAlday, PPAlday¹¹, MFulache, MFulache¹¹, EBalolong, EBalolong¹¹, HCarabin, HCarabin²², , SMcGarveySMcGarvey³³, RMOlveda, RMOlveda¹¹

1. Research Institute for Tropical Medicine, Department of Health, Alabang, Muntinlupa City, Philippines

2. Dept. of Biostatistics and Epidemiology, College of Public Health, University of Oklahoma Health Sciences, Oklahoma, USA

3. International Health Institute, Brown University, Providence, RhodeIsland, USA

SCHISTOSOMIASIS due to S. SCHISTOSOMIASIS due to S. japonicumjaponicumin the PHILIPPINESin the PHILIPPINES

SCHISTOSOMIASIS REMAINS A SCHISTOSOMIASIS REMAINS A PUBLIC HEALTH PROBLEM IN THE PUBLIC HEALTH PROBLEM IN THE PHILIPPINES.PHILIPPINES.

S. JAPONICUM INFECTION IS S. JAPONICUM INFECTION IS ENDEMIC IN ALL PROVINCES IN ENDEMIC IN ALL PROVINCES IN MINDANAO (EXCEPT THE SULU MINDANAO (EXCEPT THE SULU ARCHIPELAGO AND ARCHIPELAGO AND MISAMIS ORIENTAL), LEYTE, SAMAR, MISAMIS ORIENTAL), LEYTE, SAMAR, ORIENTAL MINDORO AND ORIENTAL MINDORO AND SORSOGON. SORSOGON.

20 MILLION PEOPLE ARE LIVING IN 20 MILLION PEOPLE ARE LIVING IN ENDEMIC PROVINCES WITH 1.9 ENDEMIC PROVINCES WITH 1.9 MILLION DIRECTLY EXPOSE TO THE MILLION DIRECTLY EXPOSE TO THE PARASITE.PARASITE.

GOAL OF THE NATIONAL GOAL OF THE NATIONAL SCHISTOSOMIASIS CONTROL PROGRAM of SCHISTOSOMIASIS CONTROL PROGRAM of

the PHILIPPINEthe PHILIPPINE’’S DEPARTMENT OF S DEPARTMENT OF HEALTH HEALTH

Eliminate Eliminate SchistosomiasisSchistosomiasis as a public as a public health problem health problem

( Prevalence of 1 percent or below ).( Prevalence of 1 percent or below ).

CHEMOTHERAPY is the MAIN CONTROL CHEMOTHERAPY is the MAIN CONTROL MEASURE AGAINST SCHISTOSOMIASIS MEASURE AGAINST SCHISTOSOMIASIS

IN THE PHILIPPINESIN THE PHILIPPINES

Approaches used in the delivery of chemotherapy Approaches used in the delivery of chemotherapy include the following:include the following:

Case finding and treatment ( 1981Case finding and treatment ( 1981--1995)1995)Case finding and treatment and Case finding and treatment and

mass treatment ( 1996mass treatment ( 1996--2000 ).2000 ).Mass treatment ( 2000Mass treatment ( 2000--present ).present ).

PREVALENCE OF SCHISTOSOMIASIS IN THE PHILIPPINES 1985 - 2004

0

2

4

6

8

10

12

85 88 91 94 99 2002Year

Per c

ent (

%)

0

20

40

60

80

100

Leyte

Samar1

Samar2

Zambo

Bukidno

nMis_

OcDav

ao N

Davao

SAgu

san

Comparison of Mass Treatment and Case Treatment Compliance in Nine Endemic Areas in

the Phils.

Mass txCase tx

Objective of the StudyObjective of the Study

To determine the difficulties associated with To determine the difficulties associated with mass chemotherapy as the main approach mass chemotherapy as the main approach

in the control of in the control of schistosomiasisschistosomiasis in the in the Philippines.Philippines.

METHODS

Mass treatment area: 50 villages selected for determining the effect of irrigation on transmission of S japonicum.

● 50 villages – predominantly rain-fed● 50 villages - with man made irrigation

systems

Elevation Map of Samar with Location of Study Sites

PROCEDURES

2. Social preparation for mass treatment

● advocacy through health education in villageassemblies and house-to-house campaigns

● refinement of treatment procedures, e.g.multiple treatment points, close follow-up ofside effects for treatment.

● improved logistics.

1. Measurement of human infection ● 3 fecal examination over 5 day period● Kato-Katz examination

● prioritization of Kato-Katz positive individuals.

Prevalence of Schistosomiasis Japonicum in Western Samar

47.54%42.11%

41.22%40.63%

39.13%37.78%

37.09%36.17%

31.15%30.00%

26.53%25.81%

25.51%25.00%

23.91%22.08%

20.74%20.59%

20.31%18.80%

17.91%16.77%

16.22%15.63%15.56%

14.67%14.60%14.58%

13.99%13.56%13.38%

12.39%10.40%

9.82%8.11%

7.25%6.90%

6.52%6.25%

5.30%4.00%

3.52%3.41%3.36%

2.91%2.03%

1.65%0.88%0.71%

0.00%

0% 10% 20% 30% 40% 50%

Bar

anga

y

Rate of Prevalence

Sinidman Oriental (98)Victory (141)Dolongan (113)Mag-ubay (121)Tabawan (148)Geragaan (103)Cagbayang (119)Sto. Niño (88)Caticugan (142)Cagboborac (125)Rizal I (151)Casab-ahan (144)Guinbaoyan Sur (138)Tingib (145)Nabang (138)Guinbaoyan Norte (148)San Pelayo (163)Can-abay (125)Cagbilwang (113)San Vicente (142)Mawacat (118)Dinagan (143)Natimonan (48)La Paz (137)Baja (75)Bayo (45)Pizarro/hiparayan (128)Cabacungan (74)May-it (155)Cabatuan (67)Pilar (133)San Fernando (128)Buenavista I & II (136)Nacube (135)Sapinit/Anquiana (77)Piñaplata (138)Roxas II (104)Cabugawan (98)Bulao-Guindapunan (93)Pagsolhugon (147)Mabuhay (50)Diaz (61)Erenas-Sn Juan (141)San Miguel (151)San Agustin (45)Cantaguic (115)Rosalim (32)Ranera (131)Hinugacan (38)Cag-anibong (61)

Average Prevalence Rate of the Study Areas:

15.76%(0.00% to 47.54%)

Schistosomiasis Transmission and Ecology in the Philippines (STEP)

Participation Rate in Mass Treatment

77%71%71%

6 8 %6 7%

6 6 %6 5%

6 1%6 0 %

59 %58 %

57%56 %56 %

55%54 %

53 %52 %

51%4 9 %

4 8 %4 8 %

4 7%4 6 %

4 5%4 5%

4 3 %4 2 %4 2 %

4 1%4 0 %4 0 %

3 9 %3 9 %

3 8 %3 8 %3 8 %3 8 %

3 7%3 5%

3 4 %3 2 %

3 0 %3 0 %

2 7%2 0 %

19 %18 %

14 %

6 7%

0% 10% 20% 30% 40% 50% 60% 70% 80%

Bar

anga

y

Participation Rate

Cabugawan (359)Sinidman Or. (434)San Fernando (1227)Dolongan (766)San Vicente (624)Cabatuan (1017)Cagbayang (650)Tingib (904)Caticugan (1268)Bayo (440)Victory (456)Mawacat (642)Roxas II (644)Erenas/S. Juan (1041)Cagboborac (271)Cabacungan (720)Sto. Niño (467)Diaz (429)Pilar (1706)Mag-ubay (1095)Natimonan (433)Dinagan (437)Guinbaoyan S. (413)Geragaan (339)Cag-anibong (422)Piñaplata (587)Rizal I (659)San Pelayo (360)Casab-ahan (630)Buenavista I&II (655)La Paz (619)Can-abay (1336)Pagsolhugon (1333)Cagbilwang (377)San Agustin (620)Nabang (466)Tabawan (486)Mabuhay (269)Bulao/Guinda. (554)Pizarro/Hipa. (385)Anquiana/Sap. (745)Ranera (218)San Miguel (211)Cantaguic (189)Rosalim (313)May-it (369)Baja (199)Nacube (492)Guinbaoyan N. (486)Hinugacan (177)

Average Participation Rate:

43.44%

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

50%

55%

60%

65%

70%

75%

80%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50Barangay

Prevalence of Infection

Participation Rate in Mass treatment

Mass Treatment Participation Rate vs. S. Japonicum Prevalence

Mass Treatment Participation Rate vs. S Japonicum Prevalence

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90

Participation Rate

S ja

poni

cum

Pre

vale

nce

50 Villages

Pearson correlation

-0.009

P-value 0.951

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

50%

55%

60%

65%

70%

75%

80%

85%

90%

95%

100%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50Barangay

Prevalence of Infection Participation Rate of Positive Cases in Mass Treatment

Mass Treatment Participation Rate of Positive Cases vs. S. Japonicum Prevalence

Reasons for Non-Participation in Mass Treatment Activities

1. Fear of side effects from the drug 1.1. from previous experience1.2. stop them from doing their farm work

while undergoing treatment.1.3. anxiety over children’s condition after

treatment.2. Perception that treatment is not needed

based on negative stool examinationresults.

3. Not informed about mass treatment activities.

0

5

10

15

20

25

30

35

40

45

50

1982 1983 1984 1985 1986 1987 1988 1989 2002*

Per

cen

t P

reva

len

ce

N=1241 from 1982-1989> 1 y/o

Prevalence of Infection in Macanip, Leyte

INTENSIVE CASE FINDING AND TREATMENT

N = 631*8-30 y/o

CONCLUSIONCONCLUSIONIn the Philippines, mass treatment approach appeared In the Philippines, mass treatment approach appeared not to be an effective strategy in the control of S. not to be an effective strategy in the control of S. japonicumjaponicum infection.infection.

Multifaceted critical factors affect the attainment of high Multifaceted critical factors affect the attainment of high coverage rates for mass treatment against coverage rates for mass treatment against schistosomiasisschistosomiasis..

Infection control must be developed on several fronts. Infection control must be developed on several fronts. This includes treatment and all the social science work to This includes treatment and all the social science work to increase adherence with mass treatment and individual increase adherence with mass treatment and individual treatment of infected people.treatment of infected people.

More research on ecological factors influencing More research on ecological factors influencing transmission such as our ecology project.transmission such as our ecology project.

ACKNOWLEDGEMENTSACKNOWLEDGEMENTS

This project was funded by the NIH/NSF This project was funded by the NIH/NSF Ecology of Infectious Diseases program, Ecology of Infectious Diseases program, NIH Grant R01 TW01582 NIH Grant R01 TW01582 –– Ecology and Ecology and Transmission of Transmission of SchistosomaSchistosoma japonicumjaponicum..