IMPACT OF REPEATED COMMUNITY-BASED SELECTIVE CHEMOTHERAPY ON MORBIDITY DUE TO SCHISTOSOMIASIS-MANSONI

The impact of repeated chemotherapy on morbidity due to schistosomiasi s mansoni was evaluated in Gihungwe (initial prevalence 58%) and Buhan dagaza/Kizina (33%), two village clusters in Burundi. Surveys were car ried out with reference to the first treatment (month 0) at months -6, -3, 0, 3, 6, 9, 12, 24, and 36. Praziquantel (40 mg/kg) was given at months 0, 12, 24, and 36 to those showing eggs in the feces with a sin gle 28-mg Kato slide. At each survey, duplicate Kato smears were exami ned, and all participants responded to a standardized medical history interview and underwent a clinical examination. In the three preinterv ention surveys, spleen and liver rates remained stable at the communit y and the individual level. The frequencies of diarrhea and abdominal pain varied to some extent, but they were consistently higher in the m ost heavily infected villages and age groups and remained relatively s table at the individual level. At the final survey, the prevalence of infection had decreased to 25%, and the frequency of diarrhea from 19- 26% to 10% in both village clusters. This impact was strongest in the younger age groups. The frequency of abdominal pain was reduced only a t the short term and in selected age groups. Organomegaly decreased on ly to a limited extent in those treated, and increased in those not tr eated, possibly due to the impact of malaria. The net result was that no measurable impact of the treatments on organomegaly at the communit y level could be demonstrated. In the light of these results, the rele vance of community-based chemotherapy in moderate foci is questioned.