IMPACT OF ANNUAL SCREENING AND CHEMOTHERAPY WITH PRAZIQUANTEL ON SCHISTOSOMIASIS-JAPONICA ON JISHAN ISLAND, PEOPLES-REPUBLIC-OF-CHINA

The impact of annual screening and treatment with praziquantel on schi stosomiasis japonica was examined on Jishan Island in PoYang Lake, Jia ngxi Province, China. Prevalence of infection in the community decreas ed from 39% in year 1 to 33% in year 3 with a corresponding decrease i n the geometric mean egg count from 51 eggs per gram of stool (epg) to 31 epg. The most dramatic changes in infection status and intensity o f infection were observed in younger individuals (0-19 years of age). The prevalence of hepatosplenomegaly also significantly decreased, aga in primarily in younger individuals. No change in the community preval ence of schistosome-induced hepatic fibrosis was observed as determine d by ultrasonography. Longitudinal cohort analysis, however, demonstra ted significant improvement in treated individuals with advanced hepat ic fibrosis. These data indicate that annual screening and treatment h ad a significant impact on infection status and morbidity and suggest that community therapy may be an effective approach to control schisto somiasis japonica in lake regions and marshlands in China. Further stu dies are necessary to determine the optimal and most cost-effective ap proach for drug delivery.