A three year follow-up of chemotherapy with praziquantel in a rural Zambian community endemic for schistosomiasis mansoni.

A resurvey for schistosomiasis mansoni was carried out in a community 2 years after chemotherapy with praziquantel was stopped. Data on infection status, morbidity, subjective symptoms, and liver and spleen enlargement were collected from participants. Results show that prevalence of Schistosoma mansoni infection and subjective symptoms of morbidity have returned to pretreatment levels. However, the population mean egg output remained low. Liver and spleen sizes in individuals who received treatment have shown a further decline compared to 2 years before. We conclude that selective mass chemotherapy with praziquantel can give the community as a whole a respite from schistosomiasis morbidity for at least 2 years despite an increase in prevalence.