Reduction in prevalence, intensity of infection and morbidity due to Schistosoma mansoni infection in a community following treatment with praziquantel.

Five hundred and twenty-three individuals from an area endemic for Schistosoma mansoni infection were followed for a 16 month period in a population-based study in rural Zambia. Those found infected in each of five surveys were treated with praziquantel (40 mg kg-1 body weight). Data on prevalence, intensity of infection and morbidity (intestinal symptoms and liver and spleen enlargements) were also gathered. At the end of the study, prevalence had fallen from 64.8% to 11.5%, intensity of infection had dropped from 28.2 to 0.5 eggs per gram of stool (geometric means) and morbidity showed marked reduction.