Reinfection after treatment of schistosome infections.

Today, chemotherapy has a central role in the control of schistosome infections. Although the costs involved may be high in relation to local expenditures on health, externally funded mass treatment programmes can lead to large reductions in the prevalence and intensity of schistosome infections. But the benefits of treatment to a community that has been involved in a mass chemotherapy programme, or to an individual patient seen in a health centre, will be limited if reinfection after treatment is rapid and intense. Despite the efficacy of the available drugs few, if any, control programmes based on mass chemotherapy have interrupted transmission and come anywhere near to eradicating schistosome infection.