Cost-effectiveness of different ways of controlling intestinal schistosomiasis: a case study.

Intestinal schistosomiasis is highly prevalent among the labourers and their families in many of the miners' villages in Maniema, Zaire. Following treatment, a quick re-infection can be observed if no measures are taken to reduce transmission. It is shown that the rate of re-infection is reduced when the water bodies around an endemic village are properly molluscicided. When, in addition to chemotherapy, a strategy of focal mollusciciding was adopted beneficial effects were visible 12 months after treatment but no longer at 20 months. In view of the comparatively small size of the human populations in the endemic villages, and due to the extent and the variety of the snail-infested water bodies, chemotherapy only, without additional measures, would seem to be the most cost-effective type of control, under the prevailing conditions. This conclusion should be revised when long term health-planning could be effectively envisaged for the area.