EXPERIENCES WITH THE CONTROL OF SCHISTOSOMIASIS-MANSONI IN 2 FOCI IN CENTRAL AFRICA

Experiences with population-based chemotherapy and other methods for t he control of schistosomiasis mansoni in two subsaharan foci are descr ibed. In the forest area of Maniema (Zaire), intense transmission of S chistosoma mansoni, high prevalences and intensities of infection, and important morbidity have been documented. Taking into account the lim ited financial means and the poor logistic conditions, the control str ategy has been based mainly on targeted chemotherapy of heavily infect ed people (> 600 epg). After ten years of intervention, prevalences an d intensities have hardly been affected, but the initial severe hepato splenic morbidity has almost disappeared. In Burundi, a national resea rch and control programme has been initiated in 1982. Prevalences, int ensities and morbidity were moderate, transmission was focal and errat ic in time and space. A more structural control strategy was developed , based on screening and selective therapy, health education, sanitati on and domestic water supply. Prevalences and intensities have been co nsiderably reduced, though the results show focal and unpredictable va riations. Transmission and reinfection were not significantly affected by chemotherapy alone, and the eventual outcome of repeated selective treatment appears to be limited by the sensitivity of the screening m ethod Intestinal morbidity was strongly reduced by community-based sel ective treatment, but hepatosplenic enlargement was hardly affected; t his is possibly due to the confounding impact of increasing malaria mo rbidity. The experiences show the importance of local structures and c onditions for the development of an adapted control strategy. It is fu rther concluded that population-based chemotherapy is a highly valid t ool for the rapid control of morbidity, but should in most operational conditions not be considered as a tool for transmission control. Inte gration of planning, execution and surveillance in regular health serv ices are essential, and sanition, provision of domestic water supply, and health education remain the cornerstones of long-term control.