The distribution and spread of schistosomiasis in relation to water resources development in Mali.

Schistosomiasis prevalence is known to be high in water resources development projects. Data from 225 villages and 34,434 persons were used to compare areas with irrigation in agricultural development projects, villages in the vicinity of small dams, settlements around a large artificial lake, communities along the Niger river and places in savanna areas without any irrigation programmes. For ten villages the prevalence rates before and after the creation of the large lake were analysed. In irrigated areas the risk of schistosomiasis infection was found to be six times higher than in savanna villages. Even in the vicinity of natural bodies of water the prevalence of infection was three times less than in agricultural development projects employing irrigation. A pre-valence of intense infections above 5%, indicating that schistosomiasis requires specialized interventions was observed only in areas with irrigation. Therefore schistosomiasis may be considered a man-made health problem in rural Mali although the infection is endemic in the whole country.