Water resources development and schistosomiasis ecology in the Awash Valley, Ethiopia.

This paper examines the impact of water resources development, particularly river regulation and irrigated agriculture, on the occurrence of schistosomiasis and its intermediate host snails in the Awash Valley. An ecologic-geographic approach based on: a combination of comparative schistosomiasis prevalence and human ecological studies of indigenous seminomadic pastoralists and migrant laborers from the Ethiopian highlands; analysis of snail intermediate host ecology-geography; and longitudinal studies of water resources development, is used to evaluate the endemicity status and changing spatial distribution of schistosomiasis mansoni and schistosomiasis haematobium. This study confirms the suitability of epidemiologic-ecologic methods for analyzing relationships between causal processes and the spatiality of schistosomiasis. In this context local schistosomiasis control programs are reviewed and recommendations made for their improvements.