Incidence of snails proliferation on trematodosis in the Delta and the lac de Guiers zones after the Diama dam opening in the Senegal River Valley

Abstract

The last malacological prospections carried out in the Delta region of the Senegal River Valley from June 1989 to January 1990 revealed a rapid proliferation of Biomphalaria pfeifferi and Lymnaea natalensis molluscs which seemed to have disappeared since 1977, while the populations of Bulinus remained stable. At the same time, several cases of human intestinal bilharziosis (Schistosoma mansani) emerged particularly at Richard-Toll where 40 % of the total population were affected. Animal distomatosis (Fasciola gigantica) have been recorded also with the first cases noticed among sheep. This new epidemiological situation is one of the first consequences of the opening in 1986 of the Diama dam in the Senegal River Valley. As a result, optimal ecological conditions favourable to the development of snails have been created.