[Epidemiology of human schistosomiasis in Mauritania. The right bank of the Senegal River as model].

A study was performed to determine the transmission and prevalence of human schistosomiasis in the Mauritanian side of the Senegal River basin. Parasitological investigations by Kato-Katz and urine filtration conducted on 1,259 school children indicated a mean prevalence of S. haematobium--29.0%, 25.9% and 34.3%, respectively, in the children of the lower, middle and high valley. Only the school children of the lower delta valley were infected by S. mansoni with a mean prevalence rate of 21.5%. The malacological investigations carried out in the water points of each visited village highlighted the presence of B. pfeifferi, B. senegalensis, B. globosus, B. umbilicatus, B. truncatus and B. forskalii. The last three species are announced for the first time in the Mauritanian side of the Senegal River. The laboratory snail infection experiments indicate that B. senegalensis and B. globosus are the most important intermediate hosts for S. haematobium in the Mauritanian side of the Senegal River basin. However, an incompatibility between the oasis strains of S. haematobium and the snails of the lower valley was noted. In the middle valley and high valley, the infection of the school children takes place during the rainy season, because of the creation of the temporary water points, in the lower valley; the transmission seems to be continuous.