[Schistosomiasis mansoni infection in a hyperendemic region of midwestern Madagascar: epidemiology, morbidity and secondary effects of praziquantel treatment].

The examination of 544 inhabitants (93.2% of the whole population) of a village in the middle west of Madagascar, where Schistosoma mansoni is hyperendemic and where no previous antischistosomal treatment had been delivered at a community level, showed a prevalence rate of 61.8%. The highest prevalences and the most intense infections were observed in the 10-24 age group. The egg count decreases dramatically from the age of 25. A highly significant relationship was found between recent histories of bloody diarrhoea and S. mansoni eggs excretion. Clinical examination showed a high frequency of splenomegalies (62.2% > or = stade 2 Hackett), with two modes: one in the 10-14 age group and the other in the 35-39 age group. The respective liability of S. mansoni and malaria remain to be clarified. Side effects after treatment of the entire population with praziquantel were observed in 27.2% of treated individuals. Side effects occurred mainly in infected people. A highly significant relationship was found between intensity of infection and frequency of these side effects which are essentially mild and disappear in the 24 hours.