Epidemiological aspects of schistosomiasis mansoni in the Americana reservoir area (S. Paulo, Brazil)

Abstract

An epidemiological study of the area around the Americana reservoir (S. Paulo, Brazil), following suspicion of several autochthonous human cases of schistosomiasis mansoni, was made. Six active foci were disclosed, the following species of mollusks having been found in the general area: Biomphalaria tenagophila; B. straminea; B. peregrina; Drepanotrema cimex; D. lucidum; Lymnaeidae; Ancylidae and Physidae. Specimens of Biomphalaria tenagophila from the foci revealed indices of infection ranging from 0,9 to 45.0 percent for Schistosoma mansoni cercariae. Laboratory mice infected both in the field and in laboratory, with material from these foci, permitted observation of entire cycle of S. mansoni. Eighty-two autochthonous human cases of schistomiasis mansoni were confirmed in the Americana resorvoir area.