Summary
This paper reports the studies on the susceptibility of Biomphalaria occidentalis from Sena Madureira (Acre) and Cuiabá (Mato Grosso) to infection by Schistosoma mansoni from São José dos Campos (São Paulo) and Paulista (Pernambuco). The attempts of infection where negative. The authors also comments about the geographical distribution of planorbid snails in the Amazon basin and the authochtonous foci known in the region. The possible role of B. occidentalis in the transmission of schistosomiasis is discussed.