In order to discover the actual distribution of the intermediate hosts of Schistosoma mansoni in the State of São Paulo, Brazil, a planorbidic survey was made in the 572 counties of the State. Investigation carried out in the State's 4th Administrative Region, which comprises 59 counties, has shown that Biomphalaria tenagophila (d'Orbigny, 1835), Biomphalaria glabrata (Say, 1818) and Biomphalaria straminea (Dunker, 1848) are found, respectively, in twenty nine, nine and two of the counties. Many cases of schistosomiasis were detected among migrants to the Region but, up to the present, only two patients - at Itu and São Roque - could have contracted, the disease in the studied area. It seems that the fluke was intermediated by B. tenagophila.
Planorbidae; Schistosomiasis mansoni; Data collection; Disease vectors; Disease reservoirs
