DEGREE OF HOST-PARASITE COMPATIBILITY BETWEEN SCHISTOSOMA-MANSONI ANDTHEIR INTERMEDIATE MOLLUSCAN HOSTS IN BRAZIL

The compatibility of Biomphalaria tenagophila, B. straminea and B. gla brata from Minas Gerais with different strains of Schistosoma mansoni was evaluated using the method of Frandsen (1979b) in standardized exp eriments. One hundred and fifty of each species of snail were individu ally exposed in the laboratory to 50 miracidia of S. mansoni lines LE, SJ and AL. The cercariae from the infected snails were counted and us ed to calculate TCP/100 indices, which were compared with those of Fra ndsen (1979b). For B. tenagophila the TCP/100 indices varied from 37,9 96 to 74,266 (class II and III). The snail was poorly compatible with LE (class II) and compatible with SJ and AL (class III). For B. strami nea the indices varied from 9,484 to 20,508. The snail was not very co mpatible with SJ (class I) and poorly compatible with LE and AL (class II). For B. glabrata the indices varied from 588,828 to 1,039,065. Th e snails was extremely compatible (class VI) with the three fines of S . mansoni. These results confirm the epidemiological importance of B. glabrata in Brazil followed by B. tenagophila and B. straminea.