Biomphalaria glabrata from Belo Horizonte, Minas Gerais, Brazil, reared in laboratory, has a level of infection of 90% when exposed to 20 miracidia of the autochthonous LE strain. The prepatent period was of 5 to 7 weeks whereas 5 to 10 % of exposed snails do not shed cercariae. The eggs of negative snails were collected and the progeny was again submitted to individual infection with 20 miracidia. The mean of infection from F14 to F20 was of 43.6%. Histological sections from F12, F14 and F15 snails showed tissue reactions in those specimens shedding less than 10 cercariae. A prepatent period of 17 to 32 weeks was observed in 35 (17.9%) of 195 infected snails. The index of cercariae of control was extremely compatible and for F12, F13 and F15 snails varied from very compatible class V to compatible class III, showing less compatibility in selected snails.
Biomphalaria glabrata; Resistance; Compatibility; Schistosoma mansoni
