A comparative histopathological study of three snails species -
Biomphalaria glabrata, B. tenagophila and B. straminea - which had been
infected with Schistosoma mansoni miracidia revealed similar qualitative
features, consisting of areas of sporocyst proliferation and
differentiation associated with reactive host reaction, at the time they
were actively eliminating great number of cercariae. However, in specimens
that were exposed to miracidia but failed to eliminate cercariae later on,
different histopathological pictures were observed in different snail
species.
While B. glabrata exhibited frequent focal (granulomatous) proliferation of
amebocytes in several organs, B. tenagophila and B. straminea only rarely
showed such reactive changes, suggesting that the mechanism of resistance
to miracidial infection probably follows different pathways in the snail
species studied.
