Human (H) and wild (S) Schistosoma mansoni strains were obtained; the H strain from eggs colected in human feces and the S strain having its source in livers of several species of wild rodents. Results of the behaviour of these strains in Biomphalaria tenagophila and in albino Mus musculus are exposed in this work, summarized as follows: the mortality rate, statistically, did not differ in the group of infected snails and in the group of control snails; however, the difference between the mortality rates in snails infected with "H" strain and with "S" strain is significant; the mortality rate being higher in the molluscs infected with "H" strain; in mice infected with "H" strain a significant linear function between the number of hepatic granulomata and the number of adult worms was verified; in mice infected with "S" strain it not was possible to establish such a correlation.
Schistosoma mansoni; Rodents; Biomphalaria tenagophila