The present study was aimed at characterising Biomphalaria
species using both morphological and molecular (PCR-RFLP) approaches. The specimens were collected in 15 localities in 12 municipalities of the southern region of the state of Rio Grande do Sul, Brazil. The following species were found and identified: Biomphalaria tenagophila guaibensis
, Biomphalaria oligoza
and Biomphalaria peregrina
. Specimens of the latter species were experimentally challenged with the LE Schistosoma mansoni
strain, which showed to be refractory to infection.