The southern known limit of occurrence of Schistosoma mansoni Sambon 1907 in
Brazil was the northeast of the State of Santa Catarina. In Rio Grande do Sul (RS) , Brazil's
southernmost state, Biomphalaria tenagophila, B. straminea and B.
peregrina were known to occur, but both mollusc and human infection was never
documented as autochthonous. The infected child found in São Valentim, RS, came
with his family from the endemic area in Minas Gerais and was not considered as an
autochthonous infection by the Sucam. B. glabrata was reported for the first time in
RS after the finding of S. mansoni eggs in a patient (OJSP) living in Esteio (20 km
from Porto Alegre), that was initially considered as an imported infection. An extended
epidemiological investigation gave support to the idea of an autochthonous infection, even
though the source of infection could not be identified.