Transmission control of schistosomiasis mansoni by introduction of a resistant strain of Biomphalaria tenagophila in areas where transmission is maintained by this species.

Biomphalaria tenagophila Taim lineage has proved to be consistently resistant to Schistosoma mansoni. Several published works have shown that this resistance is due to the innate defence system of that strain, and in cross-breedings with susceptible strains the Taim lineage presents dominant character. These findings led to the hypothesis that, introducing this strain in areas where transmission of schistosomiasis is maintained by this species, the introduced lineage would perform cross-breeding with the local snails, thus generating offsprings resistant to the parasites. The perspectives of the proposed approach, as well as some preliminary results and problems related to the first introduction without a previous use of molluscicide are discussed.