Abstract
Objective: To carry out a malacological survey to detect the presence of Schistosoma mansoni (SM) infection in Biomphalaria snails in localities with and without SANAR in order to verify the environmental circulation of SM. Methods: The survey occurred between 2017 and 2018 in 61 localities with SANAR actions and in 60 contiguous localities without SANAR. The B. glabrata (BG) and B. straminea (BS) specimens collected were examined by light exposure and crushing technique to identify larval forms of SM. Negative specimens of BS were also examined by Nested PCR technique to detect the parasite DNA. Results: A total of 5,459 snails were collected. In the 61 localities with SANAR, 204 BG and 2,056 BS were collected, with 10 sites (16.4%) presenting positive snails for SM infection against 51 sites (83.6%) with healthy snails. In the 60 localities without SANAR, 19 BG and 3,180 BS were collected, with 33 sites (55%) having positive snails for SM and 27 sites (45%) with healthy snails. Conclusion: The presence of SM DNA in snails from localities where the SANAR didn’t medicate people, guarantees the parasite circulation locally which represents biological risk and alert to the beginning of the parasitic transmission.