Resistance of Biomphalaria occidentalis from Varzea das Flores dam, Minas Gerais, to Schistosoma mansoni infection detected by low stringency polymerase chain reaction

Biomphalaria occidentalis Paraense, 1981 from Varzea das Flores dam, MG, Br azil, was exposed to infection with Schistosoma mansoni. Individual infecti on was performed with 140 B. occidentalis and 100 B. glabrata snails using LE and SJ strains. Two groups of B. occidentalis were killed after seven da y-miracidia exposure to detect S. mansoni DNA, through the low stringency p olymerase chain reaction (LS-PCR), and were negative. The infection rates w ere 69.2% (LE strain) and 96.7% (SJ strain)for B. glabrata and 0% for B. oc cidentalis. LS-PCR enabled early resistance diagnosis.