Genetic analysis of praziquantel resistance in Schistosoma mansoni.

To determine the genetic basis of the resistance of Schistosoma mansoni to praziquantel (PZQ) and to understand whether the resistance is dominant or recessive trait, a schistosome cross was undertaken between a PZQ-susceptible and a PZQ-resistant isolate using infections of the single-sex cercariae which were identified by a direct W1-specific PCR technique. The resistances of F1 and F2 generation to PZQ were evaluated using in vitro egg, miracidial and cercarial tests. The F1 hybrid progeny from crosses between the susceptible and resistant isolates were resistant to PZQ. The resistant phenotype reappeared in the F2 progeny. It can thus be considered that the PZQ resistance behaves like a dominant trait.