Laboratory induced resistance to praziquantel in experimental schistosomiasis.

To study the effect of praziquantel (PZQ) on successive generations of S. mansoni worms, infected mice were treated 6 weeks after infection with different doses of PZQ (300, 500 mg/kg.), the schistosome strain was originally obtained from an infected Egyptian patient. The eggs subsequently produced by worms that had survived the PZQ treatment were used to infect snails and mice of the following generations. The results were expressed as average number of worms and cure rates in comparison with control groups. It was found that the use of PZQ., especially in low subcurative dose may lead to the development of resistance to therapeutic dose of the drug in following generations.