Schistosoma mansoni susceptibility to praziquantel in endemic localities in Kenya
Praziquantel (PZQ) is the current anti-schistosomal drug which is extremely effective against all schistosome species that are known to infect humans and it is well-tolerated, making it suitable for mass treatment campaigns. Even though such programs have immediate and important beneficial effects, the concerns are that they inevitably leave some individuals untreated, and they do not interrupt transmission, making re-infection a certainty. What's more is that, though the efficacy of the drug is very high, reported cure rates commonly range from 60 to 95% and not 100%. This leaves open a window of opportunity for likelihood that surviving worms will recover and carryon reproduction. A significant problem associated with PZQ treatment is that it does not kill juvenile schistosomes for a period of 2-4 weeks after they infect the host. A second potential problem is the presence of drug resistance traits in natural populations of worms. It is hypothesized that a common mechanism links juvenile insensitivity and the differential response offield isolates of S. mansoni to the drug. The study purposes to investigate the underlying cause of variable sensitivity to PZQ in Kenyan field isolates of S. mansoni as part of a larger project addressing the drug's binding target and mechanism of action. S. mansoni derived from natural snail and human infections and with varied sensitivities to PZQ will be maintained in mice. The study finding will give accurate information on the level of susceptibility of Schistosomes to PZQ in Kenya, establish the correct effective dose of Praziquantel following reduced efficacy as well as data gathered formulating improved assays for monitoring the emergence of PZQ resistance.