Drugs for the control of parasitic diseases: current status and development in schistosomiasis

The morbidity caused by schistosomiasis has been controlled in China, Egypt and the Philippines mainly by the widespread use of the safe and efficacious drug praziquantel (PZQ), and by oxamniquin and PZQ in Brazil. To date, there is no evidence of development of clinically relevant resistance. Thanks to the commitment of national governments at the World Health Assembly in 2001, and the emergence of significant funding for control, it is predicted that there will soon be more widespread use of PZQ in sub-Saharan Africa, where morbidity due to schistosomiasis is most prevalent. There are currently no available alternative drugs to PZQ (with the possible exception of oxamniquin), although perhaps PZQ analogues could be developed. Artemether, used to control malaria, is effective against immature schistosomes, but is less effective against adult worms. The efficacy of myrrh, recently marketed as an antischistosomacide in Egypt, has not been independently confirmed.