Schistosomiasis and soil-transmitted helminthiasis: common drugs for treatment and control

Abstract

Schistosomiasis is a disease caused by parasitic trematode worms (schistosomes) that currently affects 200 million people living in tropical and subtropical environments. It is a chronic disease and the latest estimates for sub-Saharan Africa are that it kills > 200000 people every year. Soil-transmitted helminthiasis (STH) is caused by intestinal nematodes. More than 2 billion people are infected worldwide and the disease burden might approach that of malaria. Recognising the enormous public health significance of schistosomiasis and STH, particularly among the poor, and in view of readily available drugs that are safe, efficacious and inexpensive, the World Health Assembly recently set forth a resolution for a combined approach for morbidity control of both diseases. This review briefly summarises the geographical distribution, life cycle and global burden of schistosomiasis and STH. The current arsenal of drugs available for morbidity control, including discovery, chemistry, pharmacological properties and aspects of therapeutic efficacy and adverse events in clinical human use is then discussed. The emphasis is on praziquantel, oxamniquine and artemisinin derivatives (against schistosomes) and albendazole, mebendazole, levamisole, pyrantel pamoate and other compounds (against intestinal nematodes). The experience gained with combination chemotherapy in schistosomiasis and STH is briefly discussed. Finally, current research needs and the critical importance for development of novel anthelmintic drugs, so that chemotherapy can continue to serve as the backbone of integrated and sustainable control of schistosomiasis and STH, is highlighted.