Human schistosomiasis

Abstract

Human schistosomiasis-or bilharzia-is a parasitic disease caused by trematode fl ukes of the genus Schistosoma. By conservative estimates, at least 230 million people worldwide are infected with Schistosoma spp. Adult schistosome worms colonise human blood vessels for years, successfully evading the immune system while excreting hundreds to thousands of eggs daily, which must either leave the body in excreta or become trapped in nearby tissues. Trapped eggs induce a distinct immune-mediated granulomatous response that causes local and systemic pathological eff ects ranging from anaemia, growth stunting, impaired cognition, and decreased physical fi tness, to organ-specifi c eff ects such as severe hepatosplenism, periportal fi brosis with portal hypertension, and urogenital infl ammation and scarring. At present, preventive public health measures in endemic regions consist of treatment once every 1 or 2 years with the isoquinolinone drug, praziquantel, to suppress morbidity. In some locations, elimination of transmission is now the goal; however, more sensitive diagnostics are needed in both the fi eld and clinics, and integrated environmental and health-care management will be needed to ensure elimination. © Chataway et al. Open Access article distributed under the terms of CC BY