Schistosomiasis.

Human schistosomiasis is a common blood fluke infection in the tropics and subtropics. The organism requires a specific fresh water snail intermediate as host and this determines its geographical distribution. Humans become infected following water exposure, with rural communities and children having the highest burden of disease. Travellers to areas of high endemicity are at risk of infection as they frequently engage in pursuits that expose them to fresh water. Disease manifestations range from acute hypersensitivity reactions to chronic illness with intestinal, hepatic and bladder disease. Infection can often be asymptomatic and travellers to endemic areas should be screened for schistosomiasis after return. Treatment is highly effective, even in advanced disease, and the diagnosis should be considered in individuals with possible clinical illness who have travelled to or lived in endemic areas.