Human schistosomiasis

Schistosomiasis is a neglected tropical disease caused by infection with blood flukes of the genus Schistosoma. Widely distributed in Middle East, Southeast Asia, Latin America, and (mostly) sub-Saharan Africa, schistosomiasis is acquired upon skin penetration of infective larvae released by freshwater snails.

Acute infection might present with self-limiting hypersensitivity reactions (“Katayama fever”). Chronic infection typically leads to two main clinical patterns: intestinal or urogenital schistosomiasis, depending on the infecting species. Impairment of other body sites (e.g. central nervous system, respiratory tract) may occur. Complicated disease can manifest, amongst other signs, with hepatic fibrosis, portal hypertension, splenomegaly, upper gastrointestinal/variceal bleeding (intestinal form); renal failure, squamous-cell carcinoma of the bladder, vaginal dysbiosis, infertility (urogenital form). Conventional diagnosis is based on egg detection in faeces or urine, though sensitivity might be low. Praziquantel is the only effective first line treatment, also provided in preventive chemotherapy campaigns by mass drug administration to afflicted communities.