Schistosomiasis

Schistosomiasis, also known as bilharzia or snail fever, is a parasitic disease caused by trematode blood flukes of the genus Schistosoma. It is not a genetic disorder but rather an infectious disease acquired through contact with freshwater contaminated with the larval forms (cercariae) of the parasite, which are released by infected freshwater snails. The disease affects over 200 million people worldwide, predominantly in tropical and subtropical regions of Africa, South America, the Caribbean, the Middle East, and Southeast Asia. The disease affects multiple body systems depending on the Schistosoma species involved. Schistosoma mansoni and S. japonicum primarily affect the liver and intestines (intestinal schistosomiasis), causing abdominal pain, diarrhea, bloody stools, and in chronic cases, liver fibrosis, portal hypertension, and hepatosplenomegaly. Schistosoma haematobium causes urogenital schistosomiasis, leading to hematuria (blood in urine), dysuria, bladder fibrosis, and an increased risk of bladder cancer. Chronic infection can also cause anemia, malnutrition, and impaired growth and cognitive development in children. Eggs deposited in tissues trigger granulomatous inflammatory responses, which are responsible for much of the organ damage. Treatment is available and effective. Praziquantel is the primary drug used for all forms of schistosomiasis and is administered orally, typically as a single-day treatment. It is effective against adult worms but does not prevent reinfection. Mass drug administration programs targeting at-risk populations, particularly school-age children, are a cornerstone of control efforts. Prevention strategies include avoiding contact with contaminated freshwater, improving sanitation, and snail control measures. Research into vaccine development is ongoing but no vaccine is currently available.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Common questions about Schistosomiasis