Schistosomiasis, also known as bilharzia, is caused by parasitic flatworms of the Schistosoma species. It is contracted through contact with contaminated freshwater, where larval worms penetrate the skin. The disease causes chronic inflammation, organ damage, and can lead to complications such as liver fibrosis or bladder cancer. Treatment involves the antiparasitic drug praziquantel, and prevention focuses on improving sanitation and access to clean water. Schistosomiasis is common in sub-Saharan Africa and other tropical regions.