Schistosomiasisis a chronic parasitic disease caused by trematode worms of the genus Schistosoma. It is also known as bilharzia or snail fever. Humans become infected through contact with fresh water contaminated with the larvae of these parasites released by freshwater snails. The main species infecting humans are Schistosoma haematobium, S. mansoni, and S. japonicum. Inside the human body, these larvae develop into adult worms living in the blood vessels, producing eggs. Some of these eggs are passed out of the body in feces or urine to continue the lifecycle. Others eggs become trapped in body tissues, causing an immune response and eventually progressive damage to organs, including the bladder, kidneys, liver, and intestines. Chronic infection can lead to liver failure, kidney failure and bladder cancer.It is also associated with increased incidence of HIV transmission in affected population. Schistosomiasis is predominantly found in tropical and subtropical regions, especially in poor communities without safe drinking water and adequate sanitation. It is estimated to affect millions of people worldwide. Control efforts focus on reducing infection through drug treatment, improving sanitation, and snail control.