Schistosomiasis is a chronic, parasitic disease caused by blood flukes (trematode worms) of the genus Schistosoma. Schistosomiasis transmission has been documented in 77 countries. However those at most risk of infection are in 52 countries.
People become infected when larval forms of the parasite – released by freshwater snails – penetrate their skin during contact with infested water. In the body, the larvae develop into adult schistosomes. Adult worms live in the blood vessels where the females release eggs. Some of the eggs are passed out of the body in the faeces or urine to continue the parasite life-cycle. Others become trapped in body tissues, causing an immune reaction and progressive damage to organs.
Schistosomiais is prevalent in tropical and sub-tropical areas, especially in poor communities without access to safe drinking water and adequate sanitation. No schistosomiasis cases have been reported in Iraq during 2011 while only 5 cases were reported during 2010, which indicates that the country is moving toward the disease elimination.