Schistosomiasis, also known as bilharziasis or snail fever, is a primarily tropical parasitic disease caused by the larvae of one or more of five types of flatworms or blood flukes known as schistosomes.
Schistosomiasis is transmitted by contact with contaminated fresh water (lakes and ponds, rivers, dams) inhabited by snails carrying the parasite. Swimming, bathing, fishing and even domestic chores such as laundry and herding livestock can put people at risk of contracting the disease. Larvae emerge from the snails and swim in the water until they come into contact with an individual and penetrate the skin.
Schistosomiasis is uncommon in the United States, and the inexperienced clinician should consult an infectious disease or tropical medicine specialist for diagnosis and treatment. Praziquantel is used to treat schistosomiasis. Praziquantel is most effective against adult forms of the parasite and requires an immune response to the adult worm to be fully effective.