- Schistosomiasis, or bilharzia, is a parasitic disease caused by trematode flatworms of the genusSchistosoma. Larval forms of the parasites, which are released by freshwater snails, penetrate the skin of people in the water.
- In the body, the larvae develop into adult schistosomes, which live in the blood vessels. The females release eggs, some of which are passed out of the body in the urine or faeces. Others are trapped in body tissues, causing an immune reaction.
- In urinary schistosomiasis, there is progressive damage to the bladder, ureters and kidneys. In intestinal schistosomiasis, there is progressive enlargement of the liver and spleen, intestinal damage, and hypertension of the abdominal blood vessels.
- Control of schistosomiasis is based on drug treatment, snail control, improved sanitation and health education.
The WHO strategy on use of anthelminthic drugs now makes it possible to control schistosomiasis in poor and marginalized communities, in conjunction with interventions against lymphatic filariasis, onchocerciasis and soil transmitted helminthiasis. In highly endemic areas, severe morbidity due to schistosomiasis can be prevented by regular treatment of at risk groups targeted based on community diagnosis based on sentinel groups. Praziquantel has been safely co-administered with albendazole and ivermectin, in areas where these drugs have been used separately for preventive chemotherapy.