Schistosomiasis (a parasitic infection)

General or Other | General Practice | Schistosomiasis (a parasitic infection) (Disease)


Schistosomiasis is a disease caused by parasitic worms. This disorder is found throughout Africa, South America, Asia and the Caribbean. Infection occurs after direct contact with infected water. The immature worms enter the body by penetrating the skin and infecting the body. Also known as bilharzia.

Causes and Risk factors

Schistosomiasis is a disease that is caused by parasites (genus Schistosoma) that enter humans by attaching to the skin, penetrating it, and then migrating through the venous system to the portal veins where the parasites produce eggs and eventually, the symptoms of acute or chronic disease (for example, fever, abdominal discomfort, blood in stools). This disease is also known as bilharziasis, bilharzia, bilharziosis, and snail fever or, in the acute form, Katayama fever.

Diagnosis and Treatment

Early disease usually improves with treatment. Surprisingly, patients with hepatic and urinary disease, even with fibrosis, may improve significantly over months or years following therapy. Renal and intestinal pathology also improves with treatment, as, usually, do brain lesions (depending on their location and size). End-stage hepatosplenic disease with variceal bleeding, pulmonary hypertension with cor pulmonale, and central nervous system disease are associated with high mortality rates. Carcinoma of the urinary tract, liver, and gallbladder may cause death.

Although effective antihelmintic treatment exists, it may not reverse fibrosis and may not be readily available in endemic areas. Praziquantel is undoubtedly the most effective medication with the fewest side-effects for the treatment of all species of schistosomes. The drug seems less effective in regions of West Africa where there has been a recent invasion of the parasite, possibly due to rapid re-infections. Diminished sensitivity or resistance to praziquantel are other possibilities. ...