Schistosomiasis (Bilharzia)
Travel Health

From: Travel Health Information and Advice


Schistosomiasis (Bilharzia)
Schistosomiasis also known as Bilharzia is a parasitic disease commonly found in the tropics which can if left untreated be fatal.

Cause of Schistosomiasis
There are three species of parasitic flatworms that cause the disease; S mansoni, S. haemotobium and S japonicum.

The parasites are found in contaminated fresh water sources and they must first penetrate through the tissue of a suitable snail which acts as an intermediate host, where it remains and matures into cercariae before being released back into the water where it can survive for 72 hours.

The cercariae penetrate the skin of a human host and migrate to the portal vein where they further mature and produce further eggs. The parasites often migrate to various veins such as those found in the small intestine, large intestine, the bowel and the bladder. Any of the eggs that are produced are excreted in the faeces or urine.

Symptoms of Schistosomiasis
It is the allergic reaction from the release of the Schistososomes eggs that causes the symptoms which often vary depending on which part of the individual is affected, the patients liver is often enlarged and blood may be present in urine and stools. Symptoms can include:

Left untreated progressive damage can be done to the various organs such as the kidneys, bladder, ureters which can be fatal.

Schistosomiasis Vaccine
There is no vaccine available at present.

Preventing Schistosomiasis
To help prevent the risk of infection avoid entering fresh water sources in endemic areas, especially those which are close to villages, other precautions include:

Diagnosing Schistosomiasis
Diagnosis is achieved through a urine or stool sample. In some cases an ultrasound may be given to ascertain if any organ damage has taken place.

Treatment of Schistosomiasis
Seek medical attention as soon as possible to begin treatment with the drug Praziquantel. In severe infections two doses of Praziquantel may be necessary.

Affected Areas
Tropical and sub tropical areas such as Africa and Asia.


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