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Cures for Bilharzia

Bilharzia, or schistosomiasis, is a disease caused by fresh-water snails bearing parasitic worms in sub-Saharan Africa and other tropical countries. Worldwide, about 300 million people have the disease, with some 120 million displaying symptoms. There are limited options available today to cure bilharzia, which kills about 15,000 people each year.

  1. Nature of the Disease

    • Bilharzia was first identified by Dr. Teodor Bilharz in 1851. Parasites in contaminated water penetrate the skin of humans, their definitive host. Within weeks, worms begin growing inside their blood vessels. The worms produce eggs, some of which can lodge in the bladder or intestines. The eggs are passed on when the infected person urinates or defecates. Once hatched, the eggs develop inside snails, and the cycle is repeated.

    Infection

    • People are infected by wading, swimming, washing or bathing in water infested with bilunus, biophlaria or oncomelania snails. The disease cannot be transmitted from one person to another.

    Symptoms

    • No symptoms may be present in the early stages of infection, but people may develop a rash or itchy skin a few days after exposure. In one to two months, they may begin to cough and experience fever, chills, abdominal pain and diarrhea. Bilharzia eggs can infect and damage the liver, lungs, intestines and bladder. Symptoms are chronic with lethargy, fatigue and what appears to be anemia and malnourishment. Liver and the spleen can become enlarged and lesions develop on the central nervous system as well as polyps on the colon, bladder cancer, and pulmonary hypertension.

    Preventing Infection

    • Varieties of the bilharzia parasite are found in parts of Africa, South America, East and Southeast Asia, the Middle East, and the Caribbean. Visitors to Africa should avoid swimming in lakes in the Rift Valley; the water there, including Lake Malawai, may look crystal-clear, but still be infected. The Nile River valley in Egypt also contains bilharzia-bearing snails. People swimming in tropical fresh waters that may contain the infectious snails should dry off completely. They should only drink water from these sources that has been boiled.

    Diagnosis and Treatment

    • Bilharzia is diagnosed by presence of eggs in urine or feces. Praziquantel has been the de facto remedy for bilharzia since 1980. Considered both safe and effective, praziquantel is generally taken for two days. An international team of scientists has decoded the genome of the parasite, leading to the possibility of the development of cheaper new drugs for treating the diseases. Travelers should consult a specialist in tropical medicine or infectious diseases. No vaccine is currently available.

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