New Internationalist

Snail Fever

Issue 092

HEALTH

Bilharzia, or ‘snail fever’ is one of the infamous diseases of the tropics, affecting roughly 250 million people from China and the Philippines to Africa, the Middle East, Brazil and the Caribbean. Till now medical treatment of the crippling affliction has been dangerous, time­consuming and costly. However, a recent development by John Hopkins University scientist Ernest Bueding could be a major breakthrough in curing the disease.

Bilharzia (schistosomiasis is the text­book name) is caused by a tiny parasite, the schistosome worm, whose life cycle is spent half in the human body and half in small freshwater snails that inhabit tropical streams, rivers, lakes and swamps. The parasite’s larvae burrow into the human body where they lay eggs which are then excreted in body wastes. Once the contaminated waste contacts the water supply the newly-hatched worms migrate in search of a snail ‘host’ where they mature until the larva stage. The cycle is completed when the larva again penetrates an unwary person - perhaps a woman washing clothes, a child bathing or a man casting fish nets from the shallows of an infected river.

Estimates of the economic impact of bilharzia vary widely. But one World Bank report puts the global figure near $650 million. The new drug (amoscanate) is apparently effective in a single oral dose and appears to have no bad side effects. According to the US Agency for International Development (AID -which funded most of the research on the drug) the cost is likely to run to a little over a dollar a dose.

If it proves reliable amoscanate could put a severe crimp in the cycle of snail fever. However, to break the circle entire­ly will require a full-fledged fight against the poor hygiene and filthy sanitary conditions that breed schistosomiasis and scores of other debilitating diseases.

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