Miracle Worker Cure for river blindness

In some West African villages it is common to see children leading their blind elders to the fields, where they serve as human scarecrows. With eyes full of parasitic worms and skin covered by itchy nodules, the adults suffer from onchocerciasis, a disease that afflicts 18 million people in the developing world and permanently blinds 500,000 each year. The worms are spread by black flies, which breed near fast-flowing tropical streams -- hence the name river blindness. Last week New Jersey-based Merck & Co. announced that it will begin distributing ivermectin, a drug that halts onchocerciasis, to affected countries.

Moreover, Merck declared it would donate enough of the new drug through the World Health Organization to wipe out river blindness, possibly by the year 2000. For more than a decade, WHO has mounted spraying campaigns that have curbed the malady by attacking the carrier black flies. But in many areas the insects developed a resistance to the sprays. Enter ivermectin. The drug works by attacking the primary cause of the disease, the worms. Although it does not kill the invading parasites, biannual doses of ivermectin can prevent them from reproducing. Predicts Halfdan Mahler, director-general of WHO: "Ivermectin will revolutionize the way countries face this debilitating disease."

The new drug has one drawback. Since reinfection can always occur, most victims of onchocerciasis will have to take ivermectin for life. That is a small price to pay. Notes Hugh Taylor, a researcher at Johns Hopkins who has tested the drug in Senegal: "After treatment, people come up to me and say, 'Look how beautiful my skin is -- and no itching!' "