Medicine: 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...