| Abstract: | Infection by onchocerca volvulus, a parasitic worm, causes onchocerciasis (river blindness), a debilitating and often blinding disease endemic to tropical areas of Africa and Central and South America. The adult onchocerca volvulus invades the human host where it lives and reproduces for up to 14 years, creating millions of infant worms which cause itching, loss of skin color, rapid aging, and disfiguring skin disease in the host. Onchocerciasis often causes blindness in the human host by approximately age 35 years, and is the third leading cause of blindness in Africa. Onchocerca volvulus is transmitted among humans through the bite of blackflies which breed in fast-flowing rivers. The Onchocerciasis Control Program (OCP) was formally launched in 1974 by the UN's Food and Agriculture Organization (FAO), the UN Development Program (UNDP), the World Bank, and the World Health Organization (WHO) in Benin, Burkina Faso, Ghana, Cote d'Ivoire, Mali, Niger, and Togo. Vector control is the central strategy of the OCP, consisting of weekly helicopter spraying of larvacide to prevent the blackfly from reproducing and transmitting the disease. In addition, Merck & Co. is providing drug therapy against the infant worms in the human host free of charge to 16 million people in endemic areas. Onchocerciasis has now almost been eradicated in the 7 original target countries. Also through the OCP, by 1996, more than 34 million people were protected against the disease, about 2 million who were seriously infected have fully recovered, and an estimated 600,000 people have been prevented from going blind. 12 million infants born since the launch of the OCP face no risk of contracting the disease, and approximately 25 million hectares of arable fertile riverine land has been opened for resettlement. Labor productivity has also increased. |
