What is river blindness?

What is river blindness?Onchocerciasis (river blindness) is caused by infection with the filarial parasite Onchocerca volvulus, which is transmitted by the blackfly species. Most of the 37 million infected people live in Africa, with smaller foci in Latin America and Yemen. In addition to eye disease and blindness, onchocerciasis also causes a range of skin diseases and other systemic conditions. Currently, about 300,000 people are blind from onchocerciasis. Control measures entail larvicide spraying of blackfly breeding sites and treatment of endemic communities with the microfilaricide Mectizan® (ivermectin).

The highly effective WHO Onchocerciasis Control Programme, which operated between 1974 and 2002, covered 11 countries in West Africa (Benin, Burkina Faso, Côte d’Ivoire, Ghana, Guinea, Guinea-Bissau, Mali, Niger, Senegal, Sierra Leone and Togo). By 2002 onchocerciasis was no longer a public health problem except in Sierra Leone and some areas of Benin, Ghana, Guinea and Togo. Intense control activities will continue in these areas until the end of 2007, and surveillance is continuing in all the countries formerly covered by the Programme. Owing to civil conflict, the status of onchocerciasis has deteriorated in Côte d’Ivoire, Guinea-Bissau and Sierra Leone.

CurrentlyThe disease is endemic in:

• 30 countries of Africa (Angola, Benin, Burkina Faso, Burundi, Cameroon, Central African Republic, Chad, Congo, Côte d’Ivoire, Democratic Republic of the Congo, Equatorial Guinea, Ethiopia, Gabon, Ghana, Guinea, Guinea-Bissau, Kenya, Liberia, Malawi, Mali, Mozambique, Niger, Nigeria, Rwanda, Senegal, Sierra Leone, Sudan, Togo, Uganda and the United Republic of Tanzania);
• 13 foci scattered over six Latin American countries (Brazil, Colombia, Ecuador, Guatemala, Mexico and Venezuela)
• Yemen (although ivermectin is being distributed in a few communities, technical assistance is needed to determine the current epidemiological status of the disease so that it can be controlled).