River blindness

River blindness
Onchocerciasis, a disease caused by a parasitic worm (Onchocerca volvulus) which is transmitted to persons by biting blackflies (buffalo gnats) that breed in fast-flowing rivers. The adult worms can live for up to 15 years in nodules beneath the skin and in the muscles of infected persons, where they produce millions of worm embryos (microfilariae) that invade the skin and other tissues including the eyes. About 18 million persons are affected, mostly in Africa and also in Yemen and Latin America. Both living and dead microfilariae cause severe itching in the skin and sometimes blindness after many years. Until the 1980s, the main control measure was to use larvicides to kill immature blackflies in rivers. This method was used effectively to reduce the incidence of the disease in part of West Africa but is expensive. Since 1987, the drug ivermectin (brand name: Stromectol) has been provided by the manufacturer (Merck) free of charge to control programs for treating persons with onchocerciasis. This treatment, effective in a single oral dose administered once a year, prevents the accumulation of microfilariae in persons at risk. No drug suitable for mass treatment can kill the adult worms in the body and onchocerciasis cannot be eradicated without such means. The blindness, however, can be eliminated.

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riv·er blindness 'riv-ər- n ONCHOCERCIASIS

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blindness caused by onchocerciasis.

Medical dictionary. 2011.

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Look at other dictionaries:

  • river blindness — n. ONCHOCERCIASIS …   English World dictionary

  • river blindness — noun infestation with slender threadlike roundworms (filaria) deposited under the skin by the bite of black fleas; when the eyes are involved it can result in blindness; common in Africa and tropical America • Syn: ↑onchocerciasis • Hypernyms:… …   Useful english dictionary

  • river blindness — Pathol. onchocerciasis. [1950 55] * * * or onchocerciasis Human disease caused by a filarial worm native to Africa but also found in parts of tropical America and transmitted by several blackflies. It is so called because the flies that transmit… …   Universalium

  • river blindness — noun a tropical skin disease, sometimes also causing blindness, caused by a parasitic filarial worm and transmitted by blackflies which breed in rivers …   English new terms dictionary

  • river blindness — noun Date: 1953 onchocerciasis …   New Collegiate Dictionary

  • river blindness — noun Onchocerciasis …   Wiktionary

  • river blindness — see onchocerciasis …   The new mediacal dictionary

  • Blindness — This article is about the visual condition. For other uses, see Blindness (disambiguation). Blindness Classification and external resources A white cane, the international symbol of blindness ICD …   Wikipedia

  • river — n. 1 a copious natural stream of water flowing in a channel to the sea or a lake etc. 2 a copious flow (a river of lava; rivers of blood). 3 (attrib.) (in the names of animals, plants, etc.) living in or associated with the river. Phrases and… …   Useful english dictionary

  • river — river1 riverless, adj. riverlike, adj. /riv euhr/, n. 1. a natural stream of water of fairly large size flowing in a definite course or channel or series of diverging and converging channels. 2. a similar stream of something other than water: a… …   Universalium

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