. Cooperative economic insect report. Beneficial insects; Insect pests. - 917 - INSECTS NOT KNOWN TO OCCUR IN THE UNITED STATES A BLACK FLY (Slmulium damnosum Theobald) Economic Importance: The principal vector of human onchocerciasis, in West Africa is S. damnosum. The disease commonly causes blindness in humans. In this region alone, not including Nigeria and Cameroon, about 2 million people suffer from the disease or about one-tenth of the population, and of this number 150,000 are blind. Excessive skin irritation caused by the microfilariae often precedes failing sight. Onchocerciasis, cau
. Cooperative economic insect report. Beneficial insects; Insect pests. - 917 - INSECTS NOT KNOWN TO OCCUR IN THE UNITED STATES A BLACK FLY (Slmulium damnosum Theobald) Economic Importance: The principal vector of human onchocerciasis, in West Africa is S. damnosum. The disease commonly causes blindness in humans. In this region alone, not including Nigeria and Cameroon, about 2 million people suffer from the disease or about one-tenth of the population, and of this number 150,000 are blind. Excessive skin irritation caused by the microfilariae often precedes failing sight. Onchocerciasis, caused by a filarial worm, has an extensive dis- tribution in tropical Africa as well as Mexico, Central and South America. Simulium ochraceum Wlk. and S. metallicum Bellardi are the chief vectors in Central America. Simulium neavel Roubaud is another important carrier of the disease in Africa. The microfilariae in the skin of man are picked up by the vector in which they develop to the third stage infective larvae. The adult worms which give rise to the microfilariae often occur in nodules which may be very conspicuous when they occur on the head of an infected person. As typical of the family, the female only of S. damnosum sucks blood. The bite is painful and intense itching may follow. Distribution: Angola, Burundi, Cameroon, Congo (Brazzaville), Dahomey, Ethiopia, Gambia, Ghana, Guinea, Ivory Coast, Kenya, Liberia, Malawi, Mozambique, Nigeria, Portuguese Guinea, Republic of South Africa, Rwanda, Sierra Leone, Southwest Africa, Sudan Republic, Tanzania, Togo, Uganda, and Upper Volta. Hosts: Mainly man over most of its range but dogs, donkeys, goats, sheep, and birds also have been reported as General Distribution of Simulium damnosum Theobald Diptera: Himuliidae No. 169 of Series. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly
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Keywords: ., bookcentury1900, booksubjectbeneficialinsects, booksubjectinsect
