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Onchocerciasis transmission levels and Simulium damnosum complex biting activity at riverside and rice field sites in Sierra Leone
Author(s) -
DAVIES J. B.,
BEECHGARWOOD P. A.,
THOMSON M. C.,
McMAHON J. E.
Publication year - 1988
Publication title -
medical and veterinary entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 82
eISSN - 1365-2915
pISSN - 0269-283X
DOI - 10.1111/j.1365-2915.1988.tb00209.x
Subject(s) - onchocerciasis , biology , onchocerca volvulus , filariasis , larva , biting , sierra leone , vector (molecular biology) , dry season , veterinary medicine , paddy field , theobald , evening , ecology , pupa , helminths , zoology , medicine , biochemistry , gene , immunology , recombinant dna , physics , astronomy , development economics , economics
. Biting densities of the Simulium damnosum Theobald complex of blackflies and their levels of parasitism by Onchocerca volvulus (Leuckart) were compared at two ecologically contrasted sites in the Southern Province of Sierre Leone, West Africa: by the Tabe riverside close to Gbaiima village where onchocerciasis is hyperendemic (63.1% positive skin‐snips) and in open rice fields 2 km from the mesoendemic (54.9%) village of Senehun. Using a combination of morphometric and enzyme electrophoresis techniques, the primary vector was found to belong to the S. sanctipauli sub‐complex and was most probably S. soubrense ‘B’ ( sensu Post, 1986). In the wet season biting activity took place throughout the day at the village, but had morning and evening peaks in the rice fields. Transmission of O. volvulus was detected at the village in all months except February‐April, while in the rice fields it was detected only during September‐November and May at one tenth the level of the village. There was a significant difference between the two sites in the proportion of parous flies carrying third stage larvae in the head, but not of other larval stages.