Section 8
Chapter 7,883

The development of onchocerca dukei and onchocerca ochengi microfilariae to infective stage larvae in simulium damnosum and in members of the simulium medusaeforme group following intra thoracic injection

Wahl, G.; Ekale, D.; Enyong, P.; Renz, A.

Annals of Tropical Medicine and Parasitology 85(3): 329-338


ISSN/ISBN: 1364-8594
Accession: 007882228

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Neonate Simulium females from an endemic area of human and bovine onchocerciasis in North-Cameroon were injected in one set of experiments with microfilariae (mff) of Onchocerca dukei and in another with mff of O. ochengi. Onchocerca dukei was found to develop to infective third-stage larvae in Simulium flies: 148-third-stage larvae (28.1% of injected mff) were recovered in S. hargreavesi, seven (10.4% of injected mff) in S. vorax, and 12 (1.3%) in S. damnosum s.l. Onchocerca ochengi mff developed in S. hargreavesi at a rate of 17.3% and in S. damnosum s.l. and 16.1%, yielding a total of 77 and 32 third-stage larvae respectively. Onchocerca dukei infective larvae had a mean length of 717.3 .mu.m and a mean maximum diameter of 17.5 .mu.m, and were slightly shorter and conspicuously thinner than those of O. ochengi (748.3 .mu.m .times. 20.4 .mu.m). All larval stages of O. dukei typically had an attenuated anterior end. The implications of these findings for the epidemiology of human onchocerciasis are discussed.

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