Impact of insecticide-treated materials on filaria transmission by the various species of vector mosquito in Africa
Pedersen, E.M.; Mukoko, D.A.
Annals of Tropical Medicine and Parasitology 96(Suppl 2): S91-S95
2002
ISSN/ISBN: 1364-8594 Document Number: 235997
Nocturnally periodic Bancroftian filariasis is maintained by three mainly endophilic vectors in East Africa: Culex quinquefasciatus, Anopheles funestus and A. gambiae complex. Permethrin-impregnated bed nets provide considerable protection against these mosquitoes, but the species respond differently. The degree of protection conferred by treated bed nets was determined in Kenyan communities where all three vectors actively transmit Wuchereria bancrofti. The annual transmission potential in the communities (i.e. an estimate of the number of human infective, 3rd-stage larvae of W. bancrofti inoculated into each villager each year) was reduced by 92%, through the nets' impact on vector biting rates (reduced by 22%) and their cumulative impact on the annual infective biting rate (reduced by 95%). Thus a modest reduction in the numbers of mosquitoes biting humans, attributable to the use of the insecticide-treated nets, strongly suppressed the risk of W. bancrofti transmission.