Mbogo C N, Baya N M, Ofulla A V, Githure J I, Snow R W
Clinical Research Centre, Kenya Medical Research Institute (KEMRI), Kenya.
Med Vet Entomol. 1996 Jul;10(3):251-9. doi: 10.1111/j.1365-2915.1996.tb00739.x.
The effects of introducing permethrin-impregnated bednets on local populations of the malaria vector mosquitoes Anopheles funestus and the An.gambiae complex was monitored during a randomized controlled trial at Kilifi on the Kenyan coast. Pyrethrum spray collections: inside 762 households were conducted between May 1994 and April 1995 after the introduction of bednets in half of the study area. All-night human bait collections were performed in two zones (one control and one intervention) for two nights each month during the same period. PCR identifications of An.gambiae sensu lato showed that proportions of sibling species were An.gambiae sensu stricto > An.merus > An.arabiensis. Indoor-resting densities of An.gambiae s.l. and the proportion of engorged females decreased significantly in intervention zones as compared to control zones. However, the human blood index and Plasmodium falciparum sporozoite rate remained unaffected. Also vector parous rates were unaltered by the intervention, implying that survival rates of malaria vectors were not affected. The human-biting density of An.gambiae s.l., the predominant vector, was consistently higher in the intervention zone compared to the control zone, but showed 8% reduction compared to pre-intervention biting rates-versus 94% increase in the control zone. Bioassay, susceptibility and high-performance liquid chromatography results all indicated that the permethrin content applied to the nets was sufficient to maintain high mortality of susceptible vectors throughout the trial. Increased rates of early outdoor-biting, as opposed to indoor-biting later during the night, were behavioural or vector composition changes associated with this intervention, which would require further monitoring during control programmes employing insecticide-treated bednets.
在肯尼亚海岸基利菲进行的一项随机对照试验中，监测了引入氯菊酯浸渍蚊帐对当地疟疾媒介蚊子——嗜人按蚊和冈比亚按蚊复合体种群的影响。除虫菊酯喷雾采集：在1994年5月至1995年4月期间，在研究区域的一半地区引入蚊帐后，对762户家庭内部进行了采集。同期，每月在两个区域（一个对照区和一个干预区）进行两晚的通宵人饵采集。对冈比亚按蚊复合组的PCR鉴定表明，其亲缘种比例为：冈比亚按蚊指名亚种＞梅氏按蚊＞阿拉伯按蚊。与对照区相比，干预区冈比亚按蚊复合组的室内栖息密度和饱血雌蚊比例显著下降。然而，人体血液指数和恶性疟原虫子孢子率未受影响。此外，干预并未改变媒介的产雌率，这意味着疟疾媒介的存活率未受影响。主要媒介冈比亚按蚊复合组的人叮咬密度在干预区始终高于对照区，但与干预前的叮咬率相比降低了8%，而对照区则增加了94%。生物测定、敏感性和高效液相色谱结果均表明，应用于蚊帐的氯菊酯含量足以在整个试验期间维持易感媒介的高死亡率。与夜间后期室内叮咬相反，早期室外叮咬率的增加是与该干预相关的行为或媒介组成变化，在使用杀虫剂处理蚊帐的控制计划期间需要进一步监测。
