Arredondo-Jiménez J I, Rodríguez M H, Loyola E G, Bown D N
Centro de Investigación de Paludismo, Instituto Nacional de Salud Pública, Tapachula, Chiapas, México.
Med Vet Entomol. 1997 Jan;11(1):87-94. doi: 10.1111/j.1365-2915.1997.tb00294.x.
Responses of the malaria vector Anopheles albimanus to pyrethroid impregnated bednets made of cotton or nylon, compared with untreated nets, were investigated in houses occupied by two people inside and/or outside two bednets, in coastal Chiapas, México. The pyrethroid used was lambdacyhalothrin 30 mg a.i./m2. Bioassay mortality rates of An.albimanus exposed to treated nets for 3 or 15 min, rose from 40-55% to 90-100% for nylon nets 3-19 weeks post-treatment, but were consistently lower for treated cotton nets. An.albimanus females (collected unfed on human bait) were released in houses surrounded by curtains for trapping mosquitoes that exited from the house. Floor sheets were used in and around each experimental house for retrieving any mosquitoes knocked-down and/or killed. During post-treatment assessment for 17 weeks, An.albimanus blood-feeding success rates were 23-24% with untreated nets, 14-18% with treated cotton nets and 8-15% with treated nylon nets, significantly reduced when both human baits were inside the treated bednets, but not when one or more baits were outside the treated bednet(s) within the house. Proportions of mosquitoes leaving houses < 3 h post-release were 53-59% from houses with untreated bednets versus 65-78% with treated bednets. Except in one case (when both humans were outside treated cotton nets), these increased early exit rates were significant, whether or not the human baits were inside the treated bednets indoors. Mortality rates of An.albimanus females exiting overnight (22.00-06.00 hours) averaged 15-39% from houses with treated cotton and 16-46% with treated nylon nets, very significantly greater than the control mean rates of 6-8% mortality with untreated nets. Observations on wild-caught An.albimanus females marked with fluorescent powder and released indoors revealed that few mosquitoes (3-11%) actually contacted the bednets unless both human baits remained under them - when contact rates were 22% on treated nylon, 23% on treated cotton and 42% on untreated nets (P approximately 0.05). The mean resting time was significantly longer on untreated (14.4 min) than on treated nylon (5.8 min) or cotton (9.5 min) bednets, whereas mean resting times on other surfaces indoors were 16.5-19.8 min. Proportions exiting within 2h of release were significantly more from houses with treated houses (33-35%) than with untreated nets (8%). However, mortality rates of mosquitoes that landed on treated nets were very significantly greater (90-100%) than after landing on untreated nets (10%). Thus, despite some excito-repellency, lambdacyhalothrin-impregnated bednets (especially made of nylon) proved to be effective as an alternative to house-spraying against An.albimanus.
在墨西哥恰帕斯州沿海地区，在两张蚊帐内外居住着两人的房屋中，研究了疟疾媒介白纹伊蚊对由棉花或尼龙制成的拟除虫菊酯浸渍蚊帐的反应，并与未处理的蚊帐进行了比较。所用的拟除虫菊酯是高效氯氟氰菊酯30毫克有效成分/平方米。处理后3至19周，暴露于处理过的蚊帐3分钟或15分钟的白纹伊蚊生物测定死亡率，对于尼龙蚊帐从40%-55%上升到90%-100%，但处理过的棉蚊帐的死亡率始终较低。未在人饵上进食的白纹伊蚊雌蚊被释放到被窗帘包围的房屋中，以诱捕从房屋中出来的蚊子。在每个实验房屋及其周围使用地板布来找回任何被击倒和/或杀死的蚊子。在处理后17周的评估中，未处理蚊帐的白纹伊蚊吸血成功率为23%-24%，处理过的棉蚊帐为14%-18%，处理过的尼龙蚊帐为8%-15%。当两个人饵都在处理过的蚊帐内时，吸血成功率显著降低，但当一个或多个饵在房屋内处理过的蚊帐外时，吸血成功率没有降低。释放后<3小时离开房屋的蚊子比例，未处理蚊帐的房屋为53%-59%，处理过蚊帐的房屋为65%-78%。除了一种情况（当两个人都在处理过的棉蚊帐外时），无论人饵是否在室内处理过的蚊帐内，这些提前离开率的增加都是显著的。夜间（22:00-06:00）离开的白纹伊蚊雌蚊死亡率，处理过的棉蚊帐房屋平均为15%-39%，处理过的尼龙蚊帐房屋为16%-46%，非常显著高于未处理蚊帐的对照平均死亡率6%-8%。对用荧光粉标记并在室内释放的野外捕获的白纹伊蚊雌蚊的观察表明，很少有蚊子（3%-11%）实际接触蚊帐，除非两个人饵都在蚊帐下面——此时处理过的尼龙蚊帐的接触率为22%，处理过的棉蚊帐为23%，未处理蚊帐为42%（P约为0.05）。在未处理的蚊帐上平均休息时间（14.4分钟）明显长于处理过的尼龙蚊帐（5.8分钟）或棉蚊帐（9.5分钟），而在室内其他表面的平均休息时间为16.5-19.8分钟。释放后2小时内离开的蚊子比例，处理过的房屋显著高于未处理蚊帐的房屋（33%-35%对8%）。然而，落在处理过的蚊帐上的蚊子死亡率非常显著高于落在未处理蚊帐上的死亡率（90%-100%对10%）。因此，尽管有一些兴奋驱避作用，但高效氯氟氰菊酯浸渍蚊帐（特别是尼龙制成的）被证明是替代房屋喷洒防治白纹伊蚊的有效方法。
