Background: Arboviral diseases including dengue and chikungunya are major public health concern in Bangladesh, with unprecedented levels of transmission reported in recent years. The primary approach to control these diseases is control of Aedes aegypti using pyrethroid insecticides. Although chemical control is long-practiced, no comprehensive analysis of Ae. aegypti susceptibility to insecticides has previously been conducted. This study aimed to determine the insecticide resistance status of Ae. aegypti in Bangladesh and investigate the role of detoxification enzymes and altered target site sensitivity as resistance mechanisms. Methods: Aedes eggs were collected using ovitraps from five districts across the country and in eight neighborhoods of the capital city Dhaka from August to November 2017. CDC bottle bioassays were conducted for permethrin, deltamethrin, malathion, and bendiocarb using 3 - 5 day old F0-F2 nonblood fed female mosquitoes. Biochemical assays were conducted to detect metabolic resistance mechanisms and real-time PCR was performed to determine the frequencies of the knockdown resistance (kdr) mutations Gly1016, Cys1534, and Leu410. Results: High levels of resistance to permethrin were detected in all Ae. aegypti populations, with mortality ranging from 0 - 14.8% at the diagnostic dose. Substantial resistance continued to be detected against higher (2X) doses of permethrin (5.1 - 44.4% mortality). Susceptibility to deltamethrin and malathion varied between populations while complete susceptibility to bendiocarb was observed in all populations. Significantly higher levels of esterase and oxidase activity were detected in most of the test populations as compared to the susceptible reference Rockefeller strain. A significant association was detected between permethrin resistance and the presence of Gly1016 and Cys1534 homozygotes. The frequency of kdr alleles varied across the Dhaka populations, and Leu410 was not detected in any of the tested populations. Conclusions: The detection of widespread pyrethroid resistance and multiple mechanisms highlights the urgency for implementing alternate Ae. aegypti control strategies. In addition, implementing routine monitoring of insecticide resistance in Ae. aegypti in Bangladesh will lead to a greater understanding of susceptibility trends over space and time, thereby enabling the development of improved control strategies.

中文翻译：

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孟加拉伊蚊的抗药性状况

背景：包括登革热和基孔肯雅热在内的虫媒病毒疾病是孟加拉国主要的公共卫生问题，近年来报道的传播水平前所未有。控制这些疾病的主要方法是使用拟除虫菊酯类杀虫剂控制埃及伊蚊。尽管化学控制是很长的实践，但没有对Ae进行全面分析。埃及虫对杀虫剂的敏感性以前已经进行过。这项研究旨在确定Ae的杀虫剂抗药性状态。孟加拉国的埃及人，研究排毒酶和改变靶点敏感性作为抗药性机制的作用。方法：2017年8月至2017年11月，在全国五个地区以及首都达卡的八个社区中使用卵形诱捕器采集伊蚊卵。使用3-5天大的F0-F2非血液喂养雌性蚊子对氯菊酯，溴氰菊酯，马拉硫磷和苯达威进行CDC瓶生物测定。进行生化分析以检测代谢抗性机制，并进行实时PCR以确定敲低抗性（kdr）突变Gly1016，Cys1534和Leu410的频率。结果：在所有Ae中均检测到对苄氯菊酯的高抗性。埃及种群，诊断剂量下死亡率为0-14.8％。继续检测到对更高剂量（2X）的氯菊酯有相当大的抵抗力（5.1-44.4％的死亡率）。不同人群对溴氰菊酯和马拉硫磷的敏感性不同，而在所有人群中均对苯达威彻底敏感。与易感的参考洛克菲勒菌株相比，在大多数测试人群中检测到的酯酶和氧化酶活性水平明显较高。在苄氯菊酯抗性与Gly1016和Cys1534纯合子的存在之间检测到显着关联。在达卡族中，kdr等位基因的频率各不相同，在所有测试人群中均未检测到Leu410。结论：广泛的拟除虫菊酯抗药性和多种机制的检测突出了实施替代Ae的紧迫性。埃及人控制策略。此外，对Ae中的杀虫剂抗性进行常规监测。孟加拉国的埃及将导致人们对时空敏感性趋势的更多了解，从而有助于制定改进的控制策略。