Resistance to pyrethroids (PY) and organophosphate (OP) insecticides is widespread among populations of Culex quinquefasciatus, the major vector of lymphatic filariasis (LF). The present study was designed to detect the L1014F kdr (knockdown resistant) mutation among Cx. quinquefasciatus populations in the filarial belt of Sri Lanka. Mosquitoes were reared from field-caught larvae from seven localities where LF is endemic. Susceptibility status of Cx. quinquefasciatus to adulticides, 0.05% deltamethrin, 0.75% permethrin, 5% malathion, and the larvicide temephos was determined using the standard WHO susceptibility tests. A fragment of vgsc gene was amplified and sequenced to identify the responsible kdr mutations. The susceptibility test results revealed less than 90% mortalities for 0.05% deltamethrin, and 0.75% permethrin and temephos. For 5% malathion, all study sites except Maharagama revealed greater than 90% mortality. The L1014F kdr mutation was observed in all studied populations. Although the overall microfilaria rate is less than 1% in the country, there is a high risk of re-emergence of LF in Sri Lanka due to abundant Cx. quinquefasciatus mosquitoes, increased resistant status to currently used insecticides, imported LF cases, higher rates of microfilaria among neighboring countries, and the advancement of tourism.

中文翻译：

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斯里兰卡 Culex quinquefasciatus 蚊子的杀虫剂抗性和击倒抗性 (kdr) 的分子特征

对拟除虫菊酯 (PY) 和有机磷 (OP) 杀虫剂的抗药性在淋巴丝虫病 (LF) 的主要媒介库蚊种群中普遍存在。本研究旨在检测 Cx 中的 L1014F kdr（抗击倒）突变。斯里兰卡丝虫带的quinquefasciatus种群。蚊子是从 LF 流行的七个地区的田间捕获的幼虫中饲养的。Cx的易感性状态。quinquefasciatus对杀成虫剂、0.05% 溴氰菊酯、0.75% 氯菊酯、5% 马拉硫磷和杀幼虫剂 temephos 使用标准的 WHO 药敏试验确定。vgsc基因的一个片段被扩增和测序，以确定负责任的kdr突变。敏感性测试结果显示，0.05% 溴氰菊酯、0.75% 氯菊酯和 temephos 的死亡率低于 90%。对于 5% 的马拉硫磷，除 Maharagama 外的所有研究地点均显示超过 90% 的死亡率。在所有研究人群中都观察到L1014F kdr突变。尽管该国的总体微丝蚴发病率不到 1%，但由于Cx丰富，斯里兰卡的 LF 再次出现的风险很高。quinquefasciatus蚊子、对目前使用的杀虫剂的抗药性增加、进口 LF 病例、邻国中微丝蚴的高发率以及旅游业的发展。