Insecticide resistance levels and mechanisms in Aedes aegypti populations in and around Ouagadougou, Burkina Faso
Insecticide resistance levels and mechanisms in Aedes aegypti populations in and around Ouagadougou, Burkina Faso
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DOI：
10.1371/journal.pntd.0007439
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发表时间：
2019-05-01
影响因子：
3.8
通讯作者：
Weetman, David
中科院分区：
文献类型：
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作者：
Badolo, Athanase;Sombie, Aboubacar;Weetman, David
背景最近登革热和其他埃及伊蚊传播的虫媒病毒的爆发凸显了快速反应以有效控制病媒的重要性。关于杀虫剂抗药性和潜在机制的数据对于疾病暴发的防备至关重要，但在非洲大部分地区却很少。本文研究了铜绿假单胞菌的抗药性水平和异质性，并探讨了铜绿假单胞菌的抗药性机制。方法/主要发现对幼虫和成虫进行生物测定，以诊断耐药性的流行，并评估检测到耐药性的水平。采用生物测定法、敲低耐药（kdr）靶位点突变基因分型和候选P450基因的定量PCR表达分析进行耐药机制的研究。幼虫剂量反应试验表明敏感性的有机磷测试。成年女性也容易受到有机磷，但在城市和半城市地区怀疑对氨基甲酸酯的耐药性。所有地区的女性均表现出对拟除虫菊酯的耐药性，但与农村人口相比，城市尤其是半城市地区的耐药性流行率和水平较高。环境也与易感性相关：从半城市场地的轮胎中收集的幼虫饲养的成虫对拟除虫菊酯的抗性显著低于从大型户外饮用水容器（桶）中收集的幼虫。通过预暴露于丁二醇单酯（PBO），对测试的两种拟除虫菊酯的敏感性在很大程度上得以恢复，表明抗性的代谢基础很强。1534 C kdr突变在半城市和城市地区几乎是固定的，但在农村地区，1016 I kdr突变频率也显着较低。P450基因分析检测到单个候选基因的过度表达有限，但与易感实验室群体和其他收集地点的雌性相比，半城市地点的平均表达显着升高。结论/意义我们的结果揭示了拟除虫菊酯耐药性和成对的kdr突变在城市和半城市地点的水平对于非洲大陆来说是前所未有的。Ae的靶点与代谢机制的结合是常见的。埃及人的种群来自其他大陆，但这对非洲人来说是一个令人担忧的发现。然而，有机磷杀虫剂仍然对Ae的幼虫和成虫有效。作者摘要包括布基纳法索在内的几个非洲国家最近经历了登革热疫情。在登革热暴发时，控制登革热依赖于控制其病媒，但埃及伊蚊对杀虫剂的抗药性数据往往缺乏，特别是在非洲大陆。我们在瓦加杜古及其周边地区进行了一项研究，以评估Ae。埃及伊蚊对杀虫剂的抗药性，并调查有关机制。我们收集了埃及伊蚊幼虫从三个不同的地方和不同的繁殖地点，以评估幼虫和成虫对杀虫剂的敏感性。埃及伊蚊成虫对拟除虫菊酯类杀虫剂表现出较高的抗性，抗性的流行程度和强度取决于繁殖地的类型和地点。成虫对氨基甲酸酯的抗性不明显，幼虫和成虫对有机磷杀虫剂都很敏感。对拟除虫菊酯类杀虫剂的抗性部分由一对kdr突变（1534 C和1016 I）的高频率和与蚊子中杀虫剂降解相关的P450家族基因的过表达来解释。关于Ae的抗性和机制的数据集。来自非洲大陆的埃及伊蚊非常罕见，对布基纳法索和其他地方的登革热控制非常重要。
Background Recent outbreaks of dengue and other Aedes aegypti-borne arboviruses highlight the importance of a rapid response for effective vector control. Data on insecticide resistance and underlying mechanisms are essential for outbreak preparedness, but are sparse in much of Africa. We investigated the levels and heterogeneity of insecticide resistance and mechanisms of Ae. aegypti from contrasting settings within and around Ouagadougou, Burkina Faso.Methodology/Principal findings Bioassays were performed on larvae and adults to diagnose prevalence of resistance, and to assess levels where resistance was detected. Investigation of resistance mechanisms was performed using synergist bioassays, knockdown resistance (kdr) target site mutation genotyping and quantitative PCR expression analysis of candidate P450 genes. Larval dose-response assays indicated susceptibility to the organophosphates tested. Adult females were also susceptible to organophosphates, but resistance to carbamates was suspected in urban and semi-urban localities. Females from all localities showed resistance to pyrethroids but resistance prevalence and level were higher in urban and especially in semi-urban areas, compared to the rural population. Environment was also associated with susceptibility: adults reared from larvae collected in tires from the semi-urban site were significantly less resistant to pyrethroids than those collected from large outdoor drinking water containers (drums'). Susceptibility to both pyrethroids tested was largely restored by pre-exposure to Piperonyl Butoxide (PBO), suggesting a strong metabolic basis to resistance. The 1534C kdr mutation was nearly fixed in semi-urban and urban areas but was far less common in the rural area, where the 1016I kdr mutation frequency was also significantly lower. P450 gene analysis detected limited over-expression of single candidates but significantly elevated average expression in the semi-urban site compared to both a susceptible laboratory colony, and females from the other collection sites.Conclusions/Significance Our results reveal pyrethroid resistance and paired kdr mutations in both urban and semi-urban sites at levels that are unprecedented for mainland Africa. The combination of target site and metabolic mechanisms is common in Ae. aegypti populations from other continents but is a worrying finding for African populations. However, organophosphate insecticides are still active against both larvae and adults of Ae. aegypti, providing useful insecticidal options for control and resistance management.Author summary Several African countries including Burkina Faso have experienced dengue outbreaks recently. In outbreaks, dengue control relies on the control of its vector but data on Aedes aegypti resistance to insecticide, a key for efficient control, are often lacking, especially for the African continent. We conducted a study in localities within and around Ouagadougou to assess the Ae. aegypti resistance to insecticides and investigate the mechanisms involved. We collected larvae of Aedes aegypti from three different localities and different breeding sites to assess larval and adult susceptibility to insecticides. Aedes aegypti adults showed high resistance to pyrethroid insecticides with the prevalence and intensity of resistance depending on the locality and type of breeding site. Adults showed less pronounced resistance to carbamates, and both larvae and adults remain susceptible to organophosphate insecticides. The resistance to pyrethroid insecticides is partly explained by a high frequency of a pair of kdr mutations (1534C and 1016I) and the overexpression of genes of the P450 family linked to insecticide degradation in the mosquito. Datasets on both resistance and mechanisms in Ae. aegypti from the African continent are quite rare and are important for dengue control in Burkina Faso and elsewhere.