埃塞俄比亚东部索马里地区斯氏按蚊的杀虫剂抗性。
Insecticide resistance in Anopheles stephensi in Somali Region, eastern Ethiopia.
机构信息
Department of Biology, Jigjiga University, Jigjiga, Ethiopia.
Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
出版信息
Malar J. 2020 May 12;19(1):180. doi: 10.1186/s12936-020-03252-2.
BACKGROUND
The movement of malaria vectors into new areas is a growing concern in the efforts to control malaria. The recent report of Anopheles stephensi in eastern Ethiopia has raised the necessity to understand the insecticide resistance status of the vector in the region to better inform vector-based interventions. The aim of this study was to evaluate insecticide resistance in An. stephensi in eastern Ethiopia using two approaches: (1) World Health Organization (WHO) bioassay tests in An. stephensi; and (2) genetic analysis of insecticide resistance genes in An. stephensi in eastern Ethiopia.
METHODS
Mosquito larvae and pupae were collected from Kebri Dehar. Insecticide susceptibility of An. stephensi was tested with malathion 5%, bendiocarb 0.1%, propoxur 0.1%, deltamethrin 0.05%, permethrin 0.75%, pirimiphos-methyl 0.25% and DDT 4%, according to WHO standard protocols. In this study, the knockdown resistance locus (kdr) in the voltage gated sodium channel (vgsc) and ace1R locus in the acetylcholinesterase gene (ace-1) were analysed in An. stephensi.
RESULTS
All An. stephensi samples were resistant to carbamates, with mortality rates of 23% and 21% for bendiocarb and propoxur, respectively. Adult An. stephensi was also resistant to pyrethroid insecticides with mortality rates 67% for deltamethrin and 53% for permethrin. Resistance to DDT and malathion was detected in An. stephensi with mortality rates of 32% as well as An. stephensi was resistance to pirimiphos-methyl with mortality rates 14%. Analysis of the insecticide resistance loci revealed the absence of kdr L1014F and L1014S mutations and the ace1R G119S mutation.
CONCLUSION
Overall, these findings support that An. stephensi is resistant to several classes of insecticides, most notably pyrethroids. However, the absence of the kdr L1014 gene may suggest non-target site resistance mechanisms. Continuous insecticide resistance monitoring should be carried out in the region to confirm the documented resistance and exploring mechanisms conferring resistance in An. stephensi in Ethiopia.
背景
疟疾媒介向新地区的迁移是控制疟疾工作中的一个日益关注的问题。最近在埃塞俄比亚东部发现了淡色库蚊，这就需要了解该地区媒介的抗药性状况，以便更好地为基于媒介的干预措施提供信息。本研究的目的是使用两种方法评估埃塞俄比亚东部淡色库蚊的抗药性：（1）在淡色库蚊中进行世界卫生组织（WHO）生物测定试验；（2）对埃塞俄比亚东部淡色库蚊的杀虫剂抗性基因进行遗传分析。
方法
从 Kebri Dehar 采集蚊虫幼虫和蛹。根据世界卫生组织标准方案，用马拉硫磷 5%、丁醚脲 0.1%、残杀威 0.1%、溴氰菊酯 0.05%、氯菊酯 0.75%、吡虫啉 0.25%和滴滴涕 4%测试淡色库蚊的杀虫剂敏感性。在本研究中，分析了淡色库蚊的电压门控钠离子通道（vgsC）中的击倒抗性基因（kdr）和乙酰胆碱酯酶基因（ace-1）中的 ace1R 基因座。
结果
所有淡色库蚊样本均对氨基甲酸酯类杀虫剂具有抗药性，丁醚脲和残杀威的死亡率分别为 23%和 21%。淡色库蚊成虫对拟除虫菊酯类杀虫剂也具有抗药性，溴氰菊酯和氯菊酯的死亡率分别为 67%和 53%。淡色库蚊对滴滴涕和马拉硫磷也具有抗药性，死亡率分别为 32%，对吡虫啉的抗药性死亡率为 14%。抗药性基因座分析显示，淡色库蚊缺乏 kdr L1014F 和 L1014S 突变以及 ace1R G119S 突变。
结论
总的来说，这些发现表明淡色库蚊对几类杀虫剂具有抗药性，尤其是拟除虫菊酯类杀虫剂。然而，缺乏 kdr L1014 基因可能表明存在非靶标部位的抗性机制。应在该地区持续进行杀虫剂抗药性监测，以确认已记录的抗药性，并探索赋予埃塞俄比亚淡色库蚊抗药性的机制。
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