Seydi Gazafi Khadijeh, Tavassoli Mousa, Mardani Karim
Department of Pathobiology, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran.
Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran.
Vet Res Forum. 2023;14(9):489-494. doi: 10.30466/vrf.2023.556815.3565. Epub 2023 Sep 15.
Pyrethroid insecticides target voltage-gated sodium channels (VGSCs) that are essential for electrical signaling in the nervous system of insects. Three-point mutations at the corresponding amino acid sequence positions M815I, T917I, and L920F located in domain II conferring the knockdown resistance (kdr) are the most important mutations in pyrethroid-resistant lice worldwide. In addition, six new mutations have been reported in the extracellular loops IIS1-2 (H813P) and IIS5 (I927F, L928A, R929V, L930M, L932M) in the α- subunit of the sodium channel in lice. The aim of this study was to detect alleles resistant to pyrethroids in the domain II (S5-S6) of the VGSC gene in goat biting louse. Goat biting lice were collected from five provinces in the west and northwest of Iran. Genomic DNA was extracted from goat biting lice and species was confirmed by amplifying the cytochrome oxidase subunit I (COXI) gene. A fragment in the domain II (S5-S6) of the VGSC gene was amplified using the specific primers and the resultant polymerase chain reaction products were sequenced. Substitutions T917I, L920F, I927F, L928A, R929V and L930M were identified in the examined sequences. The results showed that all the examined lice had at least one mutation in their VGSC gene associated with pyrethroid resistance or new mutations. The presence of these mutated alleles in the VGSC gene may be due to the long-term and multiple use of pyrethroids against arthropods. Thus, the molecular detection of resistance to pyrethroid insecticides in goat chewing lice can help plot a kdr frequency map to enact effective policies to control caprine pediculosis.
拟除虫菊酯类杀虫剂作用于电压门控钠通道（VGSCs），该通道对昆虫神经系统中的电信号传导至关重要。位于结构域II中相应氨基酸序列位置M815I、T917I和L920F处的三点突变赋予击倒抗性（kdr），是全球拟除虫菊酯抗性虱类中最重要的突变。此外，在虱类钠通道α亚基的细胞外环IIS1-2（H813P）和IIS5（I927F、L928A、R929V、L930M、L932M）中还报道了六个新突变。本研究的目的是检测山羊血虱VGSC基因结构域II（S5-S6）中对拟除虫菊酯有抗性的等位基因。从伊朗西部和西北部的五个省份采集了山羊血虱。从山羊血虱中提取基因组DNA，并通过扩增细胞色素氧化酶亚基I（COXI）基因来确认物种。使用特异性引物扩增VGSC基因结构域II（S5-S6）中的一个片段，并对所得聚合酶链反应产物进行测序。在所检测的序列中鉴定出T917I、L920F、I927F、L928A、R929V和L930M替换。结果表明，所有检测的虱子在其VGSC基因中至少有一个与拟除虫菊酯抗性或新突变相关的突变。VGSC基因中这些突变等位基因的存在可能是由于长期和多次使用拟除虫菊酯防治节肢动物所致。因此，对山羊血虱中拟除虫菊酯类杀虫剂抗性的分子检测有助于绘制kdr频率图，以制定有效的山羊虱病防治策略。
