Sichuan Center for Disease Control and Prevention, Chengdu, China.
State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
Parasit Vectors. 2021 Mar 20;14(1):169. doi: 10.1186/s13071-021-04662-0.
Sichuan province is located in the southwest of China, and was previously a malaria-endemic region. Although no indigenous malaria case has been reported since 2011, the number of imported cases is on the rise. Insecticide-based vector control has played a central role in the prevention of malaria epidemics. However, the efficacy of this strategy is gravely challenged by the development of insecticide resistance. Regular monitoring of insecticide resistance is essential to inform evidence-based vector control. Unfortunately, almost no information is currently available on the status of insecticide resistance and associated mechanisms in Anopheles sinensis, the dominant malaria vector in Sichuan. In this study, efforts were invested in detecting the presence and frequency of insecticide resistance-associated mutations in three genes that encode target proteins of several classes of commonly used insecticides.
A total of 446 adults of An. sinensis, collected from 12 locations across Sichuan province of China, were inspected for resistance-conferring mutations in three genes that respectively encode acetylcholinesterase (AChE), voltage-gated sodium channel (VGSC), and GABA receptor (RDL) by DNA Sanger sequencing.
The G119S mutation in AChE was detected at high frequencies (0.40-0.73). The predominant ace-1 genotype was GGC/AGC (119GS) heterozygotes. Diverse variations at codon 1014 were found in VGSC, leading to three different amino acid substitutions (L1014F/C/S). The 1014F was the predominant resistance allele and was distributed in all 12 populations at varying frequencies from 0.03 to 0.86. The A296S mutation in RDL was frequently present in Sichuan, with 296SS accounting for more than 80% of individuals in six of the 12 populations. Notably, in samples collected from Chengdu (DJY) and Deyang (DYMZ), almost 30% of individuals were found to be resistant homozygotes for all three targets.
Resistance-related mutations in three target proteins of the four main classes of insecticides were prevalent in most populations. This survey reveals a worrisome situation of multiple resistance genotypes in Sichuan malaria vector. The data strengthen the need for regular monitoring of insecticide resistance and establishing a region-customized vector intervention strategy.
四川省位于中国西南部，曾是疟疾流行区。尽管自 2011 年以来没有报告本地疟疾病例，但输入性病例的数量却在上升。以杀虫剂为基础的病媒控制在预防疟疾流行方面发挥了核心作用。然而，杀虫剂耐药性的发展严重影响了这一策略的效果。定期监测杀虫剂耐药性对于提供基于证据的病媒控制至关重要。不幸的是，目前几乎没有关于四川省主要疟疾传播媒介中华按蚊的杀虫剂耐药性状况和相关机制的信息。在这项研究中，我们努力检测三个基因中与杀虫剂耐药性相关的突变的存在和频率，这三个基因分别编码几种常用杀虫剂的靶蛋白。
共检查了来自中国四川省 12 个地点的 446 只中华按蚊成虫，通过 DNA 焦磷酸测序检测三个基因（分别编码乙酰胆碱酯酶、电压门控钠通道和 GABA 受体）中与杀虫剂耐药性相关的突变。
AChE 中的 G119S 突变高频检出（0.40-0.73）。主要的 ace-1 基因型为 GGC/AGC（119GS）杂合子。在 VGSC 中发现了 1014 密码子的多种变异，导致了三种不同的氨基酸取代（L1014F/C/S）。1014F 是主要的耐药等位基因，分布在所有 12 个种群中，频率从 0.03 到 0.86 不等。RDL 中的 A296S 突变在四川很常见，在 12 个种群中的 6 个种群中，296SS 占个体的比例超过 80%。值得注意的是，在来自成都（DJY）和德阳（DYMZ）的样本中，几乎 30%的个体对所有三个靶标都是抗性纯合子。
四种主要杀虫剂类别的三个靶标蛋白的耐药相关突变在大多数种群中都很普遍。本调查揭示了四川省疟疾传播媒介中存在多种耐药基因型的令人担忧的情况。这些数据加强了对定期监测杀虫剂耐药性和建立针对该地区的病媒干预策略的需求。
