广东省中山市城区白纹伊蚊对拟除虫菊酯类杀虫剂的抗药性及其抗性基因突变分析

Pyrethroid resistance and associated mutations in Aedes albopictus in urban area of Zhongshan,Guangdong Province,China

目的调查2020年中山市中心城区白纹伊蚊对拟除虫菊酯类杀虫剂的抗性现状,并探究中山市白纹伊蚊野外种群电压门控钠离子通道基因(VGSC)击倒抗性(kdr)突变情况,为病媒生物的有效防治提供依据。方法2020年7-10月,在中山市城区5个不同生境采集伊蚊成蚊和幼蚊,经过实验室饲养后,挑选白纹伊蚊雌性成蚊应用成蚊接触筒法测定其对拟除虫菊酯类杀虫剂的抗药性水平;用PCR扩增中山市白纹伊蚊种群VGSC基因片段,并分析其kdr突变情况。使用SPSS 25.0软件进行统计学分析,多组间比较采用R×C列联表卡方检验或Fisher确切概率法,两两比较采用Bonferroni法。结果生物测定结果显示,中山市城区白纹伊蚊野外种群对0.03%溴氰菊酯、0.08%顺式氯氰菊酯、0.07%高效氯氟氰菊酯、0.4%氯菊酯、0.4%高效氯氰菊酯类杀虫剂的24 h死亡率范围分别为9.48%~50.82%、6.89%~40.69%、2.61%~38.13%、0.88%~50.00%和17.95%~94.00%。除金字山森林公园种群对0.4%高效氯氰菊酯表现为可能抗性外,其余均表现为抗性。共检测了318只白纹伊蚊VGSC基因,结果显示,中山市种群1532位点未出现突变,1534位点已发生突变。1534位点存在4种突变等位基因,包括TTG/L、TCC/S、TCG/S和TGC/C,TTG/L出现频率最高(57.23%);有9种基因型,分别为野生型纯合子TTC/TTC(F/F),野生/突变型杂合子TTC/TCC(F/S)、TTC/TCG(F/S)、TTC/TTG(F/L)和TTC/TGC(F/C),突变型纯合子TTG/TTG(L/L)、TCC/TCG(S/S)和TCC/TCC(S/S),突变型杂合子TTG/TCC(L/S),以突变型纯合子L/L占比最高,为41.82%。结论中山市中心城区白纹伊蚊种群对拟除虫菊酯类杀虫剂已经产生了较高程度的抗性,有必要持续监测蚊虫抗药性,并根据抗药性现状采取针对性的防治措施,降低相关蚊媒传染病的发生风险。

Objective To investigate the pyrethroid resistance and the knockdown resistance mutations in the voltagegated sodium channel gene(VGSC)of field populations of Aedes albopictus in the central urban areas of Zhongshan,Guangdong Province,China in 2020,so as to provide a reference for effective vector control.Methods Aedes adults and larvae were collected from five different habitats in urban area of Zhongshan from July to October,2020.After laboratory rearing,female adult mosquitoes of Ae.albopictus were selected for pyrethroid resistance testing using the World Health Organization tube bioassay.The VGSC gene fragments of Ae.albopictus in Zhongshan were amplified for sequencing using polymerase chain reaction.SPSS 25.0 software was used for statistical analysis.The Chi-square R×C contingency table test or Fisher’s exact test was used for multi-group comparison,and the Bonferroni test was used for pairwise comparison.Results The 24 h mortality of field populations of Ae.albopictus was 9.48%-50.82% for 0.03% deltamethrin,6.89%-40.69% for 0.08% alpha-cypermethrin,2.61%-38.13% for 0.07%lambda-cyhalothrin,0.88%-50.00% for 0.4% permethrin,and 17.95%-94.00% for 0.4%beta-cypermethrin.All the populations of Ae.albopictus showed resistance to the five pyrethroid insecticides,except for the Jinzishan population with suspected resistance to 0.4%cypermethrin.A total of 318 Ae.albopictus mosquitoes were tested for VGSC gene variants,detecting mutations at locus 1534 and no mutation at locus 1532.There were four mutant alleles at locus 1534,including TTG/L(most frequent,57.23%),TCC/S,TCG/S,and TGC/C.There were nine genotypes at locus 1534:wild-type homozygous TTC/TTC(F/F);wild/mutant-type heterozygous TTC/TCC(F/S),TTC/TCG(F/S),TTC/TTG(F/L),and TTC/TGC(F/C);mutant homozygous TTG/TTG(L/L),TCC/TCG(S/S),and TCC/TCC(S/S);and mutant heterozygous TTG/TCC(L/S).The mutant homozygote L/L accounted for the highest proportion of 41.82%.Conclusions Field Ae.albopictus populations in central urban area of Zhongshan have developed high resistance to pyrethroids.In order to reduce the risk of mosquitoborne diseases,it is necessary to continue to monitor insecticide resistance,and take targeted control measures according to resistance status.