Abstract:

Objective To understand the deltamethrin resistance level，GTS and P450 metabolic detoxification enzyme activ? ities，and mutations in the para?type sodium channel gene that confers knockdown resistance（kdr）in Anopheles sinensis mosqui? toes from malaria endemic areas along the Huaihe River in Anhui Province，China. Methods An. sinensis adult mosquitoes were collected in Lilou，Mohekou and Tuohu townships of Bengbu City，Anhui Province from August to September，2011. The insecti? cide resistance bioassays were performed on adult mosquitoes by using the standard WHO susceptibility test with diagnostic con? centrations of deltamethrin 0.05%，and the mosquito resistance status was classified based on the WHO resistance classification criteria. The metabolic detoxification enzyme activities were measured in randomly selected mosquitoes，and the IIS6 region of the para?type sodium channel gene was amplified by PCR and sequenced to detect mutations at the codon 1014. Results The knock? down rates within 60 min exposure to deltamethrin test paper were 4.1%，7.0% and 8.2%，and the mortality rates were 8.2%， 12.0% and 12.8% for mosquitoes collected from Lilou，Mohekou and Tuohu townships，respectively. These three populations were classified as highly resistant populations based on the WHO resistance classification criteria. The GST and P450 enzyme activities of the three populations were significantly higher than those of the susceptible laboratory population（P < 0.001） . L1014C and L1014F mutations were detected，and the wild type homozygote kdr genotype was not found. These three populations exhibited a small but insignificant difference in kdr allele frequencies. No mutation was found in the laboratory susceptible mosquitos. Conclu? sions The An. sinensis mosquito populations from the regions along the Huaihe River in Anhui Province are strongly resistant to pyrethroid insecticides，and exhibit significantly higher metabolic detoxification enzyme activities than the laboratory susceptible population. The high frequency of kdr mutation is identified in the mosquito populations from the region along the Huaihe River in Anhui Province，China.

Key words: Anopheles sinensis；Deltamethrin；Resistance；Metabolic detoxification enzyme；kdr；Mutation；Region along the Huaihe River

摘要：

目的 了解安徽省沿淮地区疟疾媒介中华按蚊对溴氰菊酯杀虫剂的抗性状况及谷胱甘肽S转移酶 （GSTs）、 细胞色素氧化酶 （P450s） 等代谢解毒酶活性和钠离子通道击倒抗性基因 （Knockdown resistance， kdr） 的突变情况。方法 2011 年8-9月采集安徽省蚌埠市李楼乡、 沫河口镇和沱湖乡中华按蚊成蚊样本， 采用WHO成蚊接触筒药膜滤纸接触法， 调查3 个地区中华按蚊对溴氰菊酯抗性状况。随机挑选样本采用生化法检测代谢解毒酶活性并用PCR扩增产物直接测序法检测分析钠离子通道kdr基因IIS6片段L1014位点基因型。结果 李楼乡、 沫河口镇和沱湖乡3个检测点的中华按蚊对溴氰菊酯60 min内击倒率分别为4.1%、 7.0%和8.2%， 恢复24 h后校正死亡率分别为8.2%、 12.0%、 12.8%， 均为抗性种群。3个检测点的中华按蚊GSTs和P450s活性均显著高于实验室敏感种群 （P < 0.001）。3个检测点的中华按蚊kdr基因均发生突变， 存在 L1014C和L1014F两种突变类型， 无野生纯合型 （TTG/TTG）， 实验室敏感种群kdr基因均为无突变的野生纯合型。结论 安徽省沿淮地区的中华按蚊已对溴氰菊酯产生较强的抗性， 代谢解毒酶活性比实验室敏感种群显著升高， 钠离子通道kdr基因L1014位点出现高频率的突变。

关键词: 中华按蚊； 溴氰菊酯； 抗性； 代谢解毒酶； kdr； 基因突变； 沿淮地区