背景:热带臭虫,Cimex半翅目,是热带地区一种严重的室内公共卫生害虫,会给人类带来强烈的身体不适和精神困扰。目前,杀虫剂的应用是主要的控制策略。本研究旨在评估康提地区Cimexhemipterus的抗性和抗性机制的发展,斯里兰卡。
方法:根据DDT的区别剂量确定收集的臭虫的抗性状态,马拉硫磷,丙氧素,溴氰菊酯和氯菊酯根据世界卫生组织指南进行生物测定。杀虫剂代谢酶的活性,即酯酶,谷胱甘肽S-转移酶(GST)和单加氧酶,和有机磷/氨基甲酸酯靶位乙酰胆碱酯酶(AChE)的不敏感性,通过生化测定进行评估。拟除虫菊酯/DDT靶位点的基因区域,电压门控钠通道调节蛋白(VGSC),对可能的kdr突变进行测序。
结果:DDT的臭虫种群存活率分别为71%、68%和51%,分别为马拉硫磷和丙氧磷。KT50和KT90值,用对数-probit死亡率曲线计算溴氰菊酯为62.55和123.96小时,分别。氯菊酯的这些值要高得多,其中KT50为201.10h,KT90超出可检测范围。将结果与2002年同一人群的先前报告值进行了比较。对丙氧磷的抗性从11%显着增加到51%,酯酶机制升高的个体数量增加了约20倍。马拉硫磷和滴滴涕耐药性无明显变化,在GST和单加氧酶活性方面,以及过去14年的AChE敏感性。六个kdr相关突变(Y/L995H,V1010L,I1011F,L1014F,V1016E,从VGSC基因的α区发现了L1017F/S)和非kdr相关突变(A1007S突变)。在kdr型突变中,以前仅报道了L1014F形式。半翅目,而其他昆虫则报道了其他昆虫。
结论:臭虫种群对丙氧磷产生了高抗性,酯酶活性增加。溴氰菊酯和氯菊酯的KT50增加了125倍和20倍,分别,从2002年到2016年。就作者所知,这是斯里兰卡首次显示kdr型突变可能参与C.hemipterus的拟除虫菊酯抗性的发展。
BACKGROUND: The tropical bed bug, Cimex hemipterus, is a serious indoor public health pest in tropical regions causing intense physical discomfort and mental distress to humans. At present, the application of insecticides is the major control strategy. The present study was designed to evaluate the development of resistance and resistance mechanisms in Cimex hemipterus from Kandy district, Sri Lanka.
METHODS: The resistance status of the collected bed bugs was determined against the discriminative dosages of DDT, malathion, propoxur, deltamethrin and permethrin by conducting bioassays according to World Health Organization guidelines. Activities of insecticide metabolizing enzymes, i.e. esterases, glutathione S-transferases (GST) and monooxygenases, and the insensitivity of organophosphate/carbamate target site acetylcholinesterase (AChE), were evaluated by biochemical assays. Regions of the gene of the pyrethroid/DDT target site, the voltage-gated sodium channel regulatory protein (VGSC), were sequenced for possible kdr mutations.
RESULTS: Survival percentages of bed bug population were 71, 68 and 51% for DDT, malathion and propoxur respectively. KT50 and KT90 values, calculated using log-probit mortality curves for deltamethrin were 62.55 and 123.96 h, respectively. These values were much higher for permethrin where KT50 was 201.10 h and the KT90 was beyond the detectable range. Results were compared with previous values reported for the same population in 2002. Resistance to propoxur has increased significantly from 11 to 51% with about a 20-fold increase in the number of individuals with elevated esterase mechanism. No significant change has occurred in malathion and DDT resistance, in GST and monooxygenase activities, and in AChE sensitivity for the past 14 years. Six kdr associated mutations (Y/L995H, V1010L, I1011F, L1014F, V1016E, L1017F/S) and a non-kdr associated mutation (A1007S mutation) were found from the α-region of the VGSC gene. Out of the kdr type mutations, only L1014F has been reported previously form C. hemipterus while the others have been reported from other insects.
CONCLUSIONS: The bed bug population has developed high resistance to propoxur with increased esterase activities. KT50 for deltamethrin and permethrin has increased 125- and 20-fold, respectively, over the period 2002 to 2016. To the authors\' knowledge, this is the first time that the possible involvement of a kdr type mutation in developing pyrethroid resistance in C. hemipterus has been shown in Sri Lanka.