Karunaratne S H
Department of Zoology, University of Peradeniya, Sri Lanka.
Southeast Asian J Trop Med Public Health. 1999 Sep;30(3):460-9.
Present status of insecticide resistance was investigated in two major vectors of malaria; An. culicifacies and An. subpictus, collected from a high malaria transmission area in Sri Lanka during 1996/1998. Adult and larval bioassays were carried out to obtain log-probit mortality lines for malathion, propoxur, permethrin and chlorpyrifos. Respective LD50 values were 4.45%, 0.002%, 0.16% and 0.001% for An. culicifacies and 0.66%, 0.004%, 0.004% and 0.04% for An. subpictus. Adults were also tested for WHO standard discriminating dosages of malathion, propoxur, permethrin, DDT, cypermethrin, deltamethlin and lambda cyhalothrin. Both populations were highly resistant to DDT. An. culicifacies was more resistant to malathion and An. subpictus was more resistant to chlorpyrifos. About 25% of both populations were resistant to permethrin. An. culicifacies was susceptible to propoxur, deltamethrin and lambda cyhalothrin and An. subpictus to cypermethrin and lambda cyhalothrin. Adult mosquitos were individually tested for their insecticide detoxifying enzyme activities and altered target-site, acetylcholinesterase. High general esterase activity indicated the presence of amplified esterase genes in both populations. Native gel electrophoresis resolved one elevated esterase isoenzyme, with high affinity to organophosphates, from each species. Malathion carboxylesterase mechanism was present in both populations. Higher glutathione-S-transferase activity was marked in An. subpictus. Synergistic studies showed the possible involvement of monooxygenases in resistance in both species. Acetylcholinesterase activity of approximately 80% of both populations was not inhibited by a standard dosage of propoxur. Low resistance to carbamates shows that the impact of agricultural pesticides is not significant in the development of resistance especially in An. culicifaies. Pyrethroids, other than permethrin, can be successfully used in vector control programs. Carbamates will be an alternative.
1996年至1998年期间，在斯里兰卡一个疟疾高传播地区，对两种主要疟疾传播媒介——库氏按蚊和伪威氏按蚊的抗杀虫剂现状进行了调查。进行了成虫和幼虫生物测定，以获得马拉硫磷、残杀威、氯菊酯和毒死蜱的对数-概率死亡率曲线。库氏按蚊的相应半数致死剂量值分别为4.45%、0.002%、0.16%和0.001%，伪威氏按蚊的相应半数致死剂量值分别为0.66%、0.004%、0.004%和0.04%。还对成虫进行了马拉硫磷、残杀威、氯菊酯、滴滴涕、氯氰菊酯、溴氰菊酯和高效氯氟氰菊酯的世卫组织标准鉴别剂量测试。两个种群对滴滴涕均具有高度抗性。库氏按蚊对马拉硫磷的抗性更强，伪威氏按蚊对毒死蜱的抗性更强。两个种群中约25%对氯菊酯具有抗性。库氏按蚊对残杀威、溴氰菊酯和高效氯氟氰菊酯敏感，伪威氏按蚊对氯氰菊酯和高效氯氟氰菊酯敏感。对成年蚊子分别进行了杀虫剂解毒酶活性和改变的靶标位点乙酰胆碱酯酶的测试。高的总酯酶活性表明两个种群中存在扩增的酯酶基因。天然凝胶电泳从每个物种中分离出一种对有机磷具有高亲和力的升高的酯酶同工酶。两个种群中均存在马拉硫磷羧酸酯酶机制。伪威氏按蚊中的谷胱甘肽-S-转移酶活性更高。协同研究表明，单加氧酶可能参与了两个物种的抗性。约80%的两个种群的乙酰胆碱酯酶活性未被标准剂量的残杀威抑制。对氨基甲酸酯类的低抗性表明，农业杀虫剂对抗性发展的影响不显著，尤其是对库氏按蚊。除氯菊酯外，拟除虫菊酯可成功用于病媒控制项目。氨基甲酸酯类将是一种替代选择。
