Epidemiology and Public Health Department, Swiss Tropical and Public Health Institute, Socinstrasse 57, PO Box, CH-4002, Basel, Switzerland.
University of Basel, Petersplatz 1, CH-2003, Basel, Switzerland.
Sci Rep. 2017 Jun 16;7(1):3667. doi: 10.1038/s41598-017-03918-z.
Insecticide resistance threatens the success achieved through vector control in reducing the burden of malaria. An understanding of insecticide resistance mechanisms would help to develop novel tools and strategies to restore the efficacy of insecticides. Although we have substantially improved our understanding of the genetic basis of insecticide resistance over the last decade, we still know little of how environmental variations influence the mosquito phenotype. Here, we measured how variations in larval rearing conditions change the insecticide susceptibility phenotype of adult Anopheles mosquitoes. Anopheles gambiae and A. stephensi larvae were bred under different combinations of temperature, population density and nutrition, and the emerging adults were exposed to permethrin. Mosquitoes bred under different conditions showed considerable changes in mortality rates and body weight, with nutrition being the major factor. Weight is a strong predictor of insecticide susceptibility and bigger mosquitoes are more likely to survive insecticide treatment. The changes can be substantial, such that the same mosquito colony may be considered fully susceptible or highly resistant when judged by World Health Organization discriminatory concentrations. The results shown here emphasise the importance of the environmental background in developing insecticide resistance phenotypes, and caution for the interpretation of data generated by insecticide susceptibility assays.
杀虫剂耐药性威胁到通过病媒控制降低疟疾负担所取得的成果。了解杀虫剂耐药性机制将有助于开发新的工具和策略来恢复杀虫剂的功效。尽管在过去十年中，我们对杀虫剂耐药性的遗传基础有了实质性的了解，但我们仍然不太了解环境变化如何影响蚊子表型。在这里，我们测量了幼虫饲养条件的变化如何改变成年按蚊对杀虫剂的敏感性表型。在不同的温度、种群密度和营养组合下饲养冈比亚按蚊和 A. stephensi 幼虫，并将新出现的成虫暴露于氯菊酯中。在不同条件下饲养的蚊子死亡率和体重有很大变化，其中营养是主要因素。体重是杀虫剂敏感性的一个强有力的预测因子，更大的蚊子更有可能在杀虫剂处理后存活下来。这种变化可能很大，以至于同一蚊群在根据世界卫生组织的区分浓度进行判断时，可能被认为是完全敏感或高度耐药。这里显示的结果强调了环境背景在发展杀虫剂耐药表型方面的重要性，并对杀虫剂敏感性测定产生的数据的解释提出了警告。
