Laboratorio de Referencia Nacional de Entomologia, Centro Nacional de Salud Pública, Instituto Nacional de Salud, Lima, Peru.
Laboratório de Fisiologia e Controle de Artrópodes Vetores-LAFICAVE, Instituto Oswaldo Cruz (IOC)-Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.
Parasit Vectors. 2022 Jul 11;15(1):254. doi: 10.1186/s13071-022-05310-x.
The development of resistance against insecticides in Aedes aegypti can lead to operational failures in control programs. Knowledge of the spatial and temporal trends of this resistance is needed to drive effective monitoring campaigns, which in turn provide data on which vector control decision-making should be based.
Third-stage larvae (L3) from the F1 and F2 generations of 39 Peruvian field populations of Ae. aegypti mosquitoes from established laboratory colonies were evaluated for resistance against the organophosphate insecticide temephos. The 39 populations were originally established from eggs collected in the field with ovitraps in eight departments of Peru during 2018 and 2019. Dose-response bioassays, at 11 concentrations of the insecticide, were performed following WHO recommendations.
Of the 39 field populations of Ae. aegypti tested for resistance to temephos , 11 showed high levels of resistance (resistance ratio [RR] > 10), 16 showed moderate levels of resistance (defined as RR values between 5 and 10) and only 12 were susceptible (RR < 5). The results segregated the study populations into two geographic groups. Most of the populations in the first geographic group, the coastal region, were resistant to temephos, with three populations (AG, CR and LO) showing RR values > 20 (AG 21.5, CR 23.1, LO 39.4). The populations in the second geographic group, the Amazon jungle and the high jungle, showed moderate levels of resistance, with values ranging between 5.1 (JN) and 7.1 (PU). The exception in this geographic group was the population from PM, which showed a RR value of 28.8 to this insecticide.
The results of this study demonstrate that Ae. aegypti populations in Peru present different resistance intensities to temephos, 3 years after temephos use was discontinued. Resistance to this larvicide should continue to be monitored because it is possible that resistance to temephos could decrease in the absence of routine selection pressures.
埃及伊蚊对杀虫剂的抗药性发展可能导致控制项目失败。需要了解这种抗性的时空趋势，以推动有效的监测活动，从而提供数据，以便做出基于这种数据的蚊虫控制决策。
评估了来自秘鲁 8 个地区野外采集的卵用诱卵器收集的 39 个埃及伊蚊实验室种群的 F1 和 F2 代第三代幼虫（L3）对有机磷杀虫剂倍硫磷的抗性。这些种群最初是在 2018 年至 2019 年期间从秘鲁野外的卵用诱卵器中建立的。根据世界卫生组织的建议，用 11 种不同浓度的杀虫剂进行了剂量反应生物测定。
在所测试的 39 个埃及伊蚊田间种群中，有 11 个种群对倍硫磷表现出高水平的抗性（抗性比[RR]>10），16 个种群表现出中等水平的抗性（RR 值在 5 到 10 之间），只有 12 个种群是敏感的（RR<5）。结果将研究种群分为两个地理群体。第一地理群体，沿海地区的大多数种群对倍硫磷有抗性，其中三个种群（AG、CR 和 LO）的 RR 值>20（AG 21.5、CR 23.1、LO 39.4）。第二地理群体，亚马逊丛林和高地丛林，表现出中等水平的抗性，RR 值在 5.1（JN）到 7.1（PU）之间。在这个地理群体中，PM 种群是个例外，对这种杀虫剂的 RR 值为 28.8。
这项研究的结果表明，在停止使用倍硫磷 3 年后，秘鲁的埃及伊蚊种群对倍硫磷表现出不同的抗性强度。应继续监测对这种杀幼虫剂的抗性，因为在没有常规选择压力的情况下，对倍硫磷的抗性可能会降低。
