Department of Entomology, University of Wisconsin-Madison, Madison, WI, USA.
North Shore Mosquito Abatement District, Northfield, IL, USA.
Sci Rep. 2024 Aug 3;14(1):18001. doi: 10.1038/s41598-024-69066-3.
Insect growth regulators, like S-methoprene, are heavily relied upon worldwide for larval mosquito chemical control due to their target specificity and long-lasting effects. In this study, susceptibility to S-methoprene was evaluated in Culex pipiens, a globally important vector species. Populations from 14 sites throughout the Chicago area with a long history of S-methoprene use and two sites with minimal use in Wisconsin were examined. Using a bioassay methodology and probit analyses, LC and LC values were calculated and compared to a susceptible laboratory strain to develop resistance ratios, then categorized for resistance intensity. The resistance ratios observed required the addition of another category, termed 'extreme' resistance, indicating resistance ratios greater than 100. 'Low' to 'extreme' levels of resistance to S-methoprene were detected throughout Illinois populations, with resistance ratios ranging from 2.33 to 1010.52. Resistance was not detected in populations where S-methoprene pressure has been very limited. These 'extreme' resistance ratios observed have never been documented in a wild vector species mosquito population. The relationships between historical S-methoprene use, resistance detected with laboratory bioassays, and the potential for field product failure remain unclear. However, the profound resistance detected here demonstrates a potential critical threat to protecting public health from mosquito-borne diseases.
昆虫生长调节剂，如 S-烯虫酯，由于其靶标特异性和长效作用，在全球范围内被广泛用于幼虫期蚊虫的化学控制。本研究评估了 S-烯虫酯在一种全球重要病媒蚊虫-致倦库蚊中的敏感性。研究选取了来自芝加哥地区 14 个长期使用 S-烯虫酯的地点和威斯康星州 2 个使用较少的地点的种群。使用生物测定方法和概率分析，计算并比较了 LC 和 LC 值，并与敏感的实验室品系进行比较，以确定抗性比率，然后对其进行抗性强度分类。观察到的抗性比率需要增加另一个类别，称为“极端”抗性，表明抗性比率大于 100。在伊利诺伊州的种群中检测到了从“低”到“极端”水平的 S-烯虫酯抗性，抗性比率范围从 2.33 到 1010.52。在 S-烯虫酯压力非常有限的种群中未检测到抗性。在野生媒介蚊虫种群中从未观察到如此高的“极端”抗性比率。历史上 S-烯虫酯的使用、实验室生物测定检测到的抗性以及田间产品失效的可能性之间的关系仍不清楚。然而，这里检测到的强烈抗性表明，保护公众免受蚊媒疾病的健康的潜在威胁非常严重。
