N,N-Diethyl-m-toluamide (DEET) is by far the most used repellent worldwide. When applied topically to the skin, the active ingredient has been shown to provide protection from a variety of hematophagous insects, including mosquitoes and flies. DEET’s effectiveness against ticks is influenced by a variety of factors (e.g., duration and concentration of application, drying time, route of exposure, tick species and developmental stage), and may differ from insects due to their unique chemosensory system that primarily involves the Haller’s organ. We therefore used several approaches to investigate DEET’s efficacy to repel Dermacentor variabilis at different concentrations (5, 30 or 75%), as well as explore its toxicological properties and natural variability in DEET insensitivity across populations from Manitoba, Canada. Climbing bioassays indicated that higher concentrations of DEET were more effective at repelling D. variabilis, and that ticks from some sampling localities were more sensitive to lower concentrations than others. Petri dish arena assays revealed ticks exposed to high concentrations of the repellent lose their ability to discriminate lower concentrations, perhaps due to overstimulation or habituation. Finally, our tactile assays demonstrated reduced tick survival after contact with high DEET concentrations, with mortality occurring more rapidly with increased concentration. Dermacentor variabilis from these tactile assays displayed a multitude of physiological and neurological symptoms, such as ‘hot foot’ and various bodily secretions. Overall, our study shows a strong association between repellency, concentration and the acaricidal effects of DEET on D. variabilis.

到目前为止，N，N-二乙基间甲苯胺（DEET）是使用最广泛的驱虫剂。当局部施用到皮肤上时，活性成分已显示出对各种嗜血昆虫（包括蚊子和苍蝇）的保护作用。DEET对tick的功效受多种因素影响（例如，施用时间和浓度，干燥时间，接触途径，tick种类和发育阶段），并且由于其独特的化学感应系统（主要涉及Haller's）可能与昆虫不同。器官。因此，我们使用了几种方法来研究DEET排斥皮肤变应原的功效。以不同的浓度（5％，30％或75％）进行研究，并探讨其毒理学特性和对加拿大曼尼托巴省不同人群对DEET不敏感的自然变异性。不断攀升的生物分析表明，较高浓度的DEET可以更有效地驱除D. variabilis，并且某些采样地点的tick虫对较低浓度的concentrations虫比其他采样点更为敏感。培养皿竞技场试验表明，暴露于高浓度驱虫剂的tick可能失去了分辨较低浓度的能力，这可能是由于过度刺激或习惯所致。最后，我们的触觉分析表明，与高浓度的DEET接触后tick的存活率降低，而浓度升高则死亡率更快。皮肤变种这些触觉分析显示出许多生理和神经症状，例如“热脚”和各种身体分泌物。总体而言，我们的研究表明，驱避剂，浓度和DEET对D. variabilis的杀螨作用之间有很强的联系。