Department of Biology, Brandon University, Brandon, MB, R78 6A9, Canada.
Exp Appl Acarol. 2020 Nov;82(3):379-395. doi: 10.1007/s10493-020-00550-x. Epub 2020 Oct 2.
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.
N,N-二乙基间甲苯酰胺（DEET）是目前全球使用最广泛的驱避剂。当局部涂抹在皮肤上时，其有效成分已被证明可提供对各种吸血昆虫（包括蚊子和苍蝇）的保护。DEET 对蜱虫的有效性受多种因素的影响（例如，应用的持续时间和浓度、干燥时间、暴露途径、蜱种和发育阶段），并且可能因蜱虫独特的化学感受系统而与昆虫不同，该系统主要涉及 Haller 器官。因此，我们使用了几种方法来研究 DEET 在不同浓度（5%、30%或 75%）下对变色革蜱的驱避效果，以及探索其毒理学特性和对 DEET 不敏感的自然变异性在来自加拿大马尼托巴省的种群中。攀爬生物测定表明，较高浓度的 DEET 对驱避变色革蜱更有效，并且来自某些采样地点的蜱对较低浓度比其他蜱更敏感。培养皿竞技场试验表明，暴露于高浓度驱避剂的蜱会失去区分较低浓度的能力，这可能是由于过度刺激或习惯化。最后，我们的触觉试验表明，接触高浓度 DEET 后，蜱的存活率降低，随着浓度的增加，死亡率更快。来自这些触觉试验的变色革蜱显示出多种生理和神经系统症状，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性、浓度和 DEET 对变色革蜱的杀蜱作用之间存在很强的关联。
