Deer Ticks Developing Resistance to Popular Tick Control Chemical: Implications for Lyme Disease

July 22, 2021 |A study published in the Journal of Medical Entomology finds black-legged ticks (Ixodes scapulari) in New York are developing potential resistance to widely used tick-control pyrethroid insecticide, permethrin for the transmission of Lyme disease. The study suggests continuous use of area- wide, 4-poster devices (devices that attract deer and then apply pesticide to their head, ears, and neck) to apply insecticide treatments on deer to control tick populations promotes resistance. Like mosquitoes, a subpopulation of ticks encountering chemical exposure naturally alter gene function, which results in resistance to the chemical rather than death. To assess resistance among tick populations, researchers evaluated the susceptibility of deer ticks to permethrin exposure. Deer ticks used in this study came from Shelter Island, NY, and the Cary Institute of Ecosystem Studies (CIES) in Millbrook, NY. Development of resistance is an entirely normal, adaptive phenomenon: organisms evolve, “exploiting” beneficial genetic mutations that give them a survival advantage. However, resistance is growing in all sectors of pest control. [Note: The best method to prevent tick bites and the diseases they carry is to wear appropriate clothing (light-colored that covers one’s whole body), a hat, and consider tucking one’s pants into socks. Most important is to conduct regular tick checks as it is critically important to detach a tick from one’s skin as soon as possible after the bite to reduce the chance of disease transfer. If you have an outdoor pet, do not forget to check them as well. Safely kill tick larvae with nontoxic solutions: vacuum daily during flea season (changing bag often); groom pet daily with a flea comb (cleaning comb with soap-water between brushes); frequently bathe pets with soap and water; and frequently wash pet bedding, restricting pet to only one bed.] [Burtis, James et al. Susceptibility of Ixodes scapularis (Acari: Ixodidae) to Permethrin Under a Long-Term 4-Poster Deer Treatment Area on Shelter Island, NY. Journal of Medical Entomology. 58(4):1966-1969, 2021.]