Wear and Wash Persistence of Permethrin Used as a Clothing Treatment for Personal Protection Against the Lone Star Tick (Acari: Ixodidae)12

The persistence of permethrin as a clothing impregnant under the stress of wear and washing was assayed. Human subjects were exposed to natural infestations of the lone star tick, Amblyomma americanum, in eastern Oklahoma. permethrin treatment rate of 0.125–0.2 mg/cm2 of cloth completely protected human subjects from attack by the ticks through 132 h of wear and through 3 washes with warm water and detergent. Subsequently, laboratory assays with adult mosquitoes and chemical analyses showed only a slight loss of permethrin from treated clothing subjected to wear and ca. 50% loss from 4 washes. These laboratory findings confirmed the results of the field assays.