Pilot study assessing the effectiveness of factory-treated, long-lasting permethrin-impregnated clothing for the prevention of tick bites during occupational tick exposure in highly infested military training areas, Germany

Abstract

The protective effectiveness of factory-based permethrin-impregnated polymer-coated battle dress uniforms (PTBDUs) against tick bites was evaluated at four military training areas in southwestern and central Germany where tick bite incidence is known to be high. Data were analyzed by comparing tick bite incidence using non-permethrin-treated BDUs (NTBDUs) during 2009 versus PTBDUs during 2010 and 2011, the first two years after their formal introduction for in-country use in the German Bundeswehr. During 2009, 262 individual tick bites were reported at the four training sites, resulting in a tick bite incidence of 8.8 % per exposed person when wearing NTBDUs only. In 2010 and 2011, one tick bite case occurred under field conditions each year that PTBDUs were worn, corresponding to a protective effectiveness of 99.6 and 98.6 %. These data imply an annual tick bite incidence of 0.035 and 0.078 % per exposed person, respectively. Between 2010 and 2011, a 0.8 % decline in the protective effectiveness of PTBDUs was observed. Five tick bite incidents occurred while wearing non-impregnated parkas over correctly worn PTBDUs. Ixodes ricinus ticks were collected by standard tick drags from 2009 to 2011, with high mean annual densities ranging from 28.9 to 106.5 ticks per 100 m(2), while single drags revealed tick densities between zero and 381 ticks per 100 m(2). Overall, 4596 I. ricinus ticks (54 ♂, 82 ♀, 1776 nymphs, and 2684 larvae) were collected, of which 128 (2.8 %; mean annual range, 0-10.1 %) were Borrelia burgdorferi s.l. positive. The Borrelia genospecies distribution was as follows: 112 (87.5 %) Borrelia afzelii, 10 (7.8 %) B. burgdorferi s.s., and 6 (4.7 %) Borrelia garinii. Neither the tick density means from 2009 to 2011 nor associated B. burgdorferi s.l. prevalences differed significantly among the military locations investigated. The documented tick bite reductions clearly demonstrate the powerful protective effectiveness of properly worn PTBDUs against tick bites. Nevertheless, all apparel worn over PTBDUs should also be impregnated with permethrin in order to prevent tick infestation and subsequent bites.

Long-Lasting Permethrin-Impregnated Clothing Protects Against Mosquito Bites in Outdoor Workers

“…6 Work by WilderSmith and others indicate that LLPI clothing would be a costeffective and acceptable means of preventing dengue. 34,35 Biomarkers may be the only way to quantitate mosquito bite exposure in field studies.…”

“…[4][5][6][7] Impregnated clothing is typically evaluated either by exposing mosquitoes to clothing and measuring mortality or by exposing individuals wearing impregnated clothing to mosquitoes in the laboratory. 8 However, impregnated clothing potentially performs differently under field conditions than in the laboratory.…”

Evidence for Personal Protective Measures to Reduce Human Contact With Blacklegged Ticks and for Environmentally Based Control Methods to Suppress Host-Seeking Blacklegged Ticks and Reduce Infection with Lyme Disease Spirochetes in Tick Vectors and Rodent Reservoirs

“…The majority (77%) of attached nymphs died within hours of their attachment on volunteers with permethrin-treated clothing whereas nearly all nymphs attaching to volunteers with nontreated clothing remained alive. Moderate to high levels of protection for field use of permethrin-treated clothing were also reported for Ixodes pacificus Cooley & Kohls in the far western United States, I. ricinus in Europe, and the lone star tick, Amblyomma americanum (L.) (Schreck et al 1980, 1982; Lane 1989; Faulde et al 2008, 2015; Vaughn and Meshnick 2011; Richards et al 2014; Vaughn et al 2014). Research is needed to clarify the protective effect against bites by I. scapularis nymphs of typical summer clothing treated with permethrin and worn during normal daily activities.…”

Methods to Prevent Tick Bites and Lyme Disease

“…[43][44][45][46] Permethrin has direct effects on the nervous system of arthropods and hence can kill then directly, cause "knock-down," or elicit behavioral changes that result in the arthropod leaving the host. For ticks, permethrin-treated attire is sometimes characterized as being particularly efficacious.…”