MedicalResearch: What are the main findings of the study?
Dr. Vaughn: Outdoor workers are at high-risk for tick-borne diseases. Adherence to recommended tick-bite prevention methods is poor. While permethrin treatment of clothing is highly protective against many arthropod vectors, the need for frequent reapplication lessens adherence. A double-blind randomized intervention was conducted to determine the effectiveness of long-lasting permethrin-impregnated uniforms for tick bite prevention among outdoor workers from North Carolina. Treatment group uniforms were factory-impregnated with long-lasting permethrin by Insect Shield, while control group uniforms received sham treatment. Participants completed weekly tick bite logs during two tick seasons. 130 participants reported 1,045 work-related tick bites over 5,251 person-weeks of follow-up. The effectiveness of long-lasting permethrin impregnated uniforms for prevention of work-related tick bites was 82% (p<0.001) for the first year and 34% (p=0.38) for the second year. These results indicate that long-lasting permethrin impregnated uniforms are highly effective for at least one year against tick bites among North Carolina outdoor workers.
MedicalResearch: Were any of the findings unexpected?
Dr. Vaughn: Based on the results of a previous pilot study, we were not surprised to find a high rate of protection from tick bites among subjects wearing long-lasting permethrin impregnated clothing. Some reduction in effectiveness in the second year of follow-up was anticipated, but not to the extent we observed. It is possible that other factors, such as adherence to wearing only treated uniforms during the study, and exposure to heat, sunlight, and heavy wear, may have contributed to the observed decrease in effectiveness. It is likely that occasional wearers of long-lasting permethrin impregnated clothing would experience longer duration of effectiveness.
MedicalResearch: What should clinicians and patients take away from your report?
Dr. Vaughn: For people who are frequently exposed to tick infested areas, particularly those with outdoor occupations, long-lasting permethrin impregnated clothing can provide a simple and effective option for reducing risk of tick bites and tick-borne infections.
MedicalResearch: What recommendations do you have for future research as a result of this study?
Dr. Vaughn: We would expect that long-lasting permethrin impregnated clothing is protective against many different tick species, but additional long-term studies are needed in other locations to confirm this. Future studies should also focus on effects of environmental factors on knockdown capacity of long-lasting permethrin impregnated clothing.
Long-lasting Permethrin Impregnated Uniforms
Vaughn, Meagan F. et al.
American Journal of Preventive Medicine , Volume 46 , Issue 5 , 473 – 480