Long-lasting permethrin impregnated uniforms: A randomized-controlled trial for
tick bite prevention.
Author(s): Vaughn MF(1), Funkhouser SW(2), Lin FC(3), Fine J(4), Juliano JJ(5), Apperson
CS(6), Meshnick SR(2).
Affiliation(s): Author information:
(1)Department of Epidemiology, Gillings School of Global Public Health, Chapel
Hill. Electronic address: meagan.vaughn@unc.edu. (2)Department of Epidemiology,
Gillings School of Global Public Health, Chapel Hill. (3)Department of
Biostatistics, Gillings School of Global Public Health, Chapel Hill.
(4)Department of Biostatistics, Gillings School of Global Public Health, Chapel
Hill; Department of Statistics, University of North Carolina at Chapel Hill,
Chapel Hill. (5)Division of Infectious Diseases, University of North Carolina at
Chapel Hill, Chapel Hill. (6)Department of Entomology, North Carolina State
University, Raleigh, North Carolina.
Publication date & source: 2014, Am J Prev Med. , 46(5):473-80
BACKGROUND: Because of frequent exposure to tick habitats, outdoor workers are at
high risk for tick-borne diseases. Adherence to National Institute for
Occupational Safety and Health-recommended tick bite prevention methods is poor.
A factory-based method for permethrin impregnation of clothing that provides
long-lasting insecticidal and repellent activity is commercially available, and
studies are needed to assess the long-term effectiveness of this clothing under
field conditions.
PURPOSE: To evaluate the protective effectiveness of long-lasting permethrin
impregnated uniforms among a cohort of North Carolina outdoor workers.
DESIGN, SETTING, AND PARTICIPANTS: A double-blind RCT was conducted between March
2011 and September 2012. Subjects included outdoor workers from North Carolina
State Divisions of Forestry, Parks and Recreation, and Wildlife who worked in
eastern or central North Carolina. A total of 159 volunteer subjects were
randomized, and 127 and 101 subjects completed the first and second years of
follow-up, respectively.
INTERVENTION: Uniforms of participants in the treatment group were
factory-impregnated with long-lasting permethrin whereas control group uniforms
received a sham treatment. Participants continued to engage in their usual tick
bite prevention activities.
MAIN OUTCOME MEASURES: Incidence of work-related tick bites reported on weekly
tick bite logs.
RESULTS: Study subjects reported 1,045 work-related tick bites over 5,251
person-weeks of follow-up. The mean number of reported tick bites in the year
prior to enrollment was similar for both the treatment and control groups, but
markedly different during the study period. In our analysis conducted in 2013,
the effectiveness of long-lasting permethrin impregnated uniforms for the
prevention of work-related tick bites was 0.82 (95% CI=0.66, 0.91) and 0.34 (95%
CI=-0.67, 0.74) for the first and second years of follow-up.
CONCLUSIONS: These results indicate that long-lasting permethrin impregnated
uniforms are highly effective for at least 1 year in deterring tick bites in the
context of typical tick bite prevention measures employed by outdoor workers.
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