Preventing exposure to ticks and tick-borne illness in outdoor workers ABSTRACT In North Carolina, tick-borne diseases represent a growing public health problem and an occupational hazard for outdoor workers. Currently, tick-bite prevention requires time- consuming reapplication of insecticides to clothing and exposed skin. Unfortunately, adherence to these procedures is poor. Recently, a factory-based method for long- lasting permethrin impregnation of clothing has been developed which allows clothing to retain insecticidal activity for over 70 washes (the effective lifetime of a garment). The treatment process has been approved by the US EPA and classified as non-toxic. We have preliminary evidence from a small pilot project suggesting that workers wearing this clothing have ~90% fewer tick bites than workers not wearing this clothing. In order to measure the effectiveness and safety of this clothing in protecting outdoor workers, we are proposing a randomized controlled intervention with 300 workers in the NC State Department of Environmental and Natural Resources (DENR). Outdoor workers in the Division of Forestry and the Division of Parks and Recreation will be randomly assigned to two groups. Workers will have their uniforms treated or sham-treated in a double- blinded manner. All study subjects will fill out weekly tick logs, and keep removed ticks in specimen vials for later speciation and pathogen detection. Serum samples, drawn at enrollment and study conclusion will be titered for antibody to common tick-borne pathogens. Possible clothing-related adverse events, such as rashes, will be recorded. The results of this study could lead to a simple and cost-effective method of protecting outdoor workers from tick-borne illnesses.