Factory-based permethrin impregnation of uniforms: residual activity against Aedes aegypti and Ixodes ricinus in battle dress uniforms worn under field conditions, and cross-contamination during the laundering and storage process.

The factory-based permethrin coating technique has only recently been developed. Consequently, no data are available on residual activity, laundering, and weathering resistance in impregnated battle dress uniforms (BDUs) worn under military deployment conditions, or on the cross-contamination potential of such uniforms. Herein, factory-impregnated BDUs worn-out during military deployment to Afghanistan were investigated for residual permethrin concentration, residual efficacy against arthropod vectors, and cross-contamination during laundering and storage. When compared with BDUs subjected to 50 defined washings using the U.S. Insect/Arthropod Repellent Fabric Treatment method, no significant differences in efficacy were observed against Aedes mosquitoes, but remaining knockdown activity in Ixodes ticks was significantly better in polymer-coated BDUs. BDUs impregnated by the polymer-coating method were found to be effective for the life of the uniform, ensuring protection of soldiers in the field from arthropod vectors, while causing less cross-contamination than those treated by the Insect/Arthropod Repellent Fabric Treatment method.