Preventive effect of permethrin-impregnated clothing to Ixodes ricinus ticks and associated Borrelia burgdorferi s.l. in Germany

The protective effectiveness of a factory-based, permethrin-impregnated military battle dress uniform (BDU) trouser using a new high-residual, polymer-coating technique has been evaluated by field testing against Ixodes ricinus, a vector of Borrelia burgdorferi s.l. During 36 h exposure of test subjects walking in known tick-infested habitats in the Kühkopf mountain area, Koblenz, Germany, between June and October 2006, 6 I. ricinus were found crawling with a visible excitatory effect on those legs covered with fabric impregnated with 1200 mg permethrin/m², whereas 132 ticks were collected from the negative control legs. B. burgdorferi s.l. infection was detected in 33% (2/6) adult male, 56% (9/16) adult female, 11% (6/56) nymphal, and 0% (0/46) larval I. ricinus sampled from the negative control legs. The few ticks collected from the impregnated fabric tested all negative for B. burgdorferi s.l. The mean tick infestation rate on the negative control legs of test subjects was 3.6±2.7 (mean±SD; range 0–12) per hour exposure. Permethrin-impregnated clothing conveyed a high mean protection rate of 95.5% against questing I. ricinus ticks, making it an excellent tool for the prevention of associated tick-borne diseases.