Effectiveness of host-targeted permethrin in the control of Ixodes dammini (Acari: Ixodidae)

Tubes of commercially available permethrin-treated cotton balls were distributed twice each year in 1989 and 1990 at five sites in a Lyme disease endemic area in Connecticut. Five additional sites were not treated. At each application, 48 tubes, sufficient to treat 0.4 ha, were dispersed at 10-m intervals through woodlands, around ornamental plantings, and along rockwalls. The cotton was collected by white-footed mice (Peromyscus leucopus) from the majority of the tubes, which resulted in a decrease (37.2% in 1989 and 91.5% in 1990) in the number of subadult Ixodes dammini Spielman, Clifford, Piesman, and Corwin on the mice in the treated areas. There were no significant decreases in the number of host-seeking nymphs or adults of I. dammini in 1989 or 1990 between the treated and untreated sites. The rates of infection in the host-seeking nymphs with Borrelia burgdorferi, the etiological agent of Lyme disease, at the treated sites (13.0 and 14.6% for 1989 and 1990, respectively) were comparable to those at the untreated sites (16.9 and 13.2% for 1989 and 1990, respectively). The distribution of permethrin-treated cotton around individual residences significantly reduced the number of ticks on P. leucopus but was not sufficient to reduce the risk of exposure to infected host-seeking nymphs and adults of I. dammini after two seasons of treatment.