Ticks parasitizing humans in a Lyme disease endemic area of southern New York State.

A total of 126 tick specimens were submitted by tick bite victims to the Westchester County Department of Health, White Plains, New York, and to the New York Medical College, Medical Entomology Laboratory, Armonk, New York, during 1985. These included 96 (76.2%) Ixodes dammini, 26 (20.6%) Dermacentor variabilis, and two (1.6%) Amblyomma americanum. I. dammini parasitism was reported during all months of the year except December and February and involved all life stages. Only D. variabilis adults parasitized humans, with all cases occurring in the spring and summer. The mean age of I. dammini victims was 24.5 years, with 39.0% under age 10 years. This age group also accounted for 52.0% of all D. variabilis victims (mean age, 16.8 years). The majority of I. dammini and D. variabilis were though to be acquired in the victims' yards (68.6 and 64.7%, respectively). Attachment sites for these species were significantly different, with I. dammini nymphs found most frequently on the lower extremities and I. dammini adults and D. variabilis adults found primarily on the head. Prophylactic antibiotic treatment was prescribed by a physician for 40.8% of I. dammini victims, compared with 4.5% of the D. variabilis victims. Lyme disease was reported by two patients during the course of the study. Neither had received prophylactic therapy at the time of the reported tick bite.