Ticks and Tick-Borne Pathogens of Black Bears (Ursus americanus) in New Jersey

Information on the role that American black bears (Ursus americanus) play in hosting ticks and tick-borne pathogens is limited. In this study, Dermacentor variabilis, Ixodes scapularis, and blood were collected from black bears (U. americanus) in northwestern New Jersey in the summer of 2015. D. variabilis was collected from more bears and in greater abundance overall. Two hundred and fifty-six adult D. variabilis from 18 bears were tested for Francisella tularensis and Rickettsia spp. by polymerase chain reaction (PCR). One to five ticks were pooled into 69 groups according to sex, species, life stage, and individual host. Rickettsia spp. were detected in 6 of 69 D. variabilis pools (8.6%). All D. variabilis were negative for F. tularensis. Twenty-nine I. scapularis (23 adults and 6 nymphs) were collected from 11 bears and were subsequently pooled into 14 groups in the same manner. Fourteen pools of I. scapularis from the bears were screened for Borrelia burgdorferi, Babesia spp., Anaplasma phagocytophilum and Bartonella spp. by PCR. B. burgdorferi was detected in 3 of 14 pools of I. scapularis (21.4%), Babesia spp. in 2 of 14 (14.2%), A. phagocytophilum in 1 of 14 (7.1%), and Bartonella spp. in 2 of 14 (14.2%). Fourteen bear blood samples were tested for F. tularensis, Rickettsia spp., B. burgdorferi, Babesia spp., A. phagocytophilum, and Bartonella spp. by PCR. One of 14 bear blood samples was positive for Babesia spp. (7.1%). None of the 14 bear blood samples were positive for F. tularensis, Rickettsia spp., B. burgdorferi, A. phagocytophilum, or Bartonella spp. Although Babesia spp. were detected in black bear blood, it remains unclear whether or not this pathogen can be transmitted from infected bears to uninfected ticks. The number of studies on this relationship is limited and these findings warrant further investigation of the black bear's potential role as a reservoir.