Tick (Acari: Ixodidae) and tick-borne pathogen prevalence in two suburban counties in Central North Carolina.

Abstract

North Carolina reports high incidences of spotted fever group rickettsiosis (SFGR) and ehrlichiosis, with cases concentrated in the more urban and suburban central area of the state. To define the spatial distribution of ticks and the prevalence of tick-borne pathogens in this region, tick surveillance was conducted via (1) drag sampling and (2) passive canine surveillance. Drag sampling was conducted in 18 suburban green spaces (eg, parks, sports fields) in Chatham and Orange counties between June and August 2022. During the same timeframe, animal shelters and veterinary clinics in these counties also submitted ticks found attached to dogs. One hundred eight ticks were collected, 40 of which were from suburban green spaces and 68 from canine sampling, with Amblyomma americanum (L.) ticks comprising the majority of each subgroup. Ehrlichia chaffeensis and Ehrlichia ewingii were largely concentrated in the canine sample and were present in 12% and 41% of A. americanum ticks, respectively. Rickettsia amblyommatis was the most frequently encountered pathogen overall and was detected in 30% of A. americanum from green spaces and 50% of the canine sample. In suburban green spaces, 50% of Amblyomma maculatum (Koch) ticks were positive for Rickettsia parkeri, while none of the Dermacentor variabilis (Say) ticks were positive for Rickettsia rickettsii. These results suggest that the risk of acquiring SFGR or ehrlichiosis may extend beyond rural risk factors (ie, camping, hunting, hiking) and into routine exposures in suburban counties.