Coinfection with multiple tick-borne pathogens in a Walker Hound kennel inNorth Carolina

Both dogs and humans can be coinfected with various Ehrlichia, Bartonella, Rickettsia, and Babesia species. We investigated a kennel of sick Walker Ho unds and their owners in southeastern North Carolina for evidence of tick-b orne infections and associated risk factors. A high degree of coinfection w as documented in the dog population. Of the 27 dogs, 26 were seroreactive t o an Ehrlichia sp., 16 to Babesia canis, and 25 to Bartonella vinsonii, and 22 seroconverted to Rickettsia rickettsii antigens, According to PCR resul ts, 15 dogs were infected with Ehrlichia canis, 9 with Ehrlichia chaffeensi s, 8 with Ehrlichia ewingii, 3 with Ehrlichia equi, 9 with Ehrlichia platys , 20 with a Rickettsia species, 16 with a Bartonella species, and 7 with B. canis, The detection of DNA from any Ehrlichia species was associated with clinical illness and with concurrent B. canis infection (by PCR), Both E. canis and an uncharacterized Rickettsia species appeared to result in chron ic or recurrent infection. Death in the dog population was associated with living in a dirt lot rather than the concrete kennel, Of 23 people on whom serologic testing was conducted, eight were seroreactive to Bartonella hens elae, one to E. chaffeensis, and one to R. rickettsii antigen; however, non e had clinical or hematologic abnormalities consistent with illness caused by these organisms. We conclude that kennel dogs with heavy tick exposure c an be infected at a high rate with multiple, potentially zoonotic, tick-bor ne pathogens. In addition, our findings further illustrate the utility of P CR for documenting coinfection with tick-transmitted pathogens.