Babesia conradae infection in coyote hunting dogs infected with multiple blood-borne pathogens

Abstract

Background: Babesia conradae is an intraerythrocytic piroplasm infecting dogs in the southern United States. Ticks have been suspected, but unproven, as vectors. We identified B. conradae and other blood-borne pathogens in 2 kennels of sighthounds with a history of coyote fighting. Objectives: To examine clinicopathologic abnormalities associated with B. conradae infection, risk factors for infection, and the prevalence of coinfections with other blood-borne pathogens. Animals: Fifty-five Greyhounds and Greyhound mixes. Methods: Blood samples were collected from each dog for CBC, serum biochemistry panel, conventional and real-time PCR assays (Babesia spp., hemoplasmas, Ehrlichia canis, Bartonella spp., Anaplasma spp., and Rickettsia spp.), vector-borne pathogen ELISA, and immunofluorescent serology and culture for Bartonella spp and Francisella tularensis sero-agglutination test. Associations between B. conradae infection and coyote fighting, age and laboratory abnormalities were investigated. Results: Twenty-nine dogs were PCR-positive for B. conradae. Of these, 16 were PCR-positive for other vector-borne organisms including Mycoplasma haemocanis, “Candidatus Mycoplasma haematoparvum,” E. canis, and a Hepatozoon felis-like organism. Twelve of the 20 dogs tested for seroreactivity to Bartonella spp. antigens were positive, but none were seropositive for tularemia. Infection with B. conradae was associated with a history of aggressive interactions with coyotes; lower hematocrit, leukocyte count, MCHC, platelet count and serum albumin concentration; and higher MCV, MPV, and serum globulin concentration. Conclusions and Clinical Importance: Babesia conradae infection should be considered in dogs with anemia, leukopenia, thrombocytopenia, hypoalbuminemia and hyperglobulinemia. As with B. gibsoni, aggressive interactions with other canids may play a role in B. conradae transmission.