Detection of Bartonella henselae in the Blood of 2 Adult Horses

Background: Bartonella spp. are emerging zoonotic agents that have been found in a wide variety of domestic animals and wildlife and cause a number of clinical syndromes. Bartonella sp. infection has been identified in a growing number of animal species, including cats, rodents, porpoises, and canids, but has not been reported in horses. Objective: To document the presence of Bartonella sp. in the blood of horses. Animals: One horse with chronic arthropathy and 1 horse with presumptive vasculitis. Method: Blood samples were tested for the presence of Bartonella sp. by a combination of multiplex real-time polymerase chain reaction and enrichment culture technique. Results: Bartonella henselae was isolated or detected in the blood of both horses. Conclusion and Clinical Importance: Bartonella henselae infection should be investigated as the cause of disease in horses.