Bartonella is highly adapted to mammalian reservoir hosts and increasing numbers of animal reservoir hosts have been identified. Two commonly recognized species are Bartonella henselae, which has coevolved with cats, and Bartonella vinsonii subspecies berkhoffii, which has coevolved with wild canids. Other Bartonella include a large number of species identified in rodents that might be kept as pets. The numbers of suspected and confirmed arthropod vectors (fleas, lice, sandflies, and ticks) are also increasing. Bartonella infection is an occupational risk for veterinarians. Precautions should be taken to avoid arthropod bites, arthropod feces, animal bites or scratches, or direct contact with body fluids from sick animals. The authors investigated a case in which a veterinarian was likely infected from a needle stick injury while aspirating a cutaneous neoplasm in a dog. Coinfection with other microbes is also a concern. Dogs infected with Ehrlichia canis and B vinsonii subspecies berkhoffii appear more likely to develop epistaxis. In addition, dogs with coinfections treated with doxycycline do not effectively clear Bartonella infection. Diagnosis of bartonellosis is very difficult. Bacterial isolation, polymerase chain reaction amplification, and detection of antibodies all have diagnostic limitations. New approaches to optimize a novel diagnostic platform using preenrichment culture techniques are showing promise. Treatment recommendations for dogs and cats have been extrapolated from treatment of human infections. Azithromycin and fluoroquinolones alone or with ampicillin may have positive therapeutic effects in some cases.

Commentary: Bartonellosis causes life-threatening illness and contributes to chronic debilitating disease. It is one of the growing numbers of vector-borne diseases that are emerging today. The challenges of diagnosis make bartonellosis especially troublesome. More evidence-based studies are needed to define this disease, and an understanding of its pathologic consequences in natural infection is needed.—Patricia Thomblison, DVM, MS

 Bartonellosis: An emerging infectious disease of zoonotic importance to animals and human beings. Breitschwerdt EB, Maggi RG, Chomel BB, Lappin MR. J VET EMERG CRIT CARE 20:8-30, 2010.