Bartonella organisms are considered to be emerging zoonotic disease agents. One reason for this is that we have more knowledge of these organisms and understand their etiology, reservoir potential, vector transmission, and pathogenesis in cats, dogs, and humans. Several new species and subspecies have been identified. Almost all Bartonella species are vector-borne. In dogs and cats, fleas and ticks have been recognized as the most common vectors. Bartonella henselae is the predominant agent of cat scratch disease, and cats are the primary reservoir of this organism. The cat flea, Ctenocephalides felis, plays a major role in cat-to-cat transmission. Flea control is one of the major control measures to prevent the spread of B. henselae to cats and potentially the spread to humans. The best option for an immunocompromised person who wants to obtain a cat is to choose an adult cat from a flea-controlled environment. Cat owners should also wash their hands after handling pets and clean any cuts, bites, or scratches with soap and water. Another Bartonella species, B. vinsonii subspecies berkhoffii, has been identified as an important cause of canine endocarditis and may cause endocarditis in people. No direct dog-to-human transmission has been identified. The tick is most likely the vector, and tick-control procedures should be used to prevent the transmission of this and other diseases. Flea-control measures are also important because cat fleas can transmit B. henselae to dogs.

COMMENTARY: Our knowledge base has expanded exponentially in the past several years for many infectious diseases, including bartonellosis. Most practitioners are familiar with Bartonella as the cause of cat scratch disease, but may be less informed about other aspects of the organism, such as its role in canine and human endocarditis or its widespread prevalence in both domestic and wild animals. This article presents an in-depth, current review of an important infectious agent and associated zoonoses-a must read for both the clinical and public health sides of veterinary practice.

Cat scratch disease and other zoonotic Bartonella infections. Chomel BB, Boulouis HJ, Breitschwerdt EB. JAVMA 224:1270-1279, 2004.