Bartonella is a bacteria that is prevalent in cats (more than 20% of cats are known to be exposed to the organism) and known to be spread primarily through flea bites and possibly other insect vectors, such as ticks and mosquitos. Bartonella can be transmitted to people from an infected cat through scratches or bite wounds, with the result ranging from zero clinical disease in humans with competent immune systems, to a potentially serious syndrome known as cat scratch fever, to any number of autoimmune disease manifestations. In cats, clinical disease associated with Bartonella is quite a bit more mysterious and associated with a wide variety of clinical diseases and anatomical specificity.
One of the more common manifestations of Bartonella in cats is a disease of the eye known as uveitis. Uveitis can have any number of causes in cats, but because it can be associated with Bartonella, testing for Bartonella is an integral component to working up a feline patient presenting with uveitis.
Unusually severe dental and gum disease, known as periodontal disease and gingivitis, is also known to result from Bartonella. For this reason, some veterinarians will test for Bartonella when presented with a cat with unusually severe dental and gum disease for its age.
Other presentations for Bartonella in cats include a chronic fever of unknown origin, inflammatory bowel disease, chronic respiratory disease, enlarged peripheral lymph nodes, and general stiffness brought about by pain and inflammation within the joints.
Given this myriad of clinical presentations for Bartonella in cats, it is difficult for a veterinarian to know when it is appropriate to test for it. What further complicates matters is that many cats have known exposure to Bartonella, yet have no clinical signs associated with the disease, making it difficult to necessarily attribute a given set of clinical signs to a cat that tests positive for Bartonella.
Diagnosis of Bartonella is obtained most simply and inexpensively by testing for Bartonella antibodies. However, while a negative antibody test is fairly conclusive, a positive test does not necessarily mean there is active infection, but instead simply means that the cat has been exposed to the bacteria at some point. For this reason, many veterinarians prefer to run a blood culture for suspect feline Bartonella infection.
Treatment for Bartonella consists of 6 weeks of treatment with an appropriate antibiotic. Baytril, Zeniquin, and Orbax are all effective veterinary antibiotics for use against Bartonella.
The best way to prevent Bartonella is to keep your cats protected with a good veterinary grade flea preventive, such as Frontline, Advantage, or Assurity, as flea bites are suspected to be the most common mode of transmission. Keeping your cats indoors is also an effective way to prevent infection with Bartonella, as the disease is found much more prevalently in outdoor cats versus indoor cats.
Much more is currently not known about Bartonella infection in cats than what is known. Why the disease manifests in one anatomical region in some patients while presenting quite differently in another, while many do not show signs of disease at all, is currently not known. Clearly, more research is necessary to unravel much of the mystery of Bartonella in cats.
Roger L. Welton, DVM
Founder and Chief Editor, Web-DVM.net
President, Maybeck Animal Hospital
Article updated 9/6/2012