300 Bartonella Cases Seen in Cats and Dogs in the Seattle Area 01/03–07/04
Bartonella are a group of intraerythrocytic endotheiotropic bacterium, associated in a wide range of mammals from humans to domestic small and large animals as well as many species of free-ranging wild animals worldwide. In particular, Bartonella henselae has been a noted zoonotic pathogen typically transmitted via “cat scratch disease” (CSD) often to young children, the elderly, or immunosuppressed people of any age. However, a search of PUBMED (Medline) will yield plenty of individual case reports of immunocompetent adults that have been presented for treatment. While estimates vary because only 5 states presently make Bartonellosis a reportable disease, approximately 22,000-44,000 people a year are infected and develop CSD in the United States (Jackson, et al. 1993). Many more people develop Bartonella diseases that are not categorized as CSD. The prevalence of Bartonella infection in the general population of cats in the Pacific states is estimated at 34.4% (Jameson, et.al. 1995). It is not a rare infection and with our flea-conducive environment, it is not likely to decline anytime soon. Depending upon the stage of infection the animal or person is in when presented, the signs or symptoms are quite varied and often involve inflammation in various systems (e.g., central nervous, gastrointestinal, skin, circulatory, respiratory, urinary, etc.) and many organs (e.g., eye, brain, bone, liver, heart, spleen, kidney, intestines, pancreas, lung, oral cavity including the gums, and skin). While attending veterinary school in 1985—89, it was widely believed that cats where carriers and capable of transmitting the disease via fleas, bites and scratches, however, they were unlikely to show signs of Bartonellosis themselves. There was not a good clinical test available and culturing the bacteria was a long and difficult task. Therefore, not much time was spent learning about a disease that we couldn’t detect, let alone treat. Meanwhile, physicians continued to see a steady stream of affected people, which resulted in many case reports and later review papers as they learned to recognize Bartonella diseases in their many forms and searched for effective treatments. They got better at both detecting Bartonella and treating it. The veterinary community now has the opportunity to take the extensive information developed in human medicine and bring effective care to the animals that infect, carry, and transmit this organism. Additionally, we now have evidence that Bartonella causes numerous diseases in pet cats: gingivitis, stomatitis, uveitis, URI, rhinitis, sinusitis, conjunctivitis, and inflammation of various organs. The wide tissue tropism is due to the fact that Bartonella attach to and penetrate into endothelial cells which are present in all tissues. It has been known for years that various Bartonella species can attach and destroy heart valves (especially the aortic valve) in humans because when they are replaced, the valves are cultured and the bacteria involved is identified. Last year, university veterinarians following the same line of reasoning identified Bartonella vinsonii berkhoffii, and B. clarridgeiae as causes of infective endocarditis in 5/18 California dogs (MacDonald, K.A., et.al. 2004) in their study. It is also worth noting that all of the positive dogs were also co-infected with Anaplasma phagocytophilium (formerly known as Ehrlichia equi). This paralleled an earlier case report (Breitschwerdt, et. al. 1995). It stands to reason that if we identify infectious causes of heart disease, we can treat the underlying cause and hopefully reduce the overal impact of such disease. Who knows, a case of feline thromboembolic disease might even be prevented with such testing and intervention. There are now three ways to test for Bartonella infection: culture, detection of antibody and PCR. Bacterial culture takes 3-5 weeks and the organism is still hard to grow so it is not used as a first line screening test in clinical practice. However, both commercial veterinary labs in WA State offer either the PCR or the Western Blot test (Febart™). The FeBart™ test can be mailed directly to the National Veterinary Lab (at a reduced fee). The FeBart™ test is an inexpensive screening tool that will indicate infection via quantification of antibody levels. Additionally, six months following treatment, a titer test comparing a pre- and post-treatment sample can assess the effectiveness of such treatment via antibody decay. It can be performed on cats, dogs and rabbits. A newly developed PCR test will probably detect bacteria as low as 1 Bartonella per micro liter (helpful for testing dogs who tend to have low Bartonella concentrations). This test is offered by Dr. Breitschwerdt at N.C. State University (contact Julie_Bradley@ncsu.edu). While none of the tests are perfect, using one or more on animals with signs of Bartonella-related diseases, veterinarians at Renton Veterinary Hospital (RVH) have identified 300 positive cats (of 509 total) in the last one and one-half years. Using treatment regimens developed in human medicine and later adapted to domestic animals, many have recovered from their chronic inflammatory illnesses, most of which had a 2-4 fold decrease in Bartonella antibody titers or negative culture following a positive one. Summaries will be posted of the RVH statistics and other Bartonella resource information on the WSVMA website because space in the newsletter is limited. For more information on Bartonellosis, one can visit PUBMED, a part of the National Library of Medicine, at www.ncbi.nlm.nih.gov and do a current literature search by typing in Bartonella in the search engine. The National Veterinary Laboratory has an excellent synopsis and very current quarterly newsletters (201) 891-2992 (EST) that are free of charge. AAHA offers members a free service called CITE TRACK that will email you as each new article is published and is an easy way of keeping current on an emerging zoonosis where worldwide research efforts are being reported weekly. Breitschwerdt, E.B., D.L. Kordick, D.E. Malarkey, B. Keene, T.L. Hadfield, and K. Wilson. “Endocarditis in a dog due to infection with a novel Bartonella subspecies”. 1995. J. Clin Microbiol. 33(1):154-160. Jackson, LA, Perkins, BA, Wenger, JD. “Cat-scratch disease in the United States: an analysis of three national databases. Am. J. Public Health. 1993. (83):1701-1711. Jameson P., Green C., Regnery R., Dryden, M. Marks, A., Brown, J., Cooper, J. Glaus B., and Greene, R. “Prevalence of Bartonella henselae antibodies in pet cats throughout regions of North America.” 1995. J Infect Dis Oct;172(4):1145-1149. MacDonald K.A., Chomel B.B., Kittleson, M.D. , Kasten R.W., Thomas W.P., and P. Pesavento. “A prospective study of canine infective endocarditis in northern California (1999-2001): Emergence of Bartonella as a prevalent etiologic agent.” 2004. J. Vet Intern Med 18(1): 56-64.