A 4-year-old female basset hound (Patient 1) with suspected liver disease and a seemingly healthy female Doberman pinscher (Patient 2) with high hepatic enzyme activity both turned out to have peliosis hepatitis. Peliosis hepatitis is associated with B. henselae, a gram-negative bacteria well-adapted to persist intracellularly in humans and animals. An exhaustive workup was given Patient 1 and because a western immunoblot was indicative of prior exposure to B. henselae, a polymerase chain reaction (PCR) assay was performed on 2 occasions to amplify DNA extracted from hepatic tissue. DNA base pairs were sequenced and found to be identical to a portion of B. henselae. Patient 2 was found to have high liver enzyme levels on routine examination. PCR analysis was performed on liver biopsy samples from this dog and other patients used as controls. The Doberman also was found to have a band of approximately 400 base pairs 100% identical to the published sequence for B. clarridgeiae. Clinical signs in both dogs improved dramatically when treated with azithromycin for presumptive Bartonella-induced granulomatous hepatitis as seen histologically. Patient 1 survived for 13 months and Patient 2 for +15 months before hepatic failure ensued.

Because both owners made independent therapeutic decisions to administer herbal medicines and nutritional supplements, it is impossible to assess the therapeutic efficacy of azithromycin and more prospective studies are needed to evaluate its effectiveness. The chance discovery of the Bartonella organism in the second dog emphasizes the need to investigate the role of Bartonella spp. in the development and perpetuation of chronic liver disease in dogs.

COMMENTARY: Inflammatory liver disease in the vast majority of dogs and cats is of unknown cause. With the exception of patients with primary copper retention, the disease is most often labeled as idiopathic, a situation that is frustrating for client and clinician alike. The observations of Gillespie and colleagues that at least some of these patients may have unsuspected infection with Bartonella is intriguing and sensitizes us to how much we still have to learn about liver disease in these species. Bartonella infection must now be added to the list of differential diagnoses in dogs with inflammatory liver disease. 

Detection of Bartonella henselae and Bartonella clarridgeiae DNA in hepatic specimens from two dogs with hepatic disease. Gillespie TN, Washabau RJ, Goldschmidt MH, et al. JAVMA 222:47-51, 2003.