Bartonella spp infection as a possible cause of uveitis in a cat

A 6-year-old castrated mixed-breed cat was evaluated because of unilateral anterior uveitis. The cat was seronegative for antibodies to Toxoplasma gon dii, coronaviruses, and feline immunodeficiency virus, and antigens for FeL V p27 and Cryptococcus neoformans. Antibodies to Bartonella spp were detect ed in serum and aqueous humor. The antibody coefficient (C value) for IgG a ntibodies to Bartonella spp in the aqueous humor was 4.42; values > 1 sugge st ocular production of antibodies and supports a diagnosis of ocular infec tion. Topical administration of prednisolone and oral administration of pre dnisone failed to induce a response; however, the uveitis resolved rapidly after the cat was given doxycycline orally. Clinical or laboratory evidence of immunodeficiency in this cat was not detected. Detection of a serum IgG antibody titer to Bartonella spp and ocular production of IgG antibodies t o Bartonella spp, exclusion of other causes of uveitis, and response to dox ycycline suggests that the cat may have had bartonellosis resulting in uvea l tract inflammation.