Pathogenesis of experimental infections of specific pathogen-free cats with Bartonella henselae
Abstract
Bartonello henselae infections are common in pet cats and have zoonotic potential, particularly among immunocompromised human beings. The pathogenesis of experimental B. henselae infection was studied to elucidate potential health consequences for infected cats, and to identify methods to interrupt transmission among cats, thereby reducing the risk of transmission of B. henselae to human beings. B. henselae bacteremia that persisted for 12-16 weeks developed within 2 weeks of intravenous, intradermal or oral inoculation of cats. Bacteremia was cyclic in some cats for up to 1 year. Neonatal cats were not more susceptible to infection than older cats. Cats inoculated intradermally or intravenously had fever and peripheral lymphadenopathy 2 weeks after inoculation. Cats inoculated orally had no clinical signs or lesions. Neutrophilic and lymphocytic/macrophagic infiltrates were observed in multiple tissues of infected cats during the first 4-8 weeks after infection. Extracellular bacteria were detected in the liver, spleen and peripheral blood of some cats up to 8 months after infection. Cats were not immunosuppressed following B. henselae infection, but had T and B cell responses to B. henselae, and maintained normal CD4+ and CD8+ peripheral blood lymphocyte counts. All cats inoculated intravenously or intradermally produced serum IgG anti-B. henselae antibodies. Neonatal cats inoculated orally had no detectable anti-B. henselae serum antibodies. However, in neonatal cats, bacteremia resolved as rapidly as did bacteremia of other infected cats, suggesting that serum IgG is not necessary to decrease bacteremia. Evaluation of cytokine mRNA expression by peripheral blood mononuclear cells showed a mixed T helper 1/T helper 2 response. B. henselae was not transmitted among cats venereally, transplacentally, through mammary secretions, or by casual contact. However, 2 infected female cats did not become pregnant when bred with uninfected males, suggesting that B. henselae infection may cause female reproductive dysfunction. These results are discussed in terms of the implications for devising means of preventing feline infections, thereby removing the reservoir for human infections, and in the context of the effects of B. henselae infections on feline health.
Degree
Ph.D.
Advisors
HogenEsch, Purdue University.
Subject Area
Veterinary services|Microbiology|Animal diseases|Immunology
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.