Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)

First Advisor

Richard E. Corstvet


Bartonella henselae is a zoonotic agent in which the domestic cat serves as the natural reservoir, and humans acquire potentially serious infections associated with this microorganism. The purpose of this research is to contribute to the understanding of the pathogenesis of B. henselae in the domestic cat using a molecular approach. Using sequence differences in a portion of the I 6S rRNA gene between B. henselae genotype I, and B. henselae genotype II, a nested polymerase chain reaction (nPCR) was designed and used to investigate various phases of feline bartonellosis. The nPCR detected 3.2 organisms per milliliter of blood which is below the detection limits of standard bacterial culture. Bartonella henselae LSU 16 genotype II, Bartonella henselae Baby genotype II, Bartonella henselae 87--66 genotype I, and Bartonella henselae Houston-1 genotype I were used in this study to infect cats. The PCR assay detected Bartonella DNA in 40 blood samples that were culture negative. The bacteremia as determined by PCR lasted for a period of 1 to 9 weeks longer than determined by culture methods in 10 of the 16 cats. An episode of relapsing bacteremia occurred in two cats during the infection. Of the twenty-three cats examined, Bartonella DNA was detected in various tissues from 10 of the 23 cats. The spleen of nine of the 10 cats was positive for Bartonella DNA. The other tissues in which Bartonella DNA was detected included bone marrow, lymph node, kidney, lung, liver, brain, and heart valve. Histopathological lesions associated with nonspecific antigenic stimulation were seen in the cats but organisms could not be visualized in tissue. RNA expression analysis using the RT-PCR assay with primers specific for the 16S rRNA and the citrate synthase gene (gltA) of Bartonella detected no Bartonella RNA expression in the tissue of infected cats. Bartonella genotypes remained the same throughout the period of the acute bacteremia and in the recurring bacteremia as determined by the PCR assay. The persistent Bartonella DNA detected in tissue was B. henselae genotype II. B. henselae genotype I was not detected in any of the infected cats.