Electron micrograph of Bartonella bacilliformis, the Bartonella species that is closely related to Bartonella henselae but infects humans.
Facultatively intracellular gram-negative bacteria of the genus Bartonella cause vector-borne diseases termed Bartonellosis (Dehio, 2004). The transmitting vectors for the disease are hematophagous (blood-sucking) arthropods and the reservoir hosts are mammals. Bartonella henselae, formerly known as Rochalimaea henselae, is an aerobic fastidious intracellular rod-shaped bacterium. As a feline-adapted pathogen, it colonizes endothelial cells immediately after infection. After being released in the blood stream, Bartonella bacteria infect erythrocytes and replicate within a phagosomal vesicle inside erythrocytes. The bacterium is transmitted to another host when the host is bitten by a flea or tick. The cat flea, Ctenocephalides felis, is the primary vector of Bartonella henselae.
Bartonella henselae disease is frequently subclinical; many cats are asymptomatic carriers for long periods of time. It has been reported that 30-60% of cats in the
Traditional diagnosis relies on cumbersome cell culture methods, or more recently on PCR (Ciervo et al., 2005). Seroreactivity and bacteremia are frequently detected in cats with a history of flea infestation. Many genes have been used as a target for PCR detection of Bartonella henselae, such as the 16S/23S rRNA intergenic spacer region, or the heat shock protein (groEL), citrate synthase (gltA), riboflavin synthase a-chain (ribC), cell division protein (ftsZ) and the pap31 extracellular matrix adhesion protein gene.