Many infectious diseases can cause fever in cats. Clinical signs may include diarrhea, uveitis, sneezing, nasal discharge, or abscesses. In some cats, fever is the only clinical abnormality seen. Fleas and ticks are common transmitters of infectious feline diseases.

Cats have been proven to be infected as determined by culture or DNA amplification with several strains of Bartonella spp. (B. henselae, B. clarridgeiae, B. koehlerae, B. quintana and B. bovis). Cats are the main reservoir hosts for B. henselae and B. clarridgeiae.

Bartonella henselae is the most common cause of Cat Scratch Disease, as well as bacillary angiomatosis and peliosis hepatis, which are common disorders in humans with AIDS. The organism is transmitted between cats by the flea, Ctenocephalides felis, and so prevalence is greatest in cats where fleas are common. In recent studies, the prevalence rates for B. henselae in cats and their fleas were 34.8% and 22.8%, respectively. The prevalence rates for B. clarridgeiae in cats and their fleas were 20.7% and 19.6%, respectively. Bartonella henselae survives in flea feces for days after being passed by infected C. felis. Infected flea feces are likely to contaminate cat claws during grooming and then Bartonella are inoculated into the human when scratched. Open wounds may also be contaminated with infected flea feces.

Most cats with confirmed evidence of exposure to a Bartonella spp. are clinically normal. But, clinical signs of Bartonella spp. infection can include fever, lethargy, lymphadenopathy, uveitis, gingivitis, and neurological diseases.

Blood culture, PCR assay on blood, and serologic testing can be used to assess individual cats for Bartonella spp. infection. While serologic testing can be used to determine whether an individual cat has been exposed, both seropositive and seronegative cats can be bacteremic, limiting the diagnostic utility of serologic testing. Thus, testing healthy cats for Bartonella spp. infection is not currently recommended. Testing should be reserved for cats with suspected clinical bartonellosis. If the results of Bartonella tests are positive, this agent remains on the list of differential diagnoses, but other causes of the clinical syndrome must also be excluded.

The antibiotics used for the treatment of proven or presumed bartonellosis in cats generally have a broad spectrum, are effective for other infecting organisms which can cause syndromes resembling bartonellosis, and can also have anti-inflammatory properties. Doxycycline at 10 mg/kg, PO, SID or BID for 7 d as the initial therapeutic trial, continued for 2 wk past clinical resolution of disease or for a minimum of 28 d. If a poor response is achieved by day 7 or doxycycline is not tolerated, azithromycin or a fluoroquinolone are reasonable next choices.

Bartonella spp. infections are an occupational risk for veterinary health care providers. To lessen the likelihood of acquiring a Bartonella species infection from a cat, the following are adaptations of what is recommended to HIV-infected people and other cat owners by the Centers for Disease Control and the American Association of Feline Practitioners: flea control should be initiated and maintained year-round; if a family member is immunocompromised and a new cat is to be acquired, adopt a healthy cat > 1 y of age and free of fleas; immunocompromised individuals should avoid contact with cats of unknown health status; declawing of cats is generally not required, but claws should be trimmed regularly; bites and scratches should be avoided (including rough play with cats); cat-associated wounds should be washed promptly and thoroughly with soap and water and medical advice sought; while Bartonella species have not been shown to be transmitted by saliva, cats should not be allowed to lick open wounds; and cats should be housed indoors to minimize hunting and exposure to fleas and other possible vectors.