Feline Bartonella “The Cat Scratch Disease Bacteria”

Healthy cats can carry six members of the Bartonella bacteria family in their blood, which are transmitted between cats by fleas and ticks.  The bacteria can be spread to people via cat scratches, bites, contact with fur, and probably rarely by infected fleas and ticks. 


Prevalence of Infection

The prevalence of Bartonella-infected cats varies in different geographic areas and depends on the average temperature and rainfall (humidity).  About 20% of healthy cats in the U.S. are infected carriers.  The highest infection rates occur in hot, humid climates, where conditions are favorable for fleas and ticks.  Most untreated infected cats remain infected for years or for life.


 Risk Factors for Infection

Risk factors that make cats more likely to have flea infestation and thus become infected with Bartonella are:

  • originating as a stray
  • coming from a shelter or human group
  • living in a multi-cat household
  • going outdoors often
  • living in a hot and humid area


Cat Bartonella Diseases

Cat Bartonella possess hair-like structures found on the bacteria’s surface w hich allow the bacteria to stick to, and penetrate, red blood cells and the cells that make up the walls of the capillaries.  This ability leads to the wide and varied tissue specificity observed in cats, dogs, and people.  Bartonella induce inflammatory reactions in may tissues throughout the infected animal’s body.  These tissue are:

  • oral and respiratory mucosa
  • ocular tissue
  • the gastro-intestinal tissues
  • the skin
  • organs (liver, spleen and lymph nodes) 

In fact, since capillaries are found in all tissue, all tissues are susceptible to the inflammatory effects of Bartonella.  Inflammatory reactions often occur concurrently in multiple sites, such as the oral and respiratory tissues, ocular and oral tissues, or in other combinations.  Although numerous microorganisms can cause inflammatory diseases, it appears that Bartonella are the cause of about 40-50% of the following conditions in pet cats:

Oral Diseases:  Gingivitis, Stomatitis, Oral Ulcers


Respiratory Diseases:  Upper Respiratory Disease, Rhinitis, Sinusitis


Ocular Diseases:  Conjunctivitis, Uveitis, Chorioretinitis, Corneal Ulcers, Keratis


Intestinal Diseases: Inflammatory Bowel Disease, Diarrhea (chronic), Vomiting (chronic)

Other Diseases:  Enlarged Lymph Nodes, Fever of Unknown Origin, Skin Diseases, Heart Disease


Bartonella Therapy

Antibiotic therapy of healthy infected cats and cats with Bartonella-induced diseases is effective for most cats.  Owners should be careful while treating their cats to avoid being scratched or bitten. 


Human Bartonella Disease

Bartonella, transmitted from cats, can cause 22  human diseases and cat scratch disease is only the “tip of the Bartonella disease iceberg.”  The other Bartonella diseases are:

  • Bacillary Angiomatosis & Peliosis
  • Febrile Bacteremia
  • Heart Diseases (endocarditis & vegetative  valvular disease)
  • Eye Diseases (Uveitis, Neuroretinitis, Disciform Keratitis)
  • Inflammatory Bowel Disease
  • Lymphadenopathy


Cat Scratch Disease

Cat scratch disease is the best known Bartonella disease.  More than 22,000 cases occur each year, of which more than 2,000 people require hospitalization.  The disease usually begins a few weeks after transmission of Bartonella from cats with a red papule at the site of a scratch or bit.  Lymph nodes that drain the injury site become inflamed, enlarged, painful, and may develop an abscess, which my rupture and drain.  Severe cases may progress to organ involvement, neurological complications, and rarely to coma. 


Testing for Bartonella is available at both clinics through National Veterinary Laboratory in New Jersey.  If you have any questions or concerns about your cat, please call Northstar Animal Care at (614) 488-4121 or Upper Arlington Veterinary Hospital at (614) 481-8014.


[information taken from "Cats & Bartonella" phamphlet]