Felis ISSN 2398-2950

Cat scratch disease

Synonym(s): Cat scratch fever, Bartonellosis

Contributor(s): Margie Scherk


  • Zoonotic disease caused by cat inflicted wound (bite or scratch).
  • CauseBartonella henselae (intracellular bacterium).
  • Signs: cats are usually asymptomatic; humans develop fever and lymphadenopathy.
  • Diagnosis: in humans exposure confirmed by PCR or serology.
  • Treatment: none required.
  • Prognosis: good as cats not clinically affected.
    Print off the owner factsheet Cat scratch disease Cat scratch disease to give to your client.



  • Bartonella spp are fastidious hemotropic gram negative bacteria that are vector transmitted, and, through adaptation to their host, may cause chronic bacteremia without disease.
  • Cats may be infected with B. henselaeB. clarridgeiaeB. koehlerae or B. bovis. Serologic evidence shows that pet, feral and wild cats living in temperate climates worldwide may be infected with these organisms with B. henselae being the most common species cats are exposed to. 
  • Studies in the United States have shown serologic prevalence rates of B. henselae between 5 and 40% with the higher exposure rates being in the warmer, more humid regions. In the United States, France and the Philippines, B. clarridgeiae seropositivity ranges between 10 to 31%. While cats are the main reservoir for these organisms, fleas (Ctenocephalides felis felis), ticks (Ixodes ricinus) and biting flies have also been found to be infected with Bartonella spp. 
  • Cat fleas, transmit B. henselae between cats making flea control the most important method for the prevention of the possibility of zoonotic disease. 


  • Spreads from cat to cat via cat flea.
  • Requires cat-induced trauma for transmission to man.
  • No evidence of transmission from cat to man via fleas.


  • Cats usually asymptomatic.
  • Bacteremia in cats is typically chronic with a waxing and waning nature. Bacteremia is undetectable by culture or PCR testing intermittently and IL-4 levels as well as serum antibody titers decrease or disappear for periods of time. Naturally infected cats have been shown to remain infected for up to three years; reinfection by fleas of an individual cat may occur even with different strains of the same species. This is likely due to the protective intracellular location of the parasite making it difficult for the immune system to detect and eliminate. The organisms may be found inside erythrocytes or vascular endothelial cells.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Lappin M R, Breitschwerdt E, Brewer M et al (2009) Prevalence of Bartonella species antibodies and Bartonella species DNA in the blood of cats with and without fever. Feline Med & Surg 11 (2), 141-148 PubMed.
  • Pearce L K, Radecki S V, Brewer M (2006) Prevalence of Bartonella henselae antibodies in serum of cats with and without clinical signs of central nervous system disease. J Feline Med & Sug (5), 315-320 PubMed.
  • Barnes A, Bell S C, Isherwood D R et al (2000) Evidence of Bartonella henselae infection in cats and dogs in the United kingdom. Vet Rec 147 (24), 673-677 PubMed.
  • Groves M G, Hoskins J D & Harrington K S (1993) Cat scratch disease an update. Comp Cont Ed Pract Vet 15 (3), 441-448 VetMedResource.

Other sources of information

  • Guptill-Yoran L (2006) Bartonellosis. In: (ed.) Greene C E Infectious diseases of the Dog and Cat. 3rd edition. Saunders, St. Louis, MO, 2006. pp 511-518.
  • AAFP Panel Report on Diagnosis, Treatment, and Prevention of Bartonella spp. Infections (2006) https://journals.sagepub.com/doi/full/10.1016/j.jfms.2006.05.006.
  • Wolf A M (1997) Bartonella henselae an emerging important zoonosis. In: Consultations in Feline Medicine 3. Ed J R August. W B Saunders, Philadelphia. pp 7-11.