Cat Scratch Fever (Bartonella Infection) in Cats

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Last updated on
4 min read

Key takeaways

Bartonella spp. is a type of bacteria living inside red blood cells, leading to a condition called bartonellosis. 

  • Fleas pass bartonella to cats through their feces, and cats become infected through regular grooming behavior leading to feces ingestion
  • Cats may also infect people through cat scratches or bites, hence the common name for the condition: “Cat Scratch Fever” 
  • Bartonellosis is usually asymptomatic in cats, although severe infections may lead to fever, lethargy, or swollen lymph nodes
  • Diagnostics include a physical examination, bloodwork and specific testing to identify the bacteria
  • Cases of bartonellosis showing symptoms are treated with antibiotics, although the bacteria is often resistant to therapy, making for a guarded prognosis
  • Cats without symptoms have a good prognosis without treatment
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A closer look: Cat Scratch Fever (Bartonella Infection) in Cats

Bartonella spp. are a type of bacteria transmitted to cats via fleas. Once bartonella are in the blood stream, they live in the blood vessels, which can lead to inflammation in localized areas of the body. Many cases of bartonella infection in cats have no symptoms. When present, symptoms vary depending on which organ is inflamed in response to infected blood vessels.

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Risk factors

Bartonellosis is common and found worldwide. Estimates suggest that 30-40% of cats test positive for the bacteria, although cats rarely require treatment. Cats may pass this infection to people, which emphasizes the importance of flea control to prevent cats from becoming infected.

Cats who show symptoms of bartonellosis require immediate veterinary care. These cats have a guarded prognosis. Very young, elderly, and immunocompromised cats (such as those who are FIV or FeLV positive) are at higher risk of developing symptoms.

Outdoor cats who are not on regular flea and tick control are at the highest risk of contracting a bartonella infection. Fleas are often difficult to detect in cats due to fastidious feline grooming habits.

Possible causes

Bartonella spp. is primarily carried by the cat flea, who acquire the bacteria through feeding on an infected animal. Ticks and biting flies may also transmit the bacteria. The insects shed the bacteria in their feces, which may be deposited on the fur of a cat. Cats consume contaminated waste through regular grooming behavior, becoming infected themselves. Most cats show no symptoms of bartonellosis, however they can spread the infection to other animals or humans through a scratch or bite.

Main symptoms

Bartonellosis usually shows no symptoms in cats.

Testing and diagnosis

Diagnostics include:

  • Physical examination
  • Bloodwork
  • Bacterial culture
  • Testing for antibodies against the bacteria
  • Specific testing for the bacterial DNA

Steps to Recovery

The optimal protocol for treating bartonellosis has not been established in cats. Bartonella infection is typically treated by administration of antibiotics over weeks to months according to veterinary directions. Delayed or inconsistent therapy may affect recovery.

Most cats show no symptoms of bartonellosis, and have a good prognosis without treatment. Symptomatic bartonellosis has a guarded prognosis, as bacteria is often resistant to antibiotic treatment.


Flea control for all pets in the household is essential in preventing bartonellosis. Indoor cats are also less at risk.

The condition is contagious, and may pass between cats, or from a cat to a pet parent.

Is Cat Scratch Fever (Bartonella Infection) in Cats common?

Bartonellosis is common among cats, but it is rare for cats to develop symptoms of infection.

Typical Treatment


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