Cat Scratch Disease

What is Cat Scratch Disease?

Cat Scratch Disease is a bacterial infection caused by a bacteria called Bartonella henselae. Cats become infected with Bartonella most commonly through flea bites, but can also become infected through fights with infected cats or feline blood transfusions. While some cats become ill, many carry the bacteria in their blood without getting sick. Some studies have found the Bartonella bacteria in the blood of up to 1/3 of healthy cats, particularly kittens.

Who gets Cat Scratch Disease?

People can get Cat Scratch Disease (CSD) from the scratches of domestic or feral cats, particularly kittens. The disease occurs most frequently in children under 15. Cats can harbor infected fleas that carry Bartonella bacteria and these bacteria can be transmitted from a cat to a person during a scratch.

How is Cat Scratch Disease spread?

Most infections usually occur after scratches from domestic or feral cats, especially kittens. CSD occurs worldwide and may be present wherever cats are found. Stray cats may be more likely than pets to carry Bartonella.

What are the symptoms of Cat Scratch Disease?

Common symptoms of CSD include: a low-grade fever, enlarged, tender lymph nodes, and a swollen area on the skin or pimple at the inoculation site.

How soon after exposure do symptoms appear?

The most common symptoms typically develop 1—3 weeks after exposure to CSD.

How is Cat Scratch Disease diagnosed?

A healthcare provider may make the diagnosis of CSD in a patient with typical signs and symptoms and an exposure history that makes CSD likely. Blood tests can sometimes confirm the diagnosis, but need to be interpreted with caution.

What is the treatment for Cat Scratch Disease?

The use of antibiotics to shorten the course of disease is debated. Most cases of cat scratch disease (CSD) resolve without treatment, although some patients may develop complications if the bacteria spreads more widely throughout the body. Azithromycin has been shown to decrease lymph node volume more rapidly compared to no treatment. A number of other antibiotics are effective against Bartonella infections, including penicillin, tetracyclines, cephalosporin, and aminoglycosides. Often, with serious infections, more than one antibiotic is used.

How can Cat Scratch Disease be prevented?

Avoid rough play with cats, particularly strays and kittens, to prevent scratches. Wash hands promptly after handling cats. Treat cats for fleas using fipronil and other spot-on treatments. Check with your veterinarian. Permethrin should not be used on cats. Use a flea collar. Keep cats indoors and away from stray cats. Immunocompromised individuals should avoid owning cats less than one year of age.

How can I learn more about Cat Scratch Disease?

  • If you have concerns about Cat Scratch Disease, contact your healthcare provider.
  • Call your local health department. A directory of local health departments is located at the VDH Local Health Districts page.
  • Visit the Centers for Disease Control and Prevention website at the CDC's page on Bartonella.

October 2018

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Last Updated: June 15, 2023