Bartonella henselae or cat scratch disease (CSD) FAQs

What is Bartonella henselae infection (CSD)?

Swollen lymph node in armpit and cat scratch on hand

CSD is a bacterial infection caused by Bartonella henselae. Most infections usually occur after scratches from domestic or feral cats, especially kittens. CSD occurs wherever cats and fleas are found. The most common symptoms include:

• Fever
• Enlarged, tender lymph nodes that develop 1–3 weeks after exposure
• A scab or pustule at the scratch site

In the United States, most cases of CSD occur in the fall and winter. Illness is most common in children under the age of 15.

My cat is completely healthy. How can it have an infection?

Cats most commonly become infected with B. henselae (the bacteria that cause CSD) through flea bites. They can less commonly become infected during fights with other infected cats or through feline blood transfusions. While some cats become ill, most simply have the bacteria in their blood without getting sick. Some studies have found the Bartonella bacteria in the blood of up to 1 in 3 healthy cats, particularly kittens.

Should I get my pet tested and treated for Bartonella, just to be safe?

Testing and treatment is not recommended, unless your pet is sick. For cats that do become sick, the illness usually consists of fever for 2 to 3 days. Symptoms requiring veterinary care include fever lasting more than 3 days, vomiting, lethargy, red eyes, swollen lymph nodes, or decreased appetite. Treating B. henselae with antibiotics can take a long time.

My child got scratched by the neighbor’s kitten and now my husband is worried about “CSD.” How worried should we be?

Most cat scratches do not result in CSD. Clean scratch wounds with soap and water. If your child develops a fever; enlarged, tender lymph nodes that develop 1 to 3 weeks after being scratched; or a pustule at the scratch site, see their healthcare provider. Treatment with antibiotics is usually not necessary, but may help reduce lymph node swelling.

I have a weakened immune system. Should I give my cat away?

If you are living with HIV, are being treated for cancer, or have any other condition that might suppress your immune system, you can keep your cat. You do not need to test or treat a healthy cat for Bartonella.

To reduce your risk of getting CSD:

• Keep the cat indoors.
• Avoid cat scratches, bites, and licks. Declawing is not recommended to prevent CSD.
• Promptly wash any cat scratches or bites with soap and water.
• Avoid contact with fleas.
• Treat your cat with a flea control product recommended by your veterinarian.
• If you are getting a cat, make sure it’s at least a year old, in good health, and free of fleas. Avoid and do not adopt stray cats or cats with flea infestations.