Pet Care

Cat Scratch Disease

Striped cat being held by person wearing a green shirt

What Is Cat Scratch Disease?

You’ve probably heard of cat scratch disease or cat scratch fever, but you may not know that this infection in humans is thought to be caused by bacteria transmitted in flea feces! The most common type of bacteria associated with cat scratch disease is called Bartonella henselae. Most people with cat scratch disease have been bitten or scratched by an infected cat.

What Are the General Symptoms of Cat Scratch Disease?

A person with cat scratch disease will typically develop a small red bump where they’ve been bitten or scratched. Additional symptoms include: - Swollen and painful lymph nodes, particularly around the region where the scratch or bite occurred. Lymph node swelling can last for several months.
- Fever
- Headache
- Fatigue
- Joint pain
- Skin eruptions
- Weight loss

Symptoms usually clear up on their own, but serious complications—including enlargement of the spleen and heart valve infection—can arise, particularly in immunocompromised individuals.

How Is Cat Scratch Disease Transmitted?

There are several bacterial agents, including Bartonella henselae, that are known to cause cat scratch disease. A cat can become infected with Bartonella by fleas carrying the bacteria. When the cat scratches herself, the infected flea dirt gets into her claws—and this bacteria can spread when she scratches a person or other cat. Because they are so playful—and may tend to scratch during play—kittens are more likely than adult cats to transmit the bacteria to people.

The bacteria may also be harbored in a cat’s mouth, and can be passed via bites.

Which Cats Are Most Likely to Be Infected?

According to the National Center for Infectious Disease, approximately 40 percent of cats carry Bartonella henselae at some point in their lives. As the bacteria are carried by fleas, cats who live in warm, humid, flea-friendly climates are most likely to be infected.

What Are the General Symptoms of Infection in Cats?

Most cats who carry Bartonella spp generally do not show any signs of infection. However, Bartonella infections have recently been studied as a potential cause of a variety of clinical signs in cats. It is not known how often cats become ill from Bartonella infections.

How Can I Tell If My Cat Is Infected?

Most cats who transmit cat scratch disease appear clinically healthy. There is no one simple test for Bartonella, and so attempting a diagnosis is usually reserved for clinically ill cats. If you think your cat is infected, your veterinarian can determine whether testing is appropriate.

How Are Infected Cats Treated?

Cats infected with Bartonella are generally given oral antibiotics, but treatment is not always effective.

How Can I Avoid Getting Cat Scratch Disease?

There are several things you can do to minimize your chances of getting cat scratch disease:
- Avoid rough play and other activities with cats that could lead to biting and scratching.
- Keep cats indoors to avoid exposure to fleas and ticks.
- Keep your cat’s claws trimmed.
- If you do get scratched or bitten, wash promptly with soap and water.
- Talk to your vet about an effective flea control plan—and follow it!
- Take care not to let your cat lick any open wounds or cuts you may have.
- If you develop any of the symptoms listed here, contact your doctor.

Please note, severely immunocompromised individuals are at the highest risk for complications arising from cat scratch disease and should speak to a veterinarian about risks and recommendations before getting a cat.