Cat scratch disease (CSD), also known as cat scratch fever or subacute regional lymphadenitis, is a bacterial infection affecting lymph nodes that drain the sites of inoculation. Bartonella henselae, a gram-negative rod, is considered the principal etiologic agent. CSD is one of the most common causes of chronic lymphadenopathy in children and adolescents. Patients with CSD usually have a history of sustaining a scratch or bite from a cat. The initial symptom is formation of a papule at the inoculation site, followed by solitary or regional lymphadenopathy within 1-2 weeks. In most patients, the disease resolves spontaneously within 2-4 months.
How cats and people become infected
Cats can get infected with B. henselae from flea bites and flea dirt getting into their wounds. By scratching and biting at the fleas, cats pick up the infected flea dirt under their nails and between their teeth. Cats can also become infected by fighting with other cats that are infected at the time. The germ spreads to people when infected cats bite or scratch a person hard enough to break their skin. The germ can also spread when infected cats lick at wounds that you may have.
Cats can carry Bartonella but they don’t get sick from the bacteria, so you can’t always tell if they are carriers. It’s believed that cats contract Bartonella henselae from infected fleas, but there’s no evidence that humans can contract the bacteria directly from fleas. According to the Centers for Disease Control and Prevention, up to 40 percent of cats carry the bacteria at some time in their lives, most commonly when they are kittens. Your vet can test your cat to see if it’s carrying the bacteria, but cats tend to carry the bacteria only for a short time. Treatment isn’t usually recommended.
- a bump or blister at the bite or scratch site
- swollen lymph nodes near the bite or scratch site
- a low-grade fever
- loss of appetite
Cat scratch disease facts
- Cat scratch disease (CSD) is a bacterial disease caused by Bartonella henselae.
- It is often caused by a bite or scratch from a cat. Kittens are more likely to pass on the bacteria. Cats that carry B. henselae do not show any signs of illness, so you cannot tell which cats could spread the disease to you.
- Diagnosis of cat scratch disease is made by a history of a wound caused by a cat, physical exam showing signs of lymph node swelling, indirect fluorescence assay, and enzyme-linked immunoassay blood testing, and possibly lymph node biopsy.
- Treatment for cat scratch disease includes antibiotics such as azithromycin (Zithromax), clarithromycin (Biaxin), rifampin (Rifadin), trimethoprim-sulfamethoxazole (Bactrim), and ciprofloxacin (Cipro).
You can prevent cat scratch fever by completely avoiding contact with cats. If you have a cat, you can reduce your risk of getting cat scratch fever by avoiding rough play that could lead to you being scratched or bitten by a cat. Washing your hands after playing with your cat may also help prevent the disease. Keep your cat indoors and administer anti-flea medication to reduce the risk of your cat contracting Bartonella henselae. To reduce your risk of getting CSD, avoid rough play with cats, wash cat bites and scratches thoroughly, don't allow cats to lick any open wounds you have, and contact your physician if you develop any symptoms or signs following a cat bite or scratch.