Germs can establish a home anywhere -- on the lip of a pop can, in the hairs of a mustache, under the skin of a rotten apple. Sometimes, they set up housekeeping on a sharp object -- a rusty nail, the edge of a razor, or a pin. But what if those sharp objects could strike out and cut you? If the sharp object happens to be the claws or teeth of a cat, you could get cat-scratch disease (CSD), commonly referred to as cat scratch fever.

CSD is a fairly common condition worldwide. There are approximately 24,000 cases of CSD in the U.S. annually, causing approximately 2,000 hospitalizations. Over 80% of patients are under age 21. Peak incidences are between the ages of two and 14 years. In cooler climates most cases occur from September through February, and in warmer climates the majority of cases occur in July and August.

CSD cannot be passed from person to person. It is transmitted to a person by an infected cat (most often a kitten). Several persons in the same household may develop the disease at the same time, however, as a result of handling the same infected cat. Additionally, there have been many studies predicting that fleas play an important role in transmission. It is estimated that 20-40% of cats in the U.S. carry the bacteria that causes CSD, Bartonella henselae. Although the kitten or grown cat is infected with the bacteria, it is not necessary to destroy the animal or give it any medical attention. The cat is simply a carrier of the bacteria; will appear quite healthy; and is only a carrier for a limited time (during primarily the kitten stage) before it becomes disease-free. Additionally, humans can develop immunity to CSD after exposure.

So, what are the signs CSD? Well, it starts with a lump at the site of the bite or scratch that may fill with pus and can take three to 14 days to develop. A lymph gland near the area of the injury will then enlarge (e.g., a lymph gland in the armpit enlarges if the wound is on the arm). Other symptoms include a fever of 99 to 101 degrees (and sometimes higher), headache, and fatigue. The patient generally recovers within a month. Serious complications, such as hepatitis and encephalitis, are rare and people with compromised immune systems (e.g., AIDS and cancer patients) are most at risk of becoming seriously ill.

Most cases of CSD go away without any treatment. Antibiotics may be included intreatment, but research has not yet proven their effectiveness. Nonprescription medicines, like acetaminophen, can be used to lower fever and relieve the pain of swollen lymph glands. In some cases, it may be necessary for a physician to drain lymph glands if they become red and sore, indicating that pus has collected in them. In the meantime, bed rest may be helpful, especially if the patient has fatigue or fever.

There are recommendations for the prevention of CSD. Cat owners should be encouraged to ensure that their pets receiveroutine veterinary health care that includes periodic physical examinations to prevent or detect external parasite infestations and to maintain current vaccinations against other zoonotic diseases (e.g., rabies). Also, keeping kittens indoors can reduce the potential for transmission of the bacteria. It is strongly recommended that people with compromised immune systems adopt cats older that one year of age to reduce the risk of contracting CSD. As is always the case, any cut or scratch should be promptly washed with soap and water. In addition, the public (especially children) should be educated to avoid contact with stray animals and not to tease or play rough with cats.

So, enjoy your pets, but use caution and don’t ignore a scratch, cut, or bite inflicted by a frisky kitten.

References: 1. Epidemiologic Notes and Reports Encephalitis Associated with Cat Scratch Disease - Broward and Palm Beach Counties, Florida, 1994. MMWR Weekly, September 1998.   2. Little, Susan, D.V.M. Cat-Scratch Disease. CFA Health Committee, 1998.                 3. Physicians of the Geisinger Health System. Cat-Scratch Disease. 1997 Geisinger Health System.   4. Wentz, Alyson H. Remembering who, what, when, where will help diagnose cat scratch disease. Infectious Diseases in Children, August 1997.