Nasty Infectious Diseases You Want To Avoid - Cat Scratch Disease
Cat-scratch disease (CSD) is a mild illness following the scratch or bite of a kitten or cat, caused by a small bacterium recently identified as Bartonella (formerly Rochalimaea) henselae. Three-quarters of cases occur in children and occur more often in fall and winter.
While the disease causes few problems in healthy individuals, in those with a weakened immune system the infection can become dangerous and life-threatening. There are about 22,000 cases of CSD in the United States each year.
Cats with the bacteria have no symptoms and don't appear to be harmed. The disease was first recognized in the 1950s, but the organism that causes it has only been recently discovered.
Cause - The bacteria are transmitted between cats by the common cat flea, according to a new study by University of California researchers. The animal itself does not appear to be ill, and about 90 percent of cases are caused by kittens; the rest result from grown cats, dogs, and other animals. Researchers still don't understand how the bacteria can live in the bloodstream, since blood is normally sterile and bacteria are usually killed by the immune system. While cats with the disease aren't ill, many have large numbers of organisms in their blood. The disease cannot be transmitted from one person to another, and it is not clear if one episode confers immunity.
Symptoms - The symptoms of CSD resemble the early stages of other infectious diseases, such as tuberculosis. About two weeks after a bite or scratch, the victim reports a red round lump at the site of infection and one or more swollen lymph nodes near the scratch, which may become painful and tender, with an occasional discharge. Symptoms sometimes include fever, rash, malaise, and headache. In most cases, symptoms disappear on their own.
Diagnosis - It can be diagnosed by symptoms, history, and negative tests for other diseases that cause swollen lymph glands. A blood test, developed in 1992 by the Centers for Disease Control, detects antibodies to the bacteria. The test is available free to doctors and state health departments. Biopsy of a small sample of the swollen lymph node is not necessary unless there is question of cancer of the lymph node or some other disease.
Treatment - There are no antibiotics effective against CSD, although they are often prescribed for children with severe pain or swelling. A severely affected lymph node or blister may have to be drained, and a heating pad may help swollen, tender lymph glands. Acetaminophen may relieve pain, aches, and fever over 101 degrees F. In most cases, the illness fades after one or two months.
Complications - In HIV patients, the bacteria can cause a rare, potentially fatal (yet curable) infection called bacillary angiomatosis that causes blood vessels to grow out of control, forming tumorlike masses (in bone, liver, and skin) that look like those of Kaposi's Sarcoma. Another rare complication is encephalitis, or cat-scratch disease of the brain, which appears about one or two weeks after the first symptoms of CSD. Signs of complications include unusual spots or bruises on the skin, eye infections, unusual pain, high fever (more than 103 degrees F), stiff neck, severe headache, or severe vomiting. This mimics other more serious causes of meningitis and is often treated with antibiotics.
Prevention - Other than avoiding cats, there is no way to prevent the disease. However, cats only carry the infecting organism for a few weeks during their lifetimes, so the likelihood of being reinfected, or infected by just one pet in the home, is minimal. Patients with weakened immune systems don't need to get rid of their cats, but they should inform their physicians that they own cats and avoid getting scratched. If a scratch does occur, it should be washed thoroughly with soap and water. It is also important to control fleas.