Cat-scratch disease

Cat Scratch Disease (Bartonella henselae) may be most well known as the title of a popular song, but its less glamorous identity is that of a zoonotic (transmissible from animals to people) disease. Cat Scratch Fever is caused by a bacteria that is present in up to 20 percent of domestic housecats, but only shows symptoms in a tiny fraction of that number. An even smaller number of feline Bartonella carriers will go on to transmit the disease to a person, but those who are immune compromised are especially susceptible to infection.

Symptoms and diagnosis

Most cats who carry Bartonella will not demonstrate any sign of infection, though some will develop fever, reduced appetite, and uveitis — a cloudy infection — in one or both eyes. The challenge with diagnosing Bartonella lies in its commonality in certain feline populations. A blood culture can be performed, but a positive result only says that the patient is a carrier of Cat Scratch Disease, and not that the disease is the cause of his symptoms.

Symptoms of Bartonella are similar to other common bacterial and viral infections in cats, and several such diseases will respond similarly to standardized antibiotic regimens, so obtaining a conclusive diagnosis of Bartonella is not always necessary to proceed with treatment.

Treatment and prognosis

If Cat Scratch Disease is believed to be the cause of a cat’s medical issues, veterinarians will typically prescribe an antibiotic that is effective against Bartonella, as well as a number of other bacteria which may cause similar symptoms. Cats with symptoms for Cat Scratch Disease should be tested for diseases that may cause additional weakness in the immune system, such as FIV (Feline Immunodeficiency Virus) and Feline Leukemia, but if the feline patient is by all other means, healthy, then he should be able to make a full recovery following a course of antibiotic treatment.

Prevention of Cat Scratch Disease

Bartonella is spread throughout cat populations by fleas. Cats who routinely go outdoors in areas where fleas are most common (warm, humid climates in particular), are more likely to become infected with this bacteria. In turn, humans who come into contact with cats in these regions, are most likely to experience symptoms of Cat Scratch Disease. Keeping cats indoors and current on a topical flea preventative are the most effective methods to preventing the transmission of Bartonella.

Cat Scratch Disease in humans

Most people are able to come into regular contact with a cat who is a Bartonella carrier and not contract the disease. However those with underdeveloped immune systems may show signs of serious illness, including eye infections and painful lymph nodes after being scratched by an infected cat or coming into contact with infected fleas. Mild cases of Bartonella in humans will resolve on their own, but more advanced cases of infection will require a course of antibiotics.

Sources:

Holt, Natalee M.; Bartonella; Tufts School of Veterinary Medicine; Grafton MA; January 28, 2010

NAVC Conference Veterinary Proceedings; Small Animal and Exotics Alternative Medicine-Opthamology 1, Gainesville, FL; 2007

Plotnick, Arnold; The Truth About Bartonella, http://www.manhattancats.com/Articles/truth_about_bartonella.htm, July 2, 2007