What is Cytauxzoonosis in Cats?

He was a cute little guy, still a fluffy kitten but almost full-grown. His mother brought him, his brother, and his sister to camp out in the cat house near our patio. All were feral cats we had trapped, neutered, and released some months earlier due to a lack of foster homes. In our years as cat rescuers, we had never seen such an extrovert as this male kitten. Little did we know as we worked to socialize him that we were dealing with a case of Cytauxzoonosis in cats.

The diagnosis was the result of a lot of frustration and ended sadly. We were able to pick him up and transport him to the vet. She frowned when I blurted out that I had never seen a cat get so sick so fast and wondered if it was some kind of illness peculiar to the area. It was.

What is Cytauxzoonosis in Cats?

According to PetEducation.com, this disease is caused by Cytauxzoon felis, which is a single-celled parasite. Vets first noticed it in the United States in the mid-1970s. They commonly refer to the parasite as C. felis.

The Pet Health Library reports that in this country, the bobcat is the natural host of the infection. The disease does not pass from cats to livestock. While most afflicted bobcats have only a mild case, the illness is almost always fatal among domestic cats.

When it came to getting a quick diagnosis, my question was unwittlingly on target because this illness occurs primarily in cats in the southern and southeastern U.S. Virginia marks the top border of states where it's prevalent. The culprit that bites the cat and transmits the parasite is most often the American dog tick.

Symptoms and Diagnosis

The adventuresome cat who had tried so hard to get to know us faded very quickly. We learned that his symptoms probably began within one to three weeks after an infected tick had bitten him. Cytauxzoonosis caused organ failure. Lab tests showed the parasite was in his blood. By the time of his exam, the illness had affected his spleen, lungs, and liver.

He had pretty much lost interest in eating, had a fever, and was clearly in respiratory distress. Like the fate of other cats with Cytauxzoonosis, his life was very short once infected. Many cats die within 14 days.

Veterinarians are usually able to make a diagnosis of this illness by seeing the presence of the parasite in the cat's blood sample. The disease infects tissue first, then blood. Since it progresses so quickly, irregular blood work can occur within a few days after infection.

Treatment and Prevention

Vets consider Cytauxzoonosis fatal. In the unlikely event a cat survives, he or she might still be a carrier of the disease. Treatment primarily consists of supportive care like IV fluids. A few cats have been saved through the use of diminazene aceturate. Researchers report that just one was saved after being treated with imidocarb diproprionate. These treatments attempt to prevent the cat's blood vessels from becoming clogged with the parasites.

In recent years, some cats in western Arkansas and eastern Oklahoma have survived a milder form of the disease without any treatment. Fortunately, the other members of our little guy's family never contracted the illness.

Since their habitat is the outdoors, feral cats are often victims of Cytauxzoonosis. For domestic cats, the best prevention is to keep the pet inside and to use a tick control medication if recommended by the local vet.

Sources:

http://www.peteducation.com/article.cfm?c=1+2133&aid=728

http://www.veterinarypartner.com/Content.plx?P=A&A=2716&S=1&SourceID=42

Personal experience as a cat rescuer