Feline Tick-Borne Disease Found in the Ozarks .

August 2006 - by Doctor Denise E. Roche, DVM  

Not only has summer brought warm weather, sunshine and long days, but it also has brought fleas, ticks and tick-borne diseases.  Unfortunately this summer has seen the arrival of Cytauxzoon felis- a tick-borne, protozoal blood disease that affects domestic cats and exotic cats. It has been found in Texas cougars, Florida panthers and our domestic house cats.

The natural reservoir host for the parasite is the North American Bobcat. Up to 60% of Bobcats cats carry the disease without any ill effect. The distribution of the disease in the United States corresponds with the Bobcat’s range and areas where the vector tick, Dermacentor variablis, is found. (Dermacentor variablis is the American Dog Tick which is also the carrier for Rocky Mountain Spotted Fever). The tick feeds on a carrier Bobcat and ingests the blood parasite.  The Cytauxzoon felis then replicates in the tick and infects the tick’s salivary glands.  During feeding, the tick is then able to transmit the organism from its salivary glands into a cat’s blood. Cytauxzoon felis is nearly 100% fatal in domestic cats.

Once the tick has transmitted the protozoal blood parasite to a domestic cat, incubation of the parasite may take 2 to 3 weeks. The parasite rapidly reproduces in blood cells. This causes the cells to rapidly enlarge and swell and causes a clot to form within blood vessels. The patient then becomes symptomatic.

Clinical signs of the disease include depression, anorexia, dehydration, pale mucous membranes, jaundice and a high fever. Fevers can reach as high as 106 F. Cats usually die within 2 to 3 days after the fever peak. Infected cats die from internal bleeding and shock. Despite aggressive therapy with antiprotozoal medications, blood thinners, antibiotics, blood transfusions and intravenous fluids, our pet cats die.  Deerfield Veterinary Hospital saw 2 cases of Cytauxzoon felis in 2005. 

In 2006 thus far, we have seen 5 cases.  None of our patients survived this dreadful disease despite following the latest treatment protocols from the College of Veterinary Medicine at the University of Missouri-Columbia. 

Since there is no effective treatment against this horrible disease, the best therapy then is prevention. Keeping your cat indoors is the best protection against this disease.  If your cat must go outside, then tick control is obviously paramount.  The best tick control medications are either Revolution or Frontline.  Both kill the carrier tick.  These medications are applied topically to your cat’s skin once a month.  Either of these medications is more expensive than the readily available over the counter medications, but in turn they are extremely effective and very safe.  Many over the counter flea and tick medications contain pesticides which can pose a serious health risk to your cat.

Another way to minimize your cat’s exposure to ticks is to allow your cat outside only during daylight hours after the morning dew has dried.  Ticks locate their next host by questing.  During questing, ticks climb to the edge of vegetation and extend their front legs outward while remaining anchored with their back legs.  Since ticks are susceptible to drying, they must leave their questing perch several times a day and return to the base of vegetation for rehydration.  Obviously the wetter the grass or the greenery, the longer the tick has time to quest and find a new host such as you or your cat.

There are numerous tick-borne diseases. Cytauxzoon felis is only one of them but unfortunately it is a very deadly one.  Please protect your cat against this deadly disease.