Cornell Feline Health Center
Cornell University College of Veterinary Medicine
Ithaca, New York 14853
Stiff and swollen joints, lethargy, diminished appetite, and fever are among the salient clinical signs of countless feline health disorders. In the warmer months of the year, these signs may indicate that a cat has been bitten by a tick—or a whole lot of ticks—and is in the throes of a serious illness calling for prompt veterinary treatment.
Ticks bite their hosts because they need to feed on an animal’s blood in order to move through the various phases of their development, from the larval stage to adulthood. Larvae need blood nourishment in order to develop into young ticks (nymphs); the nymphs need it in order to mature into adulthood; and the adult female needs to ingest blood in order to mate and lay the thousands of eggs that will eventually develop into a new generation of larvae. It is in their nymph and adult stages, explains William Miller Jr., VMD, a professor of dermatology at Cornell University’s College of Veterinary Medicine, that a tick will crawl onto a cat’s body, attach itself, and start to feed on the animal’s blood. If the tick is carrying an infectious agent, the pathogens will enter the cat’s circulatory system and begin to reproduce rapidly.
Well over 800 species of ticks have been identified worldwide, although only a dozen or so are associated with significant feline disease. Most notorious among tick-borne disorders—although not the most consequential in terms of potential impact on the feline population—is Lyme disease, a bacterial infection that, if treatment for it is delayed, can lead to extensive joint damage, cardiac complications, kidney failure, and neurologic dysfunction. Fortunately, cats are highly resistant to the bacteria causing Lyme disease and rarely show signs of the disease.
A number of other tick-transmitted illnesses that are observed in the United States carry prognoses that are more threatening than Lyme disease. Among the more notable, and potentially lethal, are the relatively common hemobartonellosis and the much rarer cytauxzoonosis, as well as tularemia. Hemobartonellosis is caused by a bacterial parasite that invades a cat’s red blood cells and fosters development of severe, life-threatening anemia, signs of which are pale gums, lethargy, inappetance and rapid or open mouth breathing. Cytauxzoonosis results from infection by a one-celled protozoan parasite that causes severe anemia, fever, lethargy, and breathing difficulties and is usually fatal. Tularemia, a comparatively uncommon but deadly bacterial infection results in fever, lymph node enlargement and abscess formation. In addition to the diseases noted above, other rare tick-borne disorders—such as ehrlichiosis, and babeseosis, —can affect cats and may cause fever, anemia, lethargy, and inappetance or weight loss.
If any of these clinical signs are observed, Dr. Miller advises, they should be brought to the attention of a veterinarian without delay. In some cases—tularemia and cytauxzoonosis, for example—the prognosis will not be promising; infected cats are likely to die from the infection. On the other hand, a antibiotics—such as tetracycline and doxycycline,—are apt to be effective in countering other tick-borne diseases, especially if they are diagnosed at an early stage.
A variety of topical medications that are effective in thwarting feline tick infestations are commercially available, as are tick collars that may succeed in keeping the parasites from invading a cat’s coat. Because topical medications and tick collars contain potent chemicals which cats can be exquisitely sensitive to, none should be used on a cat without the specific recommendation of a veterinarian.
Especially during the warmer months of the year, says Dr. Miller, an owner should routinely brush a cat’s coat and search for signs of tick infestation. “If you spot an attached tick,” he says, “remove it with forceps or tweezers. Reach below the tick’s body, grab it close to the head where the tick is attached to the skin, and apply steady traction to pull it out. You want to be sure to get the whole thing. And if it’s a female, there will be eggs inside the body, and you want to get rid of them in a safe manner.” This can be achieved, he notes, by dropping the egg-filled tick into a bottle of alcohol and tightly sealing it. Ticks can transmit diseases to humans, so be sure to wear gloves, avoid touching the tick with bare skin, and wash your hands after disposing of the tick. For additional advice and a video on removing ticks, see The American Lyme Disease Foundation’s website at http://www.aldf.com/lyme.shtml#removal. Above all, don’t panic if you find a tick on your cat. The vast majority of ticks don’t carry diseases and only rarely are cats affected by tick-borne illnesses.
By Tom Ewing
January 26, 2011