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Health Of Outside Cats Threatened By Tick Disease

By: Barbara Hootman


Outside cats not only have to dodge dogs, cars, and fleas, but ticks as well, to stay healthy.

The North Carolina Veterinary Medical Association recently announced two domestic cats had died in the past month from a tick-borne disease called cytauxzoonosis.

Cytauxzoonosis was first reported in Missouri in 1976.

"The disease is not a new one, but it is newly diagnosed in North Carolina," Dr. Lee Hunter, state epidemiologist, said. "It certainly has the potential to pose severe problems to outside house cats. Iíve seen several cases of it."

Cytauxzoonosis is a serious, and usually fatal, protozoal disease affecting domestic cats in the south central and southeastern portions of the United States. Rapid onset and high mortality characterize it. Those working with the disease put the percentage of mortality at about 95 percent.

The disease is transmitted when one of two immature stages of the American dog tick transmits the organism during a blood meal.

"The dog tick can lay as many as 3,000 eggs, of which all hatch into seed ticks," Dr. Jack Broadhurst, D.V.M., says. "At this stage they are tick eggs with legs. There are two immature stages of the development of a tick in which a blood meal from the host, a cat, is needed. Once the tick is mature it moves off the cat onto a dog. It is during these immature stages that the tick is the biggest threat to outside cats. Rabbits, moles and voles in most yards also carry ticks and spread that on outside cats."

There are no clinical signs of cytauxzoonosis during the first 20 days of infection, when the organism is growing within blood vessels throughout the catís body. The first signs are seen three to seven days before death occurs due to massive organ failure and bleeding disorders.

"It is a horrible death for the animal," Broadhurst said.

The natural host of cytauxzoonosis is the bobcat. The infected ticks spread from the bobcats to the free ranging domestic cats, making an easy entry into the domestic world. The free ranging outside cat has more contact with wildlife than any other domestic animal, making it subject to contracting cytauxzoonosis, rabies, fleas, ticks, and a host of other diseases.

Broadhurst has researched cytauxzoonosis thoroughly, and has successfully treated a cat with the disease. He says North Carolina is seeing more bobcats, the natural hosts of the disease, because they moved east due to the extreme drought in the west.

"When the cat starts showing clinical signs that it is sick, the time clock has started," he said. "The cat has five to six days before it is dead. The cells rupture, and the spleen and bone marrow are affected. The cat goes into shock, and it literally has no blood left. Its muscles cramp and the cat has a lot of pain."

Broadhurst says a blood test is the key to diagnosing cytauxzoonosis. Also, he says that veterinarians have to have a clinical sense of what is going on. He thinks a lot of veterinarians are still unaware that the disease is on the move throughout North Carolina.

Dr. Richard Oliver, Western North Carolina Diagnostic Laboratory in Asheville, says there are more sightings of bobcats in the Western North Carolina area than there have been in recent years. Also, he has diagnosed cytauxzoonosis in a housecat from the Madison County area two years ago, confirming that the disease is in the Western North Carolina area.

Broadhurst says cat owners and veterinarians need to pay attention to an early profile of the cat, know that the disease is in the vicinity, recognize that the feline victim is an inside-outside cat, has had no tick protection, and has had a sudden change in appetite and ability to walk.

"The veterinarian should insist a cat that is showing any of these signs be brought into the clinic for testing immediately," he said. "The veterinarian will take blood and should look for a definite pattern of high blood glucose, elevated bilirubin, (high bum), high muscle enzymes, and excessively low white blood count, and an excessively low blood platelet count."

Broadhurst emphasizes that time is not on the side of the feline victim or the veterinarian administering treatment, since cytauxzoonosis kills quickly.

"Once a veterinarian has a good idea that the disease is what is causing the trouble, treatment has to be started quickly. I have had success in treating one cat with Imizol. I think it is important that veterinarians have Imizol in the clinic, because a cat with cytauxzoonosis doesnít have time for it to be ordered, before it is dead."

Broadhust may be reached at the Cat Health Clinic in Pinehurst at 910-295-2287 (USA), for additional information.

Oliver recommends that all indoor-outdoor cat owners be viligant about ticks on their cats.

"Youíve got to tick-proof them, and groom them often to find the ticks," he said.

Given the short clinical phase of cytauzaoonosis, preventing the tick bite is the only practical approach to controlling this disease.

Dr. Judith Rozelle, of Swannanoa Pet Clinic, recommends cat owners treat their animals for tick prevention.

"Just about every veterinarianís office has products that can successfully tick-protect cats," she said. "Any product used must be labeled for cats, or it can kill the animal. You cannot use tick products for dogs on cats. Products labeled for dogs are toxic to cats. Cats have very sensitive systems, and you can kill the cat trying to save it from ticks if you donít use the right products."

Broadhust recommends cat owners control the population of ticks in their yards as much as possible.

"Reduce rabbits, moles and voles as much as possible, because they are another meal for the ticks that get on the cats," he said. "Also ticks attach themselves to grass, so the grass should be cut short and bushes cut back so that the cat will not come into contact with the ticks. Ticks are attracted to moisture, so cats should not be allowed outside following a rain or early mornings and late afternoon when the grass is wet.

The American Humane Society recommended keeping cats inside and not allowing them to roam. This is a sure way to control the tick problem.

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