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Cat Diseases: What Is Bobcat Fever and Why Is It Deadly to Cats?

Image via Andy Gin/Shutterstock

By Kerri Fivecoat-Campbell

Debbie Bunce Page routinely took her 3-year-old cat, Bobbie Socks, to the veterinarian and treated her with topical prescription flea and tick for cats. Because her cat was fully vetted, Page didn’t really worry about cat diseases. She thought that the biggest thing she had to fear with her former stray were wild predators near their rural Montreal, Missouri home.

However, on June 28, 2018, Page had to make the difficult decision to euthanize Bobbie Socks after blood tests confirmed that she had contracted bobcat fever, a tick-borne disease that is especially deadly for domestic cats.

“In the best cases, there’s a little better chance if caught early,” says Dr. Jennifer Leffel, a veterinarian with Lake of the Ozarks Animal Hospital in Linn Creek, Missouri, where Bobbie Socks was a patient. “We typically don’t see them until the late stages.”

What Is Bobcat Fever?

The tick-borne disease Cytauxzoon felis is commonly referred to as bobcat fever because the resource hosts are wild bobcats, says Dr. Leah Cohn, a veterinarian and one of the country’s leading researchers on bobcat fever at the University of Missouri College of Veterinary Medicine in Columbia, Missouri.

“Bobcats typically get the mildest form of the illness,” says Dr. Cohn. “Although we think some may get sick and die, most of them recover and carry the illness in their bloodstream.” 

Dr. Cohn explains that this cat disease is not a bacteria or virus, but rather a blood parasite that is passed around through tick bites. “The disease has been found in the American dog tick, but we believe it is primarily passed to cats through the Lone Star tick,” says Dr. Cohn. “The American dog tick appears to be less relevant in spreading bobcat fever.”

Symptoms of Bobcat Fever in Domestic Cats 

Bobbie Socks had all of the classic symptoms of bobcat fever. Page says Bobbie Socks preferred being outside during the day, but two days before Page took her to the veterinarian, she came in and slept all day.

The next day, she only drank a small bit of water, had pale gums, refused wet cat food and appeared to be running a temperature. By the time Page got Bobbie Socks to the vet, she was in liver failure. “She had so many of the organisms in her blood sample on the slide that I kept it to show staff as an example of the disease,” says Dr. Leffel. 

Dr. Cohn says the disease is so deadly because symptoms will usually not present until at least 12 days after a tick bite, and the cat’s health declines so rapidly that they will typically die within 2-3 days after symptoms first appear.

What Is the Treatment for Bobcat Fever?

If the disease is caught in the very early stages, there is a treatment protocol that includes cat antibiotics and an antiprotozoal drug. Combined with intensive hospitalization, which could last two or more weeks, and fluid and nutrients through IV, the mortality rate has improved from above 90 percent to about 50-60 percent.

However, the treatment is so expensive and hard on felines that many cat parents opt not to treat the disease. “The treatment is very hard, and even if the cat survives, they will be very sick,” says Dr. Cohn. “We always encourage veterinarians to have the discussion with cat owners about treatment so they can come to a decision that is best for them and their family.”  

Dr. Ashley Allen, a veterinarian at the University of Florida College of Veterinary Medicine in Gainesville, Florida, treated a well-documented late-stage case of bobcat fever in 2010 with the protocol.

There was little reason to expect that Frankie, the cat treated, would survive. Frankie had a temperature of 106 degrees one day, and it dropped very low the next, the typical sign of late-stage bobcat fever. “The owners wanted to try and treat, and we were able to save him,” says Dr. Allen. “Frankie is still alive today.”

That case is an example of the theory that some parts of the country possibly harbor different strains of the disease, or that some cats may have more of a tendency to survive. “We are seeing better survival rates in some regions,” says Dr. Cohn.

Dr. Cohn says bobcat fever has been found in 23 states, mostly in the Southeast, although it was recently found in North Dakota and Pennsylvania. Dr. Cohn says the illness is typically found in greater numbers in the spring and fall due to tick activity, but can be found in most areas from March to September.  

Dr. Cohn says they have been researching a vaccine for bobcat fever, but there have been some setbacks that have sent them back to the drawing board.

Can Bobcat Fever Be Prevented?

When Michael Murray adopted Maggalene, a friendly 6-year-old calico that was part Maine Coon, from a shelter in Eureka Springs, Arkansas, Murray felt a special connection. “She was the only pet I ever had; all the rest were someone else’s in the family, but she chose me,” says Murray.

When Michael’s wife, Judy, noticed that Maggalene had been lethargic for a couple of days this past spring, they took her temperature, and it was a startling 106 degrees. They wrapped her in cool towels that night and took her to their veterinarian the next morning.

Blood tests confirmed bobcat fever. She died overnight while receiving antibiotics in the animal hospital. Maggalene hadn’t been an outdoor cat, but she had recently started to venture outside. Even though she was on flea and tick treatment, she still contracted the disease.

Dr. Cohn says that with some topical cat flea and tick treatments, ticks have to actually bite a cat to die, and that gives the opportunity for the cat to become infected. According to Dr. Cohn, the only effective way to prevent bobcat fever is to keep your cat indoors.

However, if that’s not possible, she says there is a published study that says that Seresto 8 month flea and tick prevention collars for cats may be an effective preventative. Seresto claims to kill ticks through contact with no biting required. Dr. Cohn cautions, however, that there is no preventative that will provide 100 percent coverage.

Dr. Allen says that she also recommends topical treatments for outdoor cats, such as Frontline Plus flea and tick treatment for cats—especially those that may get a collar caught on something.

If you have pets that go outdoors, it also may help to treat your yard with a spray, like Sentry Home Yard and Premise flea and tick spray as well as treating your home with flea and tick prevention like Only Natural Pet EasyDefense all-in-one flea and tick powder