Cytauxzoonosis in Cats

Cytauxzoonosis in cats, also known as Bobcat Fever, is a very deadly disease that can affect domestic cats. As the natural hosts of the Cytauxzoon felis organism, infected bobcats show very mild disease signs, if any. However, the red blood cell parasite is transmitted from bobcats to cats through tick bites. Cytauxzoon can be found wherever climate conditions favor the American dog tick, Lone Star tick, and bobcats. The disease ranges from Texas to Kansas, Illinois and Ohio, and east to West Virginia. Florida and Texas cougars can also carry the disease. Humans, dogs and other species are not affected by Bobcat Fever.

What Causes Cytauxzoonosis

The single-celled Cytauxzoon felis organism can infect both the cat’s red blood cells as a piroplasm and the tissues as a schizont. The schizont stage, most deadly to cats, causes severe inflammation and swelling of the blood vessels that leads to red blood cell destruction, vessel blockage and decreased blood flow to all tissues of the body.

Symptoms of Cytauxzoonosis

Symptoms of this tick-borne illness in cats can be very subtle and hard to detect, appearing 8-16 days after a tick bite. Symptoms usually start with lethargy and fever, but then progress very quickly to jaundice (yellow skin), spleen enlargement, vascular damage, followed by pain and death in as little as one week without treatment.

Treatment of Cytauxzoonosis

For any chance of recovery, Cytauxzoon felis treatment must be started very soon after symptoms occur. Treatment with azithromycin and atovaquone, a compounded anti-malarial drug, can be effective if started early, when symptoms first start. Infected cats need intensive supportive care with hospitalization, intravenous fluids, anti-coagulation medications and nutritional support. If the cat survives, it usually makes a full recovery. The circulating piroplasms may persist for long periods, with some cats becoming reservoirs of the disease. However, they rarely become ill again after their initial infection.

Prevention of Cytauxzoonosis

While frightening, Cytauxzoon can be easily prevented. Even though no vaccine is available, cats cannot contract the disease if a tick never bites them. To avoid tick bites in cats, use quality comprehensive parasite control products that include tick prevention to protect indoor/outdoor cats, as well as those that are outdoors exclusively, such as barn and working cats. Some of the products that adequately prevent tick bites in cats include Revolution Plus for Cats, Bravecto Topical for Cats, and Advantage Multi for Cats. Indoor-only cats, especially those that share a household with dogs, should also be on a comprehensive parasite control product to reduce the risk of accidentally encountering a tick brought into the house by a dog, or on a human’s clothing. Since ticks can become active even during winter warming spells, year-round prevention provides the best protection.

If you have more questions or need help finding the best tick protection for cats, call us at 800.786.4751.

Picture of Amy Hanson with a kitten

Written by: Amy Hanson, DVM

Amy Hanson, DVM

Dr. Amy Hanson is an associate veterinarian at the Cat Clinic of Lawrence in Lawrence, Kansas. She is a 2010 graduate of Kansas State University College of Veterinary Medicine. Her special interests include felines, acupuncture and dentistry. Her hobbies include showing cats and she is a judge for the American Cat Fanciers Association (ACFA).

If you need help, call us at 800.786.4751.