Cytauxzoon Felis (Bobcat Fever)

Education Station

Cytauxzoon Felis (Bobcat Fever)

Susan Nelson, DVM

Cytauxzoon felis, also known as bobcat fever, is a blood parasite that infects domestic cats and has a very high death rate. It is commonly known as "bobcat fever" as bobcats are the main reservoir host for this disease. Bobcats harbor the parasite in their blood. Ticks feed on the bobcat and ingest the contaminated blood, and then cats become infected though a bite from an infected tick. Dogs and people are not susceptible to this disease.

Most cases of cytauxzoonosis in the United States are reported from the southeastern and south-central states between March and September. However, this disease is commonly seen in our area.

The incubation period is 1-3 weeks. Ticks may or may not be present at the time of clinical illness. Symptoms of this disease include: high fever, labored breathing, depression, dehydration, anorexia, anemia, and jaundice, which rapidly progresses to low body temperature, extreme weakness, coma, and death. The death rate is very high with this disease, even with treatment.

A milder strain of Cytauxzoon felis seems to have emerged in west Arkansas and east Oklahoma where a number of cats have survived without treatment (as do most bobcats). These cats continue to have the organisms in their blood but have no residual effects.

Diagnosis of the disease is made by a combination of clinical signs, alterations in routine bloodwork and finding the organisms in blood smears, bone marrow aspirates, or on cytology of organs and lymph nodes. Unfortunately, the diagnosis is often made on a post mortem exam for many cats.

Because the death rate is high, prevention is the best option. Cats should be kept indoors to avoid tick exposure. If cats cannot be kept indoors, then stringent adherence to routine application of tick preventive products and daily tick checks with prompt removal of all attached ticks is critical to prevent the disease. Talk to your veterinarian about the best products for your cat; and don’t forget to treat your dog as they can bring ticks into the house, which in turn can infect indoor cats.

Tick numbers in the surrounding environment can be reduced by such basic measures as removing debris and keeping shrubbery and grass closely clipped to discourage both tick populations and the wildlife species that often harbor them.

Susan Nelson, DVM is a Clinical Associate Professor in the Department of Clinical Sciences in the Veterinary Health Center at Kansas State University. In 1985, Dr. Nelson received her BA in Biology from Hastings College in Hastings, NE. She then completed her DVM at Kansas State University in 1989. After receiving her DVM, Dr. Nelson spent her next 14 years as an associate veterinarian in a companion animal practice in Manhattan, KS. In 2003, Dr. Nelson joined the faculty at Kansas State University Veterinary Medical Teaching College. She is currently a clinical instructor for senior veterinary students in the hospital’s Pet Health Center.