Cat Diseases that Cause a High Fever

Fever is an elevation in body temperature caused by a reaction to illness. Many viruses and bacteria have a preferred temperature range. Fever results from an immune response that sets the thermostat in the brain to a higher temperature. Even under normal circumstances, cats have a higher body temperature than humans. A normal body temperature for cats is anywhere from 100.5 to 102.5 degrees F. You can take your cat's temperature with an electronic ear thermometer or a rectal thermometer.

  1. Feline Infections Peritonitis

    • Feline infections peritonitis (FIP) is the leading cause of unexplained fevers in cats. The disease is incurable and difficult to diagnose. Most cats eliminate the virus on their own while others become carriers of the virus. This virus is extremely contagious and is spread through blood and feces. Blood tests are often inconclusive, and even cats who have been exposed to the virus may not develop the disease. FIP is an autoimmune disease caused by a virus. The fever results from the cat's immune system attacking the host's body where the virus-infected cells are located.

    Infection

    • Check the cat for abscesses and open wounds. An abscess occurs when a cat receives a wound that closes before it can fully heal. If you find an abscess, take your cat to the vet to have the abscess drained. Cats can also have internal infections that are not obvious on the outside. Your veterinarian will need to diagnose an internal infection with a blood test. If a cat has an infection, white blood cell counts will be elevated. Other tests may also be necessary, such as urine or fecal exams.

    Cancer

    • Cancer and tumors can cause fevers in cats. Feel your cat's body for any strange lumps or masses. If other causes of high fever are ruled out, a veterinarian may recommend an x-ray to look for internal tumors.

    Feline Leukemia

    • Another viral disease, Feline Leukemia (FeLV) is contagious and almost always fatal. It is spread through contact with urine, feces, saliva and nasal secretions. It can also be transmitted through bite wounds. FeLV causes persistent fever in cats and has a range of other symptoms such as loss of appetite, enlarged lymph nodes, eye conditions and seizures. There is a vaccine for FeLV, but once symptoms begin to manifest it's too late. A cat with the disease can live for months without showing symptoms, the whole time spreading the disease to other cats.