What is FIP?

Feline infectious peritonitis is a viral disease that can affect domestic and wild cats around the world. The virus attacks the cells of the intestinal walls, causing fever, weight loss, lethargy, and anorexia. It is fatal in more than ninety-five percent of cases.

There are two types of FIP — a wet form and a dry form. Both types of FIP have some symptoms in common: fever, anorexia, weight loss, and lethargy.

Wet form FIP

  • Accumulation of fluid in the chest or abdomen (or both)
  • Labored breathing if fluid is in the chest cavity
  • Distended stomach if fluid is in the abdominal cavity

Dry form FIP

  • Inflamed cells form on organs
  • Thirst, urination, and vomiting if kidneys are affected
  • Jaundice if liver is affected
  • Optical and neurological problems are possible

A virus called a coronavirus causes FIP. However, there is a similar coronavirus that is nearly identical to the FIP virus but does not cause as many problems. There is currently no test that can distinguish between the relatively harmless coronavirus and the FIP coronavirus. A positive test result can indicate that a cat has been exposed to a coronavirus; a negative test result can indicate that the cat is likely to not have FIP.

Diagnosing the dry form of the disease is more difficult than diagnosing the wet form of FIP. Lab analysis of the fluid can support a FIP diagnosis in wet form FIP. Diagnosing the dry form of FIP often requires a biopsy of affected organs. Most cats with wet form FIP die within two months of the onset of symptoms. Some cases of dry form FIP are able to survive, if the case is mild.

The disease is very often fatal to cats (more than ninety-five percent of cases do not survive) but is fortunately not very common. A vaccine is available, but the American Association of Feline Practitioners and the Academy of Feline Medicine Advisory Panel on Feline Vaccines do not recommend its use.