Feline Infectious Peritonitis (FIP) is a serious viral disease of cats. It is most common in an environment in which large numbers of cats live together, such as breeding facilities. There is no cure for FIP.
How Cats Get the Virus
Less than 1% of the general cat population in the United States is infected with FIP. However, the incidence can be much higher in multi-cat households, breeding facilities, and animal shelters. The disease is spread via the droppings of infected cats and sometimes via saliva or urine. The virus can survive in the environment for up to two months. However, not every cat that is exposed will get the disease. Cats that are very young, very old, unhealthy, or stressed are most susceptible.
What the Disease Does
FIP is caused by a coronavirus. Most cats infected with coronaviruses get only a mild digestive illness. The virus that causes FIP is thought to develop in some cats as a mutation of the digestive coronavirus. It then invades the immune system, infecting the white blood cells which then carry the virus throughout the body. The cats infected immune system is responsible for most of the inflammation and other symptoms associated with FIP.
Initial infection with FIP may go unnoticed. Some cats develop a mild respiratory or digestive illness, from which they soon recover. Many of these cats fight off the virus completely. Some remain carriers. Only a small number get the serious illness. Those that do may get sick within a few months, or the virus may lie dormant for years before causing symptoms.
FIP occurs in two forms. The first is called the dry form. Signs include chronic fever, loss of appetite, weight loss, vomiting and diarrhea, lethargy, and disorders of the eyes and nervous system. It can also cause failure of the kidneys, liver, or pancreas. The second form of FIP is the wet form. Cats with the wet form of FIP may have any of the signs listed above, but also suffer from accumulation of fluid in the chest and/or abdomen. Cats usually die within a few weeks or months, but may live as long as a year.
How FIP is Diagnosed
Although there are tests for FIP, they only detect exposure to coronavirus. They cannot distinguish between the relatively harmless digestive viruses and the one that causes FIP. Therefore, diagnosis involves careful consideration of the cats history and symptoms as well as laboratory results that may include tissue biopsies and fluid aspirates.
Treatment for FIP
There are no effective treatments for FIP, but medications can be given to make ill cats more comfortable and to reduce the immune systems inflammatory response. Immune modulators and antiviral drugs may also be of benefit.
The best prevention for FIP is to keep your cat healthy and avoid stressful, overcrowded living environments. Facilities that house large numbers of cats must practice good sanitation, cleaning and disinfecting litter pans frequently. Cat breeders should talk to their veterinarians about protocols for eliminating coronavirus from their breeding stock. A vaccine is now available against FIP. It has a good record of safety, and may help prevent the disease in some situations. However, FIP is a complex disease and the vaccine may not be effective for some cats. Talk to your veterinarian about your cats risk of exposure to FIP and whether he might benefit from vaccination.