Feline Infectious Peritonitis (FIP) is a viral disease caused by a virus known as the Feline Corona Virus. There are over 40 viruses in the Corona family, and most do not cause disease if your cat is infected. However, in a small percent of cats infected by Corona Viruses, the infection can develop into FIP. This tends to occur mostly in either young or old cats. It is thought that this may be due to a reaction your cat’s immune system with the virus or a mutation of the virus itself. The white blood cells become infected by the virus and carry this around the blood stream where is accumulates around vital organs. The infected cells tend to be located mainly in the brain, abdomen or kidney region, and an inflammatory reaction then occurs around the tissues. FIP differs from other infectious diseases in that the cat’s immune system actually aids the development of the disease. This makes it extremely difficult to treat- once a cat develops FIP, the disease is progressive and in most instances is fatal. There is treatment available which may give temporary relief, but this is generally unsuccessful in the long term.

FIP comes in two main forms. The first is known as ‘wet’ FIP; this is characterized by accumulation of fluids in the main organs of the body, and causes the abdomen and chest to swell. Your cat may experience breathing difficulties due to excess fluid- other symptoms can be jaundice, fever or loss of appetite. ‘Wet’ FIP can develop and progress rapidly.

The second form is known as ‘dry’ FIP; this has similar symptoms but there is a lack of fluid accumulation. The central nervous system and the eyes can be affected, although symptoms generally develop slower than with ‘wet’ FIP. Symptoms generally include loss of appetite, weight loss and anaemia.

How Do I Know My Cat Has FIP?
Cats that have contracted a Feline Corona Virus generally show very few symptoms apart from discharge from eyes or nose or sneezing. A very small percentage of cats go on to develop FIP, and this can take weeks, months or even years to develop after initial exposure to the Feline Coronary Virus.
A diagnosis of FIP can be difficult as symptoms can be very similar to many other diseases or health conditions.

You may at first notice your cat displaying such symptoms as loss of appetite and weight, poor coat condition and your cat may be generally listless and lethargic. She may also display a fever. These symptoms can then develop quite rapidly, and will progress to those characterized by either the ‘wet’ or ‘dry’ forms of FIP. Once this stage is reached, death is almost certainly inevitable.

There is currently no known cure for FIP. There are treatments available which may reduce symptoms but the disease will generally prove fatal. Available treatments are limited to ensuring your cat’s comfort and alleviating symptoms. These include antibiotics and corticosteroids, plus other treatments such as blood transfusions and draining of excess fluids. A vaccine is available but it is as yet fairly new and is thought to have only limited effectiveness in preventing FIP.

There is also no diagnostic test for FIP- there are tests to determine the presence of Feline Corona Virus antibodies in your cat, indicating an exposure to these, but the tests cannot determine whether this will develop into FIP. These tests are measured in antibody titers; a low titer result indicates a small number of Feline Coronary Virus antibodies, whilst a higher titer result indicates a larger number of antibodies. However, a cat with a higher titer result will not necessarily develop or be a carrier of FIP. Similarly, high levels of antibodies will not necessarily protect your cat against developing FIP. At present, the only sure way of diagnosing FIP is by biopsy.

Is FIP Contagious?
Although FIP is not highly contagious, Feline Corona Virus can be passed on from cat to cat through saliva and feces, or from a mother cat to her kittens. Cats most at risk of developing FIP are those with weak immune systems, very young cats or older cats. Cats with an existing infection such as feline leukaemia virus (FeLV) are also at greater risk of developing FIP.

If you have a multi-cat household there are precautions you can take. First, remember that if one of your cats develops FIP your other pets will not necessarily develop the disease. FIP is not widespread and there is no need to panic. Any cats suspected of having FIP should be separated from other cats and given separate food bowls, litter tray and bedding. These should be washed separately. Incidences of FIP can be prevented by keeping your cats as healthy as possible, ensuring that all vaccinations are up to date and ensuring that litter trays are kept as clean as possible and disinfected regularly. Be aware that FIP is generally more prevalent in large groups of cats such as catteries or shelters.