Feline Infectious Peritonitis

Feline Infectious Peritonitis occurs when a coronavirus mutates into a fatal disease in an individual cat or kitten. There is a lot of information available about FIP. Unfortunately, a lot of it is wrong.

Simple Rules

Here are some simple rules to follow, regarding FIP and the so-called vaccine.

1. Don't vaccinate for FIP. You may, in fact, be enhancing your cat's susceptibility to the disease, rather than protecting it.

2. Don't kill all your kittens or cats if one cat dies from FIP. You may lose some cats from the disease, but the rest of your cats might never be affected in any way.

3. Practice excellent hygiene in your cattery. Wash your hands frequently. Keep the litter boxes clean. The coronavirus is easily passed in/on feces from one cat to the next (it may be  transmitted in other ways too, but feces are known transmitters).

4. Reduce stress in your animals. Stress impairs the immune system. Healthy cats resist disease.

5. If you have cats with chronic health problems, please consider removing them from your breeding program. You don't have to euthanize them. Spay/Neuter and keep as a bed cat or place them where they can live a quiet stress-free life.

6. Be VERY CAUTIOUS with test results if you test for FIP. The test is not reliable. It only identifies a "titer" level related to coronavirus exposure. Coronavirus is the source of FIP, but many cats successfuly survive coronavirus infections without developing the fatal symptoms of FIP. This is not to say that you should never test for FIP, but don't rely on the results.

7. If you are a breeder, educate yourself about FIP.  Use the resources of the internet and cat lists for advice. Learn how to access the fanciers list (to subscribe: send a blank e-mail with "subscribe fanciers" in the body to majordomo@fanciers.com. Warning: high volume list!) archives for mail about FIP. Identify those list subscribers who give good advice, supported by Dr. Susan Little and Dr. Kent Cooper. The University of California at Davis is conducting research that will probably lead to useful vaccines and ways to control this disease. There are other universities also conducting research that is up to date. The research findings are moving very rapidly; advice based on research of even 5 years ago is obsolete. Look at the publish dates on everything you read about FIP.

8. If you DO lose a kitten from an illness that appears to be FIP, please have a post-mortem exam done to be sure. Unfortunately, too many veterinarians jump to the conclusion that a cat had FIP when in fact it had an abscess or a blood clot or some other disease that caused its death. A good and complete necropsy will rule out these other causes and FIP can be identified as the cause if it really was responsible.

Is my cat at risk for developing FIP?

Cats with the highest risk of developing FIP are those:

Raised or living in multi-cat households or catteries
Originating from a shelter
Kept outdoors
Infected with the feline leukemia virus (nearly 50 percent of cats with FIP are also infected with the feline leukemia virus)
Stressed from malnutrition, overcrowding or other infections

FIP occurs most frequently in young and old cats. The disease is most common in cats between the ages of six months and two years. Incidence of FIP increases again in older cats. FIP is also more prevalent in purebreds. It is thought that cats that develop the disease late in life may have been exposed to FIP as kittens and have been harboring the FIP virus for years.

How does the FIP virus spread among cats?

The FIP virus may be shed in the saliva, urine and feces of infected cats. The natural route of infection is through the mouth or nose. Thus, FIP occurs most often among cats that are housed together in multi-cat households, shelters or catteries. The FIP virus is generally unstable outside of the host cat, but has survived on dry surfaces for up to seven weeks in laboratory studies. FIP virus can be inactivated by most household detergents or disinfectants.

How do I know if my cat has FIP?

In the most dramatic form of FIP, called wet FIP, the cat’s abdomen swells with fluid as a result of widespread injury to the circulatory system. Fluid may also accumulate in the chest cavity, causing breathing difficulty. Other signs include intermittent fever, loss of appetite, weight loss and depression. (Used with permission from the Cornell Feline Health Center)

Signs of FIP:

General illness, fever, weight loss, anorexia, anemia
Swollen abdomen
Central nervous system disorders
Kidney disorders
Liver disorders
Eye disease
Death (once signs appear)

Unfortunately, no specific diagnostic test is available to identify FIP. Tissue biopsy (microscopic examination of tissue) is the only way to confirm that FIP is present. Presence of coronavirus (CV) antibodies in the blood (sometimes called a "FIP test") is generally inconclusive. A CV titer may be useful to determine if animals in a multi-cat household, shelter, or cattery have been exposed to a coronavirus, but even very high antibody levels do not accurately predict if a cat will succumb to FIP.

Feline Infectious Peritonitis (FIP)

Feline infectious peritonitis (FIP) is a contagious viral disease of cats. Young and old cats appear to be most susceptible, however cats of all ages can become infected. The
disease is worldwide and affects exotic cats (lions, cougars, bobcats, lynx, jaguars, and cheetahs) as well as domestic cats.

Cats infected with FIP transmit the virus through body fluids (respiratory and oral
secretions) and feces. Infection occurs by inhalation or ingestion of the virus. Close contact between cats is very important for transmission of the disease. The disease can also be passed from the queen to her unborn kittens or to young kittens through the milk.

Cats living in crowded, unsanitary conditions are at risk of FIP infection. Animals
infected with feline leukemia virus (FeLV) or feline immunodeficiency virus (FIV) are more susceptible to FIP than non-FeLV and non-FIV infected cats.

Clinical signs of the disease are variable and non-specific. Often, a fluctuating fever is an early symptom of FIP. Other noticeable symptoms include weight loss, fatigue, and
lack of appetite. Later, swollen abdomen, jaundice, kidney and liver disorders, and eye problems occur.

As the disease progresses, cats typically develop an "effusive" or "dry" form of FIP. The effusive form is characterized by an accumulation of thick yellow fluid in the body cavities. In the dry form, nodular masses are seen on the surface and inside certain organs: the spleen, liver, kidneys, eyes, brain, and lungs.

A thorough physical exam by a veterinarian is recommended for any cat showing symptoms of FIP. X-rays and blood tests are necessary for diagnosing the disease.

Good animal husbandry practices are important for the prevention of FIP in multicat households.

Journal of General Virology (1998), 79, 1387:1391

Characterization of determinants involved in the feline infectious
peritonitis virus receptor function of feline aminopeptidase N

Annette Hegyi, Andreas F. Kolb

Institute of Virology and Immunology, University of Würzburg, Versbacherstr. 7, 97078 Würzburg, Germany

Author for correspondence: Andreas Kolb

Feline aminopeptidase N (fAPN) is a major cell surface receptor for feline infectious peritonitis virus (FIPV), transmissible gastroenteritis virus (TGEV), human coronavirus 229E (HCV 229E) and canine coronavirus (CCV). By using chimeric molecules assembled from porcine, human and feline APN we have analysed the determinants involved in the coronavirus receptor function of fAPN. Our results show that amino acids 670:840 of fAPN are critically involved in its FIPV and TGEV receptor function whereas amino acids 135:297 are essential for the HCV 229E receptor function. We also demonstrate that a chimeric molecule assembled from human and porcine APN is able to act as a receptor for FIPV. This is surprising as neither human nor porcine APN by themselves mediate FIPV infection. These results suggest that different determinants in the APN protein are involved in mediating the coronavirus receptor function.