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FIP: Fact & Fiction
( Feline Infectious Peritonitis )

by Leah Montgomery, DVM

If there is a single health issue that most frightens the cat breeder, it is a diagnosis of FIP, Feline Infectious Peritonitis. There is a deep sense of helplessness that we feel when dealing with FIP because there is little we can do to either prevent it or treat it. Indeed, we still don't understand as much as we would like about this disease.

FIP is a disease that results when the corona virus that is often normally present in the majority of cattery cats, mutates into the FIP virus. While there is a test that results in a "titer" to measure "exposure" to the corona virus, there is no test for the FIP virus available.

Signs of FIP:

FIP is always fatal once symptoms appear, and there is little we can do.

While researchers know less about FIP then we wish, there has been significant advances in our understanding of the disease in recent years. Still, there persists some misunderstandings amongst cat breeders about the disease.

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MYTH: the FIP virus and feline corona virus are the same thing.

FACT: The common benign form of feline coronavirus is referred to as FECV (feline enteric coronavirus). When FECV mutates into a disease-causing form, it is then referred to as FIPV (feline infectious peritonitis virus). FIP is the term for clinical disease associated with feline coronavirus infection. The FIP is the resulting disease when the very rare occurrence happens of a corona virus mutating.

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MYTH: My cat caught FIP at a cat show

FACT: The corona virus mutates within an individual cat. The vast majority of cats do not "catch" FIP, but develop it themselves from their own mutant FECV.

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MYTH: I'm afraid my cat with FIP will infect all my other cats.

FACT: Cats who are ill with FIP are unlikely to be a risk to other cats and thus do not need to be isolated.

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MYTH: I bought a cat whose antibody titer was above 1:800, so that means he is infected with FIP
FACT: Antibody titers are meaningless for diagnosis of FIP or prognosis

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MYTH: Cats with FIP always have big swollen tummies

FACT: There is both a wet and a dry form of FIP. In the most dramatic form 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. The dry form of FIP shows no swollen tummy.

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MYTH: If my cat has a swollen tummy, he must have FIP

FACT: There are many other reasons a cat may have fluid in the abdominal cavity so you must check with your vet regarding a diagnosis.

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MYTH: My cat has a swollen tummy and a high corona virus titer so my vet says he must have FIP

FACT: Although a combination of symptoms may suggest a diagnosis of FIP, there is no foolproof way to diagnose FIP in a sick cat. Tissue biopsy (microscopic examination of tissue) is the only way to confirm that FIP is present. A negative antibody titer does not rule out FIP. Neither does a positive antibody titer rule in FIP as a diagnosis

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MYTH: I heard they now have a test for FIP

FACT:There is no test for FIP. Sometimes incorrectly"called" an FIP test, the test is for the presence of the corona virus only. Presence of coronavirus (CV) antibodies in the blood 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 develop FIP.

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MYTH: I heard that FIP is inherited.

FACT: FIP is NOT inherited. There may however a genetic predisposition to the development of FIP. Thus breeders are encouraged to select breeding stock showing resistance to infections of all kinds - especially fungal and viral infections. Cats with strong genetic resistance to infection will have a decreased risk of developing the mutation that leads to FIP.

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MYTH: If I vaccinate all my cats, they won't get FIP

FACT: While a vaccine is available, its effectiveness and safety is questionable

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MYTH: My cat got FIP from a new cat I bought

FACT: Transmission of FIP from cat to cat is considered to be rare.

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MYTH: Only very young kittens get FIP

FACT:The peak ages for losses to FIP are from 6 months to 2 years old (with the highest incidence at 10 months of age). Age-associated immunity to FIP appears to be possible.

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MYTH: My kitten caught FIP from its mother

FACT: Transmission of FIP from a queen to her unborn kittens has not been shown to occur.

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MYTH: If I have a titer done on a cat I and it is negative, then I know it will not get FIP

FACT: there is no way to screen healthy cats for the risk of developing FIP.

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MYTH: If you have a cat who dies of FIP, you should not get a cat for a couple years because of the FIP virus hanging around the house.

FACT: 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.

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References:

Additional Readings:

• Papers in Feline Practice Volume 23, Number 3. May/June 1995

• Addie D.D., Jarett O. Control of Feline Coronavirus Infections in Breeding Catteries by Serotesting, Isolation, and Early Weaning. Feline Practice 23(3), 92-95, 1995.
• Addie D.D., Toth S., Murray G.D., Jarett O. The Risk of Typical and Antibody Ehhanced Feline Infectious Peritonitis Among Cats From Feline Coronavirus Endemic Households. Feline Practice 23(3), 24-26, 1995.
• Fehr D., Holznagel L., Bolla S., Lutz H., Hauser B., Herrewegh A.A.P.M., Horzinek M.C. Evaluation of the Safety and Efficacy of a Modified Live FIPV Vaccine Under Field Conditions. Feline Practice 23(3), 83-88, 1995.
• Gerber J.D. Overview of the Development of a Modified Live Temperature- Sensitive FIP Virus Vaccine. Feline Practice 23(3), 62-66, 1995.
• Herrewegh A.A.P.M., Egberink H.F., Horzinek M.C., Rottier P.J.M., de Groot R.J. Polymerase Chain Reaction (PCR) for the Diagnosis of Naturally Occurring Feline Coronavirus Infections. Feline Practice 23(3), 56-60, 1995.
• Hickman A., Morris J.G., Rogers Q.R., Pedersen N.C. Eliniation of Feline Coronavirus Infection From a Large Experimental Specific Pathogen-Free Cat Breeding Colony by Serologic Testing and Isolation. Feline Practice 23(3), 96-102, 1995.
• Horzinek M.C., Herrewegh A., de Groot R.J. Persepectives on Feline Coronavirus Evolution. Feline Practice 23(3), 34-39, 1995.
• Hoskins J.D., Taylor H.W., Lomax T.L. Independent Evaluation of a Modified Live Feline Infectious Peritonitis Vaccine Under Experimental Conditions (Louisiana Experience). Feline Practice 23(3), 72-73, 1995.
• Hoskins J.D., Henk W.G., Storz J., Kearney M.T. The Potential Use of a Modified Live FIPV Vaccine to Prevent Experimental FECV Infection. Feline Practice 23(3), 89-90, 1995.
• Kass P.H., Dent T. The Epidemiology of Feline Infectious Peritonitis in Catteries. Feline Practice 23(3), 27-32, 1995.
• McArdle F., Tennant B., Bennett M., Kelly D.F., Gaskell C.J., Gaskell R.M. Independent Evaluation of a Modified Live FIPV Vaccine Under Experimental Conditions (University of Liverpool Experience) Feline Practice 23(3), 67-71, 1995.
• Pedersen N.C. An Overview of Feline Enteric Coronavirus and Infectious Peritonitis Virus Infections. Feline Practice 23(3), 7-20, 1995.
• Pedersen N.C. The History and Interpretation of Feline Coronavirus Serology. Feline Practice 23(3), 46-51, 1995.
• Pedersen N.C., Addie D., Wolf A. Recommendations From Working Groups of the International Feline Enteric Coronavirus and Feline Infectious Peritonitis Workshop. Feline Practice 23(3), 108-111, 1995.
• Postorino Reeves N. Vaccination Against Naturally Occurring FIP in a Single Large Cat Shelter. Feline Practice 23(3), 81-82, 1995.
• Richards J.R. Problems in the Interpretation of Feline Coronavirus Serology (Specificity vs. Sensitivity of Test Procedures). Feline Practice 23(3), 52-55, 1995.
• Scott F.W., Corapi W.V., Olsen C.W. Independent Evaluation of a Modified Live FIPV Vaccine Under Experimental Conditions (Cornell Experience). Feline Practice 23(3), 74-76, 1995.
• Scott F.W., Olsen C.W., Corapi W.V. Antibody-Dependent Enhancement of Feline Infectious Peritonitis Virus Infection. Feline Practice 23(3), 77-80, 1995.
• Vennema H., Poland A., Hawkins K.F., Pedersen N.C. A Comparison of the Genomes of FECVs and FIPVs and What They Tell Us About the Relationships Between Feline Coronaviruses and their Evolution. Feline Practice 23(3), 40-44, 1995.
• Weiss R.C. Treatment of Feline Infectious Peritonitis With Immunomodulating Agents and Antiviral Drugs: A Review. Feline Practice 23(3), 103-106, 1995.
• Wolf J. The Impact of Feline Infectious Peritonitis on Catteries. Feline Practice 23(3), 21-23, 1995.