Feline Infectious Peritonitis, Interpretation of a Positive
My cat has tested "positive" for FIP on a blood test, but seems healthy. Is it actually sick?
The early signs of FIP disease can be quite vague and may not be obvious. If your cat appears to be in good health and your veterinarian found no abnormalities on a physical examination, then the "positive" test means only that your cat has been exposed to a strain of Feline Coronavirus, the virus that can cause FIP. The laboratory test has detected antibodies that your cat has produced against the virus. It does not mean that your cat has FIP unless your cat has clinical signs of disease or there are other abnormal laboratory tests.
Is the virus still present in my cat?
Normally the presence of antibodies means that a viral infection has been neutralized, but with the Feline Coronaviruses (FCoV), the virus may persist even in the presence of antibodies. The test does not tell us if virus is still present in your cat. Some advanced tests that detect virus particles are available in specialized laboratories but the results of these tests (called PCR Tests) may be confusing and their interpretation is somewhat controversial.
Will my cat develop FIP disease?
"Many cats that test "positive" but are otherwise healthy live normal lives."
It is impossible to predict which cats will develop FIP. Many, if not most, cats that test "positive" but are otherwise healthy live normal lives.
When might FIP disease occur?
Even if FIP were to develop in your cat, it could be months or even years before clinical signs and symptoms occurred. For further details on this disease, see our handout "Feline Infectious Peritonitis".
What can be done to prevent FIP?
There is a vaccine for FIP but there is no evidence that this would help alter the outcome in a cat that is already positive on antibody testing. It is not advisable to vaccinate a positive cat. The outcome depends on complex factors including genetics, the specific strain of Feline Coronavirus (most strains are relatively harmless), and so on.
What clinical signs does a cat with FIP develop?
The first signs of FIP may be very vague: listlessness, lethargy, decreased or absent appetite, and variable fever. After a period of several days to a few weeks other signs will develop. The most typical form of FIP is called "wet" FIP, which refers to the accumulation of fluid that occurs in body cavities; fluid may accumulate in the abdomen giving a bloated appearance, or in the chest cavity resulting in difficulty in breathing. Some cats develop the "dry" form of FIP, which is characterized by inflammation within a variety of organs such as liver, intestine, eyes, and brain, with little to no fluid accumulation in body cavities.
What else should I do?
Make sure that your cat receives regular veterinary check-ups. Since nutrition is extremely important for maintaining a healthy immune system, make sure that you feed your cat a high quality diet such as a premium brand of cat food. Remember that infections with Feline Coronaviruses are common (up to 30% of all cats) but FIP disease is uncommon (less than 1% of cats admitted to veterinary hospitals). Therefore, it is quite likely that your cat will not develop FIP disease.
Should I keep my cat away from other cats?
It is not certain that your cat is still carrying virus and therefore it may not be infectious to other cats. Even if your cat is still infectious, the strain of virus it is shedding may be a strain that is not normally associated with causing FIP.
"Because kittens and young cats up to about six months may be more susceptible, it would be advisable to prevent contact with that age group."
Therefore, you should not be unduly concerned about occasional contact with other healthy adult cats. Because kittens and young cats up to about six months may be more susceptible, it would be advisable to prevent contact with that age group. Your veterinarian will discuss the specific recommendations for your cat based on medical history, lifestyle and risk assessment.
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