Coronavirus and FIP.

Dr. Marie replied:

Thanks for asking this question. I often see people confused about coronavirus issues in cats, so hopefully I can help explain the situation for you.

Coronavirus is really really common amongst cats. Anywhere from 20% to 90% of the cat population will be positive coronavirus if tested. (The higher numbers are for catteries and shelters).

If a cat gets coronavirus they may have a few days of diarrhea. After that, the cat gets over the virus, but they will still have antibodies in their system for quite some time. What that means is that several years later, if you tested for coronavirus, you can still see that the cat tests positive.

So, if coronavirus just causes mild diarrhea, why do we get so concerned about it? The problem is that a small percentage of cats (some sources say 2-5% and others say as high as 10%) have a genetic problem where their body can mutate coronavirus and turn it into a nasty thing called FIP (Feline Infectious Peritonitis). There is no cure for FIP. It can cause fluid in the abdomen or lesions called granulomae to form in organs. FIP is fatal.

Years ago, I used to run the test that your cat had which tells us whether the coronavirus titre is negative, low positive or high positive. The thought was that cats with a high positive test would be much more likely to go on to have FIP. Newer research, however, shows that this is not true.

Unfortunately it can be hard to determine if a cat really does have FIP. If there is abdominal fluid we can test for coronavirus in the fluid. Often what we do is combine several things to determine if there is a risk. Cats with FIP usually have weight loss, a fever that comes and goes and their albumin/globulin ratio in their bloodwork is usually lower than 0.3. There are other possible symptoms as well.

So should you worry about the fact that Romeo is coronavirus positive? In my opinion, no. If we isolated every cat that has ever been exposed to coronavirus, there would be a lot of unhappy cooped up cats in the world. The real problem that causes FIP is the genetic issue that 2-10% of cats have that can mutate the coronavirus. Really the coronavirus is not the culprit.

Hopefully that answers your question. It can be a confusing topic so please feel free to respond if you have more concerns.

Dr. Marie.

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