Feline infectious peritonitis (FIP) can be difficult to explain. As a veterinary community, there is a lot we know about the disease, however, there is still a great deal that we don’t yet understand. Here is what we do know.

How do cats get FIP?

Feline infectious peritonitis develops from a mutated coronavirus in cats (FCoV), which is different than the coronavirus COVID-19 affecting humans.

Many cats - upwards of 40% of the cat population - have been infected with feline coronavirus. Usually, coronavirus causes mild gastrointestinal disease (if any clinical signs) and the cat recovers uneventfully.

In cats that have a genetic predisposition, have a high level of stress, live in overcrowded or multi-cat households, or are immunocompromised (such as those infected with FIV or FeLV, Feline Leukemia Virus), this virus can mutate into an incredibly virulent form resulting in the disease we call FIP.

There is no single factor that guarantees a cat will develop feline infectious peritonitis, and cats with any combination of the above-mentioned characteristics may never develop FIP. As you can see, the picture is as clear as mud.

Which cats are at risk?

Feline infectious peritonitis is a disease that we generally see in young purebred cats (less than 3 years of age) that live in multiple cat households (such as catteries, where large numbers of cats are housed).

Signs of FIP in cats

So, what exactly does feline infectious peritonitis look like in a cat? The clinical signs are vague and nonspecific.

Many cats will have lethargy, weight loss, vomiting, diarrhea, fever, pale mucous membranes, a bloated abdomen and/or anorexia.

Some cats present with neurologic signs (funny eye movement, seizures and walking unsteadily, to name a few), or inflammation within their eyes.

There is no indication that a cat with FIP can transmit the disease to another cat.

How is it diagnosed?

Not easily. It is a VERY difficult disease to diagnose, because there is no single test that is conclusive.

Diagnosis is made based on the cat’s history, clinical signs, response to therapy, and a combination of various laboratory tests (bloodwork, ultrasound, radiographs, cytology of body fluids and histopathology of tissue samples). 

How is FIP treated?

FIP is a progressive, fatal disease that cannot be treated or cured. We can symptomatically treat it for a period of time to improve a cat’s quality of life, but the disease will inevitably take the cat's life.

There is a vaccine for FIP, but its effectiveness and use is controversial within the veterinary community. If you have further questions about the vaccine, please contact your veterinarian.

Mar 5, 2020
Pet Health

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