Key takeaways:
Feline infectious peritonitis (FIP) is a more severe type of feline coronavirus that only affects cats. But not all cats will develop FIP after a coronavirus infection.
There are two forms of FIP: wet and dry. They cause different symptoms. Cats can develop one form or a combination of both.
Most treatments for FIP consist of supportive therapy. But there’s a potential antiviral treatment that’s effective against FIP.
Cats are creatures of habit, so when they start acting differently, owners begin to worry. If it’s a minor issue, keeping an eye on them and consulting your veterinarian is usually enough. But sometimes, there could be something wrong if their behavior doesn’t improve.
Several conditions can make cats feel lousy. But many cat parents are unaware of one called feline infectious peritonitis. It's a rare disease, but it does happen. Learn what causes feline infectious peritonitis, its symptoms, and possible treatments.
What is feline infectious peritonitis (FIP)?
Feline infectious peritonitis (FIP) is a disease caused by feline coronavirus (FCoV), a different coronavirus than the one that causes COVID-19 in humans.
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Many cats are exposed to feline coronavirus, especially when they live around other cats. Feline coronaviruses often affect a cat’s gastrointestinal tract. In normal cases, it may cause mild diarrhea.
But in some cases, feline coronavirus can turn into FIP. This happens when the coronavirus mutates or changes while a cat is infected.
Kittens and cats under 2 years old are most at risk of developing FIP symptoms because their immune system isn’t as strong. It’s possible for older cats to develop FIP as well, especially if their immune system is weakened.
Signs and symptoms of FIP in cats
The first signs of FIP can range from fatigue to changes in appetite to fever. It can take several weeks or months before additional symptoms develop.
There are two forms of FIP: wet and dry. The symptoms a cat has can depend on which form they have.
Wet feline infectious peritonitis
Wet FIP causes fluid buildup in the chest and abdomen. This can give cats a pot-bellied appearance. This form of FIP progresses quicker than the dry form, and it’s usually easier for veterinarians to diagnose.
Other wet FIP symptoms include:
Fever
Weight loss
Lack of appetite
Difficulty breathing
Lack of energy
Dry feline infectious peritonitis
Dry FIP causes the growth of inflammatory tissue in organs, such as the:
Liver
Kidneys
Eyes
Brain
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The inflammation is the body’s attempt to remove the infection in these organs.
Dry FIP doesn’t cause much fluid buildup like wet FIP. It’s typically harder to diagnose, especially since it progresses slower.
Other dry FIP symptoms include:
Fever
Weight loss
Bleeding or pus in the eyes
Blindness or vision loss
Seizures
Poor muscle coordination
Cats can develop a combination of both wet and dry FIP. They may start with one form or switch between them as the disease progresses. The type of FIP a cat develops depends on their immune system, as well as other factors such as stress or living in crowded conditions.
Is feline infectious peritonitis contagious?
FIP starts out as feline coronavirus (FCoV), which is very contagious among cats. But most house cats are rarely exposed to FCoV because it often spreads in crowded conditions like rescue shelters or breeding facilities.
How do veterinarians diagnose FIP in cats?
There is currently no test that can diagnose FIP in cats. A veterinarian may make an FIP diagnosis if your cat tests positive for FCoV and has FIP symptoms. Or a vet may conclude it’s FIP if there are enough lingering symptoms even with a negative coronavirus test result.
Your vet may also look for evidence of viral elements in tissue samples. However, these tests aren’t completely accurate and can lead to false positive or false negative results.
How is feline infectious peritonitis treated?
Treating FIP is difficult. The earlier the diagnosis, the better. Veterinarians often recommend plenty of fluids and good nutrition. For wet FIP, removing fluid buildup helps cats breathe easier.
In some cases, veterinarians try to ease FIP symptoms with medications that suppress the immune system and improve blood circulation. Your vet may prescribe polyprenyl immunostimulant if your cat has the dry form of FIP. This is a biologic medication used to treat feline herpesvirus that is supposed to boost weakened immune systems. It has been studied for FIP, but some question its ability to prolong lifespans and ease symptoms.
Other FIP treatment options
Though FIP is difficult to treat, some new medications show promise. One is GS-441524, an antiviral medication. It is the main component in remdesivir (Veklury), a medication that’s only FDA approved to treat COVID-19 in humans.
Veterinarians in Australia have treated hundreds of cats with differing forms of FIP with both injected remdesivir and oral tablets of GS-441524. A compounded version of GS-441524 is now more widely available for cats in the U.S.
Your veterinarian can let you know about all of your cat’s FIP treatment options.
If your cat has been diagnosed with FIP, these organizations can also provide helpful resources:
How can you prevent your cat from getting feline infectious peritonitis (FIP)?
The best way to prevent FIP is to protect your cat from feline coronavirus. Typically, FCoV spreads in environments where many cats gather, like rescue shelters or breeding facilities. The cat breathes in or eats infected cat poop or comes in contact with a contaminated litter box. Daily litter box cleaning and weekly litter box disinfecting can lower the risk.
Frequently asked questions
While there’s currently no cure for FIP, an infected cat can live comfortably for many years if the symptoms are managed. Sadly, a cat that becomes severely ill, has ongoing fevers, and continues to lose weight may not live long (a few days to a few weeks).
You don’t automatically need to euthanize a cat with FIP. This decision will largely depend on your cat’s symptoms and their quality of life. Once FIP symptoms become difficult to manage, your cat’s quality of life will decline quickly. Euthanizing your cat may be one of the hardest decisions you’ll ever make. But it can be the kindest thing you do for your pet.
FIP is caused by feline coronavirus. It develops when the coronavirus mutates while a cat is infected.
FIP spreads where you find many cats living in close quarters like rescues, shelters, or breeding facilities. A cat can become infected when they eat or inhale viral particles from contaminated poop.
While there’s currently no cure for FIP, an infected cat can live comfortably for many years if the symptoms are managed. Sadly, a cat that becomes severely ill, has ongoing fevers, and continues to lose weight may not live long (a few days to a few weeks).
You don’t automatically need to euthanize a cat with FIP. This decision will largely depend on your cat’s symptoms and their quality of life. Once FIP symptoms become difficult to manage, your cat’s quality of life will decline quickly. Euthanizing your cat may be one of the hardest decisions you’ll ever make. But it can be the kindest thing you do for your pet.
FIP is caused by feline coronavirus. It develops when the coronavirus mutates while a cat is infected.
FIP spreads where you find many cats living in close quarters like rescues, shelters, or breeding facilities. A cat can become infected when they eat or inhale viral particles from contaminated poop.
The bottom line
Feline infectious peritonitis (FIP) is rare, but it’s possible for it to develop after a cat experiences a feline coronavirus infection.
Depending on a cat’s immune system, FIP can be wet or dry or a combination of both. If your cat is showing signs of FIP, consult your veterinarian as soon as possible.
Supportive therapy is normally used to treat FIP. An antiviral medication called GS-441524 shows promise for treating FIP. However, the medication is still difficult to get in the U.S.
If your cat is diagnosed with FIP, ask your vet to walk you through all of the treatment options. Hopefully, with ongoing research, there will be additional cost-effective FIP treatment options available in the near future.
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References
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Cornell Feline Health Center. (n.d.). FIP treatment GS-441524 - now available in the U.S. Cornell University College of Veterinary Medicine.
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