FirstVet
feline infectious peritonitis

Feline Infectious Peritonitis (FIP)

Feline Infectious Peritonitis (FIP) is an extremely serious viral disease that affects cats, and only cats, worldwide. It is considered one of the least understood of all cat diseases. You may have heard about FIP in the past year as it is caused by a coronavirus, specifically, a feline coronavirus known as FCoV, however, it’s important to understand that it isn’t the same virus as SARS-CoV-2 (COVID-19) which affects people. There are many different types of feline coronaviruses, including FIP, but not all cause symptoms or problems. Keep reading to learn more about FIP and how you can protect your cat.

Are you concerned about your pet?

Book a video consultation with an experienced veterinarian within minutes.

What is FIP and how is it spread?

Cats are often exposed and acquire FCoV without causing any significant symptoms and most cats will not develop FIP. FCoV can remain inactive in a cat for months, even years before they develop signs of FIP. Several factors cause the virus to change, which leads to the serious FIP infection we see in some cats.

FCoV is spread through the digestive tract and cats get the virus when exposed to stool or body fluids of cats infected with the FCoV. The virus can involve the liver, kidneys, lungs, brain, spinal cord, and eyes. It’s a fast-acting, serious, often fatal infection with no known cure at this time.

Cats often carry FCoV without symptoms and shed the virus in their stool. Other cats may be infected, develop strong immunity, and be protected from future infections. Yet other cats may be infected, manage to eliminate the virus yet get recurrent infections. FIP is usually seen in young cats under 2 years of age but can occur in cats of any age.

Symptoms of Feline Infectious Peritonitis

Initial symptoms of FIP are often nonspecific such as decreased appetite, decreased energy, weight loss, and fever which can look like other illnesses. Symptoms worsen over days, weeks, sometimes even months. Kittens affected with FIP are often smaller than their littermates, weak and thin with a rough, dull haircoat.

There are 2 forms of FIP that veterinarians describe as “wet” and “dry”.

The “wet” form causes fluid to build up in the abdomen (or stomach area) or the lungs/chest area. Cats develop increased fluid in the abdomen area which often mimics a pot-bellied appearance. Difficulty breathing with increased respiratory effort and panting, or open-mouth breathing happens when there is fluid in the chest area. The “wet” form is seen more typically in young kittens.

The “dry” form shows up gradually as loss of appetite, decreased activity or hiding/sleeping, slow weight loss, fever, and neurologic signs including sudden blindness or seizures and is found more often in adult cats. Cats can also have a combination of both forms.

How is FIP diagnosed?

FIP can be challenging to diagnose because blood tests cannot determine whether the FCoV is the one causing severe, often fatal, symptoms or the form that causes none of these symptoms. A negative FIP test result does not confirm that a cat is negative, especially when they’re showing signs of FIP. Veterinarians rely on history, such as kittens coming from animal shelters or catteries, clinical signs listed above, and physical exam findings.

Other tests which help support a diagnosis of FIP include blood tests, x-rays, ultrasound, fluid analysis, and in some cases biopsy of various organs. As FIP is difficult to diagnose, your vet may recommend a biopsy be taken to distinguish FIP from a treatable disease.

FIP can look like many other, unrelated diseases in cats. Consider referral to a Veterinary Internal Medicine Specialist (known as Diplomates of the American or European College of Veterinary Internal Medicine) who are experts in the current diagnosis options and new treatment possibilities for FIP.

Can cats with FIP be treated?

Unfortunately, there is no cure for FIP, and cats showing symptoms listed above often get sicker over days, weeks, sometimes even months and die from the virus.

Treatment for cats diagnosed with FIP focuses on supportive care and keeping them as comfortable as possible. Offer FIP-positive cats their favorite food or treats to encourage them to eat. Try to minimize stressful situations, keep them indoors, warm and comfortable, with their litter box, fresh water, and food nearby.

Veterinarians may prescribe medications but understand that these medications often only help temporarily. FIP is almost always a fatal diagnosis with few very cats living several months under supportive care.

Owners of FIP-positive cats often make the difficult decision to euthanize or put their beloved kitten or cat to sleep to prevent prolonging their suffering and pain.

Can FIP be prevented?

Because there is still so much we don’t understand about FIP and because coronavirus is easily transmitted to many cats worldwide, it’s unlikely that we can prevent FIP. A vaccine is available for FIP but has not been shown to prevent the disease, therefore it is not currently recommended.

Stress may be a factor, as cats diagnosed with FIP often come from multi-cat households (more than 5 cats), animal shelters, or breeding catteries.

Keep FIP-positive cats separated from other cats and practice basic hygiene such as hand washing, especially after scooping/cleaning the infected cat’s litter box. Vets caution owners to wait about a month after a FIP-positive cat dies before bringing a new cat into the house, which decreases the chance of exposure to the FCoV.

If a FIP-positive cat from a multi-cat household dies, vets recommend waiting a minimum of three months to see if any other cats in the household develop signs of FIP. These cats have been exposed to FCoV and can be carriers, possibly infecting any new cats that come into the home.

Cleaning with dilute bleach (1 part bleach to 32 parts water) will be enough to kill FCoV. Always have 1 more litter box than the number of cats in the home. For example, if you have 3 cats you should have a minimum of 4 litter boxes available.

Read about cats and litter boxes by clicking on the following link: The Cat-Lover’s Guide to Litter Box Bliss

Enriching your cat’s environment has been shown to decrease their stress. This includes catios, indoor cat trees, and perches, window perches, using a pheromone such as Feliway, water fountain, cat toys, food puzzles, and more.

Learn more about enriching your cat’s environment by clicking on the following link: Toys, Games, and Puzzles! How to Entertain Your Indoor Cat

Evidence has shown that genetics can make some cats more susceptible to FIP. Certain cat breeds may be more likely to develop FIP including Abyssinian, Bengal, Birman, Himalayan, Ragdoll, and Devon Rex.

When to Contact a Veterinarian

If your cat shows any of the signs listed above, you should contact your pDVM (primary veterinarian) right away.

If your cat is FIP-positive and stops eating, begins panting or open-mouth breathing, or shows signs of breathing difficulty contact the nearest vet for immediate care.

Read more:

Feline Leukemia Virus

Feline Immunodeficiency Virus

Protecting Your Cat from Feline Distemper

Need to speak with a veterinarian regarding FIP or another condition?

Click here to schedule a video consult to speak to one of our vets. You can also download the FirstVet app from the Apple App Store and Google Play Stores.

Are you concerned about your pet?

Book a video consultation with an experienced veterinarian within minutes.

Book Video Consultation
  • Low-cost video vet consultations, 24 hours a day
  • Experienced, licensed vets
  • Over 500,000 satisfied pet owners

More articles about Cat