Feline Infectious Peritonitis (FIP): Understanding, Prevention, and Treatment

Feline Infectious Peritonitis (FIP) is one of the most devastating diseases in the cat world. Once considered 100% fatal, FIP has now become a treatable and curable condition thanks to groundbreaking medical advancements.

As a Ragdoll breeder, I believe it is crucial to educate cat owners about FIP, how it develops, why purebred cats are more susceptible, and how early diagnosis and proper treatment can save lives.

What Is Feline Infectious Peritonitis (FIP) and Where Does It Come From?

FIP is caused by a mutation of the feline coronavirus (FCoV), a virus that is common in multi-cat environments such as catteries, shelters, and rescues.

• Most cats will be exposed to feline coronavirus at some point, but in most cases, it causes only mild symptoms or no symptoms at all.

• However, in a small percentage of cats, the virus mutates into FIP, leading to a severe immune response and life-threatening illness.

• Once the virus mutates, it spreads throughout the body, attacking organs and causing inflammation and fluid buildup.

Types of FIP

FIP presents in several forms, each affecting different parts of the body.

• Wet (Effusive) FIP – Characterized by fluid buildup in the abdomen or chest, leading to difficulty breathing and a swollen belly.

• Dry (Non-Effusive) FIP – Involves the development of granulomas (inflammatory lesions) in organs such as the brain, kidneys, or liver, often causing neurological symptoms or organ failure.

• Neuro FIP – Affects the brain and spinal cord, leading to neurological symptoms such as uncoordinated movements (ataxia), tremors, seizures, and paralysis.

• Ocular FIP – Causes eye inflammation, leading to cloudy eyes, vision loss, and changes in eye color or pupil size.

Each type of FIP is progressive and can be fatal without treatment, making early detection and prompt medical care critical.

Why Does FIP Happen?

While feline coronavirus exposure is common, FIP itself cannot be entirely prevented because it occurs when the virus mutates inside the cat’s body. However, certain factors increase the risk of this mutation occurring.

• Stress – The most common trigger. Stress from rehoming, spaying/neutering, illness, travel, or environmental changes weakens the immune system, making it easier for the virus to mutate.

• Genetics – Certain bloodlines are genetically more susceptible to FIP, which is why purebred cats, including Ragdolls, are at a higher risk. Responsible breeders work to reduce this risk through selective breeding.

• Age – FIP is most common in kittens under two years old, but it can affect cats of any age.

• Weakened Immune System – Cats with underlying health issues, poor nutrition, or other illnesses are more vulnerable to FIP.

Recognizing the Early Signs of FIP

Because early treatment significantly increases survival rates, it’s important to recognize the first signs of FIP and act quickly.

• Loss of appetite – A kitten that suddenly refuses food should be closely monitored.

• Weight loss – Even a gradual loss of weight can be an early warning sign.

• Lethargy – A normally playful kitten that becomes withdrawn and sleepy.

• Persistent fever – A fever that does not respond to antibiotics (usually over 103°F).

• Swollen belly or breathing difficulties – A sign of fluid buildup in wet (effusive) FIP.

• Neurological symptoms – Uncoordinated walking, tremors, seizures, or paralysis (neuro FIP).

• Eye inflammation and vision changes – Cloudy eyes, color changes, or pupil abnormalities (ocular FIP).

If your cat is showing one or more of these symptoms, contact your veterinarian immediately.

FIP Is No Longer a Death Sentence

For decades, FIP was considered incurable, and many veterinarians recommended euthanasia upon diagnosis. However, thanks to GS-441524, an antiviral treatment, FIP is now curable, and remission rates are high when treatment is started early.

Treatment Success and Remission

GS-441524 is the active compound in Remdesivir (an antiviral drug used for humans) and has been shown to effectively cure FIP in cats.

How FIP Treatment Works:

• Daily injections or oral medication for 84 days

• Regular monitoring for weight gain, appetite improvement, and energy levels

• 12-week post-treatment observation period to confirm full remission

Many cats that complete the full treatment course go on to live normal, healthy lives.

Why Some Vets Still Recommend Euthanasia

Despite the success of GS-441524, some veterinarians are still unaware of this treatment.If your vet recommends euthanasia, be your cat’s advocate and educate them about the new treatment options.

What to Do If Your Cat Is Diagnosed with FIP:

• Notify your breeder immediately if your kitten is diagnosed with FIP. Responsible breeders may provide guidance or support.

• Inform your vet that GS-441524 is available through Stokes Pharmacy, which provides legally compounded versions of the medication in the U.S.

• Join online FIP support groups for treatment resources, guidance, and success stories. Some examples include FIP Global and FIP Warriors 5.0.

With the right treatment and early intervention, FIP no longer has to be a fatal disease.

Preventing FIP: Can It Be Avoided?

While FIP cannot be completely prevented, certain best practices can reduce the risk of a coronavirus mutation.

• Minimize stress – Keep transitions smooth, introduce new environments gradually, and provide a stable routine.

• Choose a responsible breeder – Ethical breeders work to reduce FIP risk through selective breeding and careful health monitoring.

• Strengthen your cat’s immune system – Provide a high-quality diet, clean environment, and regular vet checkups.

• Reduce exposure to crowded environments – Shelters, rescues, and catteries have a higher risk of coronavirus transmission.

By following these precautions, the chances of FCoV mutating into FIP can be significantly reduced.

Hope for FIP Cats

FIP is no longer the hopeless diagnosis it once was. Thanks to scientific advancements, many cats are now living long, healthy lives after FIP treatment.

• Early detection and quick action can dramatically improve survival rates.

• New treatments are continually being developed, offering even more hope for FIP-positive cats.

• Educating pet owners and veterinarians about available treatment options is key to saving more lives.

As a Ragdoll cat breeder in NJ and cat lover, I encourage every pet owner to stay informed and advocate for their cats. If your kitten is diagnosed with FIP, do not lose hope—treatment is available, and remission is possible.