FIP Cat: The Complete Guide to Feline Infectious Peritonitis

FIP (Feline Infectious Peritonitis) is one of the most misunderstood, yet now more treatable, viral diseases in cats. Once considered a death sentence, the discovery of antivirals like GS-441524 has transformed outcomes for many cats worldwide. If you’ve recently heard a diagnosis of FIP or are looking for trustworthy prevention and treatment information, this guide will walk you through everything you need to know.

What is FIP in Cats?

Feline Infectious Peritonitis (FIP) is a severe, often fatal viral disease caused by a mutation of the feline coronavirus (FCoV). While most feline coronaviruses are harmless and reside in the intestines, in a small percentage of cats, the virus mutates and causes FIP.

FIP can affect any cat but is more common in:

• Young cats under two years old

• Cats in shelters, catteries, or multi-cat households

• Purebred cats, especially Bengals, Ragdolls, and Abyssinians
  

There are two primary forms:

• Wet (Effusive) FIP: Characterized by fluid buildup in the abdomen or chest.

• Dry (Non-Effusive) FIP: Affects organs without fluid buildup and is harder to diagnose.
  

Causes of FIP: The Feline Coronavirus Connection

Most cats become infected with feline coronavirus (FCoV) at some point in their life. It is highly contagious and spreads through:

• Fecal-oral contact

• Shared litter boxes

• Grooming
  

How Does FCoV Turn Into FIP?

In rare cases (about 5–10%), the virus mutates inside the cat’s body. This mutated virus attacks white blood cells and spreads throughout the body, triggering an overwhelming immune response. This is what leads to FIP.

Key Risk Factors:

• Age: Kittens are more susceptible due to immature immune systems.

• Stress: Crowded living conditions or sudden changes increase risk.

• Genetics: Some cats may be genetically predisposed.
  

FIP Symptoms in Cats

Symptoms vary depending on the form of FIP (wet or dry), but early signs are usually vague.

General Symptoms:

• Loss of appetite

• Weight loss

• Fever that doesn’t respond to antibiotics

• Lethargy

• Rough or dull coat
  

Wet (Effusive) FIP:

• Swollen abdomen (fluid in the belly)

• Difficulty breathing (fluid in the chest)

• Yellowish fluid drained from abdomen
  

Dry (Non-Effusive) FIP:

• Neurological signs (wobbliness, seizures)

• Eye inflammation (uveitis)

• Jaundice

• Enlarged lymph nodes
  

How is FIP Diagnosed?

Diagnosing FIP is challenging because there is no single test that definitively confirms the disease. Most vets use a combination of clinical signs, lab tests, and exclusion.

Diagnostic Tools:

• Bloodwork: High total protein, low albumin-to-globulin ratio, anemia

• Ultrasound or X-rays: To detect fluid accumulation

• Rivalta Test: A test for effusive FIP using abdominal fluid

• PCR Testing: To detect FCoV RNA in fluids or tissues

• Histopathology: The only definitive diagnosis; requires tissue biopsy
  

Important: A positive coronavirus test alone does not mean a cat has FIP.

Treatment Options:

Antivirals, GS-441524, Supportive Care

1. GS-441524 – The Breakthrough Antiviral

This is the gold standard treatment for FIP today. It’s a nucleoside analog antiviral that stops virus replication.

• Form: Injection or oral tablets

• Duration: Typically 84 days (12 weeks)

• Success Rate: Over 80% survival if treated early

• Where to get it: Available through trusted suppliers like MolnuFIP.com
  

2. Molnupiravir (MolnuFIP): A Powerful Alternative Antiviral for FIP Cats

Molnupiravir is an oral antiviral medication that has emerged as a highly effective treatment option for Feline Infectious Peritonitis (FIP), especially in cases where cats do not respond fully to GS-441524 or in regions where GS is hard to access.

MolnuFIP is a specialized formulation of molnupiravir developed specifically for feline use, combining pharmaceutical-grade purity, feline-safe dosages, and a treatment protocol supported by real-world clinical success.

3. Supportive Care

Supportive therapies help stabilize cats during treatment:

• Fluids and electrolytes

• Appetite stimulants

• Anti-nausea medication

• Liver support (SAMe, silymarin)

• Antibiotics (if secondary infections present)

• Anti-inflammatory steroids (used carefully)
  

FIP Prognosis and Life Expectancy

Without treatment, FIP is almost always fatal within days to weeks. However, with GS-441524 or molnupiravir, the prognosis has dramatically improved.

Prognosis Depends On:

• Early diagnosis and treatment

• FIP type (wet FIP responds better than dry/neurological)

• General health of the cat
  

With Treatment:

• Survival rates: 80–90%

• Long-term outlook: Many treated cats live full, healthy lives
  

Relapses can occur but are often treatable with a second round of antivirals or switching protocols (e.g., from GS to molnupiravir).

Preventing FIP in Cats

While there's no guaranteed way to prevent FIP, you can reduce the risk:

Prevention Tips:

• Maintain hygiene: Clean litter boxes daily

• Limit overcrowding, especially in shelters or catteries

• Isolate sick cats

• Test for FCoV in breeding colonies

• Strengthen immune system: Through a healthy diet and low-stress environment
  

There is currently no effective commercial FIP vaccine recommended by veterinary specialists.

FAQ About FIP in Cats

• Is FIP contagious?

Answer: FIP itself is not contagious. However, feline coronavirus (FCoV) is contagious and can spread between cats.

• Can adult cats get FIP?

Answer: Yes, though it’s more common in kittens. Any cat with FCoV is at risk.

• Is FIP curable?

Answer: While not officially "curable," FIP is highly treatable with antivirals like GS-441524 and molnupiravir.

• Can I prevent my cat from getting FIP?

Answer: Reducing FCoV exposure and keeping your cat’s immune system strong are the best prevention methods.

• How long does FIP treatment last?

Answer: The standard treatment course is 84 days, followed by a 12-week observation period.

Final Thoughts

FIP in cats is no longer a hopeless diagnosis. Thanks to breakthroughs in antiviral therapy, many cats today are surviving and thriving. If your cat is showing symptoms or has been diagnosed with FIP, early treatment with GS-441524 or molnupiravir can save their life.

To learn more or start treatment, visit MolnuFIP.com — a trusted provider of high-quality FIP antivirals and compassionate feline care support.