What is FIP?

FIP is caused by a mutation of the feline coronavirus (FCoV), a virus that is common in cats—especially those in multi-cat environments. Most cats exposed to feline coronavirus will never develop FIP, but in a small percentage of cases, the virus mutates inside the body and leads to FIP.

FIP is not typically contagious in its mutated form; it develops individually within the affected cat.

How is it Transmitted?

• The feline coronavirus (FCoV) is spread through:

  • Feces (litter boxes are the primary source)

  • Contaminated surfaces

  • Close contact between cats

• However, FIP itself is not directly contagious—it occurs when the virus mutates within a cat’s body.

Risk Factors

Cats more likely to develop FIP include:

• Kittens and young cats (under 2 years old)

• Cats in shelters, rescues, or multi-cat homes

• Cats under stress (rehoming, illness, overcrowding)

• Cats with weaker immune systems

Clinical Signs

FIP can appear in two main forms:

Wet (Effusive) Form

• Fluid buildup in the abdomen or chest

• Swollen belly (fluid-filled)

• Difficulty breathing (if fluid is in the chest)

• Lethargy

• Fever that doesn’t respond to antibiotics

Dry (Non-Effusive) Form

• Weight loss

• Persistent fever

• Neurological signs (wobbliness, seizures)

• Eye inflammation or vision changes

• Organ involvement (kidneys, liver)

Both forms can overlap, and symptoms may progress quickly.

Diagnosis

Diagnosing FIP can be challenging, as there is no single definitive test. Veterinarians typically use a combination of:

• Clinical signs and history

• Bloodwork abnormalities

• Imaging (X-rays or ultrasound)

• Fluid analysis (if present)

Diagnosis is often based on ruling out other conditions and identifying patterns consistent with FIP.

Treatment & Management

FIP is now treatable, thanks to antiviral medications (such as GS-441524 and similar drugs):

• Treatment typically lasts around 12 weeks

• Many cats respond very well, especially when treatment starts early

• Regular monitoring is required during treatment

Supportive care may include:

• Fluids

• Nutritional support

• Medications for comfort and symptom management

Early detection and prompt treatment are key to success.

Prevention

While there is no guaranteed way to prevent FIP, you can reduce risk by:

• Maintaining clean litter boxes (frequent scooping and sanitation)

• Reducing overcrowding in multi-cat environments

• Minimizing stress

• Practicing good hygiene when introducing new cats

A vaccine exists but is not widely recommended due to limited effectiveness.

Human Health Concerns

FIP cannot be transmitted to humans or other non-feline species. It is specific to cats.

Living with a Cat Diagnosed with FIP

A diagnosis of FIP is no longer a hopeless situation. Many cats go on to live happy, healthy lives after treatment. With proper veterinary care, monitoring, and a supportive environment, recovery is possible.

FIP can be overwhelming, but there is real hope. If you suspect FIP or have a diagnosed cat, working closely with a knowledgeable veterinarian can make all the difference.