Feline Infectious Peritonitis (FIP) is one of the most misunderstood yet increasingly treatable diseases in cats today. Once considered fatal, advancements in antiviral therapy have given cat owners worldwide new hope.
At BasmiFIP, we’ve helped more than 87,000 cats worldwide recover from FIP using scientifically proven antiviral therapy. This article will help you recognize the early symptoms, understand the types of FIP, and know what to do next.
What Is Feline Infectious Peritonitis (FIP)?
Feline Infectious Peritonitis (FIP) is a viral disease caused by a mutation of the feline coronavirus (FCoV) — not related to human COVID-19.
Importantly, FIP itself is not contagious. The regular form of coronavirus can spread among cats, but once it mutates into FIP, it cannot transmit between animals. This means one FIP-positive cat does not endanger others at home.
👉 Read more: Understanding FIP in Cats and How to Manage It
Common Early Symptoms of FIP in Cats
So, what are the first feline infectious peritonitis symptoms in cats that every pet owner should recognize?
Here are the most common early FIP signs, many of which may seem subtle at first:
General Early Symptoms (All FIP Types)
Persistent fever that does not respond to antibiotics
Loss of appetite or refusal to eat
Weight loss, even with normal feeding
Lethargy or reduced activity levels
Rough or dull coat due to poor grooming habits
Types of FIP
FIP in cats can be divided into two main types — Wet FIP (Effusive) and Dry FIP (Non-effusive).
If left untreated, both types can progress into Neurological FIP or Ocular FIP.
Wet FIP (Effusive Form)
Wet FIP occurs when fluid accumulates in the abdomen, chest cavity, or both.
Cats with this form often appear bloated or pot-bellied, and may struggle to breathe due to pressure on the lungs.
It’s worth noting that the abdomen can feel firm or tense even when filled with fluid. A veterinarian can remove and test this fluid to support diagnosis.
Typical symptoms include:
Swollen or distended belly
Difficulty breathing or panting
Reduced appetite and energy
Occasional coughing or weakness
Dry FIP (Non-effusive Form)
Dry FIP occurs when the infection affects internal organs such as the liver, kidneys, or lungs without visible fluid buildup.
Affected organs may become firm or enlarged, which can sometimes be felt upon gentle palpation.
Typical symptoms include:
Gradual weight loss despite normal or decreased food intake
Persistent fever and general fatigue
Pale gums or yellowing (jaundice) due to liver involvement
Because Dry FIP develops slowly, it’s often diagnosed later than Wet FIP.
Neurological FIP
When FIP affects the central nervous system, it’s referred to as Neurological FIP.
Symptoms vary depending on the severity and affected region but can include:
Tremors or seizures
Loss of balance or unsteady walking (ataxia)
Muscle weakness or partial paralysis
Changes in behavior or alertness
Difficulty jumping or walking in a straight line
Nystagmus (involuntary eye movement) — this symptom is increasingly common in neurological FIP cases
These cats may appear disoriented or fall when attempting to walk.
Ocular FIP
Ocular FIP occurs when the virus targets the eyes.
This form can cause visible changes such as:
Eye inflammation (uveitis)
Cloudiness or color change in the eyes
Reduced or lost vision
Cataracts or inflammation around the iris and lens
Anisocoria (unequal pupil sizes) — a common ocular symptom where one pupil appears larger than the other
Ocular symptoms may appear alone or alongside other FIP signs. While supportive care may help, antiviral therapy is required to stop disease progression.
Early symptoms of FIP in cats include persistent fever, appetite loss, and weight loss. As it progresses, cats may develop fluid buildup (Wet FIP), organ involvement (Dry FIP), or neurological and eye-related complications.
FIP Symptoms in Kittens vs. Adult Cats
Kittens and young cats (under two years old) are the most vulnerable to FIP because their immune systems are still developing.
Signs of FIP in Kittens:
Sudden tiredness or reluctance to play
Failure to gain weight or unexpected weight loss
Swollen belly that feels soft or fluid-filled
Rapid progression from mild to severe symptoms
Adult Cats
Adult cats tend to progress more slowly.
They may appear “off” — less playful, eating less, losing weight gradually, or hiding more frequently than usual.
Because FIP can advance quickly in kittens, even mild signs should be investigated by a veterinarian immediately.
When to See a Veterinarian
If your cat shows persistent fever, appetite loss, or unusual behavior, visit a veterinarian familiar with FIP as soon as possible.
Common diagnostic tools include:
Complete Blood Count (CBC) to detect anemia or inflammation
A/G Ratio (Albumin/Globulin) — low ratios may indicate FIP
Rivalta Test to assess abdominal fluid
PCR or Immunohistochemistry tests for viral confirmation
While no single test is 100% definitive, a combination of results and symptoms often gives a strong diagnosis.
Early detection is key — starting treatment at the earliest signs dramatically improves recovery chances.
What To Do If You Suspect FIP
If you suspect your cat has FIP, don’t panic — FIP is no longer a hopeless diagnosis.
Your first step should be contacting a vet experienced with FIP treatment.
Traditional veterinarians may still believe FIP is incurable, but recent data and thousands of success stories prove otherwise.
At BasmiFIP, we use GS-441524-based antiviral therapy, the most effective modern treatment for FIP.
Our dedicated team has guided over 87,000 cats worldwide to recovery and remission.
Next Steps:
Consult your veterinarian and discuss FIP-specific testing.
Contact BasmiFIP for expert guidance and treatment planning.
Monitor your cat’s progress throughout treatment and recovery.
👉 Learn more about treatment options and real recovery stories at basmifip.com.
FAQs About FIP in Cats
1. What are the first signs of FIP in cats?
The earliest signs usually include fever, loss of appetite, and lethargy. Over time, fluid buildup, weight loss, or eye and neurological issues may appear.
2. Can FIP be cured?
Yes. With GS-441524 antiviral therapy, FIP can be fully cured in most cases. Thousands of cats have recovered through BasmiFIP’s treatment protocol.
3. How long do cats live with FIP?
Without treatment, survival is typically limited to weeks or months.
With proper antiviral therapy, the recovery rate now exceeds 90%.
4. What should I do if my cat shows FIP symptoms?
Seek veterinary care immediately and contact BasmiFIP for specialized advice.
Early action gives your cat the best possible outcome.
5. Is FIP contagious to other cats?
No. While the feline coronavirus (FCoV) can spread, the mutated FIP form itself is not contagious.
If you suspect FIP, reach out to BasmiFIP.com today — because early detection saves lives.
