What is Feline Infectious Peritonitis (FIP) and why does it matter?
Feline Infectious Peritonitis (FIP) is a serious, progressive viral disease in cats caused by a mutated form of the feline coronavirus (FCoV). It affects the immune system and internal organs, and without timely veterinary intervention, it can be life-threatening. MaxPetz in Delhi provides expert veterinary consultation for cats showing signs of FIP, combining cutting-edge diagnostics with compassionate care.
FIP is not transmitted directly between cats in its mutated form. The feline coronavirus itself is common and usually causes mild gut symptoms — but in some cats, the virus mutates inside the body and triggers FIP. Understanding this distinction is key to managing the disease early.
Key fact: FIP occurs in two primary forms — wet (effusive) and dry (non-effusive) — each with distinct clinical presentations that require different diagnostic approaches.
What are the first symptoms of FIP in cats?
Early signs of FIP in cats can be vague and easy to miss. As the disease progresses, symptoms become more specific depending on whether the cat has wet FIP or dry FIP. Recognising these signs early and consulting a veterinarian promptly can make a significant difference.
Early signs common to both forms:
- Persistent fever that does not respond to antibiotics
- Lethargy and reduced activity
- Loss of appetite and weight loss
- Rough or dull coat condition
- Mild eye inflammation or cloudiness
Wet FIP symptoms (effusive form — fluid accumulates in body cavities):
- Visibly distended or swollen abdomen
- Difficulty breathing due to fluid around the lungs
- Rapid weight loss despite the swollen belly
Dry FIP symptoms (non-effusive form — affects organs and nervous system):
- Neurological signs: seizures, loss of balance, hind-limb weakness
- Eye changes: uveitis, retinal lesions, or blindness
- Kidney or liver enlargement detectable on examination
- Chronic weight loss and muscle wasting
Warning: A fever lasting more than 48–72 hours that does not respond to standard treatment is a red flag for FIP. Do not delay veterinary assessment.
What causes FIP in cats?
FIP is caused by a mutation of the feline coronavirus (FCoV). Understanding how this mutation occurs helps cat owners take preventive steps and recognise risk factors early.
| Factor | Detail |
|---|---|
| Root virus | Feline coronavirus (FCoV) — common in multi-cat households and catteries |
| Mutation trigger | The virus mutates within an individual cat's body; the mutated form is not directly contagious |
| Age risk | Kittens under 2 years and senior cats over 10 years are at higher risk |
| Immune status | Cats with weakened immune systems are more susceptible to viral mutation |
| Environment | Overcrowded or high-stress environments increase FCoV exposure and spread |
A fully vaccinated cat can still develop FIP, as available vaccines target the feline coronavirus but cannot fully prevent the internal mutation that leads to FIP in susceptible individuals.
How is FIP diagnosed in cats?
Diagnosing FIP is challenging because no single test confirms it definitively. Veterinarians use a combination of clinical signs, laboratory findings, and imaging to build a diagnosis. At MaxPetz in Delhi, veterinary consultations for suspected FIP include a thorough clinical assessment and guidance on appropriate diagnostic workup.
Common diagnostic steps include:
- Physical examination — assessing fever, abdominal distension, eye changes, and neurological signs
- Blood tests — elevated total protein, low albumin-to-globulin ratio, raised inflammatory markers
- FCoV antibody titre — a high titre supports but does not confirm FIP
- Fluid analysis — in wet FIP, fluid from the abdomen or chest is examined for characteristic yellow, protein-rich effusion
- Imaging (ultrasound/X-ray) — to detect fluid accumulation or organ changes
- PCR testing and immunohistochemistry — more definitive tests performed on tissue or fluid samples
A combination of consistent clinical signs, characteristic bloodwork, and fluid analysis provides a high degree of diagnostic confidence even without biopsy in many cases.
What is the best treatment for FIP in cats?
FIP treatment has advanced significantly with the development of antiviral drugs. Previously considered uniformly fatal, FIP can now be managed — and in many cases put into remission — with antiviral therapy under close veterinary supervision.
Current treatment approaches include:
- GS-441524 (nucleoside analogue antiviral) — the most widely studied antiviral for FIP; shown in research to induce remission in a significant proportion of treated cats. Treatment typically spans 12 weeks or more.
- Molnupiravir and related antivirals — emerging options being evaluated in veterinary practice
- Supportive care — fluid drainage (in wet FIP), nutritional support, anti-inflammatory medication, and management of secondary complications
- Immunosuppressive therapy — sometimes used alongside antivirals to manage the immune-mediated component of the disease
Important: Antibiotics do not treat FIP. The disease is viral, not bacterial. Using antibiotics without veterinary guidance delays appropriate care and does not address the underlying cause.
The cost of FIP treatment in India varies depending on the drug used, the cat's weight, the form of FIP, and the duration of treatment. Consult a veterinarian for an accurate estimate tailored to your cat's condition. Use the booking form on this page to arrange a consultation at MaxPetz Delhi.
Learn more about veterinary consultation services at MaxPetz or explore feline medicine care options available at our Delhi clinic.
How quickly does FIP progress, and can a cat survive without treatment?
The progression of FIP depends on the form of the disease, the cat's immune response, and how early treatment begins.
| FIP Form | Typical Progression Without Treatment |
|---|---|
| Wet (effusive) | Rapid — days to a few weeks from symptom onset |
| Dry (non-effusive) | Slower — weeks to several months, but ultimately fatal without intervention |
Without antiviral treatment, FIP is considered fatal in virtually all cases. Supportive care alone can improve comfort and extend survival briefly, but it does not address the underlying viral disease. With antiviral therapy initiated early, a meaningful proportion of cats achieve sustained remission — though close monitoring is required throughout and after treatment.
The final stages of FIP in cats typically involve severe weight loss, extreme weakness, neurological deterioration (in dry FIP), or respiratory distress from fluid accumulation. Reaching this stage without treatment significantly reduces the likelihood of a positive outcome.
When should you bring your cat to a vet for suspected FIP?
Early veterinary assessment is critical. Do not wait for symptoms to worsen before seeking a consultation. Contact a veterinarian promptly if your cat shows any of the following:
- Fever persisting for more than 48–72 hours that does not resolve with standard care
- A visibly swollen or distended abdomen, especially in a young cat
- Sudden difficulty breathing or laboured respiration
- Unexplained rapid weight loss over 1–2 weeks
- Neurological changes: wobbling, seizures, or sudden hind-limb weakness
- Eye cloudiness, redness, or sudden vision changes
- Persistent lethargy and complete loss of appetite lasting more than 2 days
MaxPetz in Delhi offers veterinary consultation for cats with suspected FIP, providing clinical assessment and guidance on the appropriate diagnostic and treatment pathway. The earlier FIP is identified, the more treatment options are available.
Book a consultation at MaxPetz Delhi
If your cat is showing signs of FIP, use the booking form on this page to arrange a veterinary consultation. Early assessment gives your cat the best chance of a positive outcome.
You can also explore our doctor consultation page to understand what to expect during your cat's first visit.