Feline Infectious Peritonitis
Feline Infectious Peritonitis (FIP) is a fatal viral disease caused by mutation of feline enteric coronavirus (FCoV) into the virulent FIP virus (FIPV). The mutated virus infects macrophages and triggers a severe immune-mediated vasculitis. FIP occurs in two forms: effusive (wet) with fluid accumulation, and non-effusive (dry) with granulomatous inflammation.
Symptoms & Signs
- Wet form: abdominal distension (ascites), difficulty breathing (pleural effusion), persistent fever
- Dry form: weight loss, fever, ocular inflammation (uveitis), neurological signs, organ granulomas
- Both: lethargy, poor appetite, progressive decline
Causes & Risk Factors
Mutation of ubiquitous feline enteric coronavirus within the individual cat. Factors promoting mutation: young age, stress, immunosuppression, high viral load environments (multi-cat households, catteries). The mutation allows the virus to replicate within macrophages and spread systemically.
Diagnosis
Challenging antemortem diagnosis. Effusive: characteristic high-protein, straw-colored fluid with low cellularity; Rivalta test positive; immunostaining of fluid. Dry form: elevated globulins, low albumin:globulin ratio, tissue biopsy. RT-PCR of effusion or tissue.
Treatment
GS-441524 (nucleoside analog) has revolutionized FIP treatment with >80% remission rates. Treatment protocol: 84 days of daily injections or oral medication. Molnupiravir as alternative. Supportive care during treatment. Previously considered universally fatal.
Prevention
Reducing coronavirus exposure in multi-cat environments. Stress reduction. Good hygiene (litter box management). Early weaning in catteries. Intranasal FIP vaccine available but efficacy debated. Avoiding overcrowding.
Prognosis
With GS-441524 treatment: >80% achieve sustained remission. Without treatment: universally fatal (days to weeks for wet form, weeks to months for dry form). Neurological and ocular forms may have lower response rates.