Feline infectious peritonitis is caused by a mutated coronavirus and was once universally fatal. New antiviral treatments have transformed FIP from a death sentence into a treatable disease, dramatically improving welfare outcomes.
Untreated FIP causes progressive deterioration including severe abdominal distension, breathing difficulty, neurological signs, and wasting before death. The welfare transformation brought by antiviral treatment is remarkable — cats that were moribund often recover to full health within weeks. Access to treatment remains a welfare equity issue, as cost and regulatory availability vary widely. Owners should seek specialist advice early, as prompt treatment when clinical signs first appear leads to the best outcomes.