Feline infectious peritonitis was until recently a virtually certain death sentence for affected cats, but antiviral drugs have transformed FIP from a welfare catastrophe to a treatable disease.
The transformation of FIP from a fatal disease causing prolonged welfare deterioration to a treatable condition represents one of the most significant welfare advances in companion animal medicine of the past decade. Before effective antivirals, cats with FIP typically declined over weeks to months through fluid accumulation causing breathing difficulty and abdominal distension, progressive neurological deterioration, and progressive weakness and organ failure — a welfare trajectory that often ended in difficult euthanasia decisions as owners hoped for recovery that could not come. Now, cats diagnosed early and treated completely can achieve long-term remission with acceptable quality of life. The welfare imperative is early diagnosis — FIP is still too often diagnosed late when welfare has already deteriorated substantially — and access to treatment regardless of financial barriers. As licensed products enter markets, cost barriers are reducing, improving welfare equity across income levels.