Feline infectious peritonitis was until recently almost universally fatal in cats; antiviral treatments now offer high cure rates, transforming the prognosis for one of the most feared feline diseases.
Cats with untreated FIP suffer a prolonged and distressing death. Wet FIP causes abdominal or chest fluid accumulation that causes breathing difficulty and abdominal discomfort. Neurological FIP causes seizures, loss of coordination, and behavioural changes. Before antiviral treatments, supportive care could only slow decline; death typically occurred within days to weeks of diagnosis. The emergence of effective antiviral treatments has been transformative, but welfare disparities remain significant. Access to licensed treatments is geographically uneven; grey-market equivalents are available in some regions but of variable quality. Cost barriers prevent some owners from accessing treatment. The distress of watching a previously healthy young cat decline rapidly, combined with the financial and logistical challenges of treatment, creates significant animal and owner welfare impacts that policy reform could address.