FIP was once universally fatal in cats, but antiviral treatments have transformed it into a manageable disease, dramatically improving welfare outcomes for affected cats.
The transformation of FIP from a death sentence to a treatable disease is one of veterinary medicine's most remarkable recent developments. Before effective antivirals, cats with FIP experienced rapidly progressive deterioration — respiratory distress from pleural effusion, neurological signs, persistent fever, and weight loss — until death or euthanasia. The welfare improvement offered by antiviral treatment is therefore profound: cats that would have died within weeks can achieve full remission. However, the high cost of treatment creates a two-tier welfare system in which cats whose owners can afford treatment recover, while those whose owners cannot face the old prognosis. Advocacy for affordable access and veterinary payment plans is an important welfare consideration.