Feline infectious peritonitis (FIP) was once a near-universally fatal disease. The development of antiviral treatments has transformed the prognosis, making this a landmark moment in feline welfare.
FIP causes profound suffering in affected cats — the wet form causes breathing difficulty or painful abdominal distension from fluid accumulation; the dry form causes neurological signs, eye inflammation, and systemic organ damage. Before antiviral treatments, diagnosis meant the family faced immediate end-of-life decisions for cats who were often very young. The transformation wrought by GS-441524 is one of the most significant welfare advances in veterinary medicine in decades: cats that would have died within weeks are now achieving full remission and returning to normal, healthy lives. The main current welfare challenge is access — in countries where licensed products are unavailable or unaffordable, cats continue to die from a now-treatable disease. Advocacy for licensed, affordable antiviral access is an urgent welfare priority.