Feline infectious peritonitis (FIP) was once a universally fatal disease in cats, but antiviral treatments now offer cure rates over 85%, though cost and access remain significant welfare barriers.
Before effective antivirals became available, FIP was a death sentence that was often prolonged and painful. Affected cats experienced progressive organ failure, fluid accumulation causing breathing difficulty and abdominal distension, weight loss, fever, and deterioration over weeks. The emergence of GS-441524 as a treatment transformed FIP from an invariably fatal disease to a largely curable one - a genuine triumph for feline welfare. However, the high cost of treatment and the fact that the primary drug source for years was grey-market imports from China created enormous inequity in which cats could access life-saving treatment. Affordable access to FIP treatment remains an ongoing welfare issue.