Feline infectious peritonitis (FIP) was until recently invariably fatal. New antiviral treatments have achieved cure rates exceeding 85%, representing one of the most dramatic welfare advances in feline medicine.
The FIP treatment revolution represents one of the most significant welfare advances in recent veterinary medicine. Before effective antivirals, FIP diagnosis was effectively a death sentence for what was typically a young, otherwise healthy cat. Affected cats experienced progressive deterioration and death over weeks to months with only palliative support available. Treatment with GS-441524 or similar antivirals can produce dramatic reversal of clinical signs within days of starting treatment, with cats who were moribund returning to normal activity and body weight within weeks. The welfare urgency lies in early diagnosis and treatment - survival rates are higher when treatment begins before severe organ damage. The treatment cost, while significant, is falling as commercial competition increases.