FIP was once universally fatal in cats but antiviral drugs have transformed it into a treatable disease, representing one of the most dramatic welfare advances in veterinary medicine.
Before effective antivirals, FIP caused devastating suffering - cats with effusive FIP drowned slowly as fluid filled their chest or abdomen, while dry FIP caused progressive neurological deterioration. Veterinarians could only offer supportive care while the animal died. The development of GS-441524 transformed this welfare catastrophe into a manageable disease. Every FIP cat that now dies without antiviral treatment represents an avoidable welfare failure, making access to these drugs a critical advocacy target.