FIP is a serious viral disease that was once universally fatal in cats. Recent antiviral breakthroughs have transformed the prognosis but raise new welfare and access-to-treatment questions.
FIP causes significant suffering: wet FIP produces breathing difficulty from chest fluid, abdominal distension, weight loss, and lethargy. Dry FIP causes neurological signs, eye inflammation, and organ failure depending on which tissues are affected. Before antiviral treatments, the welfare calculus was straightforward and tragic — early euthanasia was the most humane option. Now, treatment can return cats to full health, but the 84-day injection course is stressful for both cats and owners, and cost remains a significant barrier to access. Welfare-conscious care requires early diagnosis, prompt initiation of treatment where accessible, and close monitoring for relapse. The transformation in FIP prognosis is one of veterinary medicine's most significant recent advances.