Feline immunodeficiency virus (FIV) is widespread in cat populations but often misunderstood. FIV-positive cats can live long, healthy lives with appropriate management and do not need to be euthanised on diagnosis.
FIV is one of the most welfare-costly misdiagnoses in companion animal medicine — not because of the disease itself, but because of the euthanasia decisions it still triggers in some shelter and veterinary contexts. A positive FIV test in an otherwise healthy cat does not constitute a welfare emergency or a justification for euthanasia. The virus progresses slowly; many cats outlive their diagnosis by years. The welfare imperative is to manage FIV-positive cats appropriately — keeping them indoors to prevent spread and secondary infection, providing proactive health monitoring, and treating intercurrent illness promptly — rather than treating diagnosis as a death sentence. Shelter adoption of FIV-positive cats has improved significantly as education has spread, but unnecessary euthanasia on the basis of FIV status alone remains a welfare problem in some regions.