Feline leukemia virus (FeLV) is a retrovirus that causes immunosuppression, anemia, and cancer in infected cats, with significant welfare implications for affected cats and important prevention implications for cat owners and shelters.
FeLV-positive cats can live comfortable, good-quality lives for significant periods after diagnosis with appropriate care. The welfare obligation is to provide these cats with veterinary monitoring for secondary infections, appropriate nutrition, protection from stress and additional infectious challenges, and compassionate quality-of-life assessment as disease progresses. Many FeLV-positive cats are surrendered to shelters or euthanised unnecessarily out of misunderstanding about prognosis and management. Shelter environments are particularly hard on FeLV-positive cats — stress accelerates disease progression. With individual home environments, appropriate veterinary care, and loving attention, many FeLV-positive cats have months to years of comfortable life ahead of them at diagnosis.