FeLV is a retrovirus that causes immune suppression and cancer in cats. Vaccination, testing, and management of positive cats reduces welfare harm from this significant disease.
FeLV causes progressive immune compromise leading to recurrent infections, weight loss, and ultimately life-threatening cancers including lymphoma. The welfare trajectory of FeLV-positive cats involves periods of wellness interrupted by increasingly severe illness episodes. Welfare-conscious management of FeLV-positive cats focuses on optimizing their immune health through stress reduction, excellent nutrition, and prompt treatment of secondary infections, while providing palliative care that prioritizes quality of life as disease progresses. Preventing disease spread through testing, vaccination, and keeping FeLV-positive cats separate from FeLV-negative cats protects the welfare of uninfected household members.