Feline immunodeficiency virus and feline leukaemia virus cause chronic, progressive disease in cats. Prevention through vaccination and management reduces both infection rates and long-term welfare impacts.
FIV and FeLV impose significant welfare burdens on affected cats through chronic immune suppression, secondary infections, and cancer. The welfare impact is not just at end-stage disease — throughout the course of infection, affected cats experience more frequent illness, require more veterinary intervention, and face a reduced capacity to respond normally to environmental challenges and stressors. Prevention is the most welfare-positive strategy. Neutering male cats reduces the bite wound transmission that spreads FIV among outdoor cats; FeLV vaccination protects against the most serious infectious cause of immunosuppression and cancer in cats. For infected cats, management focuses on minimising exposure to secondary pathogens, nutritional support, and proactive treatment of infections before they become severe. FIV-positive cats managed carefully can have good quality of life for years — the virus suppresses rather than eliminates immune function, and many cats maintain stable health for extended periods.