Cat Feline Leukemia Virus: Prevention and Welfare Management

Feline leukemia virus (FeLV) is a leading infectious cause of cat death worldwide. Vaccination and testing prevent transmission and allow welfare-focused management of positive cats.

Key Facts

FeLV causes immune suppression, lymphoma, and anemia, typically causing death within 2-3 years of diagnosis
Approximately 2-3% of healthy domestic cats are FeLV positive; rates are higher in multi-cat and outdoor populations
Effective vaccination since the 1980s has dramatically reduced FeLV prevalence in vaccinated populations
Cats that regress viral infection can become latently infected carriers without clinical signs
FeLV-positive cats can live comfortably for years with appropriate veterinary management and indoor-only lifestyle

Welfare Considerations

FeLV infection causes progressive immune failure with secondary infections and cancers causing chronic suffering. Diagnosis is often delayed because early infection causes non-specific symptoms. FeLV-positive cats experience good quality of life during the regressive phase before immune compromise becomes significant, making welfare-focused management important rather than premature euthanasia. Indoor-only lifestyle protects both the positive cat from secondary infections and other cats from transmission through saliva. Multi-cat household management when a positive cat is diagnosed requires careful risk assessment and vaccination of all FeLV-negative housemates.

What You Can Do

Vaccinate all cats against FeLV, particularly those with outdoor access or in multi-cat households
Test all new cats for FeLV before introduction to existing household members
Provide FeLV-positive cats with indoor-only access, excellent nutrition, and regular veterinary monitoring
Support feral cat colony management programs that test and manage FeLV-positive individuals appropriately