Cat Feline Leukemia Virus: Prevention and Care

FeLV is a retrovirus causing immunosuppression and cancer in cats, with vaccination and testing programs dramatically reducing transmission.

Key Facts

FeLV is transmitted through saliva, grooming, biting, and mother-to-kitten nursing
Approximately 2-3% of cats in the U.S. are persistently infected with FeLV
Persistently infected cats develop progressive immunosuppression and lymphoma
Regressive infection results in viral suppression without persistent viremia in immune-competent cats
Vaccination is highly effective at preventing persistent infection
Testing before introduction to multi-cat households prevents horizontal transmission
FeLV-positive cats can live comfortably for years with appropriate supportive care

Welfare Considerations

FeLV-positive cats face progressive immune deterioration making them susceptible to opportunistic infections that cause repeated illness. Lymphoma secondary to FeLV causes pain and systemic illness. However, well-managed FeLV-positive cats can maintain good quality of life for years with appropriate care including regular health monitoring and prompt treatment of secondary infections. Indoor housing protects both FeLV cats and unvaccinated cats they might contact.

What You Can Do

Vaccinate cats against FeLV especially if they have outdoor access or live with unknown-status cats
Test all new cats for FeLV before introducing them to your existing cat household
Keep FeLV-positive cats indoors to prevent transmission and protect their compromised immune system
Provide FeLV-positive cats with regular health monitoring to catch opportunistic infections early
Adopt FeLV-positive cats from shelters - they can make loving companions with proper care
Support research into antiviral treatments that could improve outcomes for FeLV-positive cats