Cat Feline Leukemia Virus and Prevention

Feline leukemia virus (FeLV) is a serious retroviral infection that suppresses the immune system and causes cancer, but is preventable through vaccination and management.

Key Facts

FeLV affects approximately 2-3% of cats globally, with higher rates in outdoor and multicat settings
The virus is transmitted through close contact including mutual grooming, biting and sharing food bowls
FeLV causes immune suppression, anaemia, lymphoma and progressive systemic disease
Effective vaccines against FeLV are available and recommended for outdoor cats and those in multicat environments
Cats testing positive for FeLV should be housed separately from FeLV-negative cats

Welfare Considerations

FeLV infection causes progressive, ultimately fatal immune compromise in most affected cats. Unlike FIV, FeLV is more readily transmitted through casual contact — shared resources, grooming and bite wounds all represent transmission routes. FeLV-positive cats can live comfortable lives for variable periods, but their welfare requires active management of secondary infections and careful monitoring for cancer development. Vaccination is highly effective and should be a routine component of preventive care for all cats with outdoor access or exposure to other cats of unknown status. Testing new cats before introduction to an established household prevents transmission.

What You Can Do

Vaccinate outdoor cats and those in multicat environments against FeLV
Test new cats for FeLV before introducing them to a household with existing cats
House FeLV-positive cats separately from negative cats
Schedule regular veterinary monitoring for FeLV-positive cats every 3-6 months