Companion Animals

Companion Cat Feline Leukemia Virus Prevention

Feline leukemia virus causes immunosuppression and cancer in cats, but vaccination and preventing exposure to infected cats is highly effective.

Key Facts

FeLV affects approximately 2 to 3 percent of cats in North America
The virus is transmitted through saliva, urine, and milk between cats
Outdoor cats and those in multi-cat households have higher exposure risk
An effective vaccine is available and recommended for at-risk cats

Welfare Considerations

FeLV infection causes progressive immunosuppression leading to opportunistic infections, anemia, and lymphoma. The resulting chronic illness involves significant suffering over months or years. Prevention through vaccination and preventing exposure to FeLV-positive cats is far more effective than treating established infection. Routine testing of new cats before introducing them to resident cats prevents inadvertent infection spread.

What You Can Do

Vaccinate outdoor and at-risk cats against FeLV
Test new cats for FeLV before introducing them to resident cats
Consider keeping FeLV-positive cats separate or as indoor-only
Support TNR programs that include FeLV testing and management