Feline Immunodeficiency Virus and Cat Welfare

Feline immunodeficiency virus (FIV) affects cats worldwide, but infected cats can live long, quality lives with appropriate care and management.

Key Facts

FIV is a lentivirus related to HIV that affects domestic cats globally, with prevalence of 1-8% in free-roaming cat populations.
The virus is primarily transmitted through deep bite wounds, making intact male outdoor cats most at risk.
FIV-positive cats can live for years without clinical signs, often progressing slowly to immunodeficiency.
Neutering dramatically reduces transmission risk by reducing fighting behaviour.
FIV-positive cats can coexist with FIV-negative cats in stable households where fighting is unlikely.
Many shelters euthanise FIV-positive cats due to misconceptions about their welfare prospects.
Supportive care, good nutrition, regular veterinary monitoring, and indoor living extend quality of life significantly.
A vaccine was previously available but withdrawn due to interference with diagnostic testing.

Welfare Considerations

FIV diagnosis once meant near-certain euthanasia in many shelters, but evidence now supports a more nuanced approach. Cats with FIV can have excellent welfare for years or decades. The greatest welfare harms often come from decisions made after diagnosis rather than the disease itself. Reducing stigma around FIV, improving shelter protocols, and educating adopters about realistic care expectations are the most impactful interventions. Neutering and indoor management reduce both transmission and welfare-impacting injury.

What You Can Do

Adopt FIV-positive cats — they can make wonderful companions and often live long, healthy lives.
Ensure all outdoor cats are neutered to reduce fighting and FIV transmission.
Advocate for shelters to adopt non-euthanasia policies for FIV-positive cats.
Support feline health research including work on antiviral treatments for cats with FIV.
Keep FIV-positive cats indoors to protect their immune systems and prevent spread.