About FIV and FeLV

How the Viruses Spread
Both viruses are spread contagiously from cat to cat, and surveys show that up to 15 percent of sick cats are infected with the viruses. But even healthy cats may harbor infection and spread viruses to other cats. In some cats, signs of disease may not become apparent until weeks, months or even years after they first become infected with FIV or FeLV.

FIV is typically spread when one cat bites another; rarely does an infected mother infect her kittens.

FeLV is spread when the saliva or urine of an infected cat comes in contact with another cat. This can happen when cats groom each other, or when they share food and water bowls or litter boxes.

What the Viruses Do
FIV and FeLV affect cats in similar ways, primarily by interfering with the immune system’s ability to ward off infections. Bacteria, viruses, protozoa and fungi found in the everyday environment—where they usually don’t affect healthy cats—can cause severe illness in FIV- and FeLV-infected cats. Various kinds of cancer and blood diseases are also much more common in cats infected with either virus.

Signs of Possible Infection
Early signs of infection are often subtle and commonly seen in cats that are simply not feeling well. These signs include:

• Decreased appetite
• Decreased grooming
• Decreased energy

• Marked loss of appetite
• Weight loss
• Weakness
• Pale gums
• Mouth sores
• Diarrhea
• Enlarged lymph nodes

• Abscesses

We strongly recommend that you speak with your veterinarian about having your cat tested, as your cat may be at risk for FIV and/or FeLV infection. Use our online FIV/FeLV observation form to record these signs, and bring it to your veterinarian to aid in your discussion.

Humans Are Not at Risk
Research to date has shown that FIV and FeLV only affect cats.

For More Information
The Cornell Feline Health Center offers in-depth online information on both FIV and FeLV.