In Education


By Charlotte Boucher-Beaulieu, CVT

What is feline immunodeficiency virus?

Commonly known as FIV, feline immunodeficiency virus is a generally latent virus that infects domestic cats all over the world. Although similar to human HIV/AIDS, FIV is less severe and rarely causes the death of infected cats. It was identified first in the United States in the 1980s and affects cats worldwide.

What are the symptoms of FIV?

FIV rarely causes clinical signs in cats since it is mostly latent in the system. FIV weakens the cat’s immune system and therefore makes the animal more susceptible to developing infections or slows down the healing process. Sometimes, just after having contracted the virus, the cat may become lethargic, have a fever and swollen lymph nodes. As the owner of a cat with FIV, you should watch for the following signs:

  • Dull coat
  • Fever
  • Persistent or chronic infections
  • Gingivitis
  • Diarrhea
  • Weight loss

In very rare cases, FIV may also affect the nervous system. However, it is very important to mention that the vast majority of cases do not present any symptoms. Feline immunodeficiency virus only rarely affects the animal’s life expectancy. While FIV positive cats are more prone to infections, they generally do not require more follow-up than non-FIV cats.

How is FIV transmitted?

FIV is transmitted almost exclusively through deep bite wounds during aggressive fights. The bite has to be deep enough for the saliva of the infected cat to enter the other cat’s bloodstream. It is not uncommon for stray cats to carry the virus and it is more common in free-roaming, outdoor intact male cats, who fight more frequently. Since the virus does not live long outside the cat’s system, direct contact between cats is necessary for the virus to be transmitted. If a female cat gets FIV while pregnant, she can pass it to her foetuses. This virus cannot be transmitted from cat to human, just like human HIV cannot be transmitted to cats.

How do I know if my cat if FIV positive?

The virus is detectable in the blood. Your veterinarian can therefore perform a screening test at the clinic or send a sample to a laboratory. The test usually takes very little blood and the results are fairly quick. Note that if a young cat (less than six months old) tests positive, it may be due to the transmission of antibodies from its mother, and therefore be a false positive. So it is important to redo the test when the cat is older. A positive FIV diagnosis is not a valid reason to euthanize your cat since it may very well have an excellent quality of life.

How can I prevent my cat from contracting the virus?

The simplest and most effective prevention is to keep your cat indoors so that it does not come into contact with stray cats carrying the virus. As mentioned earlier, the disease can only be transmitted through deep bite wounds so an FIV-positive cat can very well live with non-carriers and not transmit it. As long as the cats get along well, it is very possible to have an FIV-positive cat at home in contact with an uninfected cat. Neutering male cats also reduced the risk of turf battles. A vaccine has already been used by North American veterinarians, but it has proven to be not very effective for the strain we have here and so the vaccine is no longer available. If your cat has already received this vaccine it may test falsely positive to the virus since the test detects the antibodies contained in the vaccine.

Is there a treatment for FIV?

No, there is no treatment for this virus. It will forever remain in the infected cat’s system. The only thing the cat’s owner can do is treat any secondary infections and provide supportive care. While an annual exam is necessary for all cats, it is even more important for FIV-positive cats. Good dental hygiene is also important to avoid or delay gingivitis problems.