Feline Immunodeficiency Virus in Cats

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Feline Immunodeficiency Virus, or FIV, is in the same family as the human immunodeficiency virus (HIV) that causes AIDS, but it only appears in cats. Although it can be fatal if left untreated, a positive test for FIV is not a mandatory death sentence for your pet. With a high-protein diet and aggressive treatment of secondary infections, an FIV-positive cat can lead a reasonably normal life for a number of years after diagnosis.

What Is FIV?

FIV is a retrovirus that only affects cats, and can be treated but not cured. As a result, cats with FIV are likely to have a shorter lifespan than healthy cats, but they can still be wonderful pets.

In the U.S., approximately 1.5 to 3 percent of healthy cats are infected with FIV. Most cats with FIV live outdoors and are thus more likely to experience bites from infected feral cats. FIV cannot be transmitted to human beings.

Symptoms of FIV

Symptoms of FIV often don't show up until years after infection. They can include:

  • Weight loss
  • Dishelved coat or fur loss
  • Lack of appetite
  • Diarrhea
  • Conjunctivitis, or inflammation of the eye
  • Discharge from eyes or nose
  • Change in behavior
  • Urinating outside the litter box or straining to urinate

Any number of these symptoms should add up to taking your cat to the vet for testing. The only way to diagnose FIV is through a blood test that looks for specific antibodies to the virus. They show up anywhere between two to weeks after exposure to FIV.

If there's the suspicion that a mother cat transmitted FIV to her kittens, a test won't be accurate until around 6 months of age. At this time, the mother's antibodies will have cleared from the kittens' systems, and the blood test will be able to detect infection.

Causes of FIV

A cat generally develops FIV after being bitten by an infected feline, though it can also be transmitted from an FIV-positive cat to her kittens during birth or while nursing.

It's incredibly rare for a cat to develop FIV by sharing food bowls or simply being around an FIV-positive cat, so there's no need to be worried if you have one cat in your household that's FIV-positive and another that's not. However, it's prudent to test all cats in the household if one is diagnosed is FIV, just to be sure.


Cats with FIV commonly live normal life spans, as long as they are not also infected with feline leukemia virus, according to the Cornell University Feline Health Center. If your cat has been diagnosed as FIV-positive, work closely with your veterinarian to design a management program. Cats with FIV, whether or not they are displaying symptoms, have a weakened immune system, so they should be closely monitored for secondary infections. In fact, in many cases, it's the secondary infections that finally prove fatal to an FIV-infected cat.

For cats with no other symptoms that in otherwise generally good health, a treatment program might simply be a matter of ensuring it gets a sound diet, possibly with added vitamins, antioxidants, and Omega-3 or Omega-6 fatty acids, as well as prompt, aggressive treatment of infections and other conditions as they crop up.

There's no cure for FIV, nor is there a specific medical treatment for the disease, even as the cat's health declines. A vet might try anti-inflammatory drugs, immune-enhancing drugs, and medication for secondary infections to keep the cat as healthy as possible.

How to Prevent FIV

Outdoor cats are most at risk of acquiring the virus, and the best way to prevent infection with the FIV virus is to ensure that your cat stays indoors. Avoid contact with other cats known to have FIV, as a bite or sexual activity can lead to infection.

There is a vaccine for FIV; however, it's not considered incredibly effective, and it will result in a positive blood test for the disease. Talk to your vet about whether the vaccine is right for your pet.

If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.
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  1. Feline Immunodeficiency VirusCornell University College Of Veterinary Medicine