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Feline Immunodeficiency Virus (FIV)

What you need to know to protect your cat

Reviewed by Missy Beall, DVM, PhD on Thursday, August 14, 2014
Posted December 20, 2011 in Cat Diseases & Conditions A-Z

Sad catOverview
Some consider Feline immunodeficiency virus (FIV) to be the cat equivalent of HIV in humans. FIV causes a highly contagious and potentially fatal retroviral infection that weakens a cat’s immune system, making him or her susceptible to illness and secondary infection. Also, like HIV, FIV reduces the ability of the immune system to fight infection. Fortunately, despite the similarities, FIV is not zoonotic—so FIV presents no risk to humans.


FIV is often called the “fighting cat” disease as it is commonly spread from cat to cat by fighting (specifically, by biting and scratching). Feline immunodeficiency virus (FIV) and Feline leukemia (FeLV) are among the most common infectious diseases in cats. FIV is nothing to meow about! In a study of more than 18,000 cats, 2.5% of them were positive for FIV.

While all cats are at risk, lifestyle, sex, and vaccination status all play an important part in reducing your cat’s risk. The following increase your cat’s risk of contracting FIV:

  • Not having been vaccinated against feline leukemia
  • Spending time outside, unsupervised
  • Exposure to a cat or kitten whose infection status is unknown
  • Living in a multiple-cat household
  • Not having been spayed or neutered
  • Aggressive behavior toward other cats
  • Symptoms of oral disease
  • Past or present abscess wounds

Cats with FIV do not always appear sick. In the early stages of the disease, many cats show few signs, so the only way to know for sure if they are infected is through a simple blood test. As the disease advances, the following symptoms may occur:

  • Weight loss
  • Loss of appetite
  • Lethargy
  • Pale gums
  • Bad breath
  • Runny eyes or nose
  • Vomiting
  • Oral disease

Most veterinarians include a screen for FIV as part of the routine tests a cat gets during his lifetime. The American Association of Feline Practitioners (AAFP) recommends testing cats for FIV as follows:

  • Cats should be tested at appropriate intervals based on their risk
  • Cats and kittens entering a new household should be tested at introduction 
  • Cats exposed to an infected cat should be tested twice—at the time of exposure and 60 days later
  • Cats should be tested before they are vaccinated for FIV
  • Cats with clinical signs should be tested

Your veterinarian can run a simple test to see if your cat has been infected with FIV. If the result is negative, they may recommend protecting your cat from FIV by having him

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