Feline Immunodeficiency Virus


Called FIV by most people, Feline Immunodeficiency Virus is a disease that can affect your cat.  Despite the similarity in name to Human Immunodeficiency Virus (HIV), there are notable differences between the two diseases.  First, you cannot get HIV from your cat, even if your cat has FIV.  The viruses are species-specific, so there is no danger to a human interacting with a FIV-infected cat.  The other important distinction is that in humans, HIV is transmitted through sexual contact or contact with bodily fluids.  FIV is not sexually transmitted, but is instead carried mostly in the saliva.

FIV is similar to FeLV in that they are both in the same virus family, and both replicate by tricking the host body into producing more of the virus every time they make new cells.  However, FIV is what scientists call a slow virus (or lentivirus).  This means that a cat infected with FIV can, with the right conditions, live comfortably for a long time. 


What are the symptoms?

Symptoms of FIV may begin with a fever and slightly swollen lymph nodes, which occur because the virus is replicating (reproducing) in the body’s white blood cells.  Unless the fever is very high or the lymph nodes very swollen, it is common for owners to overlook this initial stage, since the symptoms are subtle and can resemble other illness.  Many infected cats remain fairly healthy, with bouts of illness in between.  Other symptoms can include:

  • Upper respiratory infections
  • Weight loss
  • Bladder infections
  • Inflammation of the gums and mouth
  • Decrease in white blood cells
  • Swollen lymph nodes
  • Chronic skin infections
  • Stomach issues/diarrhea
  • Neurological disorders
  • Cancer

Since FIV attacks the immune system, it is important to understand that any disease an infected cat is exposed to will be much more difficult for them to fight off.  The same illness that an uninfected cat may deal with easily could be severely detrimental to the health of an infected cat.


How common is it?

FIV is present world-wide, but in the United States it is estimated that only 1.5-3% of cats are infected with FIV.


Which cats are at risk?

Like most viruses, cats with weakened immune systems are more likely to become infected.  This includes kittens and very young animals, very old animals, and those whose immune systems are already fighting off other illness. 

Due to the way the virus is transmitted, cats at increased risk also include unaltered (not spayed or neutered) cats who are prone to fighting.  This means male cats are particularly likely to get the disease, as they regularly engage in territory fights and will fight another male for a female. 


How is it spread?

FIV is carried in the saliva, and is almost always spread to another cat through deep bite wounds.  Originally it was thought that cats who lived together could become infected through sharing a food and water bowl with another cat, but more recent studies have shown that unless there is fighting in the household among the cats, it is unlikely for an infected cat to spread the disease to others.  It can also be spread to kittens through the milk of an infected mother cat.


How can I protect my cat?

The best method of protection is to prevent exposure to other cats that are infected with FIV, particularly strange cats as fighting is more likely.  Have your animals spayed or neutered to reduce conflict, and if possible, ensure that cats outside your home (barn cats, community cats, etc.) are neutered as well.  Less fighting means less FIV transmission!  An indoor-only cat will be much less likely to be exposed to the disease, but an indoor-outdoor cat can also be provided good protection through responsible spay/neuter programs and attention to interactions your cat has with other cats. 


If my cat tests positive for FIV, what do I do?

FIV-infected cats can live a fairly normal life.  They do require more attentive monitoring from their owner to be sure that any signs of illness are dealt with quickly, as these can much more rapidly become a serious issue.  If you have other cats in your home, be sure to test the rest of them to ensure that you know which cats may be carrying the disease, if any.  Then evaluate the stability of the household: do all of your cats get along well? If there is serious tension between your cats, perhaps consider separating the FIV-positive individuals from the rest.  If they get along well , you still may consider a separation if desired, but studies do indicate that the risk of your other cats becoming infected is low unless there is fighting or very rough play occurring.

You should also confine your FIV-positive cat to the indoors.  It is very difficult to control what cats your cat may come in contact with outside, and you can protect the other cats in the neighborhood from getting the disease from your cat by keeping him or her inside.  Also, spending time outside exposes your immune-compromised cat to a multitude of bacteria, viruses, and other potential infections that may put him or her at risk.

Speak to your veterinarian about proper maintenance care for your FIV-positive cat.  They may recommend regular wellness checkups and possibly a different diet for your cat, depending on the situation. 

For more information, please visit Cornell University’s website.



353 Sanctuary Hill Ln,
East Smithfield, PA 18817


East Smithfield, PA 18817


(570) 596-2200 - Option 2

Fax: 570-596-2222


ACS needs your help to save more lives!
Together we can make a difference.


Dog rehoming and behavioral questions
570-596-2200 Choose Extension 123
Email: cgreene@animalcaresanctuary.org
Cat rehoming and behavioral questions
570-596-2200 Choose Extension 123
Email: cgreeene@animalcaresanctuary.org
Subscribe to the ACS Newsletter!


Animal Care Sanctuary is a 501(c)(3) nonprofit organization — contributions to which are tax deductible to the fullest extent permitted by law. The official registration and financial information of Animal Care Sanctuary may be obtained from the Pennsylvania Department of State by calling toll free within Pennsylvania, (800) 732-0999.
Registration does not imply endorsement.

Tax ID- 22-1837635

©   2022 Animal Care Sanctuary

Thirsty Fish Graphic Design

Site Maintenance: Thirsty Fish Graphic Design