Feline AIDS

also known as

Immuno-Deficiency Virus or FIV

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While we, as a profession, were getting a handle on Feline Leukemia, there were some mystery cases...cats that were thought to have leukemia...but the leukemia virus couldn't be isolated.  And the disease didn't transmit the same as leukemia. 

It took 20 years, but in 1986, researchers discovered that a different Retrovirus was responsible for another immune suppressive disease that we mistook for leukemia.

This "new" disease was so similar to Human Aids that it quickly became known as Feline Aids.  (It wouldn't surprise me if some sharp,research fund raiser didn't purposely tried to link the two diseases in hopes of getting in on the huge gravy train of Human Aids Research) (Cynicism aside, it may be that the work on feline aids will, in fact, lead to the biggest breakthrough to date on Human Aids: a vaccine)

It's roughly estimated that about 2-14% of the cat population carry the Aids virus but this includes the feral and semi-wild cat population.  Among the well loved pet cat population the number of cats affected is probably about 1%.

Feline Immunodeficiency Virus, most commonly called “Feline AIDS,” is viral infection that affects the immune system of cats. It is similar to the AIDS virus that affects human beings, but it is NOT contagious to human beings.

A cat that has FIV is not able to fight off other diseases. Though most cats will eventually die of secondary illnesses, having FIV doesn't’ necessarily mean that your cat is going to die right away. Many cats with Feline AIDS live quite a long time before they become ill. You’l often see cats with FIV living in veterinarian offices or in the front office of the animal shelter.

How does Feline AIDS spread?
Feline AIDS can spread through saliva and blood, as well as mother’s milk. It can be spread from cats eating from the same bowl or from sexual contact, and it can be spread from a mother cat to her young, though these are not the way the virus is most frequently spread. The most common way that FIV is spread is from un-neutered male cats that fight for territory and receive deep bite wounds.

How is FIV diagnosed?

We now have an in-clinic test kit for Feline AIDS.  It's inexpensive and reliable... except for a couple of situations that give us false positive test results:

A negative test is reliable and means that a new kitten or young cat you just got can safely go home to mingle with your other cats

If you have a terribly sick cat and the FIV test comes up positive then we can be pretty confident that Feline AIDS is the cause and that euthanasia is probably an appropriate idea.

Here's the problem we run into occasionally:  kittens may be carrying FIV antibodies from their mother's milk for up to 6 months of age.  These antibodies may make the test come up positive but the kitten does NOT have the disease.  Because of this possibility, we recommend that the test be repeated after 6 months old.  It may very well come up negative then.  But, of course, that may put you in a bind, dealing with a kitten that may or may not be positive for a potentially fatal and contagious disease.

Here's another problem with the test:  the test will come up positive if your cat has been vaccinated with the new FIV vaccine that became available in 2002.  This makes testing a seemingly healthy stray cat that you bring in that comes up positive a dilemma.  Does it have the disease or was it vaccinated at some point in it's previous life.

How is Feline AIDS treated?

Many FIV positive cats live a normal life span but the vast majority end up dying.  For patients that come into the clinic because they are sick, and then test positive for the disease... most of these patients are dead within a few weeks.  There is no cure for FIV.

There are treatments that can help support the immune system and/or slow down the progression of the disease, and sometimes we can cure or control the secondary diseases such as pneumonia and dehydration for a while but usually such successes are limited.

As with leukemia, treatment is mainly supportive and experimental.

I'm sorry that the outlook is so grim.  Hopefully a cure or more successful treatment is around the corner.

Precautions Around Cats with Feline AIDS
Cats with FIV should be isolated from other cats. They should never eat or drink out of the same bowls or share bedding and toys. Even newborn kittens should be removed from a FIV-infected mother cat. Any other household cats that came into contact with an FIV positive cat should be tested once and re-tested 3 months later to insure that they are not infected.

Estimates about what types of cats are most likely to have the disease are also sketchy... some publications say mostly young males, some say mostly older males.  But any cat can get it, including kittens, but it seems that the number one mode of transmission is through bite wounds.  Intact males are at higher risk ONLY because they are more likely to fight and therefore get bitten, but again, any cat can get the disease. 

While bite wound transmission is thought to be the primary cause, other means are possible.  And the disease can stay dormant in the cat for several  years and then start causing trouble.  Very frustrating.

The virus itself is easily disinfected and dies within minutes upon exposure to dry surfaces.

FIV is not transmissible to people.

Many vets attempt to minimize or slow the disease using the same drugs being used to combat human aids.  And again, sometimes there are Veterinary University Experimental Treatment Programs that may accept you cat if it is Feline Aids positive.

I personally have tried immune stimulants to treat feline AIDS. Agents including interferon, staphylococcus Lysate, and Immunoregulin.  Such treatments can cause clinical improvement in infected cats. Combination therapy using these drugs with reverse transcriptase
inhibitors can also be of benefit.  Your vet may or may not be comfortable using these unapproved medications.  But while such treatments seem to help in some cases; they aren't cures.

2014 Update: There is a new treatment available.  I'm not familiar with this new treatment and I suspect that if it worked really well and was practical, there would be lots of discussion about it at our meetings... it would be a truely great event worthy of continuing education not to mention sales reps coming to our clinics to detail us on a life saving new treatment.  So far that hasn't happened.
Also notice that it is USDA approved but not FDA approved.

But maybe I'm wrong:

Lymphocyte T-Cell Immunomodulator (LTCI) is the first and only USDA-Approved treatment aid for cats infected with Feline Leukemia Virus (FeLV) and/or Feline Immunodeficiency Virus (FIV). Results from clinical studies have shown LTCI to have positive benefits on the health of cats infected with FeLV and FIV.
On This Page:
The basics for understanding this usually fatal disease of young cats.

A little about the vaccine that became available in 2002 and a new USDA approved treatment... neither of which seem to be very successful ... but maybe I'm wrong about the treatment, and if I'm not wrong, then maybe success is right around the corner.

On Other Pages about Infectious Diseases:
(There is a complete directory
of links at the bottom of the page)

Introduction page to infectious diseases in pets

Rabies in dogs and cats

Canine distemper (CDV) 

Canine parvovirus (CPV)

Infectious canine hepatitis (ICH)

Tracheobronchitis (CAV-2)
Kennel Cough


Canine herpesvirus (CHV)

Brucellosis in Dogs

Toxic Shock Syndrome in Canines caused by Streptococcus

Feline leukemia

Feline respiratory disease complex FVR, FCV, FPN

Fip: Feline Infectious Peritonitis


About other cat topics on other pages:

Cats: our introductory pages to these fascinating creatures and their medical problems

Vaccine Recommendations for cats

What To Expect When You Take A Sick Cat To The Vet
Toxoplasmosis from Cats

Urine Spraying and Marking Behavior in Cats

Feline Asthma  
Feline Heartworm Disease

Feline Reproduction & Sex

A Short History of Cats
and an interesting article about cat extermination in Australia

Feline AIDS Vaccine Becomes Available in 2002

Thousands of cats in the United States alone die every year due to feline immunodeficiency virus.

The vaccine was more than 10 years in development. Janet Yamamoto, Ph.D., an immunologist and researcher at the University of Florida, developed the patented technology responsible for this medical breakthrough.

Dr. Yamamoto also co-discovered the virus itself, along with Dr. Niels Pedersen, an international authority on retroviruses and immunologic disorders of small animals at the University of California at Davis.

The two universities hold joint patents on the vaccine, and Fort Dodge, with approval from the United States Department of Agriculture, utilized the research to develop a commercial vaccine.

"It is generally believed that transmission of FIV takes place through bite wounds inflicted during fighting, and no cat-to-human transmission has ever been reported in the literature. We do, however, see the virus spreading rapidly through the cat population with up to 15 percent of at-risk or sick cats already infected with FIV," said Dr. Yamamoto in a statement.

Although FIV is often called "feline AIDS," it is not related to human immunodeficiency virus, or HIV.

Like most vaccinations, the FIV vaccine is not 100 percent effective and not without risks

Another concern is that if tested, cats vaccinated for FIV will not, at this time, be distinguishable from cats that have actually been exposed to the disease, Dr. Werber said both will have FIV antibodies. "That could cause confusion," he said, in interpreting the test results.
2014 Update:
Most feline specialists are NOT recommending this vaccine for most cats and I'm not sure it's available anymore.
Major problems in addition to the vaccine making cats test positive for the disease include:

Not working as well as hoped.

And being a killed, adjuvanted vaccine which has been shown to cause cancer in some cats.
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