Saturday, February 28, 2009

Feline AIDS Virus

Q: Dear Dr. Gordon: My cat had a blood test recently and the results showed that he has the Feline AIDS virus. I am concerned because I have other cats in my house. Are they going to get Feline AIDS as well? Can I get AIDS from my cat?

A: Response From Dr. David Gordon: This is a great question because there is a lot of good information and misinformation regarding these viruses in cats.

Let's start with the Feline AIDS issue first. Felline AIDS is generally referred to as FIV or Feline Immunodeficiency Virus. The virus that causes Feline AIDS is a retrovirus that is in the same viral family as the Human AIDS virus. To this date, there have been no known infections of people by cats infected with the Feline retrovirus. As a general rule, FIV is generally a disease of unfriendly cats. By this I mean that most cases of FIV are transmitted by bite wounds during cat fights in cats that have spent a significant amount of their lives living outdoors. Generally speaking, cats that live indoors and co-exist peacefully have little risk of transmission of the virus. It is still recommended, however, that cats who definitively test positive be separated from uninfected cats to minimize the possibility of transmission. Experimentally, FIV has also been shown to pass from infected pregnant cats to their kittens, but in real life this seldom occurs or is isolated to a few FIV serotypes. Regardless, if an intact female cat has FIV, she should be spayed so that she will not pass the virus to future generations of kittens.

You don't mention in your original question how the vet determined that your cat has FIV or if you cat is sick or healthy. The reason these questions are important is that there are different types of tests run on cats. There is a screening test for FIV that is included in many routine blood panels. This test is an ELISA test that "tests" for the Feline AIDS virus antibody. Even though these tests are highly sensitive and specific (98%), there is a relatively high percentage (65%) of false positive results in cats that are showing no clinical symptoms. For that reason, most vets recommend that cats who test positive on the initial screening test get an additional "confirmatory test" to prove definitively that the screening test is either correct or incorrect. This is the same procedure that is done on people who initially test postivie for the Human Aids Virus. The confirmatory test for FIV and HIV is called the "Western Blot" test. If the Western Blot test is negative, your cat does not have FIV. Since there is generally a "latent" period between exposure and infection, cats that are bitten by stray cats outdoors should have FIV tests every 6 months to make sure they have not been exposed to the virus.

FIV generally has three stages of infection. In the first stage, the virus enters the cat's body and causes lethargy, fever, and swollen lymph nodes. In the second stage, the virus is, in effect, dormant and many cats appear to be healthy. This is also called the subclinical or silent phase of the disease, which can last from months to years. In the third and final phase of the disease, the cat suffers infections which overwhelm it's weakend immune system and often dies. This phase can last from months to up to a year.

It is estimated that up to 15% of the world's cat population is infected with the Feline Immunodeficiency Virus. There is no cure, but infected cats sometimes can live with the virus in their systems for up to 10 years, much of it in seemingly good health.  Using antiviral, immune supportive supplements such as Notatum and Quentans can help.