The feline immunodeficiency virus
(FIV), first discovered in a northern California cattery in 1986, is a major
cause of chronic immunodeficiency in cats. FIV is a retrovirus
belonging to the lentivirus family. It is related to the HIV virus in humans
(the virus that causes AIDS). However, these two viruses are species-specific.
HIV does not produce disease in cats and FIV does not produce disease in
FIV infection is believed to be transmitted by cat bites, such as the one
causing this infected wound.
The following information isn’t intended to replace regular visits to your veterinarian. If you think your cat may have feline infectious peritonitis, please see your veterinarian immediately. And remember, please do not give any medication to your pet without talking to your veterinarian first.
Although its exact incidence has yet to be determined, FIV has been found in
cats throughout the United States and is believed to affect 2 to 4 percent of
cats in the general population. The incidence is highest in outdoor cats and in
males 3 to 5 years of age. This suggests that cat bites, occurring during
fights among toms, are a source of virus transmission, especially since the
virus is shed in saliva.
Close or casual contact alone is not a major mode of transmission. There is
no evidence that the disease is transmitted by mating. However, if a queen
becomes infected while pregnant, she may pass the virus on to her unborn
Signs of Illness
Four to six weeks after FIV exposure, there is acute illness characterized
by fever and swelling of the lymph nodes. The white cell count is below normal.
The cat may have diarrhea, skin infections, and
anemia. After the acute
infection, there is a latent period from several months up to 12 years during
which the cat appears to be healthy. Eventually, signs of a chronic
immunodeficiency syndrome appear and progress slowly (again, over a period of
months or years).
Cats with chronic FIV infection present with a variety of unexplained signs
of ill health, including severe mouth and gum disease, long-standing
diarrhea, loss of appetite and weight with emaciation, fever, recurrent upper
respiratory infections with eye and nasal discharge, ear canal
infections, and recurrent urinary tract infections. These signs are similar to
those associated with other immunodeficiency disorders, such as feline leukemia, severe malnutrition,
immunosuppressive drug therapy, and widespread cancer. About 50 percent will
have chronic oral conditions and about 30 percent will have chronic upper
respiratory infections. Ten to 20 percent will have diarrhea. Many will show
neurological signs such as dementia. FIV-infected cats also are much more
likely to develop lymphoma.
If antibodies to FIV are found in the cat’s serum using an ELISA test, it
can be assumed that the cat is persistently viremic and can be a source of
infection to other cats, or has been vaccinated with the FIV vaccine. All
ELISA-positive tests should be confirmed with another test, such as an IFA or
Western blot immunoassay, performed at a reference laboratory. However, even
these tests cannot distinguish vaccinated cats from infected cats. Research
continues for a test that will distinguish between truly infected cats and cats
who have been vaccinated.
There are two sets of circumstances in which these tests may have a false
negative result. One is during the terminal stages of FIV when the cat is
unable to produce detectable antibodies. The other is during the early stages
when virus is present in the serum but antibodies have not yet been produced.
In the latter case, the cat can be retested in two to three months.