Feline Immunodeficiency Virus (FIV) is a virus that attacks a cat’s immune system. It is in the same virus family as Feline Leukemia (FeLV) and the human immunodeficiency virus (HIV). Because the immune system is so compromised, the cat is unable to fight off disease and cancer.
FIV is not transmitted by everyday contact (as is the case with FeLV), but it is shed in saliva and is transmitted by bite wounds. This puts free-roaming non-neutered males at greater risk because they are often in contact with other cats. FIV is usually not transferred from an infected mother to the kittens if she is infected prior to becoming pregnant.
FIV is a progressive disease that typically occurs in three different stages. The first stage, is the acute stage. In this stage, most cats experience mild disease (fever, lymph node enlargement, intermittent lethargy and decreased appetite). Most cats recover with no treatment, and rarely receive veterinary care in this stage. This stage usually occurs within 4-6 weeks of infection.
The second stage, or sub-clinical stage shows a healthy, normal cat. There are no signs of disease, but the cat’s white blood cell count continues to deteriorate. This stage can last months or years.
When the cat’s white blood cell counts reach an all-time low, the disease has entered the clinical stage. During this stage, the cat’s immune system is not functioning properly, making him susceptible to cancer and disease. The cat is now very prone to opportunistic infections. These infections, which are usually chronic, may be bacterial, fungal, or parasitic. Normally, these organisms which normally do not cause severe disease in cats, but because the infected cat’s immune system cannot keep them under control, they multiply rapidly and cause disease. Once a cat reaches this stage of disease, most have a year to live.
FIV is diagnosed with a blood test at your veterinarian’s office. FIV infection is diagnosed through tests which detect the cat’s antibodies against FIV. Antibodies are usually present 3-6 weeks after infection. Occasionally, there can be a false positive, so if your cat is positive have your veterinarian recheck again with a different test.
FIV is generally treated on a symptomatic basis. Most cats with FIV respond well to antibiotics for infections, although they may require more aggressive treatment for a longer period of time. Those that develop cancers can be treated with chemotherapy, radiation or immunotherapy. There is no approved anti-viral medications for cats available at this time.
To protect your cat from FIV, keep him indoors at all times to prevent exposure to other cats. This is especially true if your cat has tested positive for FIV. If your cat goes outside for any reason, it should be spayed or neutered to limit any kind of fighting behaviors such as territory protection.
A vaccine against FIV, produced by Fort Dodge, was approved for use in Spring 2002. It does not provide 100% protection, and vaccinated cats will test positive on the antibody test. If a cat with unknown vaccination status tests positive on an in-clinic FIV test, it is currently impossible to distinguish whether the antibodies in its bloodstream developed in response to previous vaccination, or in response to natural infection. Until a test is developed that can distinguish between vaccine-induced antibodies and antibodies that arose because of natural infection, veterinarians must evaluate the potential risks and benefits of vaccination based on each individual cats lifestyle and circumstance.