Feline Immunodeficiency Virus
Feline immunodeficiency virus (FIV) is a member of the Retroviridae family of viruses to which HIV (the human immunodeficiency virus) the virus responsible for human acquired immunodeficiency syndrome (AIDS) also belongs. Although FIV is related to HIV , based on current evidence, FIV can not be passed to humans or any other species apart from cats.
Surveys have found, approximately 1.5 to 3% of healthy cat populations are infected with FIV with up to 15% of sick cats with clinical signs of illness being infected with FIV. Free–roaming entire male cats are the most frequently infected, while cats housed exclusively indoors are least likely to be infected.
FIV is spread mainly through bite wounds. Normal contact among cats without fighting does not appear to be involved in the spread of FIV. Occasionally the virus can be transmitted from an infected mother cat to her kittens during pregnancy, the birth process, or when the newborn kittens drink infected milk. There is little evidence that sexual contact will result in infection. The environment is not a source of infection as the virus will not survive for more than a few hours outside the cat's body .
After entering the body, the virus spreads to the closest lymph nodes (glands),where it multiplies in white blood cells (bodies defense cells) known as T–lymphocytes. The virus then spreads to lymph nodes throughout the rest of the body resulting in enlargement of these nodes. Mostly this is only a mild change so may go undetected by the owner. This is followed by a fever and a overall decrease in the number of white blood cells. Anemia (or low red blood cell count ) also may develop with time. There can be a delay of weeks or months before these signs appear. The white blood cells (WBC) are responsible for protecting the body against infection so reduced numbers leave the body open to bacteria, viruses and fungi that can cause disease. Infected cats may appear normal for years with fluctuations in the WBC count between normal and deficient. Signs of immunodeficiency will however eventually develop in most cats, as their WBC count ultimately drops to a level where they are unable to protect themselves against infection.

Clinical signs related to infection with the virus include persistent fever, loss of appetite, and progressive weight loss. Secondary infections are responsible for most of the other clinical signs associated with FIV. These infection can involve the gums (gingivitis) and mouth (stomatitis), the skin, respiratory tract, gut (causing diarrhea) and bladder. Infertility and abortion may be seen in infected queens. Neurological (nerve related) disorders including seizures have been reported as has inflammation in the eye. FIV may also be a predisposing factor in some uncommon yeast and fungal infections such as cryptococcosis.


Diagnosis is based on blood testing to identify FIV antibodies. This test can be performed "while you wait" by your veterinarian. A positive test results indicates that a cat is infected with FIV. Most positive cats will be infected for life and are capable of transmitting the virus to other cats. Because it takes 8 to 12 weeks or more after infection for detectable levels of antibody appear a negative test should be repeated after this length of time if FIV is still suspected. Cats with advanced FIV infection can test negative because their immune systems are too depressed to produce antibodies however this is not a common occurrence. Kittens should not be tested until they are 6 months of age to allow any FIV antibodies passed to them in their mother milk to clear as these can produce false positive results.

There is no specific treatment for FIV . Infected cats should be kept in an environment which minimizes their exposure to other types of secondary infection. This generally means indoors and away from other cats. This also helps to prevent spread of FIV to other cats. Any secondary infections should be treated vigorously with antibiotics and for extended periods. Other supportive measures including dietary energy supplements may be of benefit to help reduce weight loss. Drugs designed to boost the immune system have been used in FIV cats however their true benefit has not been clearly established

There is no vaccine to protect against FIV currently available.