Feline Immunodeficiency Virus is a pathogen that infects one out of every ten domestic cats globally. It is seen in wild and big cats as well, though in their case it seldom leads to the AIDS-like illness that it causes in smaller felines. The virus itself belongs to the Lentivirus group, a genus in the family of RNA carrying Retroviridae. The disease it causes is Feline Acquired Immunodeficiency Syndrome, a chronic condition characterized by depleted immunity of the body, leading to multiple secondary infections.
Feline Immunodeficiency Virus, or FIV, is usually seen in feral cat populations where it spreads through deep bite or scratch wounds from one cat to the other. Occasionally it may pass from an infected mother (queen) cat to the kittens, though usually the virus resides in male outdoor cats who frequently fight with each other over territory and females. Once the virus enters the bloodstream it spreads to the lymph nodes where it may cause swelling. Next it may lead to fever and other relatively mild clinical manifestations before going dormant, as in the case of Human Immunodeficiency Virus, for an extended period of time. After many months or years, it may finally resurface and attack the body's defensive white blood cells - lowering their level below a critical limit and thus weakening the infected animal's bodily defense systems to a degree that renders it quite vulnerable to opportunistic infections.
Despite the morbidity and mortality associated with FIV, infection by it is not necessarily fatal. Many animals act as carriers and with good diet and proper veterinary care can lead a normal and healthy life for years. Along with the added care it is important that the cat be neutered/spayed and not go outdoors where it may infect other felines or contract other infections. If there are other cats in the same household, they may be separated. Usually though the risk of transmission to other house cats is low in a friendly environment. The virus does not spread to other animals and humans. Thus there is no need to euthanize a cat that has been diagnosed with FIV. The Association of Feline Practitioners advises against it and recommends timely checkup and care.
In order to prevent your cat from acquiring FIV, make sure that he/she doesn't go outdoors, particularly for extended periods without supervision. Sterilized cats and those that lead an indoor life are the ones least at risk from coming into contact with the virus. A vaccine does exist against FIV but its efficacy is not firmly established as of yet. Therefore, in this instance as in most other illnesses, prevention is better than cure!