Feline immunodeficiency virus

Feline immunodeficiency virus (FIV) is a Lentivirus that affects cats worldwide, with 2.5% to 4.4% of felines being infected. FIV was first isolated in 1986, by Niels C Pedersen and Janet K. Yamamoto at the UC Davis School of Veterinary Medicine in a colony of cats that had a high prevalence of opportunistic infections and degenerative conditions and was originally called Feline T-lymphotropic virus. It has since been identified in domestic cats. It has been suggested FIV originated in Africa and has since spread to feline species worldwide. FIV compromises the immune system of cats by infecting many cell types, including CD4+ and CD8+ T lymphocytes, B lymphocytes, and macrophages. FIV can be tolerated well by cats, but can eventually lead to debilitation of the immune system in its feline hosts by the infection and exhaustion of T-helper (CD4+) cells. FIV and HIV are both lentiviruses. However, humans cannot be infected by FIV, nor can cats be infected by HIV. FIV is transmitted primarily through deep bite wounds, where the virus present in the infected cat's saliva enters the body tissues of another cat. FIV-positive cats can share water bowls, food bowls (for both wet and dry cat food), and use the same litter box with low danger of transmitting the disease. A vigilant pet owner who treats secondary infections can allow an infected cat to live a reasonably long life. The chance that an FIV-infected cat will pass the virus to other cats within a household is low, unless there is fighting between cats, or wounds present that could allow entry of the virus from infected to non-infected cat. Newborn kittens may test positive for up to six months and most thereafter will gradually test negative. It is thought that this is due to antibodies transferred to the kittens via the mother's milk. However these antibodies are transient so subsequent testing will be negative. Once they have received vaccinations against FIV, they will, in the future, always test positive, as the various blood tests detect and show the antibodies that have developed in response to the vaccination.