Feline leukemia virus (FeLV) is one of the most common and destructive of all cat viruses. It is highly contagious and is spread primarily by saliva during catfights, grooming or mating. The virus may also be spread by blood, urine and feces. Kittens may become infected while still in the womb, at birth, or during nursing.
Currently, there is no effective treatment for cats infected with FeLV. Of the cats persistently infected, about 25% will die within one year, and 75% will die within three years. Some may live longer, but tend to have various chronic illnesses.
There are no signs specific for FeLV infection, because it can affect any organ system. The main effect of the virus is to disrupt the cat’s immune system. While anemia is the most common disorder caused by the virus, cancer and various other diseases are common. Some disorders commonly associated with FeLV include: chronic GI or respiratory disease; chronic infection of the mouth, gums and tongue; chronic eye disease; frequent or chronic skin disease and frequent or chronic urinary tract infections.
Outdoor cats (ie those exposed to other cats) are at risk for developing FeLV infection. Testing and vaccination before exposure to the virus is the best means of preventing FeLV infection. The vaccination protocol is two initial vaccines one month apart, followed by yearly boosters. Without vaccination, isolation from other cats is the only means of prevention.