Feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) can cause many types of illness as well as death in infected cats. These viruses do not infect humans or other animals.
FELINE IMMUNODEFICIENCY VIRUS Feline immunodeficiency virus is more commonly found in male cats that are not neutered and in cats that fight with other cats. It is found less often in kittens and neutered adult cats. The virus is spread through the saliva and is usually passed to other cats by bite wounds. In North America, about 3 to 5% of tested cats are found to be infected with FIV. In Latin America, up to 25% of tested cats are found to be infected.
FELINE LEUKEMIA VIRUS Feline leukemia virus infection is more commonly spread among cats that live together. The virus can also be spread from mother to kittens, and among cats that fight. It is mainly spread through saliva when cats groom each other, and when food and water bowls are shared. In North America, about 4% of tested cats are found to be infected with FeLV. In Latin America, up to 42% of tested cats are found to be infected.
SIGNS OF INFECTION A cat newly infected with FIV may show mild illness, with fever or a drop in appetite. These changes do not last more than a day or two before the cat is back to normal. After the early days of infection, the cat may not be sick for months or years. These cats can still infect other cats. Later in life, the cat’s infection may become active again, and the cat will show signs of sickness. When the virus is active, it can weaken the immune system, leaving the cat at risk for different infections. The virus can also cause cancers in infected cats. As it can take many years for the virus to become active again, many cats infected with FIV can live long and healthy lives. When first exposed to FeLV, a cat might not show any signs of illness. Some cats that are exposed to FeLV can clear the virus completely from their body. Other catsare able to control the infection, preventing illness. In some cats, the infection will become active in their body and they will develop problems such as low red blood cells (anemia) or cancer. These problems can be severe and even fatal.