In cats, the Feline Leukemia Virus can manifest in three different ways, and will thus determine what kind of future your cat has.

The first category includes the various forms of leukemia, basically a form of cancer of the white blood cells. It's similar to the disease as it occurs in humans, but the feline form cannot be spread to humans, nor vice versa.

The second category is known as lymphosarcoma, a cancerous condition that affects the lymph tissues, such as lymph nodes. It can affect many systems in the body, including digestive, kidneys, liver, brain, bone marrow and the spine.

The third category includes the non-cancerous diseases that fall under the umbrella of FeLV and include immune suppression, anemia and arthritis. However, some of these conditions can be fatal, too, if they become severe.

Cats are most commonly exposed to FeLV when they get into fights. This virus is spread mainly through saliva, and the wounds a cat receives from bites during a fight provide an entry point into the body. Cats can also get FeLV from sharing food or water bowls, grooming one another, and transmission from mother to kittens.

If your cat contracts FeLV, there are several possible outcomes, not all of them fatal. Some forms of the disease cannot be treated, however, so prevention is critical. There is a vaccine for feline leukemia, so it's a good idea to consult with your vet to see if it's appropriate for your cat. Since a cat can live quite a long time even if infected, your vet will be able to advise you whether vaccinating is necessary... or possibly too late.

However, cats infected with FeLV are dangerous to other cats, and so they must live in confined single-cat homes to prevent spreading the disease.

Since the disease is not contagious to humans, it's pretty safe to keep an infected cat in your home. Nevertheless, humans with severely compromised immune systems themselves would be well advised to avoid anything that might worsen their own conditions... and that might include a cat with leukemia virus. Be sure to ask your vet what the risks are.