FeLV, Feline Leukemia Virus, is a deadly disease that affects domestic cats and some wild ones as well.
There are 3 main types of FeLV, A, B and C. Infection of one, two or all three can occur in a cat.
A is in all FeLV diagnosed cats. It results in a severly weakened immune system.
Half of all cats infected with FeLV result in B, tumors and other abnormal growths.
C is found in only about 1% of FeLV infections and causes severe anemia.
The virus continues to reproduce, spreading via the bloodstream to other parts of the body such as lymph nodes, intestines and bone marrow. Because of the weakened immune system, cats are susceptible to other types of infection.
There is a vaccine against FeLV, but it is not 100% effective.
There is a blood test to determine the presence of FeLV which is given by the vet. It is a good idea to have your cat tested if you have a multi-cat household and/or your cats go outdoors.