Feline leukemia virus is a highly contagious viral disease of cats that affects the red and white blood cell-producing tissues of the cat. Since feline leukemia virus suppresses the cat's immune system, it is unable to fight off other diseases. Consequently, an infected cat can display a variety of diseases. The types of diseases most commonly seen with leukemia virus are a profound, irreversible anemia with low white cell count; tumors; or leukemia, for which the disease was named.
Signs of the disease include persistent infections, rapid weight loss, severe anemia, difficulty breathing, and enlarged lymph nodes. The virus is transmitted through body fluids from bite wounds, aerosol droplets, or prolonged intimate contact. Kittens can be infected through the mother cat or queen. The virus can be detected in the blood and other body fluids within 2 to 5 weeks after infection.
There are several types of blood tests available to test for feline leukemia virus. Some tests are a sensitive screen that indicate exposure to the virus; other tests will more definitively indicate if your cat has permanent infection. A positive blood test in the absence of clinical signs does not necessarily mean that your cat has the disease. Repeated, confirmatory tests may need to be performed to tell definitively if your cat has merely been exposed to leukemia virus, or if it has the disease. However, if your cat is showing clinical signs of the disease and tests positive, it likely has the disease.
There is a vaccine available to prevent feline leukemia virus. Talk to your veterinarian about a leukemia prevention program that is best for your cat.
University of Minnesota PetCARE Information Center