Introduction
Feline Leukemia is a viral infection that affects the immune system, causing secondary infections or the development of cancer in cats. Clinical signs can include persistent infections, weight loss, appetite loss, and muscle wasting. It occurs most often in cats between one-to-six years of age.
Feline leukemia virus (FeLV) infections are acquired from direct contact with infected saliva, either through mutual grooming (via open wounds or sores) or bites. However, not all cats that are exposed to the FeLV virus necessarily become infected. Younger cats tend to be more susceptible than older cats.
Outlook
When natural exposure to the FeLV virus occurs, one of three things can occur:
- The exposed cat may not become infected at all
- The cat may become infected temporarily
- It can become infected and eventually die. Cats in this last category are typically young cats and they usually die within three-to-four years as a result of FeLV-related disorders. Only in rare cases do they manage to live longer.
For cats that are only temporarily infected, one of two things can happen: some will completely eliminate the virus from their body, while the rest will carry a latent infection. In those with latent infections, the virus hides in the bone marrow. There is no virus shedding (therefore, these cats are not contagious) and they are in no risk of developing FeLV-related disorders. However, these cats can become "reactivated" at a later time if they are stressed or if corticosteroids are used.
This latent period will usually last less than nine months and most will have completely eliminated the virus within three years. These cats will test positive during the time when they are temporarily infected with the virus. Because this temporary stage only lasts about four-to-eight weeks, a cat suspected of having FeLV should be retested in six-to-eight weeks to see if the cat still tests positive. If it again tests positive, then the prognosis is usually poor. If the cat is otherwise healthy, it should be kept isolated from other cats in order to prevent it from infecting them. Outdoor activity should be discontinued.
If the test is negative, the cat can be kept in the house with other cats and will not infect them. However, there will be the possibility (albeit a small one) that the cat may become positive again at some future date. For this reason, retesting by your veterinarian should be done at regular intervals(about every three to six months).