March 12, 2010
Feline Leukemia: Continued from last week…

What happens if a cat is infected with the FeLv (Feline leukemia virus)?

When we are exposed to a virus such as a flu virus, there are two possible outcomes. Either our immune system responds to the challenge and protects us, or it is unable to respond successfully, and we develop the flu. A number of factors determine which outcome occurs and whether or not we will get sick.{{more}}

* The amount of virus (did someone sneeze directly in your face?)

* The strain of the virus (some strains are more potent than others)

* The status of our immune system.

* Age (the very young and very old are more likely to become infected)

* The presence of other infections which might cause debilitation.

The behaviour of the Feline Leukemia virus in the cat’s body is not so black or white. Instead of the two possible outcomes in the case of the flu virus, there are four possible outcomes for cats with FeLv. Understanding these, allows one to more fully understand and appreciate some of the unusual situations which may arise in cats.

Outcome #1: Immunity. The cat mounts an immune response, eliminating the infection.

This is the most desired outcome, because it means that the cat will not become persistently infected with the virus. This occurs about 40 % of the time.

Outcome #2: Infection. The cat’s immune system is overwhelmed by the virus. This is the lease desired outcome as the cat becomes permanently infected by the virus and shows signs of illness. This outcome occurs about 30 % of the time after the cat is exposed to the virus.

Outcome #3: Latency. The cat harbours the virus, but we cannot easily detect it. In this outcome, the cat may remain apparently healthy for 2 ? to 3 years before becoming ill.

Outcome #4: Immune carrier. The cat becomes a carrier of the disease. The cat will appear normal in every way, but will be capable of infecting another cat with the virus. This occurs in only 1 to 2 % of the time.


A vaccine is available to protect cats from this virus. It is advisable that all cats be vaccinated at 8 weeks of age or older against the FeLv Virus.


A simple snap test using a small amount of blood will determine whether your cat is infected or not.

What should I do to disinfect my house if a cat has recently died of FeLV?

The FeLv lives at most, only a few hours outside the cat if the environment is dry. Therefore, extensive environmental disinfection is not necessary. If you wait two days to get a new cat, you can be assured that the virus will not remain in your house.

I have a healthy cat that is infected by the virus, what does that mean?

Healthy infected cats may remain apparently unaffected by the virus for several years. However, such cats should be considered infectious and potentially dangerous to other cats. Such cats should be isolated from non infected cats to prevent spread of the infection. Many people find this undesirable or impossible and elect euthanasia to protect the non infected cats.

For further information, contact: Dr. Collin Boyle
Unique Animal Care Co. Ltd.
Tele: 456 4981