Feline Leukemia (FeLV)

If you are a cat owner, you have no doubt heard of the Feline Leukemia Virus, commonly referred to as FeLV.  It is by far the most prevalent disease in cats, killing 85% of infected cats within three years of diagnosis.  However, even though these statistics are frightening, exposure to FeLV does not mean a certain death sentence for your cat.  Many cats come into contact with the disease but are able to resist the infection. 

FeLV affects cats ONLY.  It can be passed from one cat to another through saliva and blood, and to some extent, feces and urine.  Grooming and fighting between cats is the most common way for the virus to be spread.  Kittens can also be infected in utero or through their mother’s milk. 

Symptoms include pale gums, yellow color in the mouth or whites of the eyes, enlarged lymph nodes, weight loss or loss of appetite, poor coat condition, weakness or lethargy, fever, diarrhea, and breathing difficulty.  However, these are common symptoms for many different diseases and infections so it is important to seek a veterinary diagnosis if you do notice any of these signs. 

Your veterinarian can diagnose the disease by a simple “SNAP” blood test performed at a veterinary hospital with immediate results or a different form of the test called an ELISA that can be done through their diagnostic laboratory.  The test is highly sensitive and can identify cats with very early infections.  Some cats, however, will manage to clear the infection after exposure and will test negative.  At that point, if the virus is still suspected, a second blood test called an IFA may be performed at the discretion of your veterinarian.  This test detects the progressive phase of the disease.  In general, IFA-positive cats have a poor long-term prognosis.

As mentioned above, a very large percentage of cats persistently infected with FeLV die within three years of diagnosis.  However, diligent check-ups and preventative health care can help keep these cats feeling well for some time.  Presently, there is no cure for FeLV. 

There’s good new though; you CAN protect your cat from FeLV!  Kittens may be vaccinated against the virus as early as 8-12 weeks old, followed by a booster vaccination one month later.  They will then receive boosters to the vaccination every 1 or 2 years (depending on the vaccination protocol).  If introducing a new cat to your household (especially if you already have other cats in your home), it is very important to have the new cat tested first.  The vaccine should then be given ONLY if the test is negative.  The BEST way to prevent your cat from exposure to FeLV is to keep him indoors.  All outdoor cats should be vaccinated against FeLV. If there is a possible exposure to the virus at any time such as a cat fight or interaction with another cat, have your cat tested after thirty days.  This will help assure the results of the test are accurate. 

Lastly, it’s important to remember that not all cats that infected with the virus will appear sick.  A perfectly healthy looking and acting cat may be infected and unknowingly spreading the virus.  This is why testing for the disease is so important; second only to vaccinating!