Feline Leukemia & Feline Immunodeficiency Viruses (Updated)

Feline Leukemia virus (FeLV)  and Feline Immunodeficiency Virus (more commonly referred to as “kitty AIDs” ) can both cause the cat’s immune system to become suppressed and lead to other health problems and a shortened lifespan.

There is a test available to us called a SNAP test. This test takes less than 10 minutes and is run in the office with just 3 drops of blood. 

Feline Leukemia: 

-is most often transmitted through casual contact - grooming,
   sharing of food/water bowls 

-there is a vaccine for it - and it will NOT cause a false     
  positive on the SNAP test

-can cause cancers in cats

-not transmissible to you or your dog, bird, etc

-can cause “fading kitten” syndrome where kittens in a litter fail to thrive and die

 FIV

-most often transmitted through bite wounds (unneutered    
  outdoor male cats are at the highest risk) and sexual contact

-kittens can test falsely positive - they may have antibodies
  from mom - they need to be retested every few months
  (could take up to 6mos to clear these).

-cats can live many years with this and not have any clinical
 signs

-there is a vaccine available but it DOES call a false positive
  on the SNAP test

-not transmissible to you or your dog, bird, etc.

Cats can have either one of these viruses and not be showing any clinical signs. You cannot tell by looking at the cat. And both can cause a variety of signs and illnesses (upper respiratory infections, lethargy, anemia, weight loss, loss of appetite, enlarged lymph nodes, etc). 

Which cat should be tested?

-any new cat or kitten

-any sick cat (even if previously tested negative)

-cats that are at risk (outdoors, get into fights, etc)

-before vaccinating for FeLV or FIV 

It can take months for antibodies to form to these viruses and there are a percentage of cats that will have the virus (FeLV) but it will be “hiding” in the bone marrow or other cells and NOT be detectable by blood testing. 

The best way to prevent it is to have any new cat tested before bringing into your home, have them spayed or neutered AND to keep them indoors. If they go out, have them vaccinated. I’m not a big fan of the FIV vaccine but that’s because it will cause a positive on the test. This means if someone vaccinates a cat, the cat becomes a stray and then gets tested at a shelter or before coming into someone’s home, it will be a “positive.” This could be a death sentence in some cases but they cat was not truly infected! This is why we strongly encourage microchipping these pets. If they are found as "stray" the shelter or vet will know they are owned and not condemn them. 

The FIV vaccine also does not really protect against the sub type of FIV we have here in the US (vs Europe). 

FeLV vaccination is HIGHLY effective and you can have positive cats with negative cats IF you vaccinate your negative ones. Most people though are just not willing to take any chances, which is understandable.

The American Association of Feline Practitioners, recommends ALL cats get a feline leukemia series as part of their kitten vaccination program. At a year old, we can re -evaluate their lifestyle. It is amazing how many cats that were going to be "indoor only" are, at that point, going out, even "just on the porch" is outdoors with potential exposure.

If they do test positive, it is NOT a death sentence. Cat can live with FIV for years without getting sick. Feline leukemia does tend to cause illness much quicker, especially if the cat was a kitten when infected. 

Keep them indoors because they will have significantly reduced exposure to other cats and diseases. There are some places that take these cats in and re-home them to FeLV + or FIV+ homes. 

This is a good website with more info and a quiz to find out how many positive cats are in your county/state. My only question on this ..how do they know? I don’t report the positives to Idexx. I don’t know any vets that do. So I”m not sure where they are getting the data (did they do a poll? did certain vets participate in it?). 

http://www.kittytest.com/index.jsp