Feline Leukemia Virus, like FIV, is a retrovirus; it can and will cause cancer. Retroviruses have their own RNA. This RNA template inside our feline companions, fools their bodies into replicating the virus.

FeLV transmits in many ways:
  • Saliva passed by grooming one another,
  • Common litter boxes,
  • Sneezing aspirate,
  • Shared food, and water,
  • Bites and scratches

The virus will go through stages of development.

Stage One

The first stage is the Feline Leukemia virus entering the body, most commonly through the throat, where it causes an infection that produces white blood cells which get filtered through the lymph nodes.Once these white blood cells get taken up into the lymph nodes, the virus is inside the body and can begin to replicate.

Stage Two

The RNA replication and distribution into the bloodstream and body where the virus begins to spread causing antibodies to attack the infected cells.

Cornell University Illustration of Feline Leukemia Virus symptoms

Stage Three

Next, the Feline Leukemia virus begins to overpower the immune system and actually enters the blood and organs, further infecting the intestines.  Some cats have very good immune systems and are able to fight off the infection and become immune to the virus, others will not suffer from the disease, however, will be carriers.  Those cats who do not fight off the virus go on the even more infection.

Stage Four

Bone marrow becomes infected, reproducing in the white blood cells inside the bone marrow.  This eventually overwhelms the body and many of the organs and the cat will be sick, lethargic and have not comfort in life at all.

Some, but not all of the symptoms of Feline Leukemia:

  • Abscesses
  • Amenia
  • Diarrhea
  • Ear Infections
  • Fever
  • Fibrosarcomas
  • Inflamed mucous membranes
  • Jaundice
  • Lethargy
  • Lymphomas
  • Pale gums
  • Poor coat condition
  • Swollen Lymph nodes
  • Vomiting

Prevention

Your cats do not have to fall victim to this awful disease.  There are tests that can be performed easily in your veterinarian’s office and a throat swab can be sent on to one of the many labs that do pcr testing.  Cats who are tested before moving into your home and who are kept inside or in a controlled environment outside for their lifespan will be safe from the disease. Outside cats will need to be tested and vaccinated. Once vaccinated your cat will be safe from FeLV.

Many breeders test a cat before subjecting them to their other cats and choose not to give the FeLV immunizations due to the issue with injection site sarcomas.  Please read our article on vaccinations (link) elsewhere on our site.  Please ask your breeder for proof of pcr testing (link) before you accept your Savannah kitten.

The most recent good news for protective vaccines is Merial, a leading vaccine researcher and manufacturer has developed a non-adjuvanted FeLV immunization.  This does not contain the adjuvants that normally cause the reactions from unnecessary proteins, injection site sarcomas, injection site granuloma and chronic inflammation.  Ask your vet about Merial products for this and their rabies immunizations.

We thank Cornell University for the use of the FeLV diagram.  Please donate to their research.

LSL