What is feline leukemia?

FeLV (feline leukemia virus) is an infectious virus and not a cancer as the name might suggest. When the cat is infected, a retrovirus produces an enzyme called reverse transcriptase that allows the virus to insert copies of its own genetic material into the infected cells. Though FeLV is not cancer, the resulting changes to the cells can potentially make them cancerous. The cancer can occur in a variety of tissues, organs and body sites, depending on where in the body the infected cells are located. They can also affect circulating white blood cells or other cells of the blood-forming tissues. The most common type of cancer associated with feline leukemia is lymphosarcoma or cancer of the lymphoid cells.

While cancer can develop as a result of FeLV, the virus can lead to a variety of other conditions as well including: a suppressed immune system, anemia, severe enteritis, severe dental disease, neurological disorders and even eye diseases.

FeLV is specific to members of the cat family and cannot spread to humans or other species of animals.

How is FeLV transmitted?

Cat-to-cat contact is the most common way the virus is transmitted. The virus is shed from an infected cat in large quantities of the saliva, nasal secretions, urine, feces and/or mother’s milk. Mutual grooming, sharing of food and water bowls, or bite wounds are other ways the virus is transferred from one cat to another.

Are there cats that are at greater risk of infection?

Yes. The following cats are more likely to get FeLV:

  • Cats exposed to infected cats, either through prolonged close contact or bite wounds.
  • Exposure can occur for cats living with another infected cat in the home, but primarily exposure occurs with cats that spend time outside.
  • Kittens with FeLV-positive mothers

What happens when my cat is exposed to FeLV?

Potentially nothing. Not every cat exposed to FeLV will actually develop an infection. Many are able to build immunity to the virus. As a result, about 30% of cats that are exposed successfully eliminate the virus from their bodies over a matter of weeks. The other 70% are not able to fight off the infection and become permanently infected.

If your cat is infected, it may be months or years before any of the related clinical diseases become evident. Those may include:

  • Loss of appetite
  • Slow but consistent weight loss
  • Poor coat sheen
  • Persistent fever and enlarged lymph nodes
  • Gingivitis and stomatitis
  • Urinary and upper respiratory infections

How is FeLV diagnosed?

Detecting FeLV typically begins with a rapid blood test or snap test in the vet’s office taking about 15-20 minutes for results. This test is usually just a starting point, and we frequently want to confirm test results by running an IFA or PCR Leukemia test through a reference laboratory. These two tests are more sensitive and are looking for anti-bodies bound to the leukemia virus.

In younger cats, you may potentially have a false positive for the first test if the cat is developing immunity. We typically recommend repeating the initial snap test 8-12 weeks after the first positive in young cats before confirming diagnosis or running additional testing.

How is FeLV treated? Can it be cured?

At the moment, there is no specific treatment that eliminates the virus from the cat’s body. As a result, FeLV usually leads to diseases that are ultimately fatal. However, even if your cat has been diagnosed with FeLV, you and the Just Cats team can work on an effective treatment and maintenance plan to help your feline friend. Early diagnosis and aggressive symptomatic treatment of the FeLV-related diseases can lead to some improvement in the cat’s overall condition.

Can FeLV be prevented?

Fortunately, there are simple things you can do to prevent your cat from ever getting FeLV. For example, there is a vaccine that protects a cat against FeLV. Talk to Just Cats vet about whether the vaccine is the right choice for your cat based on your cat’s individual risk factors. Some of those factors include how much time your cat spends outside, whether they interact with other cats including other cats in your household or if you foster or have a friend or family member’s cat(s) over to your house.

As with any vaccine, there is an initial course of two injections, followed by regular boosters to maintain immunity. Also before you bring any new cat into your home, make sure it has been tested for FeLV before introducing the rest of your feline family.