Ask a Vet with Dr. Sam: What is Feline Leukemia (FeLV)?

Feline leukemia virus (FeLV) is a complex retrovirus found in cats. It is the second biggest health threat to cats, surpassed only by trauma. It was first discovered in cats that had leukemia, which is a cancer of circulating blood cells. Nowadays, we know that this virus does cause leukemia—one of the few known infections that can lead a cat to develop cancer—but most cats with feline leukemia virus are asymptomatic (do not show signs of symptoms). FeLV discordant cats are those who have been exposed to the virus and tested positive, but it hasn’t infected their bone marrow yet.

Cats that are infected with this virus can either succumb to it or develop an immunity. There are three possible outcomes for cats that are exposed to FeLV. A cat can fight the infection off and become completely immune to it. They can become a carrier that never gets sick but can infect other cats, or they are unable to fight the infection and ultimately become terminally ill.

Is it contagious?

Feline leukemia is quite contagious to cats and can be found in saliva and nasal discharge and can be transferred via casual contact between cats (i.e., sharing food or water; mutual grooming; bite wounds).  It is extremely uncommon for a one-time exposure to lead to infection; rather, repeated exposure such as sharing food/water dishes and using common litter areas contribute to the spread of this virus between cats. This is why cats that are FeLV positive are usually adopted out to homes that have no other cats in the household, or to a home with another FeLV positive cat.

Should I adopt an FeLV+ Cat?

Cats with FeLV need love just as much as any other cat! In fact, maybe even more so since they are often passed over for adoption because people aren’t familiar with what to expect from living with a FeLV+ cat. Here’s what you should consider when adopting one of these special cats:

• Some cats naturally keep the virus in check for years and have a normal quality of life, they just have a shorter life expectancy. The seriousness of a cat’s FeLV infection is highly variable and based on many factors.
• The best information on keeping your FeLV cat healthy will come from monitoring your cat, which is why establishing a schedule of regular visits with your veterinarian (every six months) is key.
• Cats that are FeLV positive must be kept indoors to prevent spreading the virus to other cats and to help prevent them from getting diseases that another cat might carry.

MRFRS’s commitment to advocating for and adopting out FeLV+ cats is part of our mission to improve the lives of all cats. We never give up on finding them forever families who are willing to provide the care and love they deserve. When you’re ready to adopt, look at the FeLV+ cat profiles – it may just lead to one of the most rewarding relationships you’ll have with a pet!