6 Common Myths About Feline Leukemia Virus

Feline leukemia virus (FeLV) is one of the most common infectious diseases in cats, affecting between 2 and 3% of all cats in the United States, and 3.4% of all cats in Canada. It is a virus that attacks a cat’s immune system, weakening it.

FeLV is spread between cats through their saliva, nasal secretions, urine, feces, and milk. Cats who are infected with FeLV are at higher risk for some cancers, blood disorders, or secondary infections due to their weakened immune response.

FeLV is often misunderstood, which has led to the euthanasia of many of these special felines infected with the virus. Even the most avid cat lover may hesitate to adopt a cat with a FeLV diagnosis, or may be unsure of what is next if their cat is diagnosed. . 

Let’s explore some common misconceptions about FeLV:

• FeLV Myth #1 – FeLV is a form of cancer. 

FeLV is not cancer. It is a retrovirus that attacks a cat’s immune system, weakening it. 

• FeLV Myth #2 – FeLV can be transmitted from infected cats to other animals or people.

FeLV is highly species-specific, and cannot be transmitted to humans or other species. The virus does not survive outside of a cat’s body, meaning there is no risk of transmission to people or other animals through high touch surfaces or cuddling or petting a FeLV positive cat.

• FeLV Myth #3 – A cat diagnosed with FeLV will have a short life, or be very sick for the rest of their life.

A diagnosis of FeLV is not a death sentence! In fact, studies show that affected cats live as long as cats without FeLV. They also are not necessarily going to suffer from symptoms. Cats with FeLV are more susceptible to illness, and any illness should be treated as quickly as possible. 

• FeLV Myth #4 – Cats with FeLV can’t live with other cats.

This myth is partially true. Because FeLV is transmitted through shared food bowls, mutual grooming, and other close contact with infected cats, FeLV infected cats should be housed together. They don’t need to be isolated, but they shouldn’t be allowed contact with non-infected cats, and they should be kept inside. 

• FeLV Myth #5 – The only way to protect a cat from FeLV is to keep them away from infected cats.

Preventing contact with infected cats is definitely important, but it is also important to vaccinate your cat against FeLV. This vaccine is typically given once a cat reaches the age of 8 weeks, in 2 doses, 3-4 weeks apart. 

• FeLV Myth #6 – Healthy adult cats can’t get FeLV.

All cats can become infected with FeLV, though kittens or cats with already weakened immune systems are more susceptible. Healthy, adult cats can still contract the virus through prolonged exposure to the virus.

Diagnosing Feline Leukemia Virus

FeLV is diagnosed through a blood test. These blood tests look for the presence of FeLV antigens, as well as PCR tests that look for proviral DNA (a copy of the virus DNA which the virus creates in the cat’s body).  A recent study has shown that using these tests together in infected cats may help your veterinarian understand how severe your cat’s FeLV infection will be, to better plan for managing the infection.

Prevention & Treatment of Feline Leukemia Virus

FeLV has no cure. If your cat tests positive for FeLV, your veterinarian will help your cat if they need to be treated for specific signs of illness, such as prescribing antibiotics for bacterial infections. 

However, we can take steps to prevent FeLV infection:

• Vaccinate your cat against FeLV. 
• Have your cat tested. Testing for FeLV should be part of your cat’s regular, routine care. If you have adopted your cat from a shelter, ask if they have been tested for FeLV, as well as what the results of the test were. At Cat Healthy, our protocols recommend that cats are tested in the following situations:
  • At-risk cats: All sick cats, cats with bite wounds or oral disease, cats with known exposure to a retrovirus-infected cat, cats living in multi-cat environments where the status of every cat is not known. Sick cats should be tested regardless of a previous negative FeLV test result.
  • Newly acquired cats and kittens.
  • Cats about to be vaccinated against FeLV.
  • Cats at ongoing risk of infection (e.g. cats with access to outdoors) should be tested annually for FeLV.
• Keep your cat indoors. Cats who have access to the outdoors are more likely to acquire a FeLV infection.

Living With a Cat With Feline Leukemia Virus

Whether your cat has been newly diagnosed with FeLV, or you’ve chosen to adopt a FeLV positive cat, remember that what your cat needs the most from you is your love and caring. Form a strong relationship with your veterinarian, see them regularly, and follow their instructions for managing your cat’s health. Together, you can help your kitty live a longer, more healthy life! 

This article was written by feline specialist Dr. Liz O’Brien DVM, DABVP and sponsored by IDEXX.