8975 McLaughlin Rd., Brampton, Ontario

What Is Feline Leukemia Virus?

Feline leukemia virus (FeLV) is the second leading cause of death in cats, the viral disease unfortunately kills 85% of persistently infected felines within three years of diagnosis. The virus often causes anemia and lymphoma and since the disease suppresses the immune system, it also predisposes cats to deadly infections.

There is some good news however, about 70% of cats who encounter the virus are able to resist infection or eliminate the virus on their own.


Feline leukemia only infects cats, FeLV is passed from one cat to another through saliva, blood, urine and feces. The virus thankfully only lives for a few hours outside the hosts body. Kittens can contract the disease in utero or by nursing an infected Queen’s milk. The disease is often spread by seemingly healthy cats, so even if a cat appears healthy, it may be infected and transmitting the virus.

Feline Risk Factors

Kittens and young adult cats are more likely to contract FeLV if they come into contact with the virus as compared to older cats, it is thought that resistance increases with age. For strictly indoor cats, the risk of contracting FeLV is low. Felines living in multi-cat households or in shelters and pet stores are more at risk, especially if they share common spaces and litterboxes and bowls.


  • FeLV positive cats may exhibit one or more of the following symptoms:
  • Pale gums or jaundice
  • Enlarged lymph nodes
  • Bladder/skin/respiratory infections
  •  Weight loss and loss of appetite
  • Poor coat
  • Weakness and lethargy
  • Fever
  • Diarrhea
  • Breathing problems
  • Reproductive problems
  • Stomatitis (inflammation of the mouth)


An ELISA blood test can identify if the FeLV proteins are present in your cats’ blood, this test can be performed at McQueen Animal Hospital at your request. The test is highly sensitive and identifies infections early. However, remember that some cats will clear the infection in a few months and will then test negative.

The IFA blood test detects the progressive infection phase, if a cat tests positive in the IFA blood test they will likely not clear the virus. This test can be performed at a laboratory and if a cat tests positive, they often have a poor long-term prognosis.

Treatment for Feline Leukemia Virus

As previously stated, a majority of cat’s die within 3 years after diagnosis. There is no cure, so treatment is supportive and aims to protect them from a secondary infection.

Protecting Your Cat From Feline Leukemia Virus

Keeping your cat indoors and away from infected cats will prevent your cat from contracting FeLV. At McQueen Animal Hospital, the FeLV vaccine is optional and costs $30 to receive.

New cats or kittens over eight weeks of age should ideally be tested before entering multi-cat households. If a cat is FeLV positive, ideally it should be housed alone as to not risk infection of any other felines. Additionally, the stress of adding another feline to the household could induce an infection in the FeLV positive cat.

McQueen Animal Hospital is proud to provide you with finest quality services in animal care in the Brampton region; we are located at 8975 McLaughlin Road, L6Y 0Z6 and are happy to answer any of your questions via phone at 905-455-7387.

Author: Jessica Wilkans, RVT at McQueen Animal Hospital

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