Feline Leukemia Virus (FeLV)
What is FeLV?
FeLV is an infectious retrovirus in cats that suppresses their immune system. It affects around 2-3% of cats in the US and Canada.
Because it compromises their immune systems, cats who have FeLV are more susceptible to getting other infections. The virus can cause cancer and blood disorders as well.
There are different types of infection: Abortive, Regressive and Progressive.
-
Abortive: Have an immune response against the virus and are able to eliminate the virus before it becomes part of their genome. They won't shed the virus, but will have anti-bodies agsint it and are considered to be immune.
-
Regressive: Have a partial effective immune response to the virus, but the virus is incorporated in to the cat's genome. It can't infect other cats, and not likely to experience any clincial signs and symptoms of the virus. it is possible for the virus to reactivate and cause infections in other cats. This typically happend due to high tramatic events and illnesses.
-
Progressive: This is the worst prognosis. The virus becomes part of the cat's genome and they shed the virus and can infect other cats.
How does it spread?
FeLV spreads when cats come in contact with other cats who have been infected. Infected cats shed the virus through their saliva, feces, urine, and milk. Infected cat's can give it to other cats through biting, grooming, shared food containers, and litter boxes. It can also be passed to a kitten by their mother before they are born or through nursing. The infection survives a couple hours outside of a cat's body. Any age cat can get the virus, but kittens are at greater risk since their immune systems are not as strong.
How to prevent it?
The only way to protect a cat from FeLV is to keep cats away from being exposed to FeLV infected cats. Keep your cats indoors or supervise cats if they are outdoors.
Always test a cat for FeLV before introducing them to a home with another cat.
There is a vaccine that is available for FeLV, but it will not protect 100% of cats, but rather reduce the risk of exposure. Discuss with your vet if they recommend this for your cats.
Symptoms
FeLV can show up in many different ways. It is common for cats to show no signs if the dieses in the early stages. Over time, a cats health will decrease and signs can include the following:
-
Loss of appetite
-
Progressive weight loss
-
Poor coat condition
-
Enlarged lymph nodes
-
Persistent fever
-
Pale gums and other mucus membranes
-
Inflammation of the gums (gingivitis) and mouth (stomatitis)
-
Infections of the skin, urinary bladder, and upper respiratory tract
-
Seizures, behavior changes, and other neurological disorders
-
Reproductive failures
FeLV is the most common cause of cancer in cats. In can cause other blood disorder and lead to immune deficiency.
Diagnosis
FeLV is diagnosed through testing. Generally, more than one test is required to accurately diagnose the virus. False positives can occur in testing, so it is recommended to do additional tests in it comes back positive. Common tests include SNAP/ELISA, IFA, and PCR test.
-
Enzyme-linked immunosorbent assay (ELISA): This blood test in generally the first screening tool that the vet will run. It is used to detect the presence of free FeLV particles that are found in the bloodstream during early and late stages of infection.
-
Immunofluorescent antibody assay (IFA) - This is another blood test that detects the presence of P27 protein within the while blood cells and platelets.
-
Polymerase chain reaction (PCR) - This test detects of the virus is incorporated into the cat's genome. It is recommended to run this test if the ELISA test come back positive. One thing to note is that this test to come back positive for regressively infected cats.