Feline Leukaemia Virus (FeLV)

Feline Leukaemia Virus is a viral infection of cats which is common in stray and unvaccinated cats. The virus infects immune system cells (white blood cells) leaving the cat vulnerable to secondary infections which would not be a problem in normal, healthy cats. Cats which contract the virus are at risk of developing severe illnesses such as anaemia and eventually cancer (lymphoma).

There are a wide range of symptoms but they can include a fever, lethargy, weight loss and poor appetite. Although an infected cat may remain healthy for several years, the disease will eventually prove fatal.

How is the virus transmitted?

The most common way is from the saliva of an infected cat. This can include being bitten by an infected cat or grooming, and sharing food bowls. It can also be passed via contact with the urine or faeces and mating with an infected cat.
Another way infection is possible is via a queen to her kittens either when they are in the womb or via milk once they are born. However abortion or resorption of the kittens is common in infected FeLV cats.
The disease is not transferable to humans.

Diagnosis of FeLV

If your veterinary surgeon suspects FeLV, a blood test will be performed to detect the proteins of the FeLV virus. Sometimes several blood tests are required to determine the result. Feline Immunodeficiency Virus (FIV) is often tested for as well, as many of the clinical signs are similar.

Treatment of FeLV

There is no cure for FeLV once your cat has become permanently infected. The treatment focuses on symptomatic and supportive treatment to maintain quality of life and manage the effects of the infection such as immunosuppression, anaemia and cancer.

If a sick FeLV positive cat is diagnosed then the prognosis is usually very poor and euthanasia is the kindest option. If the cat is healthy at the time of diagnosis, the prognosis is guarded. They will be likely to develop fatal FeLV related diseases but the time frame for this to happen varies from months to years.

Prevention of FeLV

Vaccines are available to help protect your cat against FeLV infection. This should be routinely included in your cat’s vaccination course as a kitten and kept up to date yearly with an annual booster. All cats should be vaccinated against FeLV especially if coming into contact with other cats either in a multicat household or having access to roam outside. Vaccination against FeLV does not interfere with the result of an FeLV blood test.

It is unwise to knowingly have an infected cat in the household, mixing with an uninfected cat. Close contact with other cats in the household means they are at a very high risk of contracting the disease from mutual grooming or feeding bowls. An FeLV infected cat should also be kept indoors to reduce the spread of the infection to other cats in the area. This can be difficult if the cat was previously used to being an outdoor cat and quality of life as well as risks to other cats should be taken into account.
It is also advisable to know the FeLV status of a cat if for example you are introducing a new cat to the household.

Useful links:
Feline Immunodeficiency Virus (FIV)
www.icatcare.org