Feline Leukaemia Virus (FeLV)

What is Feline Leukaemia Virus (FeLV)?

Feline leukemia virus (FeLV) is a common infection of cats. It is one of the top infectious causes of cat deaths and is generally common worldwide.

When cats are infected with FeLV, most will be able to eliminate the virus and become immune to it. However, some cats do not develop this immunity, resulting in the virus spreading to other parts of the body, especially the bone marrow. This results in various blood disorders which lead to the immune system being suppressed. These cats become sick due to the effects of the blood disorders, or due to immunosuppression leading to opportunistic infections. Affected cats can also get lymphoma, a type of white blood cell cancer.

Even exposed cats that become immune to the virus can have latent (hidden) infections. These cats are known as latent carriers of the virus and are also capable of transmitting the virus. Some of these latent carriers can progress to become ill cats in times of stress.


How does a cat get infected with FeLV?

FeLV can be transmitted via several ways:

The FeLV typically survives for less than a few hours outside of a cat’s body, and are readily destroyed by most disinfectants.


What are the signs of FeLV?

It is common for cats in the early stages of infection to show no obvious signs of disease. However, the cat’s health may deteriorate progressively or there may be periods of recurrent illness.

Signs may include but are not limited to:

The above signs are not specific for FeLV, and can also be caused by other various diseases.


How can a cat be diagnosed for FeLV?

A cat can be screened for FeLV via a quick blood test to detect the presence of the virus. Other diagnostic tests that may be necessary for infected cats include blood chemistry, haematology (complete blood cell count), radiography (X-rays) and bone marrow aspiration to determine the extent of the infection.


Is there treatment for infected cats?

There is generally no direct cure for cats infected with FeLV. Treatment is mainly focused at supportive therapy, such as maintaining adequate nutrition and hydration, and treating secondary infections or conditions that arise from being infected with FeLV.

Cats with lymphoma caused by FeLV usually respond better to treatment, which include chemotherapy, glucocorticoids, interferon and supportive treatment.


How do I prevent my cat from FeLV?

There are several preventive measures that can be taken to decrease the risk of contracting FeLV:

  1. Vaccination is recommended for high-risk uninfected cats only, as current FeLV vaccinations carry a significant risk of cancer at the injection site.
  2. Multi-cat households with FeLV positive cats should be maintained as a closed colony, i.e. no new uninfected cats should be introduced to prevent the spread of infection to uninfected cats.