Feline leukaemia virus (FeLV) – what you need to know

Many cat owners fear feline leukemia virus (FeLV) but what is it? How do cats catch it? How best can you protect your cat? Here’s our expert veterinarian advice…

What is feline leukaemia?

 Feline leukaemia infects cats around the world. Between 2-4 % of cats test positive, though the incidence is probably much higher as only a small percentage of the cat population is ever tested.  It is mostly a problem in multi-cat households.  It commonly causes anaemia, cancers and a weakened immune system.  Because it suppresses the immune system it can predispose cats to deadly secondary infections.


How is it spread?

Cats persistently infected with FeLV serve as sources of infection. The virus is shed in very high quantities in saliva, nasal secretions and urine.  Smaller amounts of the virus are also shed in tears, faeces, and milk from infected mother cats. The most common mode of transmission occurs during mutual grooming, and infrequently from bite wounds, shared use of litter boxes and feeding dishes. Transmission can also take place from an infected mother cat to her kittens, either before they are born or while they are nursing. FeLV doesn’t survive long outside of a cat’s body—probably less than a few hours under normal household conditions.

What cats are at greatest risk of infection?

Infection can occur at any age but kittens are much more susceptible to infection than adult cats.  Cats that have not been immunised against the virus and that are living with infected cats or with cats of unknown infection status are at a greater risk of contracting the disease.

What are the signs of disease caused by FeLV?

During the early stages of infection, it is common for cats to exhibit no signs of disease at all. However, over time—weeks, months, or even years—the cat’s health may progressively deteriorate or be characterised by recurrent illness interspersed with periods of relative health. Symptoms can include:

  • Loss of appetite
  • Slow but progressive weight loss, followed by severe wasting late in the disease process
  • Pale gums and other mucous membranes
  • Poor coat condition
  • Enlarged lymph nodes
  • Persistent fever
  • Inflammation of the gums (gingivitis) and mouth (stomatitis)
  • Infections of the skin, urinary bladder, and upper respiratory tract
  • Persistent diahorrea
  • Seizures, behaviour changes, and other neurological disorders
  • A variety of eye conditions
  • In unspayed female cats, abortion or other reproductive failures
 How is the disease diagnosed?

A FeLV & FIV combination blood test performed by your vet.

Who should be tested?

* Any sick cat, regardless of age and previous test status

* Any cat entering a new household, especially if there are other cats in the      new household

* Any cat at risk – approximately 30 days after potential exposure, either due to access to other cats in the neighborhood, or living in a home with FeLV+ cats.

How should I protect my cat?

The only sure way to protect cats is to prevent their exposure to FeLV-infected cats. Adopt only infection-free cats into households with uninfected cats and have uninfected cats vaccinated. FeLV vaccination of infected cats is not beneficial.

Managing infected cats 

– Infected cats may still have a good quality of life.

– If managed correctly cats may remain healthy for months or years after initial diagnosis. 

– A good quality, well balanced diet is essential for cats living with FeLV 

– Preventative veterinary care such as external parasite control, deworming, annual vaccinations and dental prophylaxis is essential to reduce the stress placed on an infected cat’s immune system. 

– Avoid transmission to other cats by preventing access to outdoors and other uninfected cats in household.

Feline leukaemia virus (FeLV)  is species specific and cannot be passed on to humans, dogs or other animals apart from cats.