Feline Leukemia Virus, the silent killer

Feline Leukaemia Virus (FeLV) is a highly contagious virus that can be prevented by correctly vaccinating your cat.


1 FeLV is a virus that is transmitted between cats via infected saliva and blood. The cats are most often infected with FeLV through fight wounds, mutual grooming and even from sharing food and water dishes. Kittens can become infected via their FeLV positive mother through the placenta or milk.


2 The virus depresses the immunity, subsequently the cat will not produce a good immune response. The cat cannot fight infections and will develop secondary diseases. This often results in recurring abscesses, chronic upper respiratory diseases, eye infections, diarrhoea, mouth infections and weight loss.


3 Furthermore the virus causes the development of malignancy this then results in the development of lymphomas (tumours) in various organs such as the liver, bone marrow, intestinal tract, kidneys, and chest. Finally, the virus suppresses the bone marrow, this then results in leukaemia.


4 Some cats have higher risk factors to develop FeLV. Males are more likely to suffer from FeLV, mainly because males are more often involved in fights. Kittens are much more susceptible to infection by the virus. Cats living in multi cat households or cats that are allowed outside are more at risk of acquiring the virus.


5 Currently no treatment is available to eliminate FeLV, the cat can only receive supportive care and treatment for secondary bacterial, viral, and parasitic infections. Chemotherapy, immune-modulatory drugs, and blood transfusions can sometimes extend the life expectancy. FeLV cats should be kept indoors and separate from other cats to prevent spreading FeLV.


6 The prognosis is poor for cats infected with FeLV. The average life span after infection is two to three years.


7 Cats can easily be tested at your local veterinary clinic. A simple blood collection and quick in-house snap test can identify FeLV infected cats within 15 minutes.


8 The virus can be prevented by vaccination. Cats require initially two vaccinations. The first vaccination should occur after nine weeks of age and a second booster vaccination should be given three weeks to a month later. It is important to boost the vaccine on a yearly basis. Cleaning well can also help to prevent the disease. The virus can only survive a couple of days in the environment and disinfectants can easily kill the virus.

Please feel free to contact us for further information or to book a vaccination or testing visit at Family Vet Clinic.

Written by Dr Tessa Brouwer, BVSc, MSc, BSc



Ettinger and Feldman-Textbook of Veterinary Internal Medicine, 2005, Client Information Sheet Feline Leukemia Virus Vaccinations

Larry Patrick Tilley, Francis W.K. Smith, Jr., 2007, Blackwell's five-minute veterinary consult: canine and feline. Fourth edition Ames, Iowa: Blackwell

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