The question in the title is incomplete because it implies that the question is about cancer; a type of blood and bone marrow cancer but when leukaemia is spoken about in the context of domestic cats it means a virus, specifically, the feline leukaemia virus (FeLV) which is the most important cause of cancer in cats and which significantly contributes to the severity of other feline diseases. Click this link for a plain language article on FeLV.
Having got that out of the way, and having noted that we are referring to a virus, you will find varying answers to the question. A book1 written by 4 veterinarians that I often refer to, states that “the incidence of active infection varies. About 1-2% of healthy free-roaming cats are infected”. The incidence will be higher in catteries and in multi-cat households. Sometimes the incidence of the presence of the virus in their blood will be as high as 20-30%.
Cornell Feline Health Center tells us that the feline leukaemia virus affects between 2-3% of all cats in United States. They do mention that there are now effective vaccines and accurate testing procedures which has reduced this virus’s significance over the past years.
A study: “Outcome of cats referred to a specialized adoption program for feline leukemia virus-positive cats” dated 2020 states: “Approximately 3–4% of cats in the USA test positive for feline leukemia virus (FeLV), a diagnosis that affects an estimated 60,000 cats in animal shelters each year.”
RELATED: “2 FeLV kittens in need of a home” – FeLV kittens and cats can and should live good lives.
As to the UK, the Blue Cross organisation say that between 1-2% of cats in Britain are permanently infected with the virus and the majority will die within 4 years of detection of the virus. Although they do say that this percentage is estimated. It is the number one killer virus in the UK of cats. It impairs the cat’s immune system leaving it obviously vulnerable to a variety of diseases and infections.
Although the percentages are low, in pure numbers the figure will be high. If 3% of all cats in the United States are affected by this disease, it represents 2.7 million cats. By way of contrast, the number of domestic cats in Belgium is estimated to be 1.7 million.
RELATED: Vet explains basic difference between FeLV and FIV (audio)
It is believed that feral or free-roaming urban cats may have an incidence as high as 40%. The DVM 360 website states that the infection rate is anywhere from 3%-14% of domestic cats “depending on geographic location, sex, lifestyle and general health”.
Adoptable FeLV cats
Please read this section too. It is important for the cats’ sake. They are sentient beings deserving of our love, even more so as they are vulnerable. The article continues below the slide show which is a series of links to further pages in this topic.
RELATED: Lifespan of cats with FeLV?
It must be stressed, however, that FelV positive cats can live good lives. They do live good lives in the right homes. They are adoptable and they are good cats. The best situation for a FeLV positive cat is to live their life in an indoor-only environment and be the only cat in that environment. After that it is down to providing excellent care including a nutritionally balanced diet and a veterinary examination at least twice a year according to DVM 360.
I’m not going to cover treatments. I do have pages adoptable FeLV cats which you can select in the slideshow above. Simply click on the relevant link and you will be taken to that page.
RELATED: T-Cyte Treatment for FeLV and FIV Cats? Does it Work?
1. Cat Owner’s Hand Veterinary Handbook page 89 3rd Ed.
