FeLV – Feline Leukaemia Virus

This disease belongs to three fatal cat diseases – FIP (feline infectious peritonitis), FIV (the so-called cat AIDS) and FeLV (feline virus leukaemia). I have already introduced you to the first two diseases, now it’s time to look at cat leukaemia.

It is a retrovirus infection which often occurs together with FIV. It has similar symptoms but besides gradual degradation of immune system, it is also manifested by anaemia and an increase in tumour incidence and mainly by leukaemia. A long incubation period is characteristic for this disease and it may even take up to several years.

A cat might get infected with FeLV by bites or licking from another cat but also indirectly, for example by food contaminated with saliva. Cats most often fell ill between 2 and 4 years of age. The severity of the disease is then influenced by the age, health condition of the cat and the amount of virus it was exposed to.

The virus attacks the lymphoid tissue and bone marrow after being in contact with a cat and it can stay there permanently. Many infected cats can withstand the primary infection, recover and they become carriers of the virus or they become immune against FeLV and the virus gets fully eliminated from the body.

Similarly to FIV, the primary symptoms are not specific. The whole immune system is weakened and it is not able to fully function and the cat is more prone to common diseases. Common problems are diarrhoea, fever, swollen lymph nodes, eye and nose discharge. However, these are the symptoms of many other diseases. Typical symptoms for FeLV are an increase in tumour incidence, mainly lymphoma and leukaemia.

The treatment is similarly to FIP and FIV only supportive, to suppress the symptoms and prolong the life. Also, the tumours caused by FeLV react worse to chemotherapy. However, many positive cats might live long years without any symptoms. But when the immune system is attacked and tumours start to occur, the end is coming.

The infected cat might be diagnosed with a blood test, i.e. finding the viral antigen in blood. As some cats are able to fight cat leukaemia and get rid of the virus, it is recommended to repeat the test after a few months. If you are afraid of FeLV and your cats is at risk of infection (for example the cat lives outdoors), you can have them vaccinated. However, it needs to be provably uninfected, for the infected cats, the burden to the immune system could even cause the full disease outbreak.

Breeding stations test all their kittens can keep their breeding “clean”. Therefore, if you get a pure-bred cat, you don’t have to worry that it would have FeLV in its blood. However, if you have another cat at home, you should have it tested before the arrival of a new member.