Feline leukemia virus (FeLV) is a retrovirus that infects cats. FeLV can be transmitted from infected cats when the transfer of saliva or nasal secretions is involved.
Feline leukemia virus (FeLV) is one of the most common and important infectious diseases in cats, affecting between 2-3% of all cats in the United States and Canada.Loss of appetite. Progressive weight loss. Poor coat condition. Enlarged lymph nodes.

Symptoms of Feline Leukemia Virus. Cats infected with FeLV may exhibit one or more of the following symptoms: Pale gums. Yellow color in the mouth and whites of eyes. Enlarged lymph nodes. Bladder, skin, or upper respiratory infections. Weight loss and/or loss of appetite.

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ABCD cats & vets: GUIDELINE for Feline Leukaemia Virus Infection.

Not all feline leukemia virus (FeLV) infected cats are the same. There are different stages of infection, different outcomes, and different disease manifestations. Some infected cats will go on to live a nearly normal lifespan while others may die within months to a few years.
Feline Leukemia Virus (FeLV) is a serious infectious disease affecting cats. It's a retrovirus that can suppress a cat's immune system, making them susceptible to other infections and certain types of cancer.