Infection with the feline leukemia virus may not cause any symptoms initially. But as the disease progresses, the cats health may deteriorate. The cat may become prone to frequent infections and illnesses. This virus affects different body systems like the gastrointestinal system, respiratory system, nervous system and reproductive system.

 It can also lead to the development of anemia, breakdown of the immune system and formation of tumors and abnormal tissue growths. Cancers like lymphosarcoma and leukemia may also develop. Signs of this condition may include loss of appetite, weight loss, poor coat condition, enlargement of the lymph nodes, fever, inflammation of the gums and mouth, skin infections, urinary tract infections, respiratory infections and persistent diarrhea. Cats with feline leukemia virus infection are more prone to rhinitis, pneumonia and breathing problems.

The disease affects the nervous system and causes seizures, hind limb paralysis and urinary incontinence. Infertility, abortions and fetal death is also seen more frequently in cats affected with FeLV. Since the immune system is weakened, it cannot fight off infections efficiently. The affected cat may experience periods of health interspersed with periods of illness and infections. Wounds and abscess in the affected cats take a long time to heal because of poor immunity.