A. These are all signs of an upper respiratory tract infection.
Viruses are the most common causes of upper respiratory infections (URIs) in cats. Feline calicivirus and feline herpesvirus account for for most of contagious upper respiratory problems. Bacterial infection can then be present at the same time.
It is quite important to keep his nose clean from crusts and discharge as quite commonly cats lose their appetite as well.
I would recommend to take him to your veterinarian to have him checked and have appropriate treatment give (possibly antibiotics).
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