Feline calicivirus (FCV) is a virus of the family Caliciviridae that causes disease in cats. It is one of the two important viral causes of respiratory infection in cats, the other being feline herpesvirus. FCV can be isolated from about 50% of cats with upper respiratory infections
There is no specific treatment for FCV. Antibiotics are used for secondary bacterial infections, and immune modulators, such as lymphocyte T-cell immune modulator, have been used for immune support. Nursing care and rehydration are used for dehydrated and anorexic cats. Corticosteroids or azathioprine may be used for polyarthritis. Stomatitis is very difficult to treat. Antibiotics, corticosteroids, and tooth extractions all have been used with varying success. Cats on corticosteroids must be monitored carefully for worsening of any upper respiratory infection.
I take it the cat is in isolation with Sneezeshields on your pen if he is in a pen, or isolated from any other cats and that you have barriers in place if he has his own room in your home and that you have sneeze barriers on the door to the room
There is no treatment as such but antibiotics do help, I have a Carrier living with us and apart from an occassional weepy eye he is fine