Q. My Maine Coon sisters have snotty noses, need to clean crust off at least daily, now they have "bad breathe". Cold or sinus or other infection?
DR. MASSIMO ORIOLES, DVM, MRCVS
A. Possibly upper respiratory tract infection, considering the signs that you are describing. I would recommend to take them to your veterinarian as further treatment may be needed (including antibiotics). Most common causes of upper respiratory tract infections are viral infections with sometimes secondary bacterial infection.
Bad breath could be due to the infection and discharge, especially if thick and pussy, but it could be due as well to dental/periodontal diseases or may be diet related.
DAVID ELBEZE, DVM, MRCVS
A. Usually snotty nose is due to an upper respiratory infection - this needs to be diagnosed by a vet and is treated with antibiotics.
I'm not sure the bad breath is related to the upper respiratory infection, it's usually due to gingivitis or teeth problems.
Take them to the vet and have them checked properly for both of those symptoms.