Mice can easily contract respiratory infections, including pneumonia. Signs of a respiratory infection can include nasal discharge, lack of appetite, lethargy, weight loss and difficulty breathing.
If you see any of these signs of illness in your mouse, take it to a veterinarian right away. Respiratory infections in mice can quickly become fatal if untreated.
To help prevent respiratory infections in your mouse, keep its cage clean and remove soiled bedding daily. Use only dust-free bedding in the cage, and don’t expose your mouse to cleaners or anything that gives off strong fumes. Keep the cage out of damp, drafty locations as well.