Q: I am really worried. My mouse has been lying on top of her house, sleeping most of the time, and hardly doing anything active. Yes, she is alive, but I am really worried. What should I do for her?
A: Unfortunately, there is not much you can do at home, safely, for your mouse. From your description, your mouse seems to be very sick, but like many small mammals, we cannot always make a diagnosis just from a description.
A mouse that is not moving, that is not active, not eating or drinking well, is described as being nonspecific sick. Almost all disease that can affect mice will cause them to look nonspecific sick. Until we know what is causing your mouse to be sick, we do not know if the best treatment includes antibiotics or anti-inflammatories or both types of medications.
While a veterinarian will try to give medication specific to the disease condition, he or she will also support your mouse with fluids and food as any mouse that is nonspecifically sick typically does not eat or drink. The disease may not be severe, but not eating or drinking will quickly debilitate and kill your mouse.
Giving fluids and food to your mouse at home can be very dangerous due to the small volumes that are needed and the technical skill necessary to hold and treat mice without harming them. If you are very skilled, your veterinarian and his or her technicians may be able to show you how to safely treat your mouse at home, but I would not attempt this until you are shown exactly how to give fluids under the skin and safely give medication by mouth without causing aspiration into the trachea and lungs.