A mouse infestation must be taken seriously because mice can carry a number of diseases. Diseases such as Hantavirus, Salmonellosis, and Lyme are a few of the common diseases that mice can carry and transmit. Some diseases, like Hantavirus, can be transmitted by simply touching an infected mouse or by breathing in fumes that are released in mouse urine. Mice can bite if they feel threatened so it is wise to avoid trying to pick them up. If a bite does occur, wash the area with soap and seek immediate medical attention if you believe the bite to be serious.