Deer mice are the most probable carriers of hantavirus
"The deer mouse is about six inches long to the tip of its tail. It is yellowish brown to grayish white on top, has a white belly and feet, large ears, and a furry tail that is white on the underside."
http://www.metrokc.gov/health/prevcont/hanta.htm
Most of what you will find is the standard brown house mouse which is a much less likely carrier. It has a scaly tail and is brown underneath.
But it is always a good idea to take appropriate precautions!