The Hantavirus is a potentially fatal respiratory virus which progresses extremely rapidly, sometimes moving from flu-like symptoms to death in only a few days. Hantavirus is transmitted in the feces of the deer mouse, and possibly other rodents. it is contracted when the pieces of these feces are breathed into the lungs (sounds fun eh?) Most cases of this virus have been in rather remote areas of the southwestern US, usually when someone is cleaning out a small space such as a trailer filled with mouse feces. If you see mouse feces and are concerned about this you should spray them with a mixture of bleach and water and mop them up. spray any dead mice found with bleach and water before removal. Although a great deal of hype is attatched to this virus, since it is so fast-moving and dangerous, it is actually very rare. (although people probably survive it thinking they had a particularly nasty flu, and never report it to doctors) Nevertheless, it is advisable NOT to inhale powdered mouse feces.