Compared to other rodents the Deer Mouse has been around for a long time in the Pacific NW They are often cute, yet when they get into your home it is another story!! They can get into an entry point hole as small as the thickness of your baby finger.
The Deer Mouse, as with mice in general, urinate non-stop laying down a pheromone trail of urine to mark their area. Rats often defecate and urinate in one area near their nesting sites. When the mice urine crystalizes, it becomes airborne and can get into the lungs. That is the concern in getting the Hanta Virus.