Hantavirus, who's at risk?

The Centers for Disease Control (CDC) recently announced that up to 10,000 people who visited Yosemite National Park this summer were at risk for developing an infection caused by Hantavirus.  Most of these potential victims stayed in the Park’s tent-cabins that, unbeknownst to Park authorities, had been infested with mice that carry the potentially fatal virus.  Since the span of time from