US agencies work to tackle Yosemite's virus outbreak
1 September 2012 Last updated at 10:51 BST
Thousands of people who have been holidaying in California's Yosemite National Park have been alerted following an outbreak of a deadly virus.
Two people have died and four others have been infected by Hantavirus, a rare lung disease.
Lola Russell, of the Centers for Disease Control and Prevention (CDC), said they were working closely with various agencies to tackle the situation.