Cases of the hantavirus disease that recently killed four in California occur regularly in many parts of the U.S.

"Whenever I stay in backcountry huts in Northern California's Sierra mountains, I fight back paranoia spurred by posted signs describing the ominous hantavirus, a rare but deadly sickness spread by rodents who nest in cabins and congregate around likely sources of food and shelter. This year, my paranoia is even more founded: Two people have died and four more are recovering from the virus in what's being described as an unprecedented outbreak this summer in Yosemite. Park officials have traced the cases back to a cushy tent compound called Curry Village where those afflicted stayed at some point over the summer, and have alerted 3,000 visitors via email of potential exposure to the virus.

US wilderness outfits and public health officials have been warning about hantavirus for years, ever since an outbreak of the "Sin Nombre" virus, a type of hantavirus, was newly identified in the Four Corners region of the country in 1993. Since then, 602 cases of hantavirus pulminary disease, the fatal sickness asssociated with the virus, have been reported in 34 states. So why all the fuss about the six confirmed cases in Yosemite?

There are several strains of hantavirus around the world, and a few of them cause hantavirus pulmonary syndrome (HPS), a flu-like respiratory illness that results in death almost 40 percent of the time."

Maddie Oatman reports for Mother Jones September 3, 2012. [2]