The deadly face of the Hantavirus. The little-known virus is spread through the deer mouse's droppings and urine.
The National Park Service sent out a nationwide alert to health providers this Wednesday, warning them to be on the lookout for visitors to Yosemite National Park who might have encountered the often-lethal Hantavirus.
The warning comes as public health officials investigate a probable fourth case of Hantavirus Pulmonary Syndrome in a Californian visitor to Yosemite National Park.
The state Department of Public Health isn't releasing details. But a spokeswoman says the person stayed at Yosemite's popular Curry Village during the same period as three other park visitors who are confirmed to have contracted the extremely rare viral infection.
Two of those cases were fatal; the first death occurred when a Bay Area man died in July, and the second victim died last weekend in Pennsylvania.
The National Park Service's Office of Public Health is now investigating the unprecedented outbreak.
"To see a cluster of what right now is three, possibly four cases that are all associated with one location — not one family but different people in the area — that's unusual," said Dr. David Wong, chief of the epidemiology branch for the National Park Service Department of Public Health.
Yosemite Park officials are now contacting all 1,700 people who stayed at the tent cabins in the Boystown area of Curry Village from June 10 through August 24 to inform them of the possible Hantavirus exposure.
Wong says his agency has also sent alerts to every health department in the United States, and is now contacting health care providers to warn them about outbreak.
"We are working with the CDC [Centers for Disease Control and Prevention] now to send an alert to health care providers today," said Wong, "[saying that] if they see someone who might have symptoms, to think about [Hantavirus] as a diagnosis even though it’s rare."
Wong says Hantavirus is carried mostly by deer mice and spread to humans through airborne particles of mouse feces and urine. About 20 percent of all deer mice (which typically live at higher elevations) carry the virus.
People infected with Hantavirus Pulmonary Syndrome suffer flu-like symptoms that include fever
and muscle pain. Hantavirus can lead to severe difficulty with breathing and, in the most serious cases, death.
Since the virus was first identified in the United States almost 20 years ago, about 60 people in California have been infected. Approximately 1/3rd of them have died.