Officials from the California Department of Public Health confirmed six cases of hantavirus infection at Yosemite National Park last week. The disease, which spreads through rodent urine, saliva and droppings kills one out of three people infected. So far, three deaths from the virus have been linked back to Yosemite, according to the Center for Disease Control.
The site of infection has been narrowed down to the cabins in Curry Village, specifically those with double walls. Mice build nests in the insulation between the cabin’s outer canvas wall and an inner wall made of drywall or plywood. Considering visitors to the cabins, as well as friends and family members who might have dropped by, the CDC estimates that up to 10,000 people may have been exposed.
Deer mice, which have white bellies and gray or brown bellies, are most likely to be carrying the hantavirus in Yosemite. They can squeeze into holes only one-quarter-inch in diameter.
Hantavirus Pulmonary Syndrome is an uncommon lung disease with symptoms that include fever, chills, cough, headaches, gastrointestinal problems, muscle aches and fatigue. The incubation period ranges from a few days to six weeks, but generally appears between two and four weeks. Infected individuals should be taken to an intensive care unit immediately.
Yosemite park officials made efforts to prevent a hantavirus outbreak last April, a response to a 2010 report from the California Department of Public Health citing the illness of a visitor to Yosemite’s Tuolumne Meadows area. The report found that 18 percent of mice trapped and tested in various parts of the park carried the virus.
So far, 2,700 warning emails and letters have been sent out visitors who stayed in Curry Village this summer. Two epidemiologists are working in the park to analyze the percentage of the mice population carrying the disease and to assess whether more mice are living in the park this year than in previous years.
Please call the Yosemite National Park non-emergency phone line (209-372-0822) for all questions and concerns related to Hantavirus in Yosemite National Park, or visit the National Park Service website for more information.