By Lauren Sommer

Curry Village tent cabins at Yosemite National Park. (Jun Seita: Flickr)
Curry Village tent cabins at Yosemite National Park. (Jun Seita: Flickr)

State public health officials are warning 1,700 people who stayed in Yosemite National Park‘s Curry Village tent cabins since mid-June about hantavirus. Three people who stayed in the tent cabins this summer have contracted the illness and two people have died. There may be a fourth case as well.

A group of the tent cabins are closed as public health officials investigate the cases. The state health department had previously warned the park about the risk.

Hantavirus is a serious illness which causes flu-like symptoms. It can progress rapidly and has a 38 percent mortality rate, according to the Centers for Disease Control. There is no known treatment, although prompt admission to the ICU and oxygen therapy can be helpful.

The virus is spread through mouse droppings, says Vicki Kramer, Ph.D., Chief of the Vector-Borne Disease Section of the California Department of Public Health.

“If rodents do invade an area, it’s important not to sweep, not to vacuum because that causes the virus to become airborne,” she said.

Hantavirus is rare. There have been only 60 cases in the last two decades in California. Kramer’s department has been working with the park since two previous hantavirus cases in 2000 and 2010.

Two years ago, it was recommended park staff be trained in cleaning standards — which Kramer says the park did. Health officials also recommended putting up warning signs in the tent cabins. But the park didn’t follow that recommendation.

“We certainly want to put signs up in places,” said Yosemite National Park spokesman Scott Gediman. “But we’ve learned over the years that to sit there and have a sign everywhere listing every potential danger is both impractical and something we have to balance.”

Gediman says there are signs up now. Tent cabins are being inspected and retrofitted to prevent mice from getting in.

The Los Angeles Times reports that officials are testing deer mice across the park in an effort to learn what is causing the outbreak. Park ranger Jana McCabe told the Times they are “pretty confident that it’s not a cleanliness issue.”

McCabe continues:

“We’ve reviewed the cases; we’ve reviewed the cleaning methods,” she said. “It makes you start wondering, what has changed? What is going on in the environment? That’s really the question.”

After confirming the first two infections earlier this month, Yosemite officials began catching deer mice and disinfecting the Curry Village cabins. They also contacted health authorities.

… The California Department of Public Health said Tuesday afternoon that it had recommended a closure of affected cabins “due to the level of mouse activity and presence of the hantavirus.” Gediman said the closure was part of the cleaning and repair process already underway.

California Watch: Scientists Calls to Warn Yosemite Visitors Went Unheeded

Listen to Lauren Sommer’s report:

Hantavirus Investigation at Yosemite Continues 30 August,2012State of Health

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