By Ben Margot, AP
In this photo from Sunday Oct. 23, 2011, tents are seen in Curry Village in Yosemite National Park, Calif.
By Laura Bly, USA TODAY
U.S. officials have warned travelers from 39 other countries, most in the European Union, that those who stayed in certain Yosemite National Park tent cabins earlier this summer may have been exposed to a rare but deadly mouse-borne hantavirus, a park service epidemiologist told Reuters Tuesday.
Of the 10,000 people the federal Centers for Disease Control estimate could be at risk of contracting hantavirus pulmonary syndrome from their stays in Yosemite between June 10 and August 24, some 2,500 live outside the USA, said Dr. David Wong.
Six cases of the rodent-borne disease have been linked to Yosemite, and two men, from northern California and Pennsylvania, have died. Park officials traced five of the cases to 91 "signature tent cabins" in Curry Village, one of Yosemite's most popular campgrounds. They said a design flaw allowed mice to nest between the double walls of the insulated cabins. Another approximately 400 canvas-walled tent cabins in Curry Village remain open.
Britain's Health Protection Agency said in a statement Monday that officials were "providing health advice and information ... about the ongoing situation in the U.S." to about 100 people believed to have traveled to the national park between June 10 and Aug. 24.
Yosemite officials have sent emails and letters to 3,100 people who reserved any of the 91 signature tent cabins during that timeframe, urging them or anyone in their party to seek immediate medical attention if they start to show the initial flu-like symptoms of the disease, Associated Press reports.
Through 2011, the CDC had identified a total of 587 cases in 34 states. Of those cases, 556 occurred in or after 1993, when an outbreak in the "Four Corners" area of the Southwest killed at least 26 people. About three-quarters of the victims live in rural areas, and 36% of reported cases have resulted in death.
Spread through urine, droppings or saliva of infected rodents, primarily deer mice, hantavirus takes between one and six weeks before causing symptoms in humans, officials say. The disease is generally transmitted when people come in contact with an enclosed area that has been infested by mice, and most infections are caused by breathing small particles of mouse urine or droppings that have been stirred up into the air.
If the virus is contracted, says Yosemite's website, symptoms include fever, headache, and muscle ache, and the disease progresses rapidly to severe difficulty in breathing and, in some cases, death.
News of the outbreak has rattled recent visitors, notes the Los Angeles Times. Rangers have fielded thousands of calls from concerned travelers, the park is answering questions on its Facebook page and a spokeswoman with the park's lodging concessionaire Delaware North told the Times the company had a 20 percent cancellation rate for a usually sold-out Labor Day weekend.
Nearly 4 million people visit Yosemite each year, and about 70 percent of those congregate in Yosemite Valley, where Curry Village is located.