Officials say six cases of the rare hantavirus pulmonary syndrome (HPS) have been confirmed over the past three weeks.Two people have died after staying in one of the so-called `"Signature'' cabins of Curry Village in Yosemite Valley.
Park concessionaire Delaware North sent letters and emails this week to nearly 3,000 people who reserved the insulated Signature cabins between June and August, warning them that they might have been exposed.
More than 90 cabins in Yosemite National Park are closed indefinitely after the site was found to be at the center of the mouse-borne virus.
Park officials said the double-walled design of the 91 cabins that were closed Tuesday made it easy for mice to nest between the walls. The disease is carried in the feces, urine and saliva of deer mice and other rodents.
The presence of HPS was confirmed after two park visitors fell ill after staying in Tuolumne Meadows, about 4,000 feet higher than Yosemite Valley. It said that 18 percent of mice trapped for testing at various locations around the park were positive for hantavirus.
The illness that begins as flu-like symptoms can taketwo to six weeks to incubate before rapid acute respiratory and organ failure.
"The disease often progresses rapidly to respiratory distress, requiring supplemental oxygen and/or intubation, non-cardiogenic pulmonary edema and shock," the Centre for Disease Control and Prevention( CDC) said.
There is no cure and anyone exhibiting the symptoms must be admitted to hospital. More than 36% of people who contract the rare illness will die from it.
The guests being warned stayed in Curry Village's tent cabins in June, July or August. So far all victims who have fallen ill stayed in the cabins in June.