UP TO 10,000 people who were guests in certain lodging cabins at Yosemite National Park might have been exposed to a deadly mouse-borne virus.

Park concessionaire Delaware North Co. 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.

The cabins hold up to four people, and park spokesman Scott Gediman  said yesterday that means up to 7,000 more visitors might have been exposed to the virus that so far has killed two people and sickened four others.

Meanwhile, more than 1,000 calls a day are coming into Yosemite’s new hantavirus hotline as visitors frightened about the growing outbreak of hantavirus pulmonary syndrome call seeking answers.

“We’re reaching out and they are reaching out to us, and we are trying in every way shape and form to be transparent and forthright,” he said. “We want to tell people this is what we know. The most important thing is the safety of park visitors and employees.”

On Thursday, the California Department of Public Health confirmed that a total of six people have contracted the disease at Yosemite, up from four suspected cases earlier in the week.

Alerts sent to state and county public health agencies, as well as local doctors and hospitals, have turned up other suspected cases that have not yet been confirmed, according to the Centers for Disease Control and Prevention.

The illness that begins as flu-like symptoms can take six weeks to incubate before rapid acute respiratory and organ failure.

There is no cure, and anyone exhibiting the symptoms must be hospitalised. More than 36 percent of people who contract the rare illness will die from it.