The signature tent cabins in Curry Village at Yosemite National Park have… (Tomas Ovalle / For The Times )
YOSEMITE NATIONAL PARK -- The brass padlocks on the signature tent cabins at Curry Village are the first sign that something is amiss as one of the park's last busy weekends of the year gets underway.
Then there's the medical masks that Jil Johnson, 50, packed for herself, her 8-year-old son and his friend.
The locks bar entrance to the park's 91 signature tent cabins, where park officials believe a deadly outbreak of hantavirus originated in June, sickening four people and killing two. The cabins are now closed indefinitely as officials wait to see if their efforts to close gaps between the cabin walls are enough to keep out virus-carrying deer mice.
Johnson, who stayed in another area of Curry Village, brought the masks just in case. She warned her son and his friend when they arrived Wednesday not to stir up any dust or dirt that can include mouse droppings, the most common way the virus spreads to humans.
In the end, they didn't don the masks. But the Monterey physical therapist said Friday that she was still concerned.
"I'll be nervous for the next couple of weeks," Johnson said.
Many recent visitors to Yosemite expressed the same concerns as the number of confirmed hantavirus cases rose to six this week. The California Department of Public Health said four cases, including the two fatal ones, have been traced to the cabins. Investigators hope to pinpoint the origin of the two additional confirmed cases among former park visitors.
Yosemite spokesman Scott Gediman said park officials and public health authorities discussed notifying other recent visitors who stayed elsewhere in Curry Village or beyond, but concentrated their efforts on those they felt were most at risk.
"We hope it's contained," Gediman said. "But am I going to stand there and tell you it is? I mean, of course not. I can't do that. That's why we're erring on the side of caution."
Park officials said they have sent letters and emails to some 3,100 people who reserved one of the cabins between June 10 and Aug. 24. The national Centers for Disease Control and Prevention issued another nationwide alert Friday, saying an estimated 10,000 people stayed in the cabins during that time.
Some who camped in Curry Village both then and later this week said they were not told about the outbreak when they arrived.
Camille Chu, 39, said she and her husband were not warned about hantavirus when they checked into one of the now-shuttered cabins Aug. 24. She also said she didn't receive an email notification until Wednesday night, after she called the park.
"People need to know now," Chu said. "You should always err on the side of caution and that's not what they did. I'm infuriated. I'm very upset."
Norbert Kubilus, 63, and his wife spent four days in another section of the village beginning June 10. Although they are out of the park's target group, Kubilus said he still would like to know more about what's going on.
He said he had some flu-like symptoms a few weeks after returning from the park. They passed, but Kubilus said had he known hantavirus was a concern, he would have gone to his doctor "just to make sure it wasn't that."
Gediman said the park has received more than 5,000 calls since opening an emergency phone line Tuesday.
Some have questioned Yosemite's preparedness — records show the California Department of Public Health warned the park about the potential for hantavirus in reports dating back five years. In a 2007-2010 summary on vector-borne diseases in California's national parks, the agency said deer mice infected with the virus had been found at "several locations in the park."
It also cited a 2010 case of hantavirus traced to Tuolumne Meadows — only the second confirmed case of the virus linked to Yosemite before this summer.
The report recommended enhanced inspections, trapping, additional staff training and posting of information about hantavirus and other similarly transmitted diseases at staff lodging and visitor centers.
"Campgrounds and other areas that host large numbers of visitors should be posted with information about potential plague risk and prevention measures," the report said. "Rodent activity within campsites should be discouraged."
The health agency also mentioned the risk for hantavirus at Yosemite in two annual reports, in 2007 and 2010. Those summaries advised Yosemite to better educate employees and visitors about hantavirus risk, and to take steps to reduce the chance of contracting the disease by fixing "rodent harborage" opportunities.
The park followed those recommendations, Gediman said, and updated its directive regarding staff hantavirus training and visitor protocol in April. He said that before the outbreak, information about hantavirus was available with other park literature when guests checked into camping areas. After the first cases, he said, pamphlets were distributed to every vehicle upon entering the park.
Although officials plan to review their handling of this outbreak after public health authorities complete their investigation, Gediman said they "feel really good" about both their preparedness and outreach to visitors.
"We don't feel that, if we had to do it again, we would do anything differently," he said.
Not all were worried in Curry Village this week. Lounging outside his tent cabin Thursday afternoon, Sean Darrah, 42, said hantavirus was "something to think about" but that it didn't deter his plans.
"You can't really shut down Yosemite because of mice," he said.