May 21, 2013 (CIDRAP News) – A federal auditor found no major flaws in the National Park Service's (NPS's) handling of the hantavirus outbreak at Yosemite National Park last summer, but the auditor called for closer reviews of plans for visitor lodgings to prevent vector-borne diseases.
Ten Yosemite visitors suffered Sin Nombre hantavirus infections in the summer of 2012, and three died; 9 of the 10 cases were linked to the "Signature" tent cabins in the park's Curry Village, according to the report by the US Department of Interior's Office of the Inspector General (DOI OIG). People can contract the virus through contact with infected mice or their urine, droppings, or saliva.
The tent cabins were converted from employee housing to visitor lodgings in 2009, a process that included winterization. The cabins were owned by Delaware North Companies Parks and Resorts (DNC), a Yosemite concessionaire.
The NPS's contract with DNC requires independent inspections for new construction or "significant project work," but the requirement didn't apply to the tent-cabins because the winterization was considered routine annual maintenance, the report says. Yosemite officials didn't find any rodent nests during routine inspections of the tent-cabins because they were hidden in the walls and inspections didn't include any dismantling.
The OIG also found that Yosemite provided information about hantavirus risks to visitors, but it was geared to the park's backcountry, where hantavirus is more common. Visitors to Curry Village would have had to find hantavirus information on their own, using online sources such as the Centers for Disease Control and Prevention, the report says.
When the outbreak was identified, the NPS "worked to contain and remediate the infection and prevent further outbreaks," the OIG found. The outbreak led to the closure and removal of the Signature tent-cabins, along with plans for replacing them.
In responding to the outbreak, the report says, the NPS worked to contact Yosemite visitors and inform the public, invited the California Department of Public Health to review DNC winterization plans for the replacement tent-cabins, and increased its involvement in lodging inspections and public education.
In other responses to the outbreak, DNC has stepped up trapping of mice, and Yosemite's health officer has increased inspections of tent cabins and monitoring of DNC hantavirus education efforts.
The report makes two recommendations for general NPS policy:
- NPS health, safety, and building officials should review plans for new visitor accommodations and modifications for vector-borne disease vulnerabilities before the agency authorizes such work.
- The NPS should inspect visitor accommodations cyclically for vector-borne disease risks.
In addition, the report makes two recommendations pertaining specifically to Yosemite tent-cabins:
- DNC should report the results of its facility monitoring to Yosemite health and safety officials
- Educational material about hantavirus should be provided to all overnight park visitors, regardless of where they stay.
See also:
May 20 DOI OIG report on Yosemite response to hantavirus
May 20 DOI OIG news release on the report
