Yosemite Hantavirus cases not connected to the Eastern Sierra

The recent spate of Hantavirus-caused deaths in Yosemite National Park does not mean a spate of Hantavirus-caused deaths in Mono County.

It doesn’t mean there won’t be any deaths, either.

It’s an issue locals know about since the Eastern Sierra is considered a “hotspot” for Hantavirus infections.

“California has a high rate of Hantavirus infections, and Mono County is one of the counties with the highest rate of Hantavirus in the country, so yes, it’s a possibility that someone in the county could get still get Hantavirus this year,” said Dr. Rick Johnson, Mono County Public Health Officer.

“But that is always the case during the Hanatavirus season. Do the increased cases in Yosemite mean we will see increased cases? No.”

“Those have all been traced to a small area of the park, except one, the last case that was identified, which has been traced to a backcountry cabin,” he said.

The incubation period for the virus, contracted by most of the currently identified victims in June, is almost over, with just another week or so to go, he said.

On the home front, though, it is still summer, meaning the deer mice that carry the virus are still out and about, meaning exposure to the virus is still very possible. Just don’t assume, if such a thing happens, that it is connected to the Yosemite cases in any way, he said.

There has been only one case of Hantavirus confirmed in Mono County this year—a young woman who survived the infection earlier this year, he said.

But it is not time to relax your guard either, given the season is not over and Mono County’s dubious distinction as a hot spot for the virus.

“We always have to be vigilant here,” he said.

And there are some unusual aspects to the Yosemite cases, he said.

Hantavirus cases do occur in “clusters” of states, regions, etc., but all but one of the eight cases in Yosemite appear to stem from a much smaller area than usual, a cluster of tent cabins in the heart of Yosemite Valley.

“No one yet knows why there have been seven infections (including three deaths) that all stem from the same small area,” he said. “That is one of the things under investigation by the National Park Service, the State Department of Public Health and the Center for Disease Control. But we will have to wait for their reports and those are a few weeks to months out yet.”

The eighth and most recently identified case stems from a victim who was exposed to at least one of the four High Sierra camps that are scattered across the Yosemite backcountry. All four camps require at least a several mile hike from any developed area, meaning the mice that carry the disease are very unlikely to be connected to the mice that infected the other seven victims in the Curry Village area.

If Eastern Sierra residents visited the camps recently and are experiencing any of the symptoms of Hantavirus—flu-like aches, respiratory problems, etc.—it’s time to check with a doctor, Johnson said.

“It’s likely the reason the eighth victim, who had mild symptoms and is recovering, got identified is because he asked for the test, after he saw the park information about Hantavirus everywhere,” Johnson said. “He asked for the test, and probably would not have made the connection to do so, if he wasn’t aware it might be an option.” Given the mild symptoms,

For more information about the Hantavirus situation in Yosemite, go to http://www.nps.gov/yose/planyourvisit/hantafaq.htm.

For additional information on preventing HPS, visit the Center for Diseasen Control (CDC)'s hantavirus
website at http://www.cdc.gov/hantavirus/index.html.