2nd death from hantavirus in Yosemite Mice spread hantavirus to tent cabins at Curry Village

Another visitor to Yosemite National Park this summer who contracted the hantavirus while staying in the popular Curry Village has died, park officials said Monday.

That makes three confirmed cases, including two deaths. A fourth case, also reported Monday, is being investigated.

All four visitors stayed in Curry Village, a collection of tents and cabins at the eastern end of Yosemite Valley, over a one-week period in mid-June. Park officials are now contacting everyone who has stayed in the tent cabins since mid-June to warn them about the virus and advise them to seek medical attention if they have any symptoms of infection.

"This is being taken very seriously," said park spokesman Scott Gediman. "We've been able to isolate the cabin area, we've done the thorough cleaning, we're monitoring the area, we're trapping mice and testing them. We're making sure the cabins are shored up. We're being very active, and we have been since the cases came to light."

Hantavirus is a rare viral infection carried by mice and passed to humans by the rodents' feces or urine. Most people infected with the virus suffer flu-like symptoms first, including fever, headache and muscle pains, often in the thighs, back and hips. After two to seven days, many patients have severe difficulty breathing and can die.

No cure available

Patients may not develop symptoms until one to six weeks after exposure. There is no cure or virus-specific treatment for hantavirus.

The first victim reported was a 37-year-old Alameda County man who died in late July. The second victim was a woman from Southern California who survived the infection. The third victim is a man who lives in another state and also died in July.

No immediate information was available on the fourth victim, who is expected to survive. Public health officials are waiting for lab tests to confirm that the fourth victim has hantavirus, but given the symptoms it's likely that patient also contracted the virus in Yosemite, Gediman said.

Difficult to diagnose

Public health officials aren't expecting to find more cases of hantavirus, but since it's a rare disease that can be difficult to diagnose, it's possible other victims may still be found, Gediman said. The two newest cases were reported to California public health officials only last weekend, although both victims had been symptomatic for weeks.

All four of the victims stayed in Curry Village's "signature tent cabins" over a one-week period in mid-June. Curry Village has 408 tent cabins with wood frames and canvas sides; 91 of those cabins are higher-end, with more insulation and other amenities.

Gediman said contractors are currently making improvements to all of the signature cabins, including replacing the insulation and checking carefully for areas where mice could get into the structures.

"They're doing everything they can to eliminate areas where mice can get into the cabins," Gediman said. "This was never because the cabins were dirty, it was never because we didn't take care of them. This is just because approximately 20 percent of all deer mice are infected with hantavirus. And they're here in Yosemite Valley."

Spread by deer mice

Hantavirus is spread primarily via deer mice, which generally live at higher elevations and, in California, are most common in the eastern Sierra. Lab tests taken after the first two victims fell ill confirmed that the hantavirus was present in fecal matter from mice trapped near Curry Village.

These four cases are the first ever to be reported from Yosemite Valley, although the national park has had two cases in past years, both in visitors to the higher-elevation Tuolumne Meadows.

There have been about 60 cases of hantavirus pulmonary syndrome reported in California since the virus was identified in the United States in 1993. About a third of those patients died.