A third case of rodent-borne hantavirus believed to have originated in Yosemite's Curry Village in June has been confirmed, and it was the second resulting in death, officials said Monday.
Two weeks ago, park officials reported that the uncommon disease transmitted by rodents has killed one man and made another person ill after they returned from trips to the park.
According to health officials, the two people likely contracted the disease after staying in Curry Village, a popular park location with cabins and restaurant facilities.
Those victims were a man from the Bay Area and a woman from Southern California who stayed at the park in June, according to park officials. The Bay Area man died in late July; the woman is recovering.
The discovery of the second fatal case was reported Monday.
In an unconfirmed fourth case, an individual who visited the park may have contracted the disease, officials said. That person is believed to be recovering.
The two deaths occurred in July and have been reported by park officials as the results of an investigation that has linked those suffering from the disease to the park.
All of the cases have involved people who stayed in Curry Village's "Signature Tent Cabins" in mid-June.
Park officials are trying to contact visitors who stayed in the tent cabins between June and August.
Visitors are being advised to seek immediate medical attention if they exhibit any symptoms, which begin with fever and aches, but can rapidly progress to life-threatening illness. Early medical attention is critical for individuals who contract the disease.
"The health of our visitors is our paramount concern and we are making every effort to notify and inform our visitors of any potential illness," said Don Neubacher, Yosemite National Park Superintendent, in a press release.
Hantavirus is transmitted through feces, urine or saliva of infected wild mice, primarily deer mice. Most human victims are infected by inhaling small particles of mouse urine or droppings that have been stirred into the air.
Park officials said they have increased measures to reduce visitors' risk of exposure to hantavirus with strategies including inspection and cleaning of rooms and cabins, exclusion of deer mice and other rodents from buildings, maintaining good housekeeping and sanitation levels, and educating the public about the dangers of the disease and how to avoid getting it.
If visitors notice rodent droppings, they shouldn't clean the mess themselves, officials said, adding that staff is trained to safely dispose of the waste.
Other cases of hantavirus were believed to have originated at the park in 2000 and 2010.
Since hantavirus was first identified in 1993, there have been about 60 cases in California, including about five this year. One in three cases in the state was fatal. Throughout the United States, fewer than 590 cases have been reported.