(CBS/AP) CHARLESTON, W.Va. - Health officials confirmed on Thursday that a third person who visited Yosemite National Park this summer has died after contracting the hantavirus, a rodent-borne illness that kills one-third of the people that contract the virus.
The man, who is from West Virginia, is one of eight Yosemite visitors who have been confirmed to have the the virus.
Five people are ill from the outbreak reported last week by park officials, who said up to 10,000 guests could have been exposed to hantavirus pulmonary syndrome from sleeping in the cabins since June 10.
More infections could be reported. Alerts from the U.S. Centers for Disease Control and Prevention sent to public health agencies, doctors and hospitals have turned up other suspected cases that have not yet been confirmed. This week the European CDC and the World Health Organization issued global alerts for travelers to any country to avoid exposure to rodents.
Dr. Rahul Gupta, director of the Kanawha-Charleston Health Department, declined to release details of the West Virginia victim at a news conference.
Gupta said the victim had visited the park since June but declined to be more specific, citing the family's wish to grieve in private.
The other deaths occurred in California and Pennsylvania. Those that were sickened also were from California and the National Park Service said Wednesday they were either improving or recovering.
Seven of the cases involved guests at the insulated "Signature" cabins in the park's historic Curry Village section. The California Department of Public Health said the other case involved someone who stayed in several High Sierra Camps in a different area of Yosemite in July.
Yosemite officials said the cabins have been closed and the park is reaching out to overnight guests who have stayed in the cabins. Yosemite National Park spokeswoman Kari Cobb told CBSNews.com said that part of the problem is that the "signature" tents are made out of an outer layer and inner later. The space inbetween them is filled with insulation, and authorities believe.
Gupta declined to elaborate on whether anyone was traveling with the Kanawha County victim, although he said his department knew of no other cases of hantavirus.
"The time has lapsed in a way that it should not be a concern," Gupta said.
Health officials say the disease isn't spread from person to person. There is no cure for the virus, which can affect people of any age. The disease is carried in the feces, urine and saliva of deer mice and other rodents and carried on airborne particles and dust.
People can be infected by inhaling the virus or by handling infected rodents. The hantavirus causes Hantavirus Pulmonary Syndrome (HPS), which can lay dormant for one to five weeks. Infected people usually have flu-like symptoms including fever, shortness of breath, chills and muscle and body aches. The illness then progresses to rapid acute respiratory and organ failure.
Anyone exhibiting the symptoms must be hospitalized. More than 36 percent of people who contract the rare illness will die from it.
Health officials said there have been 602 hantavirus cases nationally since the virus was first identified in 1993. The Yosemite cases are unique because they occurred in clusters, while previous cases have been individual exposures.
Park concessionaire Delaware North Co. had sent letters and emails to nearly 3,000 people who reserved the cabins between June and August, warning them that they might have been exposed. Because the rooms can hold up to four people, up to 7,000 more visitors might have been exposed, a park spokesman has said.
Yosemite's hantavirus hotline has received thousands of calls about the outbreak.
"We want to make sure that visitors have clear information about this rare virus and understand the importance of early medical care," Yosemite Superintendent Don Neubacher said Wednesday. "We continue to work closely with state and national public health officials, and we urge visitors who may have been exposed to hantavirus to seek medical attention at the first sign of symptoms."
More than 60 hantavirus cases have been diagnosed in California since 1993. In West Virginia, the densest population of carrier mice are found in higher elevations. Gupta said only three cases of hantavirus have been documented in the state since 1981.
In 2004, a Virginia Tech graduate student who was conducting field studies of small mammals in Elkins died after contracting the disease.
"People do not need to freak out," Gupta said. "This is not a common disease."