Two more cases of hantavirus have been linked to Yosemite National Park, including one that resulted in the death of a West Virginia resident, officials announced Thursday.
Three people have now died of the rare, rodent-borne disease after visiting the park this summer; five others have been sickened.
Yosemite officials announced the two additional cases; the death was confirmed by the Kanawha-Charleston Health Department in West Virginia, which said that a Kanawha County resident who visited the park "in recent months" died of the disease.
Yosemite officials previously traced the cases to the "signature tent cabins" in the park's popular Curry Village campground, saying a design flaw allowed mice to get inside the walls of the insulated cabins. But Thursday, park officials said that although seven of the cases had been linked to the cabins, one was believed to have originated in the High Sierra Camps, a different area of the park.
Public health agencies across the U.S. have been warned about the outbreak, and alerts were issued internationally this week. The national Centers for Disease Control and Prevention initially said 10,000 people who stayed in the signature tent cabins between June 10 and Aug. 24 were at risk; that number could rise now that a case originated outside Curry Village.
Spread through urine, droppings or saliva of infected rodents, hantavirus takes one to six weeks before causing symptoms in humans, officials said. The disease is generally transmitted when people come in contact with an enclosed area that has been infested by mice.
The disease is rare — 587 cases were diagnosed nationwide from 1993 and 2011, of which about one-third were fatal, according to the CDC.