LOS ANGELES (LA Times) — U.S. health officials have notified 39 other countries whose citizens may be at risk for hantavirus after recently traveling to Yosemite National Park, where a deadly outbreak of rodent-borne disease has been traced.

Dr. David Wong, an epidemiologist with the National Park Service’s Office of Public Health, told the Los Angeles Times that health officials believe 2,000 to 2,500 people from outside the United States possibly have been exposed to the disease.

Last week, the national Centers for Disease Control and Prevention said up to 10,000 people were at risk after staying in the “signature tent cabins” in Curry Village between June 10 and Aug. 24.

U.S. Department of Health and Human Services officials used an international health notification network to share the latest advisory over the weekend.

“Notification’s still important,” Wong said. “That’s why we extended to international countries once we had that information.”

Six hantavirus cases, two of which were fatal, have been linked to the park. Yosemite officials have traced five of the cases to the tent cabins, saying a design flaw allowed mice to get inside the walls of the insulated cabins.

Park officials have sent letters or emails to some 3,100 people who reserved any of the 91 signature tent cabins during that period, urging them or anyone in their party to seek immediate medical attention if they start to show the initial flu-like symptoms of the disease.

Spread through urine, droppings or saliva of infected rodents, hantavirus takes between one and 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.