Three people who camped in California’s Yosemite National Park have died after being infected with the hantavirus.

As a result, American health officials are expanding their warning to more than 22,000 visitors, of which as many as 2,500 live outside the U.S.

Eight people have been infected with the rare rodent-borne virus after using cabins in the park over the summer.

The warnings say that the virus is not contained to just one area.