California health officials are investigating a second possible case of plague in less than a month in another tourist who fell ill after visiting Yosemite National Park.
The California Department of Public Health said Tuesday the case occurred in a patient from the U.S. state of Georgia who visited Yosemite, the Sierra National Forest and surrounding areas in early August.
“Warnings issued in California regarding plague were useful all the way across the country in Georgia. Those warnings helped the patient get the prompt medical attention necessary to recover from this illness,” said Karen Smith, director and state health officer for the department.
The Centers for Disease Control and Prevention is testing the person to confirm "the presumptive positive case," officials said.
Authorities announced on August 6 that a child from near Los Angeles who visited Yosemite in mid-July tested positive for plague. She was treated and has since recovered.
Plague is an infectious bacterial disease that is carried by squirrels, chipmunks and other wild rodents and their fleas. When an infected rodent becomes sick and dies, its fleas can carry the infection to other warm-blooded animals or humans.
After evidence of the plague was discovered, health officials closed two park campgrounds in Yosemite National Park. Crane Flat Campground - where the infected child and family were staying - reopened last week after authorities treated it for four days with an insecticide.
Park officials have also closed Yosemite's Tuolumne Meadows Campground through Friday so authorities can fumigate the area after two dead squirrels were found to be carrying the plague.
Authorities said the risk to humans is low despite the presence of the plague in wild rodents at both campgrounds over the past two weeks.
Yosemite National Park, located in northern California's Sierra Nevada mountains, is the third-most visited of America's national parks, and one of the oldest.