Officials said they are working to protect campers after a child contracted the plague after visiting the park’s Crane Flat campground. Medical experts are attempting to determine if the child’s case can be definitively connected to the cases of plague found in wildlife in the area or if they contracted the bacterial disease at a different location.
Dr. William Schaffner, an infectious disease expert at Vanderbilt University Medical School, said a key component of staying safe while camping is using bug spray and doing everything possible to keep rodents out of a campsite. He said it’s important to keep food clear so that rodents are not attracted to campsites. Additionally, even a dead rodent doesn’t mean it’s safe from causing infection.
“There’s a tendency to want to get rid of it. I would advise not doing that,” Schaffner said, explaining that infected rodents are most dangerous when dead as infected fleas look for their next host. "Don’t try to clean up the area.”
The California Department of Public Health is warning anyone visiting the area in Yosemite to wear bug spray, avoid rodents and to never feed wildlife.
Both the Crane Flat and Tuolumne Meadows campgrounds at Yosemite have been closed after park officials found infected wildlife in the area. They are treating rodent burrows with pesticides in an effort to halt the spread of disease.
“Studies have shown when you kill squirrels in an area you’re at higher risk for plague,” Buttke explained as to why they target fleas. “The fleas don’t have hosts,” and can jump to people.
Plague is endemic to the area now but not native, and as a result it can have devastating effects on wildlife in the region. Buttke said multiple rodent species have faced extinction as a result of a plague outbreak.
Buttke stressed that human cases of plague in Yosemite park are exceptionally rare with the last confirmed case occurring in 1959.
“It’s not a routine occurrence,” she explained. But “we’re definitely seeing more activity nationwide.”
“The ultimate answer is we don’t know at this time,” she said.
Buttke said park officials are working to develop a new vaccine that will protect wild rodents from the bacterial disease, but that has not been released yet.