Two ground squirrels trapped during routine monitoring at the Cedar Grove Campground on Palomar Mountain in southern California have tested positive for plague, County Vector Control officials announced.

Officials said the squirrels represented a low risk of transmission because their blood tests showed that their exposure was not recent, but that they were conducting flea-control measures and posting plague-warning signs at Cedar Grove and nearby Doane Campground as a precaution, the La Jolla Light reported.

Jack Miller, director of the Department of Environmental Health, said people could take simple steps to protect themselves from possible exposure when camping and visiting parks.

“It is important that campers avoid contact with squirrels and their fleas,” Miller said. “Set up your tents away from squirrel burrows, don’t feed squirrels and warn your children not to play with squirrels.”

Plague is a bacterial disease of wild rodents that can be transmitted to humans through the bite of infected fleas. To date, there have been no locally acquired human cases of plague reported in San Diego County. Flea populations are monitored, and control measures are taken as necessary at campgrounds to reduce the potential for human exposure.