Ground squirrels from Dark Canyon Campground and Marion Mountain Campground tested antibody-positive this month for plague, according to state and local health officials.


The Riverside County Environmental Health, Vector Control Program was notified about the positive blood tests by the California Department of Public Health. The U.S. Forest Service district rangers and safety officer also have been notified. The tests on squirrels from Dark Canyon Campground and Marion Mountain Campground were conducted on June 8 and June 13, respectively. The antibody-positive test means the squirrels had been exposed to the disease sometime in the past.

Plague is a rare bacterial disease in rodents that can be transmitted through the bite of infected rodent fleas. The disease has been detected in ground squirrels, chipmunks, and other wild rodents throughout many mountain regions in Southern California. The last positive plague samples in the San Jacinto Mountain Range were in 2012 and 2002. All campgrounds are continuously posted to remind campers that plague has been found in the area in the past.

Riverside County Vector Control routinely samples wild rodents in mountain recreational areas during the summer months for the presence of plague antibodies. Follow-up rodent surveillance and an environmental assessment of the two campgrounds will be conducted this week. Risk to the public is currently considered to be low and campgrounds will remain open during follow-up investigations.

Plague is spread by the bite of infected rodent fleas. Therefore visitors and campers should take the following precautions:

  • Do not set up tents on or near rodent burrows
  • Do not feed or pick up any wild animals
  • Do not touch or handle any dead animals
  • Keep pets on a leash while camping and ensure they have been treated against fleas
  • Report any sick or dead rodents to campground staff
  • Contact your family medical provider if you experience any illness after camping in mountain areas