The Riverside County Department of Public Health reported that ground squirrels from Dark Canyon and Marion Mountain campgrounds tested antibody-positive this month for plague, according to state and local health officials.

The tests on squirrels from the two campgrounds 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.

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.

The California Department of Public Health notified the County Environmental Health, Vector Control Program, about the positive blood tests. Riverside County Vector Control routinely samples wild rodents in mountain recreational areas during the summer months for the presence of plague antibodies. The U.S. Forest Service district rangers and safety officer also have been notified.

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.

Since the plague is typically spread by the bite of infected rodent fleas, 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. For more information, contact the VCP at 951-766-9454 or