State officials are closing Fallen Leaf Lake Campground from June 27-July 1 in order to apply a pesticide to “minimize potential future plague risk,” according the U.S. Forest Service.

Campers must check out by noon Monday. The gate will likely reopen the morning of July 1.

California Department of Public Health officials want all rodent burrows to be dusted with a pesticide to reduce the number of fleas that can carry plague. The pesticide to be used, DeltaDust, is a pyrethroid that has minimal effects to people or pets with direct contact. Pyrethroids are a man-made version of pyrethrins, which are natural insecticides made from chrysanthemum flowers.

Test results confirmed on June 20 that four out of 15 rodents tested positive for exposure to plague. Health officials are not aware of any human contact with infected rodents or fleas at the campground.

Plague is naturally present in many parts of California, including higher elevation areas of El Dorado County and is spread by squirrels, chipmunks and other wild rodents and their fleas. People may get plague if bitten by an infected flea or through close contact with an infected rodent or pet. Plague can be prevented by avoiding contact with wild rodents, and by keeping pets away from rodent burrows. Risk of acquiring plague is low when precautions are taken.

Symptoms of plague usually show up within two weeks of exposure to an infected animal or flea, and include fever, nausea, weakness and swollen lymph nodes. Plague can be effectively treated with antibiotics if detected early.