Local, state and federal officials are urging caution after a chipmunk near Taylor Creek Visitor Center was found with plague last week.
The rodent was rolled up in a ball, shaking and struggling to breathe when it was discovered by a U.S. Forest Service employee, Forest Service spokeswoman Cheva Heck said.
Vector control officials were contacted and captured the animal, which tested presumptive positive for the bacteria that causes plague, Yersinia pestis, Heck said.
The disease is rare, highly infectious and can be fatal, according to a Wednesday statement from the El Dorado County Environmental Management Department.
But plague is curable in its early stages with diagnosis and treatment. Symptoms include high fever, chills, nausea, weakness and swollen lymph nodes in the neck, armpit or groin.
People are typically exposed to plague through an infected flea bite, handling an infected rodent or exposure to an infected pet - especially cats, according to the statement.
Residents and visitors to picnic spots and campgrounds should take precautions to protect themselves against the disease following the discovery, said Bob Hartmann, El Dorado County's interim public health officer, in the statement
"Individuals can greatly reduce their risk of becoming infected with plague by taking simple precautions, including avoiding contact with wild rodents and their fleas," Hartmann said. "Do not feed rodents in picnic or campground areas and never handle sick or dead rodents. Also, leave your pets at home when visiting areas with elevated plague risk."
Public health officials urge people to wear long pants tucked into boot tops to reduce exposure to fleas, apply insect repellent containing DEET on socks and trouser cuffs and avoid walking, hiking or camping near rodent burrows. People should also report any sick or dead animals to forest, campground or local health officials, according to the county.
The county urges anyone who develops symptoms within two weeks of possible exposure to seek immediate medical attention and inform the physician they have been in an area where plague is known to exist.
Pet owners should keep their animas leashed and away from dead rodents and be taken to a veterinarian if they become sick following a visit to the Taylor Creek area, according to the statement.
Additional rodent surveillance is planned in the area this week to assess public risk. The Forest Service is awaiting further recommendations from California Department of Public Health based on the results.