A resident of South Lake Tahoe, California, has tested positive for plague, local health authorities announced this week. The individual, who is recovering at home under medical care, is believed to have been bitten by an infected flea while camping in the area.
El Dorado County health officials said the California Department of Public Health (CDPH) notified them of the case. “Plague is naturally present in many parts of California, including higher-elevation areas of El Dorado county,” said Kyle Fliflet, the county’s acting director of public health. He urged precautions for people and pets when outdoors, especially where wild rodents are present.
Plague is caused by the bacterium Yersinia pestis and is typically transmitted through flea bites from infected squirrels, chipmunks, and other wild rodents. Dogs and cats can also carry infected fleas into homes. Symptoms, which appear within two weeks of exposure, include fever, nausea, weakness, and swollen lymph nodes. Early detection allows effective treatment with antibiotics.
While human cases are extremely rare, the CDPH routinely monitors rodent populations for plague activity. In El Dorado County, surveillance from 2021 to 2024 found 41 rodents with plague exposure. So far in 2025, four rodents have tested positive, all within the Tahoe Basin. The last human case in the county was in 2020, also linked to South Lake Tahoe. Two cases were reported in 2015 after exposure in Yosemite National Park.
In 2021, the US Forest Service closed several sites at Lake Tahoe after discovering plague in chipmunks. Last year, Colorado also confirmed a human case. The Centers for Disease Control and Prevention estimates an average of seven human plague cases annually in the US, mostly in the western states.
