A resident of South Lake Tahoe, California, has tested positive for bubonic plague, state health officials confirmed this week. The individual, whose identity has not been released, is believed to have contracted the illness after being bitten by an infected flea while camping near Lake Tahoe. Authorities said the patient is receiving medical care at home and is recovering.
El Dorado County officials stated that the California Department of Public Health has been notified and an investigation into the incident is underway. This marks one of the few reported cases of Bubonic Plague in California in recent years.
Health Officials Urge Caution in Outdoor Areas
“Plague is naturally present in many parts of California, including higher elevation areas of El Dorado County,” said Kyle Fliflet, the county’s acting public health director. “It’s important that individuals take precautions for themselves and their pets when outdoors, especially while walking, hiking, and camping in areas where wild rodents are present.”
The disease, caused by the bacterium Yersinia pestis, spreads primarily through fleas that have fed on infected wild rodents such as squirrels and chipmunks, according to the U.S. Centers for Disease Control and Prevention (CDC). Domestic animals, including cats and dogs, can also carry infected fleas, posing additional risks to people.
Local health officials are urging residents and visitors to avoid contact with wild rodents, keep pets away from rodent burrows, and use flea control products on animals. While plague cases are extremely rare, authorities emphasize that early diagnosis and antibiotic treatment make recovery likely.
Between 2021 and 2024, El Dorado County surveillance identified 41 rodents with evidence of exposure to plague, underscoring the ongoing presence of the disease in the region.
Understanding Bubonic Plague
Bubonic plague is one of three forms of plague infection and is named for the painful, swollen lymph nodes, or “buboes,” that typically develop in the armpit, groin, or neck. Symptoms include sudden fever, chills, headaches, muscle aches, and swollen lumps that may become filled with pus. If left untreated, the illness can progress to septicemic or pneumonic plague, both of which are potentially fatal.
The plague has a notorious history. During the 14th century, the so-called Black Death killed an estimated 25 million people in Europe—roughly two-thirds of the population at the time. Spread largely by fleas carried on rats aboard ships, the outbreak reshaped global history.
Though less common today, plague remains present in parts of Africa, Asia, South America, and the western United States. The CDC reports that the U.S. sees an average of seven cases annually, with most occurring in northern New Mexico, northern Arizona, southern Colorado, and parts of California, southern Oregon, and western Nevada.
Rare but Persistent Threat
Despite its deadly reputation, modern medicine has made plague a treatable disease. Antibiotics can successfully cure infections when administered promptly, and public health surveillance continues to monitor rodent populations to identify potential risks.
El Dorado County officials stress that outdoor enthusiasts in the Sierra Nevada and other high-elevation areas should remain vigilant, particularly during the summer months when human interaction with wildlife is more frequent.
“Taking precautions doesn’t mean avoiding the outdoors,” Fliflet said. “It simply means being smart about minimizing exposure risks for both people and pets.”
