A person in California has tested positive for the Black Death, which strikes just a handful of Americans every year.

A resident from the well-known vacation spot of Lake Tahoe has contracted the plague after likely being bitten by an infected flea during a camping trip, officials believe.

California health officials said the person is under the care of a medical professional and is recovering at home. 

This marks the first confirmed plague case in the county since 2020, which was also thought to have originated in the South Lake Tahoe area. Before these instances, California had not reported any cases of the disease since 2015.

The most recent US case was last month, in Colorado. That patient did not survive. 

The Centers for Disease Control and Prevention (CDC) notes that, on average, only seven plague cases are reported annually in the U.S., despite its historical impact that once decimated nearly half of Europe’s population.

Untreated plague has a mortality rate of 30 to 60 percent in the US. But if it spreads to the lungs or bloodstream, it’s nearly 100 percent deadly. 

Areas like California and New Mexico experience more frequent occurrences due to a higher prevalence of rodents carrying Yersinia pestis, the bacterium responsible for the plague.

A person living near Lake Tahoe (pictured) tested positive for the plague (file photo)

The above CDC map shows confirmed plague cases in the US from 1970 to 2023

Kyle Fliflet, the acting director of public health for El Dorado County, stated: ‘Plague naturally exists in several regions of California, including the higher-elevation parts of El Dorado County.’

‘It is crucial for people to be cautious for their own safety and that of their pets when they are outdoors. This is especially important during activities such as walking, hiking, or camping in areas where wild rodents live.’

Plague symptoms strike within one to eight days, with fever, chills, and debilitating fatigue. 

It’s often accompanied by painful swollen lymph nodes (buboes) in the groin or armpits. Left untreated, it can ravage enters the bloodstream and travels to the lungs, causing deadly infections. 

Once the disease enters cells, it kills them by releasing deadly toxins. 

Infection can arise from handling infected cats, rodents, or their fleas.

According to the California Department of Health, there were 45 ground squirrels or chipmunks with evidence of exposure to the plague bacterium in the Lake Tahoe Basin from 2021 to 2025.

The plague, sometimes referred to as the Black Death, wiped out 25 to 50million people in Europe. This was thought to be 30 to 50 percent of the population. 

Plague cases in the US today are rare, with fewer than 10 every year. They mostly occur in the Four Corners region (New Mexico, Arizona, Colorado, Utah), where rodents and fleas thrive. 

Modern antibiotics and hygiene have drastically reduced deaths, but the disease remains endemic in wildlife. Health officials urge caution in high-risk areas.

Plague is an infectious disease caused by the bacterium Yersinia pestis, which is carried by fleas and transmitted between animals. The picture above is a 3D illustration of the bacterium

The above CDC graph shows both fatal and non-fatal US plague cases from 2000 to 2023

El Dorado County health officials urged residents and visitors to avoid exposure to rodents or ticks. They recommended wearing long pants tucked into boots and using a bug repellent with DEET.

Additionally, people in the area should never feed or touch wild rodents and refrain from camping new animal burrows or dead rodents.

Plague was also detected in Arizona last month when an unidentified resident became the state’s first death from the disease since 2007.

The resident’s cause of death was pneumonic plague, the most dangerous form of the Black Death, which spreads by inhaling droplets of saliva emitted from an infected person or animal coughing or sneezing.

Colorado and New Mexico were also recorded plague cases last year. The New Mexico patient was the first to be infected with and die of the plague since 2020. Colorado’s was the state’s first death since 2007.