California Resident Tests Positive for Plague

Last week, California health officials confirmed that a South Lake Tahoe resident tested positive for pneumonic plague. The individual is currently under the care of a medical professional and is recovering at home.

Health officials reported that the person may have been bitten by an infected flea while camping in South Lake Tahoe area. They continue to investigate the situation.

Prior to the current case, the most recently reported case of human plague in El Dorado County was in 2020, likely exposed in the South Lake Tahoe area.

“Plague is naturally present in many parts of California, including higher elevation areas of El Dorado County,” said Kyle Fliflet, El Dorado County’s acting director of public health. “It’s important that individuals take precautions for themselves and their pets when outdoors, especially while walking, hiking and or camping in areas where wild rodents are present.”

Plague is caused by the bacterium, Yersinia pestis. Plague bacteria are most often transmitted by the bites of fleas that have acquired the bacteria from infected squirrels, chipmunks, and other wild rodents, such as prairie dogs. Dogs and cats may also bring plague-infected fleas into the home. People can get plague when they are bitten by infected fleas.

As CMM previously reported, a northern Arizonian died in July from pneumonic plague, a severe lung infection caused by the Yersinia pestis bacterium. The death in Coconino County, according to officials, was the first recorded death from pneumonic plague since 2007. Colorado health officials also confirmed a human case of plague in a Pueblo County resident.

Plague is rare in humans. According to the U.S. Centers for Disease Control and Prevention, an average of seven human plague cases are reported each year in the U.S.  

The risk to the public remains low, including the risk of human-to-human transmission. The last reported occurrence of human-to-human transmission was reported in 1924, according to the National Institutes of Health, and is typically spread through respiratory droplets. In the U.S., most cases happen in rural areas of northern New Mexico, northern Arizona, southern Colorado, California, southern Oregon and far western Nevada.