A South Lake Tahoe resident has tested positive for the “Black Death,” according to El Dorado health officials.

“Plague is naturally present in many parts of California, including higher elevation areas of El Dorado County,” county public health officer Dr. Nancy Williams told the San Francisco Chronicle on Wednesday:

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. Human cases of plague are extremely rare but can be very serious.

The presently unidentified individual was described as an “avid walker,” and is suspected of contracting the disease from an infected flea while on a walk with their dog. Fleas are known carriers, often acquiring the plague from infected rodents.

Health officials routinely test animals. Between 2016 and 2019, 20 animals in the South Lake Tahoe area tested positive. The last confirmed cases of plague spreading to humans in California originated in Yosemite National Park, where two visitors were infected.

Experts advised against panic, reiterating that this is a long-standing health issue. “Bubonic plague in the U.S. is not the same scenario as the historical Black Death, and we do not need to be afraid of it in the same way,” Susan Jones, a professor of ecology, evolution and behavior at the University of Minnesota College of Biological Sciences, explained.

This does not represent the first sighting of the plague in 2020. A squirrel tested positive in Colorado in July, though no human transmission was reported. But more recently, China is currently grappling with a wave of infections centered in Inner Mongolia.