California health authorities have confirmed the first case of the plague in five years, with a resident of South Lake Tahoe testing positive after believed bitten by a flea carrying the potentially deadly disease.
El Dorado County officials said in a statement that the California Department of Health notified them about the infection, which is caused by bacteria called Yersinia pestis, typically transmitted by infected fleas.
Officials said the person who contracted the plague underwent medical treatment and is at home recovering. Identified in the report as an “avid walker,” the person may have been bitten by an infected flea while walking their dog along the Truckee River Corridor north of Highway 50 or the Tahoe Keys area in South Lake Tahoe, officials noted.
“Human cases of plague are extremely rare but can be very serious,” said Dr. Nancy Williams, El Dorado County Public Health Officer.
Fleas can get the Yersinia pestis bacteria from squirrels, chipmunks, or other rodents.
“Plague is naturally present in many parts of California, including higher elevation areas of El Dorado County,” Williams said, adding that people should take extra care of themselves and their pets when outdoors, especially when engaged in activities in places that are home to wild rodents.
South Lake Tahoe, a popular tourist destination, has signs posted in several areas warning people of the presence of plague.
“Surveillance activities in El Dorado County from 2016 to 2019 found a total of 20 rodents (ground squirrels or chipmunks) with evidence of exposure to the plague bacterium,” officials said in a statement. Infected rodents were found in the South Lake Tahoe area, at or near the Tallac Historic Site, Fallen Leaf Campground, and/or Taylor Creek Visitor Center, officials added.
This is the first time someone in El Dorado County someone became infected with the disease, which typically includes symptoms of fever and swollen lymph nodes. The plague is treatable with antibiotics but, if diagnosed late and with delayed treatment, it can be fatal.
“Plague is an ancient disease which has caused epidemics of illness and the deaths of millions of people throughout history,” the California Department of Public Health says on its website.
Besides wild rodents, domestic cats can also catch the plague from infected fleas and can pass the infection on to their owners.
El Dorado County health officials said the last reported cases of plague in California were traced to Yosemite National Park in 2015, where two people were believed to have come into contact with infected rodents or their fleas. Both of those people underwent treatment and subsequently recovered. Before that, the last reported human cases of the plague in California date back to 2006.
About one-third of Europe’s population died from the plague during a major outbreak known as the “Black Death.”