CA Resident Tests Positive For Plague

SOUTH LAKE TAHOE, CA — A California resident has tested positive for plague, according to authorities.

El Dorado County health officials were notified by the state health department that the South Lake Tahoe resident tested positive and may have been bitten by an infected flea while camping in the area, according to a county news release. The person is under the care of a medical professional and recovering at home, and health officials are investigating the situation.

Plague is naturally present in parts of California, including areas with higher elevation in El Dorado County, according to 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 or camping in areas where wild rodents are present,” he said in the news release.

Plague is caused by the bacterium Yersinia pestis and is most often transmitted by the bites of fleas that have acquired it from infected squirrels, chipmunks and other wild rodents, according to the news release. Dogs and cats can carry the fleas, and people can get plague when they are bitten by infected fleas.

Symptoms typically occur within two weeks of exposure to an infected animal or flea, and include fever, nausea, weakness and swollen lymph nodes, the news release said. Plague can be effectively treated with antibiotics if detected early.

The state health department monitors rodent populations for plague activity in California. Surveillance in El Dorado County from 2021-24 found 41 rodents with evidence of exposure to the plague, according to the news release. So far in 2025, four rodents have tested positive, all from the Tahoe Basin.

Human cases of plague are extremely rare but can be very serious, the news release said.

Prior to the current case, the most recently reported human case in El Dorado County was in 2020, likely due to exposure in the South Lake Tahoe area. Two people were reported with plague in 2015 after being exposed to infected rodents or fleas in Yosemite National Park. All were treated and recovered.

The U.S. averages seven human cases per year, according to the Centers for Disease Control and Prevention, which reports that the nation’s last urban plague epidemic was in Los Angeles, ending in 1925.

To prevent plague, El Dorado County advises the following:

• Do not feed squirrels, chipmunks or other wild rodents.
• Never touch sick, injured or dead rodents.
• Do not allow your pets to play with or pick up sick, injured or dead rodents.
• Do not camp, sleep or rest near animal burrows or areas where dead rodents are seen.
• Look for and obey posted warning signs.
• Wear long pants tucked into boot tops and spray insect repellent containing DEET on socks and pant cuffs to reduce exposure to fleas.
• Leave pets home if possible; otherwise keep pets on a leash.
• Protect pets with flea control products.
• Cats are highly susceptible to plague and can pose a direct threat to humans. Keep cats away from rodents. Consult a veterinarian if your cat becomes sick after being in contact with rodents.
• If you get sick after being in an area where plague is known to occur, consult a physician and tell them you may have been exposed to plague.