SOUTH LAKE TAHOE, Calif. (NewsNation) — Health officials have confirmed a case of plague at South Lake Tahoe, the first in California in five years.

El Dorado County officials said Monday the California Department of Public Health notified them of the positive test of a local resident, who is under medical care while recovering at home.

Plague bacteria are most often transmitted by fleas that have acquired it from infected squirrels, chipmunks and other wild rodents. Dogs and cats may also carry plague-infected fleas.

Health officials believe the South Lake Tahoe resident may have been bitten by an infected flea while walking a dog along the Truckee River corridor or in the Tahoe Keys area on Tahoe’s south shore. The situation is under investigation, county health officials said.

The last reported human cases of plague in California were in 2015 when two people were exposed to infected rodents or their fleas in Yosemite National Park. Both were treated and recovered.

No human cases have been reported since, but authorities did find evidence that a total of 20 ground squirrels or chipmunks around South Lake Tahoe had been exposed to the plague bacterium from 2016-19. Those rodents were identified near the Tallac Historic Site, Fallen Leaf Campground or Taylor Creek Visitor Center.

“Symptoms of plague usually show up within two weeks of exposure to an infected animal or flea and include fever, nausea, weakness and swollen lymph nodes,” El Dorado County health officials said. “Plague can be effectively treated with antibiotics if detected early.”

In order to avoid exposure, health officials recommend not feeding squirrels, chipmunks or other wild rodents, as well as leaving pets at home if possible, NewsNation affiliate KTLA reported. Other preventative measures include not touching sick or dead rodents and prohibiting pets from playing with or picking up sick, injured or dead rodents.