EL DORADO COUNTY (KRON) — Health officials in El Dorado County are warning people to take precautions around wild rodents, after a squirrel near South Lake Tahoe tested positive for plague.

The dead squirrel was found in a picnic area last month and the animal was sent to the state laboratory for testing. The El Dorado County Health Department says the test results came back positive on Sep. 2.

Health officials said they are not aware of any human contact with the squirrel. Officials have posted warning signs in the area where the animal was found, and people are advised to report any dead or sick rodents.

County officials say plague is naturally present in parts of California. It’s spread by wild rodents and their fleas. Humans can contract the disease through flea bites or close contact with an infected animal.

Plague causes fever, nausea and swollen lymph nodes. It can be treated with antibiotics.

The discovery of the squirrel comes after two human cases of the disease were reported earlier this summer.

In both cases, the victims had visited Yosemite National Park. Both people were treated and recovered, health officials said. The two were the first reported human cases in California since 2006.