A resident of California has tested positive for plague as the state marks its first case in five years. Health officials have notified the Department of Public Health about the case on Monday, but have not revealed any details on the person's identity.

According to a press release from the El Dorado County Health and Human Services Agency, the patient is being treated and cared for by medical professionals and recovering at home. The patient from South Lake Tahoe is said to be an avid walker and may have contracted the disease from a bite of an infected flea while walking their pet dog along the Truckee River Corridor or perhaps along the Tahoe Keys area on Tahoe's south shore.

Plague bacteria are often transmitted by fleas that have acquired it from infected animals such as squirrels, chipmunks and other wild rodents. Dogs and cats are not spared as plague-infected fleas may attach themselves to domestic pets when they are let loose. The disease is caused by bacterium called Yersinia pestis, and can be transmitted to humans from the bites of infected fleas.

Symptoms to watch out for include, fever, nausea, swollen lymph nodes and weakness. These usually manifest within two weeks of initial contact with an infected animal. Although the disease can be treated with antibiotics, it can be fatal if it is not caught and treated in its early stages.

The World Health Organisation says the mortality rate is estimated between 30 percent and 100 percent if left untreated.

According to the Centre of Disease Control and Prevention, cases of human plague are quite rare with an average rate of seven persons per year. Dr Nancy Williams, El Dorado County Public Health officer, said: "Plague is naturally present in many parts of California, including higher elevation areas of El Dorado County. 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."

Health officials have reported to have found 20 rodents carrying evidence of the bacterium between 2016 and 2019. At this time, signs advising the public of the plague and ways to prevent exposure can be seen in several areas around South Lake Tahoe.

The last reported case of plague in California was in 2015, when two people were exposed to infected rodents with fleas in Yosemite National Park. Both individuals fully recovered.

Squirrel with the plague found in LA (wiki commons)