Plague threat rises in California: What you need to know now

A recent case of plague has emerged in South Lake Tahoe, California, prompting public health officials to raise awareness and urge caution. The person infected is recovering at home under medical care after possibly being bitten by an infected flea during a camping trip.

The plague, caused by the bacterium Yersinia pestis, remains present in various parts of California, including higher elevations such as El Dorado County.

This disease is rare but potentially serious, and its threat increases during outdoor activities involving exposure to wild rodents.

What are the symptoms and risks of the plague?

Plague often presents in three forms: bubonic, septicemic, and pneumonic. The most common, bubonic plague, causes flu-like symptoms such as fever, chills, weakness, and swollen lymph nodes called buboes.

Pneumonic plague affects the lungs and can spread from person to person, making it particularly dangerous.

Symptoms usually appear within two weeks of exposure to infected fleas or rodents. Early antibiotic treatment is crucial to preventing severe complications or death.

Did you know?
The bubonic plague bacterium Yersinia pestis can survive in rodent fleas and remains active in nature even after centuries since the Black Death.

How can residents and campers protect themselves?

Officials advise avoiding contact with wild rodents such as squirrels and chipmunks and not feeding or handling them. Pets, especially cats, should be kept away from rodents to reduce risk, as they can carry infected fleas into homes.

When outdoors in areas with known plague activity, wearing long pants, using insect repellents with DEET, and avoiding camping near rodent burrows or dead rodents are important preventive measures.

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Plague cases in California and local environment updates

This recent case is the first human plague infection reported in El Dorado County since 2020. Surveillance from 2021 to 2025 found numerous rodents in the Tahoe Basin with evidence of plague exposure, indicating the bacterium's active presence in the local ecosystem.

Nationally, approximately seven plague cases occur annually in the U.S., primarily in western rural areas such as northern New Mexico and Arizona.

Public health efforts and safety recommendations

The California Department of Public Health and local authorities closely monitor rodent populations for plague activity. Public health officials stress the importance of being alert to posted warnings and seeking medical care if symptoms appear after potential exposure.

The cooperation between health agencies and the public is vital to managing this rare but serious disease, especially as outdoor activities rise during the season. Taking precautions now can protect both individuals and communities from this ancient but still relevant health threat.