A South Lake Tahoe resident in California has tested positive for the plague, according to local authorities. The case was confirmed this week by the California Department of Public Health (CDPH), which alerted El Dorado County health officials.

Continues below advertisement

The individual is now recovering at home under medical supervision, officials said. Preliminary investigations suggest that the person may have contracted the infection from a flea bite while camping in the South Lake Tahoe area, a beloved destination in California’s mountain region. Authorities continue to probe the circumstances of the case.

“Plague is naturally present in many parts of California, including higher-elevation areas of El Dorado County,” said Kyle Fliflet, the county’s acting public health director. “People should take precautions for themselves and their pets when outdoors, especially while hiking, camping, or walking in areas where wild rodents live.”

Continues below advertisement

The plague, caused by the bacterium Yersinia pestis, is most often transmitted through the bites of fleas that have fed on infected squirrels, chipmunks, or other wild rodents. Pets can also carry infected fleas into homes, increasing the risk of exposure. Health officials advise the public to avoid contact with wild rodents and keep animals away from rodent burrows.

While human plague cases are extremely rare, they can be severe. Symptoms typically appear within two weeks of exposure and include fever, nausea, fatigue, and swollen lymph nodes. Early detection is critical, as the infection can be successfully treated with antibiotics.

CDPH conducts routine monitoring of rodent populations across California for signs of plague. Between 2021 and 2024, surveillance in El Dorado County identified 41 rodents that tested positive for exposure to the bacterium. In 2025 alone, four rodents, all within the Tahoe Basin, have already tested positive.

This is not the region’s first encounter with plague. The last human case in El Dorado County occurred in 2020 and was similarly linked to South Lake Tahoe. Previously, two cases were reported in 2015 after exposure in Yosemite National Park. All affected individuals were treated successfully and recovered.

Public health concerns have occasionally prompted action in the area. In 2021, the US Forest Service temporarily closed several Lake Tahoe sites after detecting plague among chipmunks. Vector control teams carried out targeted eradication treatments to limit the risk of transmission.

Plague is not confined to California. Colorado health officials reported a human case last year, highlighting that the disease, though rare, remains present in parts of the western United States. According to the Centers for Disease Control and Prevention (CDC), the US sees an average of seven human plague cases annually, most of them in western states.

Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources.

Newsweek AI is in beta. Translations may contain inaccuracies—please refer to the original content.

A California resident has tested positive for plague after camping in the South Lake Tahoe area.

Health officials in El Dorado County believe the individual may have been bitten by an infected flea. The individual is currently under medical supervision and is recovering at home.

A few human plague cases are reported each year in the United States, most commonly in two regions: northern New Mexico, northern Arizona, and southern Colorado or California, southern Oregon, and far western Nevada.

The El Dorado County health department told Newsweek, “Human cases of plague are extremely rare, so the likelihood of other residents acquiring it are low, particularly if they take the precautions we listed in the press release.”

Why It Matters

Plague is a potentially life-threatening disease caused by the bacterium, Yersinia pestis. While it can be cured with antibiotics, these must be given to a patient as soon as possible in order to prevent serious illness or death.

According to the Centers for Disease Control and Prevention (CDC), there are usually an average of seven human plague cases reported each year across the country, with most cases in northern New Mexico and Arizona.

In July, a person in Arizona died from plague, the first recorded death from pneumonic plague since 2007.

Main image, Lake Tahoe in California is pictured in June 2025. Inset, a bubonic plague smear demonstrates the presence of the Yersinia pestis bacteria that causes the plague in this undated photo. Main image, Lake Tahoe in California is pictured in June 2025. Inset, a bubonic plague smear demonstrates the presence of the Yersinia pestis bacteria that causes the plague in this undated photo. Getty Images/AFP/Brooke Hess-Homeier/AP

What To Know

In 1900 rat–infested ships first introduced plague into the country, which resulted in disease epidemics in port cities. The last urban plague epidemic occurred in Los Angeles in 1924.

Nowadays, plague cases are much more scattered and are often in rural areas, the CDC reported.

Plague bacteria are typically transmitted via flea bites, when the fleas have acquired the bacteria from infected squirrels, chipmunks and other wild rodents. In some cases, pets like dogs and cats may also bring plague-infected fleas home.

Avoiding contact with wild rodents and keeping pets away from rodent burrows can help to prevent potential exposure to plague bacteria.

If a person has plague pneumonia, then the bacteria can also be spread through cough droplets in the air, which can be inhaled by another person.

When a person is infected with plague bacteria, it usually takes symptoms less than two weeks to appear. These can include fever, nausea, weakness and swollen lymph nodes.

The California Department of Public Health routinely monitors rodent populations for plague bacteria, and surveillance activities in El Dorado County between 2021 and 2024 found a total of 41 rodents, such as ground squirrels or chipmunks, with evidence of exposure to the plague bacterium.

An additional four rodents have tested positive for the disease in 2025, and health officials reported that all were located in the Tahoe Basin.

What People Are Saying

Kyle Fliflet, El Dorado County’s acting director of public health, 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.”

The El Dorado County health department told Newsweek: “The state department of Public Health conducts surveillance of rodent populations and monitors them for any number of viruses. As in this case, if a rodent or human tests positive for plague, the state contacts county health officials. We publish press releases, post on social media platforms and the county website, conduct media interviews, etc. to raise awareness about how to avoid plague and how to report a sick or dead rodent.”

What Happens Next

Health officials are continuing to monitor the situation.

Update 8/22/25, 3:30 a.m. ET: This article has been updated with a comment from the El Dorado County health department.

A man was hospitalized in El Dorado County, California, after being diagnosed with bubonic plague, a rare infection caused by the Yersinia pestis bacteria, transmitted through a flea bite during a camping trip, as announced by health authorities on August 21, 2025. The patient, whose identity was not disclosed, is recovering at home under medical supervision with antibiotic treatment. This is the first case reported in the region since 2020, prompting authorities to heighten prevention alerts in rural and camping areas. The plague, historically linked to devastating pandemics, remains present in wild rodents in the western United States, requiring vigilance from campers and residents. The case underscores the need for preventive measures against fleas and rodents to avoid further infections.

The incident occurred in a mountainous area known for its population of wild rodents, such as squirrels, which are natural reservoirs for the bacteria. The U.S. Centers for Disease Control and Prevention (CDC) reports an average of seven human plague cases annually in the country, with most occurring in states like California, New Mexico, and Colorado.

Preventive measures include using DEET-based repellents.

Avoiding contact with wild rodents is essential to reduce risks.

Pets should be regularly treated for fleas.

The current situation shows no signs of an outbreak, but it highlights the importance of vigilance in natural areas.

Origin of the bacteria and risks in rural areas

Bubonic plague is caused by Yersinia pestis, a zoonotic bacterium that circulates among rodents and fleas in natural environments. In El Dorado County, the presence of squirrels and marmots facilitates the bacteria’s persistence in the ecosystem. The recent case, reported in a camping area, reignites concerns about human exposure in rural regions.

Transmission occurs primarily through bites from infected fleas, which contract the bacteria after feeding on sick animals. Direct contact with bodily fluids from infected rodents also poses a risk. The El Dorado patient, who developed symptoms after outdoor activity, was diagnosed quickly, allowing for immediate treatment.

Peste Negra – Foto: matejmo/istockphoto.com

Local authorities, in collaboration with the CDC, are monitoring the bacteria’s circulation in wild rodents. In 2020, a similar case in the same region prompted educational campaigns, which are now being reinforced. The swift medical response in the current case demonstrates the effectiveness of antibiotics, such as doxycycline, when administered early.

Forms of the disease and warning signs

The plague manifests in three main forms, each with distinct symptoms and risks:

Bubonic : Characterized by painful swelling of lymph nodes (buboes), it is the most common and least severe form if treated early.

: Characterized by painful swelling of lymph nodes (buboes), it is the most common and least severe form if treated early. Pneumonic : Affects the lungs and can be transmitted through respiratory droplets, increasing the risk of contagion.

: Affects the lungs and can be transmitted through respiratory droplets, increasing the risk of contagion. Septicemic : The bacteria spread through the bloodstream, potentially leading to severe complications like septic shock.

: The bacteria spread through the bloodstream, potentially leading to severe complications like septic shock. Early diagnosis: Symptoms such as fever, chills, and localized pain require immediate attention, especially after exposure to high-risk areas.

In the El Dorado case, the patient presented the bubonic form, with symptoms like high fever and swollen lymph nodes, successfully treated. The pneumonic form, though rare, is more concerning due to its potential for human-to-human transmission. The septicemic form, less common, can progress rapidly if untreated.

Early diagnosis is critical. Individuals frequenting rural or camping areas should watch for symptoms appearing within two weeks of potential exposure and seek medical care immediately.

Preventive measures for campers and residents

Preventing the plague relies on practical steps to minimize contact with fleas and rodents. Health authorities recommend:

Using DEET-based repellents on exposed skin during outdoor activities.

Avoiding camping near rodent colonies or piles of debris that may attract animals.

Treating pets with flea control products to prevent the introduction of infected fleas into homes.

Keeping yards and residential areas free of trash or dense vegetation that may harbor rodents.

Local campaigns in El Dorado are distributing educational materials in parks and camping areas, providing guidance on identifying dead rodents, which may indicate the presence of the bacteria. The CDC also advises that anyone experiencing fever or swollen lymph nodes after outdoor activities should seek medical attention promptly.

Public education is a key tool in endemic areas. Clearing land and reporting dead rodents help map high-risk areas, enabling swift interventions.

History of the plague in the United States

Bubonic plague arrived in North America in the early 20th century, likely through ships carrying infected rats. Since then, the bacteria have established themselves in wild rodent populations, such as squirrels, marmots, and field rats, particularly in the western U.S.

Between 1970 and 2020, approximately 500 human cases were recorded in the U.S., with an 11% mortality rate in untreated cases. States like New Mexico, Arizona, and Colorado account for the majority of cases, followed by California. The low incidence is due to ongoing surveillance and access to effective treatments.

The El Dorado case serves as a reminder of Yersinia pestis’ continued presence in nature. While medical advances have significantly reduced risks, exposure in rural areas requires constant care.

Actions by authorities to mitigate risks

El Dorado County authorities, in collaboration with the CDC, are inspecting camping areas and trails to identify potential rodent hotspots. Traps for rodents and flea testing are being used to monitor bacterial circulation.

Active monitoring : Public health teams are conducting inspections in natural areas.

: Public health teams are conducting inspections in natural areas. Educational campaigns : Flyers and signs provide campers with prevention guidance.

: Flyers and signs provide campers with prevention guidance. Rapid intervention : Suspected cases are treated immediately to prevent complications.

: Suspected cases are treated immediately to prevent complications. National collaboration: The CDC supports local efforts with resources and guidelines.

The response to the current case was effective, with the patient recovering and no signs of transmission. However, authorities emphasize that ongoing vigilance is essential in regions where the bacteria is endemic.

Curiosities about the plague’s history

The plague has a storied past, with significant impacts on human history. Some notable points:

In the 14th century, the Black Death killed about 50% of Europe’s population.

Doctors wore long-beaked masks, believing they protected against the disease.

Traces of Yersinia pestis have been found in 3,300-year-old archaeological remains.

In the U.S., rodents like marmots are the primary bacterial reservoirs.

Though treatable today, the plague’s history underscores the importance of preventive measures and vigilance. Combining education, monitoring, and effective treatment keeps risks under control, but the bacteria’s presence in nature demands constant attention.

Highlights

South Lake Tahoe resident tests positive for plague after camping, likely infected by flea bite

Patient recovering at home under medical care following early detection and treatment

Four rodents in Tahoe Basin tested positive for plague bacteria in 2025, adding to 41 cases from 2021-2024

Last human plague case in El Dorado County occurred in 2020 in the same South Lake Tahoe area

Health officials emphasize preventive measures for outdoor enthusiasts and pet owners in endemic areas

California Camper Tests Positive for Plague After Lake Tahoe Flea Bite

El Dorado County Confirms Rare but Treatable Disease in Popular Recreation Area

SOUTH LAKE TAHOE, Calif. (KPEL News) — A South Lake Tahoe resident has tested positive for plague after likely being bitten by an infected flea while camping in the area, El Dorado County health officials announced Tuesday.

The person is recovering at home under medical care, with health officials investigating the exact circumstances of the infection.

Get our free mobile app

“Plague is naturally present in many parts of California, including higher elevation areas of El Dorado County,” said Kyle Fliflet, El Dorado County’s Acting Director of Public Health. “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.”

What Campers and Outdoor Enthusiasts Need to Know

Plague is caused by the bacterium Yersinia pestis, most often transmitted by bites of fleas that have acquired the bacteria from infected squirrels, chipmunks and other wild rodents. Dogs and cats may also bring plague-infected fleas into homes. According to the US Centers for Disease Control and Prevention, there’s an average of seven cases of human plague reported annually in the United States.

Getty Images Getty Images loading…

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. Plague can be effectively treated with antibiotics if detected early.

Current Plague Activity in the Tahoe Basin

Public health officials in California monitor rodents in the area to determine whether they carry plague. From 2021 to 2024, 41 rodents were found to have been exposed to the plague bacteria. Four additional rodents tested positive in 2025, all identified in the Tahoe Basin.

El Dorado County officials noted how rare human cases of plague are, with the last reported case in the South Lake Tahoe area in 2020. Before that, two people tested positive for plague in 2015 after they were exposed in Yosemite National Park.

How to Prevent Plague While Camping and Hiking

Health officials recommend several prevention strategies:

For Outdoor Activities:

Do not feed squirrels, chipmunks or other wild rodents

Never touch sick, injured or dead rodents

Do not camp, sleep or rest near animal burrows or areas where dead rodents are observed

Wear long pants tucked into boot tops and spray insect repellent containing DEET on socks and pant cuffs to reduce exposure to fleas

For Pet Owners:

Leave pets home if possible; otherwise keep pets on a leash

Do not allow pets to approach sick or dead rodents or explore rodent burrows

Protect pets with flea control products

Pet cats are highly susceptible to plague and can pose a direct threat to humans. Keep cats away from rodents

Understanding Plague in the Modern Era

Plague occurs in the western U.S., with most cases in northern New Mexico and Arizona. Most human cases in the United States are acquired in two regions: Northern New Mexico, northern Arizona, and southern Colorado; and California, southern Oregon, and far western Nevada.

CDC Chief Dr. Thomas Frieden Updates Media On Dallas Ebola Response Getty Images loading…

Over 80% of United States plague cases have been the bubonic form. In recent decades, an average of seven human plague cases have been reported each year (range: 0–17 cases per year).

The recent Lake Tahoe case occurred against the backdrop of heightened awareness following a death from pneumonic plague in northern Arizona in July 2025, marking the first recorded death from pneumonic plague since 2007.

Get our free mobile app

When to Seek Medical Attention

Health officials advise that 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. Early antibiotic treatment is highly effective against all forms of plague.

A California resident has been confirmed to have tested positive for the plague, likely due to a flea bite while camping in the South Lake Tahoe area, according to health officials. The El Dorado County Health and Human Services Agency announced the individual’s recovery is underway at home, with medical supervision.

The California Department of Public Health (CDPH) alerted local officials about the case, leading to an ongoing investigation into the incident. Health officials suspect that the flea bite occurred during the individual’s camping trip, prompting further exploration of the situation.

Plague bacteria, known scientifically as Yersinia pestis, are typically transmitted by fleas that have fed on infected animals, such as squirrels, chipmunks, or other rodent species. El Dorado County has seen an increase in plague-positive rodents, having identified 41 during the period from 2021 to 2024. In 2025 alone, four additional infected rodents have been found in the Tahoe Basin.

Human infections are exceedingly rare in the United States, averaging about seven reported cases annually, primarily in the western states, including northern New Mexico and Arizona. Symptoms usually start with the bubonic form of the plague, characterized by fever, headache, chills, weakness, and swollen lymph nodes. If left untreated, the infection can escalate to septicemic plague, which may cause severe abdominal pain and bleeding into the skin.

Kyle Fliflet, the acting public health director for El Dorado County, emphasized the prevalence of plague in many regions of California, especially in higher-elevation areas. He urged outdoor enthusiasts, including campers and hikers, to take necessary precautions for their safety and that of their pets, particularly in areas where wild rodents are known to inhabit.

The current case marks the first human infection in El Dorado County since 2020, with the last recorded instances in the South Lake Tahoe area. In 2015, two individuals contracted the plague after exposure in Yosemite National Park but made a full recovery following treatment. Prior to that, the last human cases in California were documented in 2006.

Health authorities continue to monitor and investigate this latest case closely. Officials have reassured the public that the affected individual is stable and receiving appropriate medical care.