5 Things To Know About Plague After New CA Infection

SOUTH LAKE TAHOE, CA — For the first time in some five years, a person in California recently tested positive for the bubonic plague, the extremely rare infection that once drove the "Black Death" in the Middle Ages.

El Dorado County health officials were notified by the state health department that a South Lake Tahoe resident had been infected while camping.

Authorities believe the person may have been bitten by an infected flea while they were camping in South Lake Tahoe. Officials are still investigating, but the person is reportedly recovering at home.

Here are five things to know about plague.

What is plague?

Plague is a rare but dangerous disease that comes from a bacterial infection. There are three types of plague — bubonic, septicemic and pneumonic. More than 80 percent of plague cases in the U.S. are bubonic.

The word plague tends to dredge up images of the "Black Death," the destructive Medieval pandemic that killed tens of millions of Europeans in the Middle Ages.

Although medical advancements have made the infection survivable, it hasn't disappeared.

In fact, it has sickened several people in the Golden State within the last 10 years.

How common is plague in California?

Plague is naturally present in parts of California, including areas with higher elevation in El Dorado County, according to Kyle Fliflet, El Dorado County’s acting public health director.

Before this month, the most recently reported human case in El Dorado County was in 2020, likely due to exposure in the South Lake Tahoe area. In 2015, two people became ill with plague after being exposed to infected rodents or fleas in Yosemite National Park. All were treated and recovered.

All three were able to make a full recovery.

“The risk is incredibly low,” Dr. Jones-Lopez told the New York Times this month. “If you’re living in this country, you’re at much higher risk of a long list of other things,” he said, adding, “things like measles.”

The U.S. averages seven human cases per year, according to the Centers for Disease Control and Prevention, which reports that the nation’s last urban plague epidemic was in Los Angeles and ended in 1925.

In California, plague tends to spread among woodland creatures in the foothills, plateaus, mountains and coast. For example, infected rodents may be found in rural recreational and wilderness areas such as the Angeles National Forest, San Gabriel Mountains and the Tahoe Basin.

How does plague spread?

Plague occurs naturally in the western areas of the U.S., where it circulates among wild animals, according to the Centers for Disease Control and Prevention.

Plague is caused by the bacterium Yersinia pestis, which is typically spread through infected fleas and wild rodents. Other creatures that can carry the disease are chipmunks, wood rats, marmots and mice.

People usually get plague after being bitten by or handling an infected flea or rodent. People can also be sickened by infected pets, especially cats, according to the CDC.

Humans can become infected when handling tissue or body fluids of an infected animal.

"For example, a hunter skinning a rabbit or other infected animal without using proper precautions (e.g., gloves) could become infected with plague bacteria," the CDC says. "This form of exposure most commonly results in bubonic plague or septicemic plague."

However, sick humans and animals can sometimes pass the disease to one another if the infected party coughs, spewing plague bacteria into the air.

These bacteria-containing droplets can cause pneumonic plague if they are inhaled. This would require close contact with the person or animal that has pneumonic plague.

But person-to-person spread has not been seen since LA's rat-driven outbreak of 1924.

Scientists believe that plague spreads between populations of certain rodents at low rates, without causing many of them to die. Infected rodents and their fleas serve as "long-term reservoirs for the bacteria," according to the CDC.

What are the symptoms of plague?

Symptoms of the bubonic plague typically occur within two weeks of exposure to an infected animal or flea and include the following:

• Fever
• Nausea
• Weakness
• Swollen and painful lymph nodes
• Chills

Pneumonic plague includes "rapidly developing" pneumonia with shortness of breath, chest pain, cough and sometimes bloody mucus.

Meanwhile, septicemic plague can cause abdominal pain, shock and bleeding into the skin or other organs. Skin and other tissues can turn black and die, particularly on the fingers, toes and nose. This infection can occur if bubonic plague is left untreated.

Plague can be effectively treated with antibiotics if detected early.

How to prevent plague

Mostly, Californians don't need to fret too much about plague. But for those who live in areas where plague occurs naturally, several steps can be taken to reduce the risk of being sickened.

“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. “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.”

To prevent plague, health authorities advise the following:

• Do not feed squirrels, chipmunks or other wild rodents.
• Never touch sick, injured or dead rodents.
• Do not allow your pets to play with or pick up sick, injured or dead rodents.
• Do not camp, sleep or rest near animal burrows or areas where dead rodents are seen.
• Look for and obey posted warning signs.
• Wear long pants tucked into boot tops and spray insect repellent containing DEET on socks and pant cuffs to reduce exposure to fleas.
• Leave pets home if possible; otherwise keep pets on a leash in areas where the risk is high.
• Protect pets with flea control products.
• Cats are highly susceptible to plague and can pose a direct threat to humans. Keep cats away from rodents. Consult a veterinarian if your cat becomes sick after being in contact with rodents.
• 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.