What Californians should know about the plague after a new case in El Dorado County
A South Lake Tahoe resident is recovering at home from a case of bubonic plague, public health officials announced late Monday — that is the same Black Death that killed millions of people across Europe in the 1300s.
Fortunately, the modern world has something that didn’t exist back then: antibiotics, said Dr. Stuart Cohen of UC Davis Health, and these medicines can cure the illness if it’s diagnosed in time.
Public health officials in El Dorado County said the resident likely got the disease as a result of a flea bite while out for a walk with their dog along the Truckee River Corridor north of Highway 50 or the Tahoe Keys area in South Lake Tahoe. They described the individual as an avid walker.
“Plague is naturally present in many parts of California, including higher elevation areas of El Dorado County,” said Dr. Nancy Williams, El Dorado County’s public health officer. “Human cases of plague are extremely rare but can be very serious.”
The Sacramento Bee posed several questions about plague to Cohen, and here are his answers:
What is plague?
Plague is an infection caused by the bacterium Yersinia pestis. Whether it’s the Black Death, bubonic plague or pneumonic plague, they’re all caused by that same bacteria. It can be transmitted by fleas that get the bacteria by feeding on an infected animal or from breathing in the bacteria.
The South Lake Tahoe resident had the black plague, or septicemic plague. It sends the patient’s body into septic shock. The blood pressure falls, making it hard for organs or extremities like fingers and toes to get enough oxygen.
When people end up with really low blood pressures, they can get gangrene in the digits. So, the skin turns black. I think that’s part of the basis for the name.
Whether bubonic or pneumonic, Cohen said, it all likely fits under the same category since there wasn’t much differentiation.
In addition to having fevers, chills and sweats and headaches, Cohen said, patients can have lymph node that swell larger than ping-pong balls and perhaps a skin lesion where the flea bite started. Those swollen lymph nodes are called buboes and give the bubonic plague its name.
Septicemic plague is what you have when the bacteria poison the bloodstream and lower people’s blood pressure. With pneumonic plague, people breathe in the bacteria from infected animals. That’s why many wilderness areas have signs telling people not to touch or go near sick animals.
“There’s a famous case,” Cohen said. “I think it was maybe the last case up in Tahoe where a woman’s cat got plague. Cats eat some of the rats outside and a cat got sick. Then when the owner was trying to take care of it, like all good pet owners do, and she happened to breathe in the bacteria. If people have pneumonic plague, it can also be transmitted from person to person.”
In a hospital setting, he said, these patients are placed in isolation to limit transmission of the disease.
Is the plague still deadly?
It depends. There are antibiotics that will treat plague, but if somebody who has bubonic plague doesn’t receive antibiotic therapy, the mortality rate is about 50%.
If people have so-called septicemic plague or pneumonic plague and they don’t get antibiotics, it’s 100% fatality. With the administration of antibiotics, we probably have mortality rates down around 5% or maybe 10% for the septicemic type of illnesses.
How do you diagnose plague?
The patient in Tahoe had the more typical picture for people that have septicemic plague. She had positive blood cultures, but it’s typically positive cultures from the blood or from a buboes, the giant lymph nodes.
Physicians can take samples of patients blood or from the buboes and send it to a lab where technicians will stain it and identify it.
What symptoms do people develop, aside from the enlarged lymph nodes?
They come in with fever and then if there are no skin lesions, they typically have fever. Their blood pressure has dropped. They may have some gastrointestinal symptoms such as nausea, vomiting or diarrhea.
If they have pneumonic plague, they’re short of breath. They have some respiratory illness as well.
It depends on the form, but in general, the one thing that is consistent is that they all have fevers and chills and headaches. And, it’s very sudden in onset.
Do people increase their risk of getting this when they take pets into wilderness?
You just have to be thoughtful and cautious. I don’t think you should say people shouldn’t live in the weathers nor should they take their pets into the wilderness.
When it comes to pets, El Dorado County officials recommended that people leave them at home if possible or keep them on a leash. They advised against allow pets to approach sick or dead rodents or explore rodent burrows and to protect them by using flea control products.
Since cats are highly susceptible to plague and can pose a direct threat to humans, they urged owners to keep them away from rodents and to consult a veterinarian if your cat becomes sick after being in contact with rodents.
Here are some other suggestions they had:
▪ Do not feed squirrels, chipmunks or other wild rodents, and never touch a sick or injured one.
▪ Do not camp, sleep or rest near animal burrows or areas where you can see dead rodents.
▪ Wear long pants tucked into boot tops and spray insect repellent containing DEET on socks and pant cuffs to reduce exposure to fleas.
▪ Consult a doctor if you think you may have been exposed to plague.
Is plague making a comeback?
It’s not a very common illness. The U.S. Centers for Disease Control and Prevention notes that there are typically only about seven cases a year.
The last reported human case of plague in there were when two people Yosemite National Park tested positive in 2015. Both were treated and recovered. Before that, the last case in the state was in 2006.
That’s as far east as it goes, he said, and most of the disease clusters around the geography that defines the Navajo reservation going into southern Colorado, California and Oregon.
Most cases occur in the summer — May through October —because that’s when people are out and that’s when the fleas are most active. A lot of times, it’s kids who get infected because they’re the ones who are not wearing insect repellent or not doing other things to avoid bites.
This story was originally published August 18, 2020 at 4:39 PM.
