Bubonic Plague in the US: Symptoms and Treatment of the ‘Black Death’
Wild rodents in the American West often carry bubonic plague. Officials advise avoiding contact with animals and taking good care of pets.
A person in Pueblo County, Colorado, about 100 miles (160 kilometers) south of Denver, has been infected with the bubonic plague, local health officials reported Monday.
Last week, state and local officials identified the case based on preliminary test results. Trysten Garcia, a spokesperson for the Pueblo Department of Public Health and Environment, said in an email Tuesday morning that it was bubonic plague. Previous announcements were more general, saying it was “plague.” The infection was initially reported on Friday. The department said the person had been hospitalized for bubonic plague but was improving. Because plague is locally endemic, it is difficult to trace the source of the infection, Garcia said.
Bubonic plague, which wreaked havoc in Europe and Asia during historic pandemics, is caused by the bacterium Yersinia pestis. It is transmitted by fleas, which are often carried by rodents in the wild, including rats and prairie dogs. It occurs when infected fleas bite humans or when humans touch or skin an infected animal.
Most human cases in the U.S. have occurred in the Southwest—northern New Mexico, northern Arizona, and southern Colorado—and the West—California, southern Oregon, and far western Nevada. According to the Centers for Disease Control and Prevention, the U.S. averages seven human cases of plague per year.
In March, a New Mexico man died from the plague, state health officials said. In February, Oregon officials identified a human case of the plague. The Oregon case likely came from an infected domestic cat.
Bird flu: CDC reports fourth case of bird flu in U.S. in 2024 in Colorado
What are the symptoms of bubonic plague?
Symptoms can develop after an incubation period of one day to one week, according to the World Health Organization. The plague typically causes sudden fever and chills, severe headache, muscle aches, nausea and vomiting.
A common symptom is swollen, painful lymph nodes called buboes, which give the most common form of the disease its name, bubonic plague. These manifest on the body as swellings in the armpits, groin and neck, according to the Mayo Clinic. Buboes range in size from less than a half inch to about 4 inches. Bubonic plague does not spread from person to person, according to the CDC.
Other forms of plague include pneumonia, which occurs when the bacteria infect the lungs; and septicemia, when the bacteria infect the blood. Pneumonia can spread when a person breathes in respiratory droplets from an infected person. These droplets can remain in the air for an hour after an infected person coughs. Pneumonia can also occur when the bacteria from untreated bubonic plague or septicemia spread to the lungs. Septicemia does not spread from person to person.
WHO estimates that 30% to 60% of people die from bubonic plague. Pneumonic plague is fatal if left untreated.
There is no vaccine for plague in the U.S., the CDC said. People who develop symptoms of the plague should see a health care provider immediately. Antibiotics can treat the plague, but a person should be evaluated immediately to prevent serious illness or death, Alicia Solis, manager of the infectious disease and emergency management program at the Pueblo County Department of Public Health, said in a statement.
How can you avoid this?
Wild rodents in the American West often carry plague. With that in mind, Pueblo County health officials warned people to clear areas where rodents can hide and breed near homes, garages, barns or recreation areas. People should not let pets hunt or roam in rodent areas, including prairie dog colonies, and they should regularly treat dogs and cats for fleas. Officials warned that flea collars have not been shown to be effective against fleas infected with plague. Officials also warned people not to let their pets sleep with them.
People should also avoid contact with dead animals. If you must handle sick or dead animals, use insect repellent with 20 to 30 percent DEET to protect yourself from fleas, officials said. Use a long-handled shovel to pick up an animal and place it in a garbage bag outside.
Health News: Ozempic vs Mounjaro? There’s a Clear Winner for Weight Loss, Research Finds
‘Black Death’
The plague has been found on every continent except Oceania, but the most endemic countries are the Democratic Republic of Congo, Madagascar and Peru. Historically, the disease decimated the world’s population. In the 14th century, the bubonic plague spawned the infamous Black Death pandemic, which killed an estimated 50 million people, according to the WHO. More than a quarter of Europe’s population died, although some estimates are higher. Later outbreaks occurred in China and India.
Previous US Outbreaks, Misconceptions
The United States did not see the same number of deaths from the plague as other regions, although outbreaks did occur over the decades. In 1900, the plague was introduced on rat-infested ships leaving affected areas, leading to epidemics in port cities like San Francisco, where racist public health policies wrongly blamed the Chinese community for bringing the disease and making them particularly susceptible, as journalist David K. Randall wrote in “Black Death at the Golden Gate.” By the mid-1920s, Los Angeles had the nation’s largest urban epidemic, with more than 30 deaths. In Southern California at the time, public health officials blamed the “Mexican district” just east of downtown.
But the plague was caused by fleas that spread to urban rat species. These fleas then infected rodent species in the rural West with the plague, creating a reservoir of plague that continues to this day.
