You probably learned about the plague in school. You probably learned about it in the past tense. For most of us, it feels like something that belongs in history books, next to the carts in the street and the sealed houses.
It doesn't. According to the World Health Organization, the plague is still an active human disease. Most of the cases reported to the agency between 2019 and 2025 came from the Democratic Republic of the Congo and Madagascar.
The culprit has not changed. The bacterium Yersinia pestis still lives in wild rodents and the fleas that bite them. When those fleas bite a person, or when someone handles an infected animal, the bacteria get a new host.
Where the plague still circulates today
In Madagascar, bubonic cases turn up nearly every year during the epidemic season, which runs from September to April, the WHO fact sheet notes. The Democratic Republic of the Congo accounts for most of the rest of the global case load.
Also read: A disease that killed millions is still lurking in America
The United States has its own quiet reservoir. According to the CDC, an average of five human plague cases are reported each year, with a range of zero to seventeen. The cases cluster in two regions.
The first zone covers northern New Mexico, northern Arizona and southern Colorado. The second covers California, southern Oregon and far western Nevada. Over 80 percent of US plague cases have been the bubonic form.
2026 has already brought cases to the western US. A resident of Apache County, Arizona recovered after treatment, Newsweek reported in April. It was the county's first human plague case since 2015.
In June, New Mexico health officials confirmed the state's first human plague case of the year after a woman in Santa Fe County died from the disease.
Also read: More than 1 in 10 US adults now take weight-loss drugs
Suspected cases also drew WHO attention further east, with reports from Russia prompting a formal query to the Russian authorities in October 2026.
The three forms and why early treatment matters
Plague takes three forms. The bubonic form is the most common, and it starts with fever, chills, weakness and swollen, painful lymph nodes called buboes.
The pneumonic form attacks the lungs and can spread from person to person through coughing. The septicemic form spreads through the bloodstream and can cause tissue damage and organ failure.
Untreated pneumonic and septicemic plague are almost always fatal, the WHO notes. The bubonic form has a case fatality ratio of 30 to 60 percent without treatment. Caught early, all three respond to common antibiotics.
Also read: Vitamin supplement was linked to a 65% lower risk of death
The CDC puts it plainly. Plague can be cured with antibiotics, but these must be given promptly to prevent serious illness or death.
That is why anyone in a plague-endemic area who develops sudden fever, painful swollen glands or breathing trouble after being outdoors should contact a doctor without waiting.
Simple steps that lower the risk
For readers in the western United States, the CDC's prevention list is short and practical. Keep rodent habitat away from the house. Remove brush, rock piles, cluttered firewood and anything that attracts rodents.
Wear gloves when handling or skinning potentially infected animals. Keep fleas off pets with flea control products. In endemic areas, do not let outdoor cats or dogs sleep on your bed, since free-roaming animals can bring infected fleas indoors.
Also read: 13.5 million children got no vaccine in 2025: WHO is noticing a large problem
A plague vaccine is not currently available in the United States, according to the CDC, and new candidates are still in development.
Also read: Why a glass of milk in the evening may be worth considering
This article is made and published by Aksel Kryhlmand, who may have used AI in the preparation.