FLAGSTAFF, Ariz. — A chilling and rare tragedy unfolded this week in northern Arizona, when a Coconino County resident died from a fast-moving case of pneumonic plague—the first confirmed fatality from the disease in the region in nearly two decades.

The unidentified patient arrived at the Flagstaff Medical Center Emergency Department with symptoms so severe that doctors immediately began life-saving resuscitation efforts. Despite “appropriate initial management,” Northern Arizona Healthcare confirmed the patient died that same day. Hours later, rapid diagnostic testing pointed to Yersinia pestis, the deadly bacterium behind the plague.

On Friday, Coconino County Health and Human Services confirmed the worst: the death was caused by pneumonic plague—a severe lung infection that can develop from untreated bubonic plague or through inhalation of infected droplets from a person or animal carrying the disease.

“Our hearts go out to the family and friends of the deceased,” said Coconino County Board of Supervisors Chair Patrice Horstman. “We are keeping them in our thoughts during this difficult time.”

It is unclear when exactly the death occurred, but officials made it clear that the case is not related to a recent prairie dog die-off northeast of Flagstaff in the Townsend-Winona area, which had already raised plague concerns. That incident is still under investigation, and wildlife in the area is being tested for fleas and treated to reduce possible transmission.

Though the plague sounds like something ripped from medieval history books, it still haunts the rural western United States. According to the Centers for Disease Control and Prevention (CDC), an average of seven human plague cases are reported annually in the U.S.—mostly in remote parts of Arizona, New Mexico, Colorado, and California.

The plague exists in three forms: bubonic (marked by swollen lymph nodes), septicemic (which infects the bloodstream), and pneumonic, the most virulent and dangerous. Pneumonic plague occurs when the bacteria reach the lungs or are inhaled directly from another infected host. It spreads quickly and can be fatal within 24 hours without prompt antibiotic treatment.

Officials emphasized that while the disease remains rare, early detection is critical. “If you suspect you are ill with a contagious disease,” the hospital said in a statement, “please contact your health care provider. If your illness is severe, go to the Emergency Department and ask for a mask immediately.”

The Flagstaff Medical Center is working closely with both Coconino County and the Arizona Department of Health Services to investigate the patient’s case, determine the source of infection, and trace any possible exposures.

According to the CDC, humans are most often infected through bites from fleas carried by rodents or by handling animals that harbor the bacteria. Prairie dogs, squirrels, and other small mammals are known reservoirs for Yersinia pestis, and sudden die-offs among them are a major red flag for health officials.

Coconino County officials had just begun flea collection efforts in the Townsend-Winona area when the unrelated fatal case was confirmed. Local health officials are treating burrows and advising residents in rural areas to take precautions: use flea control on pets, avoid handling wild animals, and report unusual wildlife die-offs immediately.

Symptoms of plague can develop within 2–6 days of exposure and typically begin with fever, chills, weakness, and swollen lymph nodes. Pneumonic plague, in particular, adds severe respiratory symptoms such as cough, chest pain, and bloody mucus. Without rapid treatment, it is almost always fatal.

The last pneumonic plague fatality in Coconino County occurred in 2007, involving a resident who had come into contact with a plague-infected animal.

While the name “plague” still evokes the devastation of the 14th-century Black Death that wiped out nearly a third of Europe’s population, experts stress that modern antibiotics are highly effective—if administered quickly.

Still, this week’s sudden death is a sobering reminder that even in the 21st century, ancient diseases can still strike without warning.

Health officials are urging the public not to panic, but to remain vigilant and informed.

“We are taking all necessary precautions,” the county’s health department stated, “and we will continue to monitor the situation closely.”