A Northern Arizona patient died this week after becoming infected with a severe form of plague, according to public health officials.

“(We) recently cared for a patient in the Flagstaff Medical Center Emergency Department and despite appropriate initial management and attempts to provide life-saving resuscitation, the patient did not recover,” Northern Arizona Healthcare (NAH) said in a statement to USA TODAY on July 11, adding that the patient died that same day.

The Arizona Department of Health Services has conducted rapid diagnostic testing and issued a “presumptive diagnosis of Yersinia pestis, the bacteria that causes the plague,” NAH said in a statement.

Plague is the same illness that killed millions of people in Europe during the Middle Ages. Today, it is rare but can crop up mostly in rural parts of the western U.S. and certain parts of Africa and Asia, the Centers for Disease Control and Prevention (CDC) said on its website.

The Airzon resident died from pneumonic plague, a severe lung infection, Coconino County health officials said in a press release on July 11. There are an average of seven human plague cases reported each year in the United States and the risk to the public remains low, according to Coconino County Health and Human Services and the CDC.

Read more: A New Mexico man has died after contracting the bubonic plague: Here’s what to know

Arizona patient died of pneumonic plague, says hospital

Citing privacy laws, Northern Arizona Healthcare said it was unable to release more information about the patient who died.

“The NAH team is saddened by this loss of a community member,” the agency said in a statement.

“Out of respect for the family, no additional information about the death will be released,” Coconino County Board of Supervisors Chair Patrice Horstman added in a news release.

In a July 11 statement, Coconino County health officials confirmed this to be the first recorded death from pneumonic plague in the county since 2007. In the previous case, the patient contracted the disease after interacting with an infected dead animal.

The Arizona Department of Health Services did not immediately respond to USA TODAY’s requests for comment.

What is Yersinia pestis and what does it have to do with plague?

Yersinia pestis is a bacterium that causes a potentially life-threatening disease called plague. Plague is spread among wild rodents and other animals. Doctors can cure human patients of the disease with antibiotics, but it must be treated promptly, according to the CDC.

Humans usually contract plague from being bitten by an infected flea or by touching an infected animal, the CDC said. 

When was plague first reported in the U.S.?

Plague was first reported in the U.S. in 1996. At the time, two out of five infected patients died, with neither being formally diagnosed until after succumbing to the illness, according to the CDC.

Investigators said one of the patients, an 18-year-old, likely became infected about six days before his first doctor’s visit when he was bitten by fleas while walking through a prairie dog colony in Navajo County, about 103 miles east of Flagstaff, Arizona. Investigators found traces of the bacterium in multiple pet dogs living near the prairie dog colony, the report said. 

Prairie dogs are “highly susceptible to plague but are not considered a long-term reservoir of the disease,” according to officials in Coconino County, where the most recent patient died. The county’s statement also said the death is not related to recent reports of prairie dog deaths nearby.

Symptoms and what to do if you suspect you have the disease

Coconino County health officials said symptoms in humans typically appear within one to eight days after exposure.

According to the CDC, there are three primary forms of plague:

• Bubonic plague – Bubonic plague is most commonly spread via a flea bite. After a two to eight day incubation period, patients may develop fever, headache, chills, weakness and one or more swollen, painful lymph nodes.
• Septicemic plague – Septicemic plague is most commonly spread through flea bites or exposure to infected animals. Patients develop fever, chills, weakness, abdominal pain, shock, and possibly bleeding into the skin and other organs. Skin and some tissues can turn black and die, primarily on fingers, toes, and the nose. Septicemic plague can develop on its own or from untreated bubonic plague. 
• Pneumonic plague – Pneumonic plague is the most serious form of the disease. It occurs when someone has untreated bubonic or septicemic plague in their lungs, or when a person inhales infectious droplets coughed out by another person or animal with pneumonic plague. The incubation period of pneumonic plague following inhalation can be as short as 1 day. Pneumonic plague is the only form of plague that can be spread from person to person. Patients develop fever, headache, weakness and pneumonia with shortness of breath, chest pain, cough and sometimes bloody or watery mucus.

To avoid contracting the disease, county officials suggest staying away from wild animals; using veterinarian-approved flea treatments on pets; removing brush, rock piles, trash, and lumber from around homes and outbuildings; and avoiding campsites next to rodent burrows.

Saleen Martin is a reporter on USA TODAY’s NOW team. She is from Norfolk, Virginia – the 757. Email her at [email protected].