Colorado health officials have confirmed a human case of the bubonic plague in Pueblo County, sparking concerns regarding the potential spread of the disease, which can be fatal if not treated.

A recent press release by the Pueblo Department of Public Health and Environment noted that the department is currently working with the Colorado Department of Public Health and Environment to investigate the case.

While the health department did not release information regarding the person who was reported to have contracted the plague, the press release provided a warning to the public, saying, “We advise all individuals to protect themselves and their pets from plague.”

According to Fox News, Timothy Brewer, M.D., who is a professor of medicine and epidemiology at the University of California, Los Angeles, explained that the bubonic plague is caused by a bacterium known as Yersinia pestis, which is believed to have been first introduced in North America around 1900.

“Since its introduction 120 years ago, it has become endemic in ground squirrels and rodents in the rural Southwestern U.S.,” Brewer told Fox News.

According to the Centers for Disease Control and Prevention (CDC) website, while the plague can affect people of all ages, roughly half of reported cases are found in individuals between the ages of 12 and 45.

Fox News reported that while 1,000 to 2,000 cases of the plague are reported to the World Health Organization every year, only an average of seven cases are reported in the United States each year.

According to Fox News, the bubonic plague is fatal in 30% to 60% of untreated cases. However, if patients are treated with antibiotics, the fatality rate is less than 5%.

The Pueblo Department of Public Health and Environment’s press release explained that typical symptoms of the plague include fever and chills, severe headaches, muscle aches, swollen lymph nodes, nausea, and vomiting.

Erica Susky, a certified infection control practitioner, told Fox News that the plague can spread by droplets from infected individuals.

“The more common risk of exposure in the U.S. is from pets, rodents and fleas,” Susky added. “Pets can sometimes be infected when encountering an infected flea or rodent and may pass it along to their pet owners from a bite or if the pet is ill.”

Susky explained that the best way to prevent the spread of the plague is to avoid contact with fleas and rodents.

“One way to do this is to ensure the home is rodent-proof by eliminating places where rodents may enter and hide,” Susky stated.

Susky also urged people to “treat pets promptly” if they discover a flea infestation and to seek proper treatment from a veterinarian “if a pet becomes ill.”