A person identified only as an adult has died of plague in Pueblo County, Colorado, the Pueblo City-County Health Department announced on Wednesday. The victim is the second person to have died from plague in Colorado this year.

Plague, which killed roughly a third of the population of Europe at the end of the Middle Ages, causes fever, chills, and swollen and painful lymph nodes as it spreads throughout the body. While normally treated by antibiotics, the disease can become deadly if untreated. “We extend our deepest condolences to the family,” said Sylvia Proud, public health director of the Pueblo City-County Health Department, reported local media.

The victim may have contracted the disease, caused by the bacterium, Yersinia pestis, after being bitten by fleas on a dead rodent or other animal, according to health officials. "Although Turkey Creek is confirmed for plague after testing a dead prairie dog, it could occur elsewhere in Pueblo County as well," said Proud, adding that residents are encouraged to report any unusual die-off of rabbits or prairie dogs, local media reported.

Plague is predominately reported in Africa, Asia and South America, but occasionally it occurs in the southwestern United States. Roughly 1,006 plague cases occurred in the United States between 1900 and 2012, mainly in its bubonic form, according to the Center of Disease Control (CDC).

A 16-year-old high school student was killed in Larimer County, Colorado, by a rare strain of the infection known as septicemic plague, when the bacteria reaches the blood stream, reported the Denver Post.

At least 64 cases of human plague have been reported in Colorado since the state began recording the data, and nine have died from the disease, including the death in Pueblo. The plague death in Pueblo is the first incident in Pueblo County in 11 years, according to local media.

"This highlights the importance to protect yourself and your pets from the exposure to fleas that carry plague," Proud said.