Officials say two people in China are being treated for the plague — the same one that caused the Black Death pandemic in the 1300s.
The two patients, from a province in Inner Mongolia, were diagnosed with pneumonic plague, a severe lung infection caused by the Yersinia pestis bacterium, state-run news outlet Xinhua reports.
They are being treated in Beijing’s Chaoyang District.
Back in May, a Mongolian couple died from bubonic plague, one of the three types of plagues caused by the bacterium, AFP reported at the time.
They reportedly ate raw kidney from a marmot as part of a local folk remedy thought to promote good health.
The two deaths in May resulted in a quarantine of the area for six days, which prevented tourist groups from leaving the region.
The bacteria is typically transmitted through flea bites and infected animals, CNN reports. The plague comes in three forms: pneumonic, which affects the lungs; bubonic, which affects the lymph nodes; and septicemic, which affects the blood.
The World Health Organization (WHO) says if pneumonic plague is left untreated, it is always fatal. The global organization reported 3,248 cases of the disease from 2010 to 2015, including 584 deaths.
According to the Guardian, the WHO said it understood that close contacts of the two patients were being screened and managed.
The Democratic Republic of the Congo, Madagascar and Peru are the three countries in which pneumonic plague is most endemic.
In 2015, two people in Colorado died from the plague, Fox 13 reports. According to the broadcast station, there were eight reported cases in the state in 2014.
At least one person dies every year from the plague in Mongolia, likely from eating raw meats, the National Center for Zoonotic Disease reports.
The Black Death was one of the most deadly diseases to ever affect humankind. From 1347 to 1351, it is estimated to have wiped out anywhere from 75 million to 200 million people.