A city in northern China’s Inner Mongolia Autonomous Region raised its health warning Sunday after a herdsman was diagnosed with bubonic plague, according to local authorities.

Bayannur issued a third-level alert in its five-tiered plague warning system, which was introduced in the region this month. The alert will remain in effect until the end of the year, Bayannur’s health commission said. The city of 1.7 million inhabitants has also prohibited hunting and eating animals that could potentially carry the bacteria that causes plague.

Authorities have requested that the public report any dead marmots or people with fever of unknown cause, while noting the “risks of further spread of plague among people.”

Plague is a severe infection caused by the Yersinia pestis bacteria, which is found in some mammals including mice, marmots, and other rodents, as well as their fleas. The two most common forms of plague — categorized in China as a “Class A,” or most severe, infectious disease — are pneumonic and bubonic.

The patient diagnosed with bubonic plague in Bayannur is currently being treated at a local hospital and is in stable condition, the city’s health commission said.

Last week, two cases of bubonic plague were also reported in the neighboring country of Mongolia. Both were said to be linked to the consumption of marmot meat, according to The New York Times.

Plague is not uncommon in China, where isolated cases are reported from time to time in the country’s northern and western regions. Five cases of plague were reported in the country last year, according to the National Health Commission.

Before Sunday’s notice, the most recent plague cases in the region were in November, when four people including a couple who later sought medical help in Beijing were diagnosed with the disease. Meanwhile, another case — this one fatal — was reported in the northwestern Gansu province in September.

After the November outbreak, the National Health Commission asked Inner Mongolia to enhance its surveillance of plague in rodents and rodent predators, as well as train local doctors to diagnose and treat the disease.

Correction: A previous version of this story said authorities had warned of the risk of human-to-human transmission. They had warned of the risk of further plague cases among people without specifying the mode of transmission.

Editor: Bibek Bhandari.

(Header image: A marmot in its natural habitat near Yushu, Qinghai province, Aug. 31, 2017. Pu Xiaoxu/Beijing Youth Daily/People Visual)