BEIJING (Reuters) – Chinese health authorities on Thursday reported a fresh case of bubonic plague in the country’s northern Inner Mongolia region, bringing the total number of plague cases to four since the beginning of the month.

A rural herder in Siziwang county was diagnosed with the disease in a local hospital, according to a statement released by the Inner Mongolian health commission.

Prior to the diagnosis the herder had been active in an area where plague sources had been identified, it said.

The person is in a stable condition after treatment at a local hospital and four other people have been quarantined.

The bubonic plague, known as “Black Death” in the Middle Ages, is a highly-infectious and often fatal disease that is spread mostly by rodents. It also has a deadlier variant called pneumonic plague.

Earlier this month three people from Inner Mongolia were hospitalized for plague in two separate cases that were linked to eating wild animals. Two of the people were diagnosed with pneumonic plague and one with bubonic plague. Authorities previously said the two cases were unrelated.

The latest reported case is not in the same region of Inner Mongolia as either of the two earlier cases, and so far there have been no fatalities reported.

Plague cases are not uncommon in China, but outbreaks have become increasingly rare. From 2009 to 2018, China reported just 26 cases and 11 deaths.

(This story corrects headline from ‘bubonic plague’ to ‘plague’, and clarification of pneumonic v. bubonic plague in story)

(Reporting by Cate Cadell; Editing by Shri Navaratnam)