BEIJING--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 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.

Earlier this month three people from Inner Mongolia were hospitalized for plague in two separate cases that were linked to eating wild animals. 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.