BEIJING (AP) — Parts of a northern Chinese city have been quarantined after state media said a man there died of bubonic plague.

The Chinese news agency Xinhua said Tuesday that 151 people were under observation in the city of Yumen in Gansu province after authorities determined they had come in contact with a man who had died of the plague July 16.

Xinhua said investigators determined the man had contracted the bacterial infection from a marmot he had fed to his dog. The report said all the people under quarantine were in good health, but 10 checkpoints were still blocking off parts of the city.