On August 2, the authorities quarantined Zigortang after a dozen people were sickened with pneumonic plague, a lung infection that can kill a human in 24 hours if left untreated.

The quarantine zone covered an area of 3,500 square kilometres (1,400 sq mi) centred on the town.

The first casualty was a 32-year-old herder who had fallen ill after burying his dog, which had died suddenly after eating a marmot infected with the bacterium Yersinia pestis.

The 10 people sickened, mostly relatives of the herder, were undergoing isolated treatment in hospital, managed by the local health bureau.

[6] Authorities urged anyone who had visited Zigortang town since mid-July and has developed a cough or fever to seek hospital treatment.

Medical workers in Zigortang were disinfecting and killing rodents and insects that can be carriers for the bacterium that causes the plague.