From Wikipedia:
The Black Death was one of the most devastating pandemics in human history, resulting in the deaths of an estimated 75 to 200 million people in Eurasia and peaking in Eurasia from 1321 to 1353. Its migration followed the sea and land trading routes of the medieval world. This migration has been studied for centuries as an example of how the spread of contagious diseases is impacted by human society and economics.
The disease is caused by Yersinia pestis, which is enzootic (commonly present) in populations of ground rodents in Central Asia.[1] Morelli et al. (2010) reported
the origin of the plague bacillus to be in China.[1] An older theory places the first cases in the steppes of Central Asia, and others, such as the historian Michael W. Dols,
argue that the historical evidence concerning epidemics in the Mediterranean and specifically the Plague of Justinian point to a probability that the Black Death originated in Central Asia,[2] where it then became entrenched among the rodent population.[3]
Nevertheless, from Central Asia it was carried east and west along the Silk Road, by Mongol armies and traders making use of the opportunities of free passage within the Mongol Empire offered by the Pax Mongolica.
It was reportedly first introduced to Europe at the trading city of Caffa in the Crimea in 1347.[4] The Genoese traders fled, bringing the plague by ship into Sicily and the south of Europe, whence it spread.
- - -
China should literally be cut-off and blockaded from the rest of the planet.
Not only the Black Death and other plagues have orginated from their lands, but in the last few decades there have been several diseases from China which have spread to the world.
In 2019, instances of bubonic plague were reported in Inner Mongolia, which is controlled by China.
The Black Death Plague is still alive in China.
https://www.theguardian.com/world/2019/nov/18/china-records-third-case-of-deadly-bubonic-plague
