<P> The plague disease , caused by Yersinia pestis , is enzootic ( commonly present ) in populations of fleas carried by ground rodents , including marmots , in various areas including Central Asia , Kurdistan , Western Asia , Northern India and Uganda . Due to climate change in Asia , rodents began to flee the dried out grasslands to more populated areas , spreading the disease . Nestorian graves dating to 1338 -- 1339 near Lake Issyk Kul in Kyrgyzstan have inscriptions referring to plague and are thought by many epidemiologists to mark the outbreak of the epidemic , from which it could easily have spread to China and India . In October 2010 , medical geneticists suggested that all three of the great waves of the plague originated in China . In China , the 13th - century Mongol conquest caused a decline in farming and trading . However , economic recovery had been observed at the beginning of the 14th century . In the 1330s , a large number of natural disasters and plagues led to widespread famine , starting in 1331 , with a deadly plague arriving soon after . Epidemics that may have included plague killed an estimated 25 million Chinese and other Asians during the 15 years before it reached Constantinople in 1347 . </P>
<P> The plague disease , caused by Yersinia pestis , is enzootic ( commonly present ) in populations of fleas carried by ground rodents , including marmots , in various areas including Central Asia , Kurdistan , Western Asia , Northern India and Uganda . Due to climate change in Asia , rodents began to flee the dried out grasslands to more populated areas , spreading the disease . Nestorian graves dating to 1338 -- 1339 near Lake Issyk Kul in Kyrgyzstan have inscriptions referring to plague and are thought by many epidemiologists to mark the outbreak of the epidemic , from which it could easily have spread to China and India . In October 2010 , medical geneticists suggested that all three of the great waves of the plague originated in China . In China , the 13th - century Mongol conquest caused a decline in farming and trading . However , economic recovery had been observed at the beginning of the 14th century . In the 1330s , a large number of natural disasters and plagues led to widespread famine , starting in 1331 , with a deadly plague arriving soon after . Epidemics that may have included plague killed an estimated 25 million Chinese and other Asians during the 15 years before it reached Constantinople in 1347 . </P>
when did the black death start to spread
when did the black death start to spread
1338 -- 1339
1338 -- 1339