A Genomic and Historical Synthesis of Plague in 18th Century Eurasia.

Plague continued to afflict Europe for more than five centuries after the Black Death. Yet, by the 17th century, the dynamics of plague changed, leading to its slow decline in Western Europe over the subsequent 200 years, a period for which only one genome was previously available. Using a multidisciplinary approach, combining genomic and historical data, we assembled Y. pestis genomes from nine individuals covering four Eurasian sites and placed them into a historical context within the established phylogeny. CHE1 (Chechnya, Russia, 18th c.), is now the latest Second Plague Pandemic genome and the first non-European sample in the post-Black Death lineage. Its placement in the phylogeny and our synthesis point toward the existence of an extra-European reservoir feeding plague into Western Europe in multiple waves. By considering socio-economic, ecological and climatic factors we highlight the importance of a non-eurocentric approach for the discussion on Second Plague Pandemic dynamics in Europe.