Distinct clones of Yersinia pestis caused the black death.

Stephanie Haensch,Mark Achtman,Raffaella Bianucci,Derek Hurst,Marco Vermunt,Michel Signoli,Barbara Bramanti,Sacha Kacki,Michael Schultz,Minoarisoa Rajerison,Elisabeth Carniel,Darlene A Weston

doi:10.1371/journal.ppat.1001134

Abstract

From AD 1347 to AD 1353, the Black Death killed tens of millions of people in Europe, leaving misery and devastation in its wake, with successive epidemics ravaging the continent until the 18th century. The etiology of this disease has remained highly controversial, ranging from claims based on genetics and the historical descriptions of symptoms that it was caused by Yersinia pestis to conclusions that it must have been caused by other pathogens. It has also been disputed whether plague had the same etiology in northern and southern Europe. Here we identified DNA and protein signatures specific for Y. pestis in human skeletons from mass graves in northern, central and southern Europe that were associated archaeologically with the Black Death and subsequent resurgences. We confirm that Y. pestis caused the Black Death and later epidemics on the entire European continent over the course of four centuries. Furthermore, on the basis of 17 single nucleotide polymorphisms plus the absence of a deletion in glpD gene, our aDNA results identified two previously unknown but related clades of Y. pestis associated with distinct medieval mass graves. These findings suggest that plague was imported to Europe on two or more occasions, each following a distinct route. These two clades are ancestral to modern isolates of Y. pestis biovars Orientalis and Medievalis. Our results clarify the etiology of the Black Death and provide a paradigm for a detailed historical reconstruction of the infection routes followed by this disease.

Highlights

Of the numerous epidemics in human history, three pandemics are generally accepted as having been caused by plague
Several historical epidemic waves of plague have been attributed to Yersinia pestis, the etiologic agent of modern plague
The most famous of these was the second pandemic which was active in Europe from AD 1347 until 1750, and began with the ‘Black Death’

Summary

Introduction

Of the numerous epidemics in human history, three pandemics are generally accepted as having been caused by plague. In 1347, an epidemic known as the Black Death spread from the Caspian Sea to almost all European countries, causing the death of one third of the European population over the few years [2]. A third plague pandemic began in the Yunnan region of China in the mid-19th century, and spread globally via shipping from Hong Kong in 1894. During this last pandemic, the etiological cause of plague was identified as Yersinia pestis, a Gram-negative bacterium [3,4]. The Y. pestis F1 protein capsule antigen has been detected in ancient plague skeletons from Germany and France by immunochromatography [8,9]

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