Journal Article

Eighteenth century Yersinia pestis genomes reveal the long-term persistence of an historical plague focus

Herbig, Alexander, Sahl, Jason, Kuch, Melanie, Bos, Kirsten I, Holmes, Edward C, Dutour, Olivier, Golding, G Brian, Fourment, Mathieu, Krause, Johannes, Schuenemann, Verena J, Wagner, David M, Poinar, Debi, Forrest, Stephen A, Waglechner, Nicholas, Poinar, Hendrik N, Keim, Paul, Klunk, Jennifer

2016

Overview

The 14th–18th century pandemic of Yersinia pestis caused devastating disease outbreaks in Europe for almost 400 years. The reasons for plague’s persistence and abrupt disappearance in Europe are poorly understood, but could have been due to either the presence of now-extinct plague foci in Europe itself, or successive disease introductions from other locations. Here we present five Y. pestis genomes from one of the last European outbreaks of plague, from 1722 in Marseille, France. The lineage identified has not been found in any extant Y. pestis foci sampled to date, and has its ancestry in strains obtained from victims of the 14th century Black Death. These data suggest the existence of a previously uncharacterized historical plague focus that persisted for at least three centuries. We propose that this disease source may have been responsible for the many resurgences of plague in Europe following the Black Death. A bacterium called Yersina pestis is responsible for numerous human outbreaks of plague throughout history. It is carried by rats and other rodents and can spread to humans causing what we conventionally refer to as plague. The most notorious of these plague outbreaks – the Black Death – claimed millions of lives in Europe in the mid-14th century. Several other plague outbreaks emerged in Europe over the next 400 years. Then, there was a large gap before the plague re-emerged as threat in the 19th century and it continues to infect humans today, though on a smaller scale. Scientists have extensively studied Y. pestis to understand its origin and how it evolved to become such a deadly threat. These studies led to the assumption that the plague outbreaks of the 14–18th centuries likely originated in rodents in Asia and spread along trade routes to other parts of the world. However, it is not clear why the plague persisted in Europe for 400 years after the Black Death. Could the bacteria have gained a foothold in local rodents instead of being reintroduced from Asia each time? If it did, why did it then disappear for such a long period from the end of the 18th century? To help answer these questions, Bos, Herbig et al. sequenced the DNA of Y. pestis samples collected from the teeth of five individuals who died of plague during the last major European outbreak of plague in 1722 in Marseille, France. The DNA sequences of these bacterial samples were then compared with the DNA sequences of modern day Y. pestis and other historical samples of the bacteria. The results showed the bacteria in the Marseille outbreak likely evolved from the strain that caused the Black Death back in the 14th century. The comparisons showed that the strain isolated from the teeth is not found today, and may be extinct. This suggests that a historical reservoir for plague existed somewhere, perhaps in Asia, or perhaps in Europe itself, and was able to cause outbreaks up until the 18th century.Bos, Herbig et al.’s findings may help researchers trying to control the current outbreaks of the plague in Madagascar and other places.

• Publisher: eLife Science Publications, Ltd,eLife Sciences Publications Ltd,eLife Sciences Publications, Ltd
• Subject: 18th century / ancient DNA / Archaeology / Bubonic plague / Chromosomes / Deoxyribonucleic acid / Disease / DNA / Epidemics / Epidemiology / Epidemiology and Global Health / Europe - epidemiology / Genetic aspects / Genome, Bacterial / Genomes / Genotype / Health aspects / History, 15th Century / History, 16th Century / History, 17th Century / History, 18th Century / human history / microbial evolution / Microbiology and Infectious Disease / Molecular Epidemiology / Outbreaks / Pandemics / pathogen genomics / Pathogens / Phylogenetics / Plague / Plague - epidemiology / Plague - history / Yersinia pestis / Yersinia pestis - classification / Yersinia pestis - genetics / Yersinia pestis - isolation & purification