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Researchers analyze Justinian’s plague bacteria

A new study has analyzed in greater detail the effects of the so-called “plague of Justinian,” a pandemic that hit Europe. It is believed that the pandemic broke out in 541 AD and lasted at least until 750 AD.

Analyzing data on 21 archaeological sites in Europe and the Mediterranean area, a group of researchers from the Max Planck Institute for the Science of Human History in Germany and Harvard University collected new information on this pandemic. First of all, it seems to have spread to a wider area than previously thought. The effects should have also reached post-Roman England.

The bacterium that caused it is Yersinia pestis, the same one that caused the so-called “black plague,” another pandemic that spread throughout Europe during the Middle Ages and killed nearly half of the continent’s population. Despite being less known than the black plague, Justinian’s plague was just as lethal, according to the researchers. It is so named because it began during the reign of Emperor Justinian who ruled the empire from Constantinople.

It was precisely the pandemic that began in the areas of Constantinople and spread to Mediterranean ports at the beginning.

Researchers, reconstructing the genomes of Yersinia pestis taken from samples collected from archaeological sites in various European locations, first confirmed that they initially hit coastal areas, probably through ships that docked at ports.

They then discovered that the plague also spread to Great Britain, a new piece of information regarding this pandemic, which among other things shows the profound interconnection of trade between the Mediterranean area and Great Britain itself. They then found some genetic diversity among the analyzed strains that evidently evolved during the two centuries of the duration of the pandemic.

Research is also important because “it shows the potential of paleogenomic research to understand historical and modern pandemics by comparing genomes through millennia,” says Johannes Krause, director of the Max Planck Institute, a method that could lead the way for similar studies in future.