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Yersinia pestis is the bacterium responsible for the first plague pandemic (and all plague pandemics since) – Justinian plague from 541 to 750 AD. This public health crisis killed nearly 100 million people in Asia, Africa and Europe in the first five years alone.
At present, an international team of researchers writing in the Proceedings of the National Academy of Sciences and led by the Max Planck Institute for the Science of Human History has analyzed the remains of 21 victims and reconstructed eight plague genomes to discover advanced bacteria and their impact. he had on Europe of the Middle Ages.
The Justinian plague, named in honor of Justinian I, ruler of the Eastern Roman Empire (or Byzantine), began in 541 AD. As a result of an epidemic in Central Asia, the disease spread to Egypt before reaching Istanbul (then Constantinople), capital of the Empire, and the rest of the country. Continental Europe. A series of recurring epidemics over the next two hundred years or so have decimated Europe and the Mediterranean basin, wiping out up to 25% of the population and contributing to the collapse of the Mediterranean Sea. 39, Eastern Roman Empire.
Recent research has identified the culprit as Y. pestis, its mode of spread and the relationship between the different strains that appeared during the pandemic remained a mystery. By reconstructing the genomes of eight strains from 21 burials in Austria, Great Britain, France, Germany and Spain, scientists have been able to compare their structure with that of earlier and earlier strains of the bacteria.
The results show that there were many more strains of Y. pestis during the Justinian plague that we had thought, many of them were closely linked genetically and some could have coexisted at the same places and at the same time.
Interestingly, the team was able to confirm for the first time the presence of plague in Anglo-Saxon England with genetic evidence. At least four of the 149 individuals buried at Edix Hill Cemetery near Barrington, Cambridgeshire, between 500 and 650 CE, were tested positive at Y. pestis and almost certainly died.
"Given that the Edix Hill Cemetery served a small community or communities of 50 to 65 people, this was to be a major traumatic event, comparable to the Black Death," said Craig Cessford of the Department of Public Health. Archeology of the University of Cambridge, UK. , said in a press release.
"It is unlikely that Edix Hill has the particularity of being affected by Justinian plague, more likely by most, if not all, of Anglo-Saxon England." a major historical event on which one could guess only in the past., which means that the history of the first Anglo-Saxon England must be rewritten ".
The researchers were also able to detect signs of convergent evolution between different strains, those that appeared later during the pandemic revealing large deletions in their genetic code that reflect similar adaptations found in plague genomes from the last stages of the second pandemic (or Black Death).
"[T]this Y. pestis strains independently developed similar characteristics. Such changes could reflect an adaptation to a distinct ecological niche in western Eurasia where plague circulated during both pandemics, "said co-author Maria Spyrou of the Max Planck Institute.
In addition, "the fact that all genomes belong to the same lineage is indicative of the persistence of plague in Europe or the Mediterranean basin during this period, instead of multiple reintroductions," co-authored Marcel Keller, from the Max Planck Institute. now at the University of Tartu, added.
One of the things that the team could not do was to identify the origins of the plague before the outbreak of the 541 outbreak in Egypt. Although the team says that it is likely that it has appeared in Central Asia several hundred years ago.
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