Scientists Revive Ancient Plague to Learn Clues About Epidemic that Wiped Out Half of Europe
Scientists have taken molecular clues in recent days from ancient plague victims’ bones and determined that the same bacterial infection that caused the Black Death of the Middle Ages in Europe and Asia may have also caused the earlier Justinian plague.
The Justinian plague is believed to have killed around 50 million people in the Byzantine Empire, says a press release from the researchers on EurekaAlert. Reports online say the plague of Justinian lasted from 541 to 542 AD, but the press release from EurekaAlert says it lasted for two centuries.
“Recent molecular clues from ancient plague victims have suggested that plague may have been caused by the same bacterium, Yersinia pestis , which was responsible for the Black Death. But the geographic reach, mortality and impact of the Justinian pandemic are not fully known. Both information from ancient hosts and bacteria could shed light on the role of plague, which has afflicted mankind for more than 5,000 years,” the press release states.
German scientists led by Michaela Harbeck, Johannes Krause and Michal Feldman found the Yersinia pestis germ in skeletons that date back to the 6 th century AD. They were excavated from a burial site in Alternerding near Munich. The press release states that the genome of the bacteria from these skeletons date back to the plague’s inception.
Remains of a woman, left, and man, right, excavated at Altenerding and found positive for presence of Y. pestis (© State Collection of Anthropology and Palaeoanatomy Munich).
The scientists generated what the press release calls the first “high-coverage genome” of the bacteria that caused the Justinian plague. The study has revealed new insights about the bacteria and its evolution since the Byzantine era. The new analysis revealed features that previous coverage of a draft genome did not show, including 30 mutations and structural rearrangements in the Justinian strain and also corrected 19 false positive mutations.
This mosaic in a church in Ravenna is a portrait of Justinian. ( Wikimedia Commons )
One of the co-authors of the study, Michaela Harbeck, is quoted in the press release as saying:
“The fact that the archeological skeletons which gave these exciting insights were excavated over 50 years ago underscores the importance of maintaining well curated anthropological collections. We were very fortunate to find another plague victim with very good DNA preservation in a graveyard just a few kilometers from where the individual analyzed in Wagner et al. was found. It provided us with the great opportunity to reconstruct the first high quality genome in addition to the previously published draft genome.”
The analysis shows that the plague bug was more genetically differentiated than previous research and theory had led scientists to believe.
These findings will help the researchers to develop guidelines on improving the authenticity and quality of data captured in ancient pathogens or germs.
The findings coincide with a research upsurge in reports of the plagues in some areas of the world, and they have developed a high-quality reference system to give insight on evolutionary changed and adaptation of the disease plus its impact on humans.
"Our research confirms that the Justinianic plague reached far beyond the historically documented affected region and provides new insights into the evolutionary history of Yersinia pestis , illustrating the potential of ancient genomic reconstructions to broaden our understanding of pathogen evolution and of historical events," research colleague Michal Feldman is quoted in the press release. "Our reanalysis of previous datasets stresses the importance of following strict criteria to avoid errors in the reconstruction of ancient pathogen genomes."
Plague in an Ancient City ( public domain )
An article by John Horton on the online Ancient History Encyclopedia says the plague arrived from China and India in 541 AD and continued to ravage the Mediterranean region for 225 years. The black rat transmitted the disease to fleas, who bit humans and caused up to a 70 percent mortality rate.
The plague is named after the Byzantine Emperor Justinian, who reigned at the inception of the outbreak. The later Black Death or bubonic plague, caused by the same bug, of the 14 th century Europe is believed to have killed about 50 million people.
Featured image: Skulls of two plague victims buried together in one grave at the Altenerding cemetery near Munich, Germany (Credit: State Collection of Anthropology and Palaeoanatomy Munich)
By Mark Miller