The Justinian plague around 1400 years ago was the first historically documented pandemic in human history. Now researchers have proven the pathogen of this plague in the epicenter of late antics pandemic for the first time – in the Middle East. In the event of dead from a late antique mass grave of the Jordanian city of Gerasa, they demonstrated the DNA of the plague bacterium Yersinia Pestis. It testifies to the high virulence of this pathogen and a rapid outbreak of the plague.
Between 541 and 750, almost half of all people in the Eastern Roman Empire died in repeated epidemics of a late antique pandemic. Parts of Germania, Gaul and large parts of the Middle East were also affected. Historical reports suggest that the plague was the plague. Favored by late antiquity volcanic eruptions and the wet -cold climate caused by them, the pandemic spread from the Middle East over large parts of Europe. Millions of people died. However, despite numerous indirect indications of the plague as the author of this late antique pandemic, there have been no clear evidence of the plague bacterium or plague graves from the eastern Mediterranean of that time. Only in England, Germany and France have around a handful of graves have so far been identified with clearly documented plague victims.
Searching for traces in a late Roman metropolis
Now a research team around Swamy Adapa from the University of South Florida provides the long -sought proof. For their study, the scientists had examined several teeth of late antiquities from the city of Gerasa in Jordan, around 50 kilometers north of the Jordan capital Amman. “Gerasa was an important metropolis during the Greek-Roman and Byzantine times. It is still considered one of the largest and best-preserved sites of Roman architecture outside of Italy,” explain the researchers. Gerasa comprised several temples, three theaters, a hippodrome and numerous other splendid buildings and was surrounded by a city wall with towers and gates.
Earlier excavations had already shown that the hippodrome of Gerasa no longer served as a place of horse racing in the sixth century. Instead, the stands and adjoining rooms were used as workshops. But at the beginning of the seventh century this and the workshops also ended. Around this time, some chambers of the hippodrome were converted into mass graves: around 150 adults and 80 children and adolescents were buried there around 1,400 years ago. “Since the discovery of the mass grave, the location and the relics have no longer been accessible and only a small number of teeth have been available for studies today,” explain Adapa and his colleagues. So so far it was unclear how these people died.
Clear evidence of DNA of the plague bacterium
The researchers have now received more clarity through eight teeth of deaths from the mass grave of Gerasa. “With targeted DNA analyzes made of historical materials, we were able to win genetic material from eight human teeth that were recovered from graves under the former Roman hippodrome in Gerasa,” reports co-author Greg O’Corry-Crowe, from the Florida Atlantic University in Fort Pierce. In the teeth of the dead, the researchers discovered the DNA of the pester regulator Yersinia Pestis. Accordingly, the examined fatalities were infected with the plague – and probably died of the plague. The DNA of the pathogen there is also good with the few late antics of Yersinia Pestis in Europe, as Adapa and his colleagues report.
“This discovery provides the long -sought definitive detection of Yersinia Pestis at the epicenter of the Justinian plague,” explains Adapa’s colleague Rays Jiang. “For centuries we had to rely on written reports on a devastating illness, but had no hard biological evidence for the plague. Our finds close this gap and for the first time allow a direct genetic view of the pandemic in the center of the Eastern Roman Empire.” The analyzes also showed a large genetic agreement among the pester paths, which were proven in various dead. The team therefore assumes that the fatal plague spread very quickly in Gerasa at the time.
“The civilian infrastructure of the Eastern Roman metropolis – including aqueducts, bath houses, storage camps and amphitheater – not only brought people and were together, it also unintentionally made it easier to spread pathogens,” explain Adapa and his colleagues. The densely populated districts of Gerasa created ideal conditions to transmit the plague using fleas and lice. The mass grave in the former hippodrome also suggests that so many people died within a short time that the cemeteries were no longer sufficient. “This gives us Gerasa a rare insight into how earlier societies reacted to such a medical catastrophe,” says Jiang. “During this time, the place originally built for the entertainment of humans became a mass grave. This shows how the urban centers were overwhelmed by the plague at the time.”
Source: University of South Florida; Specialist articles: genes, DOI: 10.3390/Genes16080926
