Scientists discover bacterium responsible for first epidemic in human history

An international team of scientists has discovered genomic evidence of the bacterium responsible for the first recorded epidemic in human history—the Justinian Plague, which occurred between 541 and 750 AD.

While studying a mass grave in the ancient city of Jerash in Jordan, researchers from the United States, India, and Australia identified the bacterium "Yersinia pestis". The finding is linked to one of the deadliest pandemics in history, which may have claimed up to 100 million lives, according to the journal Pathogens.

“Until now, there had been no direct genomic evidence of the Justinian Plague. For centuries, we relied on written records describing this devastating disease, but we lacked solid biological proof of the plague’s presence,” the study’s authors noted.

Experts emphasized that many mysteries of the first pandemic—which altered the course of history—remain unsolved.

The Justinianic Plague represents the first recorded outbreak of bubonic plague in West Eurasian history—the same devastating disease that caused the 14th-century "Black Death"—and struck the Mediterranean world at a critical point in its historical trajectory, during the reign of Roman Emperor Justinian, who was attempting to restore imperial authority.

For decades, scholars have debated the disease’s lethality, its social and economic consequences, and the routes through which it spread. In 2019-20, several widely reported studies claimed that historians had greatly overstated the impact of the Justinianic Plague, labelling it an ‘inconsequential pandemic.’ In a later journalistic piece, written just before COVID-19 emerged in the West, two researchers even suggested that the Justinianic Plague was ‘not unlike our flu outbreaks.’

In a 2021 study published in Past & Present, Cambridge historian Professor Peter Sarris argues that these studies neglected or downplayed new genetic evidence, relied on misleading statistical analyses, and misrepresented the accounts provided by ancient texts.

Sarris says: “Some historians remain deeply hostile to regarding external factors such as disease as having a major impact on the development of human society, and ‘plague scepticism’ has had a lot of attention in recent years.”

A Fellow of Trinity College, Sarris criticizes the tendency of some studies to use search engines to calculate that only a small fraction of ancient literature mentions the plague and then crudely conclude that it was considered unimportant at the time.

Sarris says: “Witnessing the plague first-hand obliged the contemporary historian Procopius to break away from his vast military narrative to write a harrowing account of the arrival of the plague in Constantinople that would leave a deep impression on subsequent generations of Byzantine readers. That is far more telling than the number of plague-related words he wrote. Different authors, writing different types of text, concentrated on different themes, and their works must be read accordingly.”

By Nazrin Sadigova