Paleogenetics makes it possible to better understand history. By working on eight teeth found in a common pit in Jerash, Jordan, archaeologists made it possible to identify the bacteria Yersinia Pestis as a pathogen of the Plague de Justinien, which raged between 541 and 750 AD. AD in the Byzantine Empire and in the Mediterranean. According to the study published on August 27, 2025, this epidemic would have caused between 10 and 100 million dead and led to major upheavals in the Empire.
According to written sources, the disease has started in the port of Peluse (Tell El-Farama, Basse-Égypt) before spreading by sea around the Mediterranean to Jerash, then a commercial crossroads. The city became a vast epidemic home and a necropolis.
This research, carried out by the University of Florida du Sud (USF) and the Atlantic University of Florida (FAU), focused on bodies dated between 550 and 660, found in the funeral chambers of an old Roman racetrack of Jerash converted into a common pit. If traces of Yersinia Pestis had already been identified in Western Europe, the DNA analysis of Jerash provides the first proof of the predominance of the bacteria in one of the major households of the pandemic.
A study of the same team aimed to retrace the evolution of the bacteria by comparing old and modern strains. It confirms the hypothesis of multiple foci, from promising animals, rather than that of a single strain diffused on a large scale. Researchers also argue that urban densification may have favored a particularly rapid spread.
The same team is now carrying out research on the black plague, due to the same bacteria, whose first wave touched Europe between 1346 and 1353. It is particularly interested in Venice and the first public health measures set up, in particular on the island of Lazzaretto Vecchio, used as quarantine area, where 1,200 bodies are currently studied by the USF. At the same time, the medico-legal anthropologist Matteo Borrini analyzed 200 bodies from Lazzaretto Nuovo, another Venetian island dedicated to the isolation of the patients.
