DNA traces of the plague bacillus were found in the teeth of two men who lived about four thousand years ago, making them the earliest possible victims of plague found in Austria. The results of the research were published in the journal Archaeologia Austriaca.

Plague

A highly contagious disease caused by the Gram-negative bacterium Yersinia pestis has afflicted humanity since ancient times. References to this disease can be found in various historical sources, including the Bible’s First Kingdom Book, which describes a devastating epidemic in various cities of the Middle East. More famous cases of plague epidemics include the Plague of Justinian, which occurred in the middle ages, and the Black Death.

Earliest case of plague infection

The first mention of this disease dates back to 1200 BC, but recent archaeological and paleogenetic research has shown that the plague bacterium infects humans even earlier. The earliest known case of infection was found on the territory of modern Latvia, where the remains of an infected person who lived between 5432 and 4973 were discovered. Similar cases were found in Russia, for example, in a person from the archaeological culture of Athanasius who died between 4838 and 4617 years ago.

A tomb with the remains of two people with the plague / Photograph: ÖAW / Archaeprotect

In 2018, Austrian archaeologists excavated the Drazenhofen cemetery and uncovered 22 tombs associated with the Unetic culture of the Early Bronze Age, which flourished from 2200 to 1550 BC. The remains of these people were then given to paleogeneticists for ancient DNA analysis.

Geneticists found plague bacillus DNA in the teeth of two men. These individuals were buried on the outskirts of the Drazenhofen cemetery, and one of the tombs also contained the remains of a woman. Both men lived relatively short lives, dying between the ages of 22 and 30 and 22 and 27, respectively. Radiocarbon dating of their teeth estimates their lifetimes to be around 2128-1931 and 2026-1884 BC. with a confidence level of 95.4 percent. So these are the earliest cases of plague bacillus infection found on the territory of modern Austria.

View of the excavated cemetery in Drazenhofen / Photo ÖAW / Archaeprotect

an interesting discovery

After analyzing the sequenced DNA of the plague bacillus, geneticists made several important observations. Specifically, they found that a putative virulence factor known as the ymt gene was missing in the bacterial genomes. This gene encodes phospholipase D, an essential element that protects the plague bacillus in the gut of its most dangerous vector, the southern rat flea (Xenopsylla cheopis).

To date, the earliest known bacteria containing this gene have been isolated from approximately 3,800-year-old remains excavated at Log Culture’s Mykhailivskyi II Mound, located in the Samara region.

In addition, the scientists stated that the men in the Drazenhofen tomb were infected with the plague bacillus belonging to different genetic lineages, suggesting that they probably contracted the deadly infection from different sources.