German geneticists have found the oldest plague patient
German geneticists examined the remains of four people who lived in Latvia more than five thousand years ago and found that one individual was infected with the oldest known strain of the plague bacterium Yersinia pestis – the oldest case of plague infection. Scientists assume that this disease spread rather slowly at that time, and the man became infected through the bite of an animal, for example, a beaver. The article was published in the journal Cell Reports. The plague has been known since ancient times, evidence of which is found in many early written sources, for example, in the Bible. However, the general fear of this disease emerged after the medieval pandemics, especially the Justinian and Black Death. Outbreaks of plague led to severe demographic changes and social upheaval. So, in the second half of the 18th century, Moscow was engulfed in the Plague Riot. Today in Russia, cases of infection with this disease are rare, although in some regions, for example, in the Astrakhan region or the Altai Republic, there are natural foci. You can learn more about where it is now possible to become infected with the plague and why it has not yet been completely defeated, can be found in our material “Territory of the Black Death”.
For a long time, it was believed that the first cases of plague infection occurred about three thousand years ago. However, in 2015, geneticists analyzed DNA sequences obtained from the teeth of 101 people from Eurasia who lived during the Bronze Age. They found that seven individuals suffered from the plague, and two representatives of the Afanasiev culture from Gorny Altai met with the causative agent of the disease about 4,800 years ago – these are the oldest known cases.
Julian Susat, together with colleagues from the University of Kiel, examined the remains of four people found at the Rinnukalns site in Latvia. They belonged to two adult men 20-30 and 35-45 years old, a girl 12-18 years old and a baby boy. Radiocarbon dating has shown that these people lived about 5,300-5050 years ago.
The researchers sequenced DNA from the remains of all four individuals. In the course of further work, which included screening for pathogens, they found that a man in his 20s and 30s was infected with the plague. Geneticists were able to restore the DNA sequence of the bacterium Yersinia pestis, which turned out to be basal in relation to all known ancient and modern strains. This early and independent lineage arose about seven thousand years ago, shortly after the separation from Yersinia pseudotuberculosis.
The lifestyle of the infected individual corresponded to that of an ordinary hunter-gatherer in the Baltic region of the time. Analysis of its genome has shown that it is associated with populations of eastern hunter-gatherers that inhabited the forest-steppe zone between the Black and Baltic seas six thousand years ago.
Scientists suggest that the ancient strains had lower virulence. Almost all known early cases are sporadic infections. Probably, the man from Rinnukalns was infected by an animal bite, which led to the development of a septic form of the plague. Among the potential carriers of this disease, genetics named beavers, whose bones are present in the parking lot.
Earlier on N + 1, we already said that researchers from Denmark and Great Britain found evidence indicating the death of seven people from the Bronze Age from the plague, and in the Volga region they found the oldest causative agent of the medieval Black Death.