Scientists have discovered the earliest known strains Plague In the wreckage of a 5000-year-old hunter-gatherer.
“Amazing” discoveries push back the first appearance of Yersinia pestis (Yersinia pestis) For over 2,000 years studying Ben Klauskiola, a senior author who is a biochemist and archaeologist at Keele University in Germany. Said in a statement.. He added that this date is probably close to when the bacteria first evolved.
Carry the plague Hunter-gathererCalled “RV2039,” was a man between the ages of 20 and 30 and was one of four people whose bodies were excavated from a burial site near the Baltic Sea in Latvia. Analysis of samples from male teeth and bones revealed that he was probably the only one buried in illness. Researchers have used genome sequencing to reconstruct the bacterial genome and believe that the bacterium is likely to be part of a lineage that emerged about 7,000 years ago. Yersinia pestis Split from predecessor, Yersinia pseudotuberculosis.
Relation: Killer Photo: Plague Gallery
Analysis also revealed that even in this early stage of its history, most of the important genes for fatal diseases are already present. “Very surprising is that this early strain already has a more or less complete gene set. Yersinia pestis, And only a few genes are missing. But even the slightest change in genetic setting can have a dramatic impact on pathogenicity, “says Krause-Kyora.
Modern plague variants contain one important thing that was missing from the newly discovered ancient strains. It is a gene that allows fleas to carry the disease. This indication significantly increased the rate at which Yersinia pestis infects human hosts, enters the body, migrates to the lymph nodes, and rapidly replicates. The host then forms a painful pus-filled bubo on the skin. From now on, the name of bubonic plague will be given.
However, the disease had to kill its host to switch to fleas as a means of transmission. The death of the old host encourages fleas to move to the new host and take over the disease. Researchers speculate that this new gene caused the plague to die.
This early strain of Yersinia pestis was not yet flea-borne, so scientists believe the bacteria originally invaded the bodies of hunters. Rodent bite, Probably from Beaver, a common carrier of plague’s predecessor Y. pseudotuberculosis And the most remaining species were recorded there. Once there, the course of the disease was rather slow, with bacteria slowly accumulating in large numbers in the bloodstream of men and continuing until death.
Relation: The most deadly virus in history
The three pandemics that bacteria will continue to cause Worst biological event In human history.The first pandemic, the Justinian plague (which occurred between 542 and 750 AD), affected the Mediterranean population. 40% decrease By the end of the 6th century. The second and most notorious pandemic caused by this disease was the 14th century Europeans. Black death, Approximately killed 25 million people — Between 33 and 50% of the European population. The third, lesser-known pandemic began in 1855 in Yunnan, China. Killed more than 12 million people Only in India and China.
The people buried around RV 2039 were uninfected and he was carefully placed in the tomb. This is two signs that he did not have a later contagious version of the disease. However, because of its presence in his blood, scientists still believe that Yersinia pestis may have killed him.
The idea that this ancient bacterium slowly replicated and was passed down from rodents to humans is supported by the fact that scientists have discovered that other ancient skeletons have been infected. Yersinia pestis Elsewhere where people lived very different lifestyles. “Isolated cases of infection From animals to people It can explain the different social environments in which these ancient sick humans were discovered. It is found in grassland nomads, fishing hunter-gatherers, and peasant communities. It’s a completely different social situation, but it always happens spontaneously. Yersinia pestis The incident. “
The painting of the early plague as a slow-acting, less toxic disease poses a serious challenge to the theory of the development of European and Asian civilizations.
One of these theories is that plague was responsible for the significant decline in Western Europe’s population towards the end of the Neolithic era. In 2019, a modern Swedish tomb containing 78 bodies buried in a hurry Dates for about the same period A set of bones and teeth owned by a woman, like RV 2039, also contained fragments of the phytophthora. Live science previously reported..
In fact, relics containing traces of Yersinia pestis have been found in archaeological sites throughout Eurasia and are dated to coincide with the rapid decline of the Neolithic population 5000 to 6000 years ago.
Another theory is that the plague occurred in European “mega settlements” that existed 6, 100-5, 400 years ago, including 10,000-20,000 people.But new research suggests Y. plague It may have been possible to split from Y. pseudotuberculosis As far back as 7400 years ago, the European population had not yet grown beyond its sparsely populated collections.
The mystery of this depopulation, and whether it was caused by an early pandemic, is not yet fully understood. Researchers believe that their work can open up further research into the history of plague and provide valuable insights into early human history and genomics, as well as disease evolution.
“Various pathogens and the human genome have always evolved together. We know that Yersinia pestis is likely to have killed half of the European population in a short period of time. Therefore, it has a significant impact on the human genome. I should give it, “said Krause-Kyora. “But even before that, there could have been a major turnover of immune genes at the end of the Neolithic era, and at that point there could have been significant changes in the pathogen status.”
Their findings were published in the journal on June 29th. Cell report..
Originally published in Live Science.
