Vladimiri BazaliiskiiArchaeologists have been excavating these prehistoric burials in Siberia for decades, but theyve now been found to contain historys first known bubonic plague cases.Though historys most infamous outbreak of the bubonic plague is the Black Death that killed half of Europe in just seven years during the mid-14th century, this lethal infection has actually been with humankind since before the dawn of recorded history. Now, scientists have just discovered the first known cases of bubonic plague in human history and they date back a whopping 5,500 years. While analyzing the skeletons of 46 prehistoric hunter-gatherers unearthed in Siberia, researchers found 18 cases of the plague. These plague victims are 500 years older than the previous earliest-known plague victim, and challenge commonly-held notions of how the plague spread during prehistoric times.The Discovery Of The First Known Bubonic Plague Victims In Human HistoryArchaeologists have been excavating the site of this discovery four prehistoric cemeteries around Lake Baikal in Siberia for decades. The region has been important for prehistoric research, as it was rich in resources and places where hunter-gatherers buried their dead for generations.Researchers have been intrigued by these mass hunter-gatherer graves for years, which contain an unusual number of children and adolescents.As detailed in a recent study published in Nature, researchers have made an historic discovery about these graves. The team analyzed the DNA of 46 skeletons from these burial sites that date back 5,500 years and found that 18 were infected with Yersinia pestis, the bacteria responsible for the bubonic plague.Angela LieverseDNA analysis of the hunter-gatherer skeletons revealed plague bacteria in 18 of them.There was very clear radiocarbon evidence that this mass mortality event took place over a very, very short period of time, so all of these deaths are occurring contemporaneously with each other, lead study author Ruairidh Macleod said to CNN.After radiocarbon analysis, researchers determined that two outbreaks of the plague occurred in this region a few hundred years apart.The researchers determined that these Siberian hunter-gatherers became infected with the plague after skinning and eating large rodents called marmots, which have historically been known to carry the plague bacteria. Marmot teeth pendants were also discovered buried in the graves. And with no plague doctors around, or any medical knowledge of any kind, these hunter-gatherers would have been helpless to the infection and succumbed to the torturous symptoms within a short span of time.Angela LieverseResearchers extracted DNA from teeth to illustrate how the plague was particularly lethal for children.The new study also found that the skeletons of the children and adults displayed genetic kinship, and that sometimes families were buried together. This indicates that there was a lack of understanding of how the disease spread, because family members might have become infected with plague while caring for one another.This plague strain, which is different from previously studied strains both ancient and modern, was particularly deadly for children.In order to understand why, researchers extracted genomes from the skeletons teeth, which revealed a superantigen, a microbial toxin that can cause dangerous and extreme immune responses. This toxin mainly affected children between the ages of 7 and 11 years old.How These Discoveries Change The Story Of The Bubonic Plagues OriginsThe plague has been responsible for some of the worst pandemics in human history. The most infamous is of course the Black Death of the 14th century that killed as many as 50 million people in less than a decade. Between the start of the Black Death in 1346 and the end of the plagues worst years in 1353, nearly half of Europe was wiped out.Vladimiri Bazaliiskii/Baikal Archaeology ProjectEntire families were killed off, with victims often deposited into one joint grave.Researching the origins of the plague remains important so that we can understand how different strains of it could evolve and spread even today.These recent findings push back against previous research concerning how the plague spread in ancient times, particularly in terms of human-to-human transmission and prevalence in hunter-gatherer societies.Before this study came out, researchers assumed that plague outbreaks only occurred in high-density areas or settlements, as opposed to small, nomadic hunter-gatherer groups.Hunter-gatherers are constantly moving around the landscape. The theory is that infectious disease cant really take hold and devastate entire communities in this way. Typically, if somebody gets ill, theyll move somewhere else. The fact that were finding this happening in an isolated group of prehistoric hunter-gatherers challenges that epidemiological theory, Macleod said at a news conference, according to CNN.Vladimiri Bazaliiskii/Baikal Archaeology ProjectThough historys most infamous outbreak of the bubonic plague is the Black Death that killed half of Europe in just seven years during the mid-14th century, this lethal infection has actually been with humankind since before the dawn of recorded history.Additionally, in previous research, older strains of the plague seemed to lack the characteristics that allowed them to spread, indicating to scientists that these early plagues rarely caused outbreaks. This older research left scientists unclear on the prehistoric origins of the plague and how it was transmitted before fleas and livestock became some of the primary vectors.Now, with the evidence of this small prehistoric outbreak in hand, researchers are questioning these previously-held notions of how the plague spread in ancient societies.Previous research has only found what seem to be sporadic, relatively isolated infections of the earliest versions of Y. pestis with no compelling evidence of human-to-human transmission chains, but the datasets may have simply been too incomplete to assess this as a possibility. This study changes that, Ian Light-Maka, a postdoctoral associate at the Max Planck Institute for Infection Biology in Berlin, told CNN.While this research is groundbreaking and likely suggests that there was prehistoric human-to-human transmission of the bubonic plague, more studies need to be done at comparable sites before we can completely rewrite the early history of humanitys most infamous infection.After reading about the earliest-known cases of the bubonic plague, learn about the Antonine Plague that killed 5 million ancient Romans. Then, discover how researchers found eight new populations of ancient hunter-gatherers in Europe.The post Historys First Known Cases Of The Bubonic Plague Were Just Found In 5,500-Year-Old Skeletons Unearthed In Siberia appeared first on All That's Interesting.