A hunter-gatherer’s skull of an animal that inhabited Europe more than 5,000 years ago contains traces of the earliest bacteria that caused the bubonic plague. The findings should provide some important clues about the origin and evolution of this long-standing pathogen enemy. which is the cause of the worst epidemic in human history.
epidemic caused by Yersinia pestis Bacteria and are often spread through contact with animals or from flea bites. In this form it is called the plague. It can also become a very serious respiratory disease that spreads between people, known as the pulmonary plague. The third, very rare and often fatal form is called anemia bubonic plague and occurs when bacteria enter the bloodstream.
though now There are many Through improved sanitation and the availability of antibiotics, in middle age, the plague will routinely spread across Europe, Asia and Africa. by leaving the calamity behind black death In the mid-14th century, it was thought to be one of the deadliest plagues ever. It kills about a third of the total population in Europe and at least 50 million people worldwide.
Like other organisms, human pathogens have evolved over time. Scientists are very interested in solving questions when Y. pestis The first human encounter and how it eventually turns into something that can cause black death. But the international team of researchers behind the new research said they didn’t even intend to search for the ancient plague they did.
Their study found that published In Cell Reports on Tuesday They were simply looking for traces of DNA left in the remains of a young man’s skull buried some 5,000 to 5,300 years ago near the Salaca River in Latvia, near an area of shells called Rinnukalns. middens is place where beginning man Throw away trash and evidence of life in the house. Fortunately, this analysis included screening for potential pathogens. And that’s when DNA codes for known proteins are found to be specific. Y. pestis. From these parts They reconstructed the genome of this species, dubbed RV 2039 (same name as the man), and compared what they found with other ancient species. that has been rebuilt
Researchers say RV 2039 comes before these other examples of Y. pestis and may represent the beginning of evolution as a distinct species. even if it is an extinct bloodline If their findings are correct It could change some of the assumptions about the existence of bacteria in those days.
“Our findings provide evidence for this bacterium in a hunter-gatherer group. and more clarification in the early stages of Y. pestis evolution and diversity,” they wrote.
Scientists believe that Y. pestis separated from another type of bacteria known as Yersinia pseudotuberculosis For example, thousands of years ago But the study authors argue that their findings could push the current timeline of estimates that this split happened about 7,000 years ago. Additionally, they say there is evidence that this version of the plague is better controlled than its version. behind the plague
Like the plague in ancient times These bacteria lack adaptations that help them spread from fleas. which are believed to have initiated their evolution into more serious diseases. Because the DNA appears to have been recovered from the man’s bloodstream. So it is possible that he may have died from a deadly epidemic. But the high number of plague DNA showed that the infection was resistant without causing death. the researchers said It cited research showing that mice with more modern plague bacteria were less prone to disease.
in any case Finding this man, who was carefully buried alongside the others, without epidemic show that no matter what he has Humans at that time were not considered a serious disease. Combined with evidence from ancient plague cases, The authors argue that this version might not be able to cause a pandemic. Instead, it was intermittently infected by bites from multiple rodents acting as natural hosts. if it’s true That would leave a serious dent in the latest theory that the early emergence of the pulmonary plague. cause The outbreak was widespread during that time. This was due to the trade routes between the Neolithic settlements.
“'[B]Considering the genomic data It is indistinguishable that the RV 2039 and other early models are transmitted less than later species. which only led to local outbreaks,” they wrote.
It is possible that the ancient plague debate will not be resolved with a single study. But the discovery was incredible for a different reason. the researchers said
The burial site and skull were first discovered in the late 19th century by amateur archaeologist Carl Georg Count Sievers Sievers and his advisers. German physician Rudolf Virchow argued that the site must be prehistoric. But their theory was widely criticized by others at the time. Ultimately, the man’s skull appears to have disappeared after World War II. But it is rediscovered in the collection of Virchow’s work curated by the Anthropological Society of Berlin. ethnology And prehistoric in 2011, the subsequent carbon dating confirmed its age. Prove it to Sievers and Virchow.
“Virchow was in no position to diagnose plague with Rinnukalns skull. However, thanks to Virchow’s advanced scientific approach, remains excavated by Sievers are kept in his collection. which they survived the fluctuations of time without injury. Therefore, a later diagnosis is still possible. even after 145 years have passed,” the study authors wrote.