The causative agent of the black death was in Britain for 4 thousand years before the start of the epidemic

Black death, or black pestilence - the mostthe deadliest pandemic in human history caused by plague. Its peak was in 1346-1353, but periodically outbreaks occurred until the 19th century. According to various estimates, it claimed the lives of 30 to 60% of the population of Europe. The causative agent of this disease is the plague bacillus (Yersinia pestis). In a recent study, scientists found the bacterium's DNA in the teeth of two British people who lived thousands of years before the Black Sea began. This is the oldest case of Y. pestis infection known to date and is changing the way scientists understand the spread of the disease and the evolution of this bacterium.

The plague agent spread across Europe thousands of years before the pandemic

The oldest plague burials in Brittany

In an article on bacteria on teethNeanderthals, we said that the teeth are actually the repository of the genome, since the teeth are fossilized during the life of a person. The tartar contains the DNA of not only the person himself, but also all the bacteria that got into his mouth.

In a recent study, scientists studied the teethpeople whose remains were found in the burial place, according to radiocarbon dating, about 4000 years old. The burial was a mass grave, which was discovered in Charterhouse Warren back in the 70s of the last century. Several dozen people were buried in it, including two teenagers. According to scientists, such a burial is not typical for that region and time.

Mass grave at Charterhouse Warren, where the remains of teenagers infected with the plague bacillus were found

The most interesting thing is that there are 28 people fromthis grave there were traces of serious injuries incompatible with life. Therefore, scientists came to the conclusion that people who died a violent death were buried in this place.

Genetic research has shown that twoteenagers from this mass grave had the DNA of the plague pathogen on their teeth. However, according to scientists, it is unlikely that it was the plague that caused their death. Moreover, there is a possibility that they were infected with the plague in general at the time of death. But this is far from the only evidence of the spread of Yersinia pestis in Britain as early as the Bronze Age.

The site in Levens where the remains of a woman infected with the plague 4,000 years ago were found

Scientists also found the DNA of this bacterium on the teethwoman, whose remains were found in a ring cairn in Levens (county of Cumbria). She lived around the same time as the teenagers from the mass grave. The woman's age was 35 to 45 years. As for her causes of death, scientists also cannot confirm that she died due to the plague.

How did the plague spread across Europe?

As the researchers report in the journal NatureCommunications, in all three cases, they did not find a mutation in the genome of the plague bacillus that provides it with transmission through fleas. As you know, in the Middle Ages, fleas and rats became the main carrier of a dangerous pathogen. From the above, we can conclude that the bacterium Yersinia pestis in the Bronze Age was less lethal. Obviously, at some point, the wand mutated, which caused a terrible epidemic.

To find out how the bacterium spread inBritain and how it evolved at the same time, scientists conducted an additional study, as a result of which they were able to detect the DNA of a bacterium on the teeth of 34 people who lived in the Bronze Age. As it turned out, the mutation, as a result of which the bacterium began to be transmitted through fleas, appeared about 3800 years ago.

Plague wand Yersinia pestis 4000 years ago was not as deadly as it was in the Middle Ages

The results of the study suggest thatthe bacterium was brought to the British Isles much earlier than scientists thought. By the way, the most ancient traces of bacteria were found in Eurasia. Their age is approximately 5000 years. The fact that the plague bacillus traveled a long distance speaks of its contagiousness. But at the same time, it did not cause such deadly epidemics that arose in the Middle Ages.

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Scientists hope that further researchwill allow us to more accurately establish what effect the plague had on humanity 4,000 years ago, and whether it had any effect at all. But most importantly, the study of the genomes of ancient bacteria will make it possible to understand which genes are of key importance in the spread of infectious diseases. This is really useful information, because the WHO calls now to prepare for a new pandemic, which may turn out to be much worse than COVID-19.