Plague may have caused a mysterious population collapse in northern Europe over 5,000 years ago, DNA evidence suggests. Image source: Theodor Kittelsen, via Picryl.
New research based on DNA evidence suggests the plague may have caused a population collapse in northern Europe over 5,000 years ago.
Europe experienced a rapid population decline around 5,400 years ago, especially in the northern regions of the continent.
The cause of the Neolithic decline is contentious among experts, with some speculating an agricultural crisis while others suspect disease.
Scientists have previously found two Neolithic cases of plague in Latvia and Sweden, but it is uncertain if these were isolated incidents or part of a wider outbreak.
To uncover more evidence, a team of researchers analysed the skeletal remains of 108 Neolithic Scandinavian people who were found buried in eight stone tombs in Sweden and one in Denmark.
Sequencing the remains revealed 18 of them were infected with Yersinia pestis — the bubonic plague — at the time of their deaths.
Three separate strains of bacteria were obtained from the samples, two of which were only found in a few teeth from those buried in older tombs.
The third strain had genetic variation which researchers believe could have made it significantly more virulent.
University of Copenhagen geneticist and lead author Frederik Seersholm said, “We learned that the Neolithic plague is an ancestor to all later plague forms.”
“It’s present in a lot of individuals, and it’s all the same version, which is exactly what you would expect if something spreads very quickly,” Seersholm told New Scientist.
“Of course, this is very, very hard to test, because you can’t really just grow an ancient [bacterium].”
“It’s worth noting that all of these individuals were buried properly,” he added.
“If there was in fact an epidemic, we only see the very beginning of it.”
A later form of the Y. pestis pathogen caused the 6th century Justinian Plague and the 14th century Black Death.
University of Copenhagen geneticist and co-author Martin Sikora said, “This high prevalence of plague indicates that plague epidemics played a substantial role in the Neolithic decline in this region.”
“Indeed, it seems plausible that the decline seen in other parts of Europe was also in some way affected by plague,” said Sikora.
“We do already have evidence for plague in other megalithic sites in different parts of Northern Europe, and seeing how prevalent it was in Scandinavia, I would expect a similar picture to emerge once we study these other megaliths with the same resolution.”
The study was published in Nature Portfolio and can be read in full here.
