Emily Chan
The researchers used a technique called “deep shotgun sequencing,” which allowed them to extract detailed information, even from ancient remains with extensive damage.
The discovery that 17 percent of the analyzed individuals were infected with the plague suggests that the plague was common in Scandinavia during the late Stone Age.
One family was traced over six generations, and the researchers observed at least three plague outbreaks in that time from different strains of plague.
The ancient waves of plague followed a familiar pattern. After the Black Death of 1347 to 1353, smaller periodic outbreaks occurred until the 17th century.
It is unclear how the disease spread during the Neolithic period, but experts do know that it was not through fleas like in the Middle Ages.
The ancient strains did not contain the mutation that allowed the disease to survive in the insect’s digestive tract.
Throughout the years, there have been many theories and much speculation over what triggered the decline of the Neolithic farming population. The new data has helped debunk some ideas that were heavily debated, such as war and climate change.
“In connection with the population decline at the end of the Neolithic, both war and outbreaks of infectious diseases, including plague, have been suggested,” Seersholm said.
“There have been several theories involving the plague, and one of them suggested that the plague could not cause an epidemic—but that assumption no longer holds.”
A lack of evidence of war and major climate change makes plague the leading cause.
