Tiny organisms found in ancient graves linked to destruction of human populations

Findings about the impact of the plague thousands of years ago in Europe comes, as a man in the United States was found to be infected with a modern strain.

An Neolithic era family grave in Falbygden, Sweden.
Bones in ancient family graves in Falbygden, Sweden were analysed by the scientists. Source: Frederik Seersholm

Tiny organisms found in trace amounts in ancient bones are believed to have contributed to the destruction of human populations thousands of years ago.

DNA from 100 neolithic people, across six generations, found evidence of the plague-carrying bacterium (Yersinia pestis). Looking at a period of 120 years, researchers found repeated outbreaks of the disease infecting Scandinavian farmers.

"We find that the neolithic plague was widespread, detected in at least 17 per cent of the sampled population and across large geographical distances," the researchers reported.

Grisly images of the family grave sites at Falbygden, in southwest Sweden, show the bodies that experts from Australia’s Curtin University and their colleagues from University of Copenhagen analysed for their paper published in the prestigious journal Nature this week.

Analysis of these settlements resulted in other insights into early human life — particularly family structure. While there were no instances of females with multiple partners, they found four males with more than one reproductive partner.

Related: Mysterious 52,000-year-old image unearthed inside tropical island cave

Neolithic bones piled up inside a grave at Falbygden, Sweden.
The bones of 108 people from between 5,300 and 4,900 years ago were examined. Source: Karl-Göran Sjögren

The team tested bones from 108 individuals, in bones dated to between 5,300 and 4,900 years ago. And the community was sickened by three distinct waves of viruses. The first two were small and contained, but the third was more extensive.

While avian flu and Covid-19 are the diseases that have captured our fears this decade, the plague, which is spread by fleas that live on rats continues to kill a few hundred people every year, mostly in Africa. Between 2010 and 2015 there were 3,248 plague cases reported around the world, resulting in 584 deaths. And this week a person in the US state of Colorado was discovered to be infected.

What caused the decline of neolithic populations in Europe has long been debated. Some have argued it was caused by agricultural failures, climactic change, or mass migration. But others have blamed illness, singling out an early form of the plague.

The Neolithic age was characterised by a shift from hunting and gathering to farming and this resulted in a jump in population density and permanent settlements. The plague outbreaks were discovered at the beginning of the Neolithic Decline which brought a sudden end to many communities.

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