A man who died more than 5,000 years ago in Latvia were infected with the strain (strain) bacteria the earliest known, according to new evidence.
Scientists identified him as a new competitor to “patient zero” – as the first person to be infected – in diseases that cause plague `Black Death`.
The epidemic swept across the Europe in the 1300s which killed half its population.
Subsequent waves continued to strike regularly for several centuries, causing millions of people to die.
“To date, this is the oldest plague victim we have,” said Dr Ben Krause-Kyora of the University of Kiel in Germany of the 5,300-year-old body.
The man was buried with three others at a Neolithic burial site on the banks of the Salac River, Latvia, which flows into the Baltic Sea.
The researchers sequenced DNA from the bones and teeth of all four individuals, and tested them for bacteria and viruses.
They were surprised to find a hunter-gatherer – a man in his twenties – infected with an ancient plague strain, caused by the bacterium Yersinia pestis.
“He was most likely bitten by a rodent, caught the main infection Yersinia pestis and died a few days [kemudian] – maybe a week later – due to septic shock,” said Dr Krause-Kyora.
Researchers suspect the ancient strain arose about 7,000 years ago, when agriculture began to emerge in central Europe.
They suspect the bacteria may have jumped sporadically from animals to humans without causing a major outbreak.
Over time, the bacteria adapted to infect humans, eventually developing what became known as the bubonic plague, which was spread by fleas and raged in medieval Europe, causing millions of deaths.
The idea that early plague strains were slow to spread challenges many theories about the development of human civilization in Europe and Asia.
And that casts doubt on the hypothesis that the disease caused a large-scale population decline in Western Europe at the end of the Neolithic Age.
Several other researchers welcomed the study, but said it was possible that the outbreak had spread widely in Europe at this time.
Humans usually get plague after being bitten by rat fleas that carry plague bacteria or harbor them on infected animals.
The disease still exists today, but can be treated with antibiotics if caught early.
The research was published in the journal Cell Reports.
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