The Plague Dates Back To nearly 3000 BC

However, before this occurred, the plague was occurring in humans in Eurasia 3,000 years before the first recorded bubonic plagued epidemic.

The study’s authors do not believe this means that scientists have been wrong about what caused the frighteningly quick spread of the plague during the time of Black Death.

The villain behind the sixth century’s Plague of Justinian, the Black Death, killing 30%-50% of the European population in the mid-1300s is Y. pestis.

The Plague of Justinian is thought to have played a significant part in debilitating the Byzantine Empire, and the much older putative plagues have been connected with the diminishing of Classical Greece and most probably deteriorated the strength of the Roman Army.

The virulence gene protects the Y. pestis bacteria from being destroyed by the toxins in flea guts, allowing it to reproduce and multiply unhindered. This drilling gave a powder the DNA of which researchers examined searching for bacteria of the plague.

“Our results show that plague infection was endemic in the human populations of Eurasia at least 3,000 years before any historical recordings of pandemics”, the study authors wrote. The team’s interest was sparked by the reasons behind these migrations.

“It might be that (plague) will eventually burn itself out”, said Brendan Wren, dean of the faculty of infectious and tropical diseases at the London School of Hygiene and Tropical Medicine.

“Perhaps people were migrating to get away from epidemics or re-colonizing new areas where epidemics had decimated the local populations”.

To further probe this mystery, an global team led by Danish researchers sequenced the DNA pulled from the teeth of 101 Bronze Age humans excavated from around Europe and Asia. These teeth were obtained from various museums and archaeological excavations. Seven of them (one each from present-day Armenia, Poland and Estonia and four from what is now Russia) carried bacterial DNA sequences that bore a striking similarity to the Y. pestis genome.

“The underlying evolutionary mechanisms that facilitated the evolution of Y. pestis are still present today”, said Allentoft.

“The Bronze Age plague represents an intermediate state where it had not yet evolved the capabilities to be transmitted by fleas or cause bubonic plague”.

Samples taken from the Iron Age human remnants (1200 B.C.), suggest that – about 2000 year later – Yersinia pestis had developed the ymt gene. Further analysis suggested that the original pathogen that Y. pestis evolved from first emerged around 5,783 years ago.

Besides widespread transmission through fleas, another secret to Y. pestis’ success has been its stealthy evasion of the host immune system.

The new findings may have more than historic significance, says another researcher, Simon Rasmussen of the Technical University of Denmark. While it’s conceivable that people’s involvement with Y. pestis backpedals way longer than any authentic historical record, the oldest proof pulled from human skeletons only dates back around 1,500 years. They will also search for ancient DNA remains of other blood-borne bacteria and viruses. “Our findings reveal that one can find ancient pathogenic microbes in ancient human material showing no obvious morphological signs of disease”, Willerslev says. “So plague is just one disease to look at, and one could explore all kinds of diseases like this in the future”.