The plague was around as early as 3,000 BC —study

Probably the plague outbreak most people are familiar with is the Black Death in Europe, which took place around 541-544 AD, but a recent study published in the journal Cell says that the plague may have been busy killing off people as early the Bronze Age.

 

The plague is caused by a bacteria called Yersinia pestis. Pneumonic plague involves bacterial transmission through human-to-human contact while bubonic/septicemic plague involves fleas as a vector for the bacteria.

 

Confirmed historical plague pandemics include the Plague of Justinian (541–544 AD), the Black Death in Europe (1347–1351 AD), and a third pandemic that emerged in China in the 1850s before turning into a major epidemic in 1894. Other suspected but unconfirmed earlier outbreaks include the Plague of Athens (430–427 BC) and the Antonine Plague (165–180 AD).

 

In the current study, researchers sequenced ancient bacterial genomes obtained from Bronze Age (3,000-1,000 BC) skeletons obtained in Europe and Asia. Their findings suggest that the Y. pestis bacterial strain responsible for bubonic plague pandemics may have descended from a less infectious version of Y. pestis that was already present in 3,000 BC.

 

According to Nature, the researchers got the idea to check for Y. pestis in the Bronze Age skeletons after earlier genome studies found that there was a huge exodus of people from what is now Russia and Ukraine, into Europe and central Asia.

 

“But we didn’t know what the cause of these quite sudden migrations was,” said evolutionary geneticist Morten Allentoft, from the Natural History Museum of Denmark. Allentoft was part of the team that sequenced DNA from the Bronze Age skeletons.

 

The team analyzed 89 billion raw DNA fragments from the skeletons. Seven out of the 101 skeletons tested positive for Y. pestis, two of which had enough plague DNA for the researchers to generate complete genome sequences.

 

The Bronze Age strains were similar to the Black Death plague strains, but were found to be less infectious, since they lacked a gene that would enable the plague to colonize flea guts. According to microbiologist Wyndham Lathem from the Feinberg School of Medicine at Northwestern University, this means that Bronze Age victims probably suffered from pneumonic plague rather than bubonic plague. — Bea Montenegro/TJD, GMA News