Plague In Humans May Be ‘Twice As Old’ But Didn’t Begin As Flea-borne, Say Cambridge Research

by Benson Agoha | Cambridge Research

"These results show that the ancient DNA has the potential not only to map our history and prehistory, but also discover how disease may have shaped it" - Eske Willerslev

* Image Credit: via Cambridge Research

Bubonic plague and other communicable diseases that wiped a large part of human populations in Europe and Asia has been around longer than humans first thought, according to a study by Cambridge Research.

Using ancient DNA, Senior auhor of the report, Professor Eske Willerslev of Cambridge University’s Department of Zoology and his team found that plague has been endemic in human populations for more than twice as long as previously thought, and that the ancestral plague would have been predominantly spread by human-to-human contact – until genetic mutations allowed Yersinia pestis (Y. pestis), the bacterium that causes plague, to survive in the gut of fleas.

To arrive at their conclusion, the researchers used bacteria from the DNA of adults, the oldest of whom died 5,783 ago, which was when the evidence of plague was noticed.

The team of international researchers from University of Denmark and Cambridge found that the Y. pestis, which causes plague, had originated and was widespread much earlier than previously thought. and they narrowed the time window as to when and how it developed, and believe that the underlying mechanisms that facilitated the evolution of Y. pestis are present even today.

* Image Credit: via Cell 

Prof. Willersley said that learning from the past may help us understand how future pathogens may arise and evolve. Furthermore, the team believe that because the Bronze Age was a highly active migratory period, it could have resulted in the spread of pneumonic plague.

Co-author Dr Marta Mirazón-Lahr, from Cambridge’s Leverhulme Centre for Human Evolutionary Studies (LCHES) said "the Bronze Age was a period of major metal weapon production, and it is thought increased warfare, which is compatible with emerging evidence of large population movements at the time."

She said "If pneumonic plague was carried as part of these migrations, it would have had devastating effects on small groups they encountered,” adding that “Well-documented cases have shown the pneumonic plague’s chain of infection can go from a single hunter or herder to ravaging an entire community in two to three days.”

Click to read the [ Full Cambridge Report here ].