A deadly pandemic of mysterious origins: This might sound like a headline from today, but scientists have spent centuries trying to determine the cause of the Black Death that decimated the medieval world.
Researchers claim they are now able to pinpoint the source of the plague in a region of Kyrgyzstan after analysing DNA from an ancient burial site.
Philip Slavin, a historian who was part of the team that published their work Wednesday in Nature, stated that “We actually managed to put to rest all these centuries-old controversies regarding the origins of Black Death.”
The Black Death was the first wave of a nearly 500 year-long pandemic. According to estimates, it killed as many as 60% of Europe’s Middle East, Africa and Europe in just eight years (1346-1353).
Ancient DNA traces origin of Black Death https://t.co/NNd656FmhG
Slavin is an associate professor at University of Stirling in Scotland, who “always been fascinated by the Black Death” and discovered an intriguing clue in an 1890 paper that described an ancient burial site in northern Kyrgyzstan.
It reported that there was a spike in burials between 1338 and 39, and that many tombstones said people had “died from pestilence”.
Slavin stated to reporters, “When you have one-two years of excess mortality it means something funny was happening there.”
He said, “But it wasn’t just any year — thirteen38 and 1339 were just seven or eight years prior to the Black Death.”
It was a lead but not more than that without knowing what caused the deaths of the people who lived at the site.
Slavin has teamed up to study ancient DNA.
Maria Spyrou, a University of Tuebingen researcher and author of the study, said that they extracted DNA from seven individuals buried at this site.
Spyrou explained to AFP that teeth have many blood vessels and give researchers “high odds of detecting blood-borne pathogens which may have caused death of individuals” Spyrou said.
After the DNA had been extracted and sequenced it was compared to a database of thousands upon thousands of microbial genes.
Spyrou said that one of the biggest hits was a hit for Yersinia Pestis, also known as plague.
She also stated that DNA showed “characteristic damage patterns,” which indicated that there was an infection in the DNA of the deceased.
The “Big Bang” event that saw existing plague strains suddenly diversify has been tied to the Black Death.
Scientists believed it could have occurred as early as 10 centuries ago, but they were unable to pinpoint the date.
The team of researchers painstakingly reconstructed Y. pestis’ genome from the samples they collected and discovered that the strain found at the burial site predated diversification.
The team also discovered that rodents found in the region today were carrying the same ancient strain. This helped them conclude that the “Big Bang” occurred in the area just a few days before the Black Death.
Michael Knapp, associate professor at New Zealand University of Otago, said that the research had some limitations. He was not involved in this study.
Knapp stated that “data from far more individuals and times…would really help clarify what this data really means.”
He acknowledged that it might be difficult to find more samples and said the research was still “really valuable”.
Sally Wasef from Queensland University of Technology said that the work provided hope for unravelling other ancient scientific mysteries.
She told AFP that the study had shown how strong microbial DNA recovery could be used to reveal evidence to resolve long-lasting disputes.
The World Health Organization reports that there were 3,248 reported cases worldwide in 2010-2015, which resulted in 584 deaths. The most affected countries were Peru, Madagascar, and the Democratic Republic of the Congo.
Infected rats were transported on steamships to introduce the plague to the United States in 1900. Los Angeles was the last major urban outbreak of plague-like symptoms in America between 1924-1925.
The U.S. Centers for Disease Control and Prevention states that people usually get septicemic or bubonic plague from being bitten by a flea carrying the bacterium. The disease can also be contracted by humans if they touch infected animals.
