The black plague, or black death as it’s also referenced, is a deadly infectious disease which killed off more than a third of Europe’s population during the middle ages. The bacteria responsible for the disease has been confirmed by genetic scientists as Yersinia pestis, and recently, building off the research which found this particular strain, German scientists have successfully sequenced the entire genome of the bacteria. According to their study, the bacteria responsible for one of the most devastating pandemics in human history has little changed in the past 600 years.

Through their remarkable research, German, Canadian and American scientists have managed to reconstruct for the first time the genetic structure of a pathogen older than 100 years, which will now allow them to track changes in the disease’s evolution and virulence, offering at the same time a better understanding of modern infectious diseases.

“The genomic data show that this bacterial strain, or variant, is the ancestor of all modern plagues we have today worldwide. Every outbreak across the globe today stems from a descendant of the medieval plague,” said Hendrik Poinar, of Canada’s McMaster University, who worked with the team.

“With a better understanding of the evolution of this deadly pathogen, we are entering a new era of research into infectious disease.”

For their rearch, the time escavated skeletons from London’s East Smithfield “plague pits”, a common burial ground home to the final resting place of thousands of people struck by the black plague. Eventually, they found promising specimens and subsequently proceeded in extracting, purifying and enriching specifically for the pathogen’s DNA from the dental pulp of five bodies. Linking the 1349 to 1350 dates of the skeletal remains to the genetic data allowed the researchers to calculate the age of the ancestor of Y. pestis that caused the mediaeval plague.

So it has it, that the vicious bacteria during its more than 660 years of evolution has remained more or less the same.

“We found that in 660 years of evolution as a human pathogen, there have been relatively few changes in the genome of the ancient organism, but those changes, however small, may or may not account for the noted increased virulence of the bug that ravaged Europe,” says Poinar.

“The next step is to determine why this was so deadly.”

After it peaked during 1348 and 1350, the plague went on to erupt in a few isolated, not so dramatic cases well until the 19th century. Its modern ancestor exist to this day, however, and is reportedly responsible for killing 2,000 people each year.

Johannes Krause Of Germany’s University of Tubingen, who also worked on the study, said the same approach could now be used to study the genomes of all sorts of historic pathogens.

“This will provide us with direct insights into the evolution of human pathogens and historical pandemics,” he said in a statement.

The black plague sequenced genome research was published in the latest edition of the journal Nature.