14 DAY TRIAL // Scientists with the National Institute of Allergy and Infectious Diseases in the United States claim to have reached a better understanding of how and why the Black Death came to happen in Europe back in the 1300s.
More precisely, these brainiacs maintain that they have successfully pinned down the genetic changes that occurred in an ancient bacterium and that ultimately resulted in the Black Death.
In a recent paper, the scientists detail that, according to evidence at hand, Yersinia pestis (YP), i.e. the bug blamed for the Black Death, evolved from a bacterium dubbed Yersinia pseudotuberculosis (YPT).
By the looks of it, it was about 6,000 years ago that YPT underwent a series of genetic changes that eventually made it possible for it to populate not just the guts of mice, but those of fleas as well.
The National Institute of Allergy and Infections Diseases scientists who worked on this research project explain that YP came to life in China and then worked its way westward by infecting both humans and animals.
In their paper in the journal Cell Host & Microbe, the scientists show that this switch from YPT to YP was the result of both addition and removal of genes, Phys Org tells us.
This is despite the fact that, more often than not, microbes looking to become more potent and consequently more dangerous do so merely by adding genes such as the ones that would make them resistant to antibiotics.
When switching to YP (that's the bug responsible for the Black Death, for those who are having trouble keeping up), YPT added just one gene and lost three. These changes both increased transmissibility and made it deadly.
“Remarkably, only four minor changes in the bacterial progenitor, representing one gene gain and three gene losses, enabled transmission by flea vectors,” the researchers explain in the summary for their paper.
Courtesy of these genetic changes, the more lethal YP could not only infect fleas but also stick around in their bodies, where it set up camp close to their mouth. Consequently, it could be transmitted to humans whenever an individual was unlucky enough to get bitten by a flea.
In case anyone was wondering, the Black Death hit Europe – and hit it hard, some might want to add – between the years 1347 and 1351. It killed about 30 to 50% of Europe's entire population, i.e. 75 and 200 million people, and many refer to it as one of the most devastating epidemics in human history.