Photo: McMaster University
Isn't this a plot in many an apocalypse Hollywood movie?
Scientists have succeeded in reconstructing the genetic code of a deadly strain of bacteria that killed nearly a quarter of the human population during the Justinian Plague, back in the days of the Roman Empire. The plague, caused by the bacterium Yersinia pestis, made another appearance in Europe several centuries later - and that time, it got a moniker you're probably familiar with: the Black Death, which killed nearly half of the entire human population.
So, what could go wrong?
Anyways, back to the story: When housing developers were digging up a farmland outside Munich, Germany, they found skeletons in a mass grave of people who died from the plague, including a tooth which dental pulp still contained traces of blood. And in that blood was DNA of the plague bacteria.
David Wagner of McMaster University and his team managed to extract the plague DNA from the tooth, and discovered something interesting, as reported by Nell Greenfieldboyce of NPR's Morning Edition:
They think the strain of bacteria that caused the Justinian plague jumped from rodents into humans and then died out, the team wrote Tuesday in the journal The Lancet Infectious Diseases. The later emergence of the Black Death seems to have been caused by a separate event.
The DNA also suggests that, like the Black Death, the original source of the plague was in China, says microbiologist Paul Keim, another member of the research team at Northern Arizona University. "So the ecological reservoir for plague, the historical reservoir, is in China," Keim says. "And it's this emergence, this pattern over and over again, with people moving commodities, rats and fleas around the world that we're able to document."
Overall, this ancient strain is not that different from modern ones that still circulate in places like Arizona, says Keim.
So, could Black Death strike again? Well, consider this: currently, every year, about a dozen people in the United States catch the disease. They're treated with antibiotics, but there's a concern that the plague bacterium could develop drug-resistance through the overuse of antibiotics and become a major threat once again.