What a hidden graveyard from the Roman Empire can teach us about plague

The bodies were discovered by accident.

While digging sewers to a suburban development outside of Munich, Germany, construction workers saw what appeared bones . It turns out that not a single corpse. There were huge bunches of them, extending below gardens and roads – 1,451 to be exact. Archaeologists and explorers children who later were excavated had no way of knowing that these bodies could help scientists understand one of the most deadly diseases on earth.

This disease is the plague. And a document published on Tuesday, 51 years after those skeletons were discovered for the first time, provides a detailed analysis of the DNA of the bacteria responsible for filling the old cemetery in Altenerding – and kill one-third and half the population of the known world at the end of the Roman Empire.

The finding is not only a historical curiosity. It is a tool for the advancement of biomedical science.

These ancient DNA fragments form a kind of evolutionary file, which tells the story of a relatively harmless stomach virus that became rampant murderer. Researchers hope to use that history to find similar transformations in bacteria today, and to help prepare for future outbreaks -. Both the plague and other pathogens

The bodies in Altenerding died in the first known plague pandemic, which began around 541, centuries before the Black Death that swept Europe in the Middle Ages. People fever occurs, with swellings in English or under the arm. They would be dead three days later.

“The Emperor Justinian Roman, ruling in Constantinople, ordered an imperial official to count the bodies coming out of the gates, and there were many who gave up, “said Michael McCormick, a historian at Harvard who studies the plague of Justinian, and one of the authors of the article. “They paid around 230,000.”

Most people assume plague disappeared with the Middle Ages, but it is still very much alive. Hundreds of patients get bubonic plague in Madagascar each year, and there are scattered infections in other parts of Africa, Asia and the Americas, as well. Last year, there were at least 15 cases in the United States, mainly transmitted through fleas that fed on prairie dogs and other wild rodents in the west.

To find and analyze samples of the plague of the 21st century, researchers need look no further than the rats in Madagascar, or ground squirrels in Arizona.

However, ancient samples are harder to get.

Plague remains
Museum Erding The excavation of the cemetery Altenerding during a visit by a delegation from the district of Upper Bavaria, in 1967.

scientists had not even thought of looking for plague in the bodies exhumed from Altenerding until 2014, when another team published the results a similar cemetery about 20 miles away. That was a little more obvious, because five or six bodies had been thrown into one hole, suggesting some kind of infectious disease rapidly spreading.

The previous document provided further evidence that the pandemic of Justinian was in fact the same disease as the Black Death. But scientists wondered if they could get a better Altenerding DNA sample.

So they entered the collection of Anthropology and Paleoanatomy State of Munich and began pulling teeth.

“It turns out that with a pathogen bloodborne like the plague, the teeth tend to be pretty good time capsule for DNA,” said David Wagner, a biologist at the University of North Arizona, and author of the 2014 “At the bottom of the teeth, there is a lot of blood vessels that feed the dental pulp.”

But like the saved cookies in a pantry for too long, the DNA begins to crumble over time -. And search for 1,500 years, the plague is a crapshoot

“Even if you have two teeth from the same individual, you are not necessarily going to get the DNA of both teeth,” said Michal Feldman, a researcher at the Max Planck Institute for the Science of History of Humanity, and one of the authors of the new study.

Only two of 20 skeletons studied DNA produced reliable pest, and only one of them had enough for analysis.

were determined

But researchers: Using a drill, which extract a powder fine bones, and filtered out everything that was not DNA. Then, with a little contemporary plague as a magnet, which removed the genetic material from the disease, leaving behind DNA from dead and 15 centuries worth of biological contaminants own.

was not much, but it was enough for the sequence , and the results were more detailed than what was found in 2014. The team found about 30 points in the genome that were different from other strains of the plague.

None of those bits of DNA can only explain why, 5,000 years ago, the bacteria that caused little more than upset stomach evolved into the terrible scourge that is Yersinia pestis. Nor can they tell us exactly what made each pandemic to emerge and then to retreat plague.

However, this type of study “allows us to make a timeline of important genes,” said Wyndham Lathem, a researcher at Northwestern plague.

Some of these genes may have been acquired from other bacteria, and microbes have a habit of slipping each other and exchange genetic material through temporary openings in their membranes. This type of behavior is taking place all the time – and this is how the first antibiotic resistance may have arisen in the plague in the 1990s That means that certain virulence traits as – or resistance -. Potentially could be passed from one species to another

And so we learn about how these evolve into a type of bacteria could have much wider implications.

“Understanding what happened during the history, understanding, when the plague came, and how they change – which is very interesting from a basic point of view,” said Elisabeth Carniel, a researcher at the plague at the Pasteur Institute in Paris “But also note that such events can reoccur at any time, anywhere in the word. understanding how it happened in pestis could be useful to be prepared in case of other types of outbreaks. “

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