When the Black Death, the infamous mid-14th century plague, took out 30 to 50 percent of the European population, it continued to resurge throughout Europe and lead to a continuous level of high mortality and social disarray for the next three centuries. However, the abrupt disappearance of the plague left many unanswered questions relating to its origin, where it hid between outbreaks and what stimulated resurgences. Now, researchers at the Max Planck Society seek to answer these questions and have reconstructed complete pathogen genomes from victims from the Great Plague of Marseille, which is assumed to be the final outbreak of the medieval plague in Europe.
The team used teeth from plague pits in Marseille and examined small fragments of DNA preserved in the fossils.
"We faced a significant challenge in reconstructing these ancient genomes," Alexander Herbig, a computational analyst that participated in the research, said in a press release. "To our surprise, the 18th century plague seems to be a form that is no longer circulating, and it descends directly from the disease that entered Europe during the Black Death, several centuries earlier."
Given its unique features that separate it from all modern plagues, the team believes that they have uncovered an extinct form of the disease. Although the geographic source of the disease has yet to be pinpointed, there are many candidates due to the variety of areas that Marseille shipped and received from. However, it also could have originated closer to home.
"Our results suggest that the disease was hiding somewhere in Europe for several hundred years," said Kirsten Bos, lead author of the study.
"It's a chilling thought that plague might have once been hiding right around the corner throughout Europe, living in a host which is not known to us yet," said Johannes Krause, who participated in the research. "Future work might help us to identify the mysterious host species, its range and the reason for its disappearance".
The findings were published in the Jan. 21 issue of eLife.
