The plague bacteria that swept through medieval Europe had been declared extinct just over a month ago. A quick google search reveals articles with headlines such as ‘Medieval plague bacteria strain probably extinct’ and ‘Black death strain extinct’. Few writers mentioned that the original research on which they reported was a technical paper first and foremost, and not a comprehensive investigation into the evolution of the Medieval plague.

It’s ironic that a study that was published last week shows that the Black Death is far from extinct. On the contrary. The plague bacteria that still infect thousands of people every year trace back their ancestry to the plagues of the fourteenth century. Interestingly, this new research was carried out by the same scientists that published the other plague study in August, so what has happened here?

In their first paper, researchers lead by Johannes Krause and Hendrik Poinar announced that they had successfully extracted and sequenced some DNA of a medieval strain of  Yersinia pestis, the bacterium that causes plague, from the teeth of a dozen Black Death victims. These remains had been excavated from the  East Smithfield burial grounds in London by the Museum of London Archaeology before. During the height of the London plague epidemic, between 1348 and 1349, thousands of bodies were buried at East Smithfield.

FULL