First accepted Submitter alPillan Quince wrote The bacteria behind the Black Death was a very unusual story. His ancestor was a soil bacterium unpretentious and current strains of Yersinia pestis infects even thousands of people every year, but no longer causes result of horrible symptoms associated with medieval plagues. The radical differences, in fact, had led some to suggest that we were wrong to blame the bacteria. Now, the researchers obtained DNA from some of the victims of the plague in London , and confirmed that Y. pestis seems to be to blame. But the sequences also suggest that strains of bacteria that we see today may differ from those that are raging across Europe.