Black Death may have been lurking for centuries: DNA of plague victims in France backs up theory that bacteria lay dormant

*.The plague in 14th and 18th centuries was caused by Yersinia pestis

*.Bacteria thought to have killed 30% to 50% of the European population

*.Study found same strain of bacteria in victims that died 300 years apart

*.Follows study of German victims' DNA which came to same conclusion black Death, a mid-fourteenth century plague, killed 30 to 50 per cent of the European population in just five years.

The pandemic was caused by the Yersinia pestis bacteria with millions dying from the disease in two major outbreaks. Thousands of years before it wreaked havoc in the second wave of deaths, the bacteria may have been passed around as a harmless microbe.

This is the conclusion of the Max Planck Institute for the Science of Human History in Germany who reconstructed complete pathogen genomes from victims of the Great Plague of Marseille,This plague raged from 1720 to 1722 and is conventionally assumed to be the last outbreak of medieval plague in Europe.