The Black Death rapidly spread along the major European sea and land trade routes. (Photo credit: Wikipedia)
It has long been thought the Black Death, the plague that decimated the population of Britain in the mid-14th century, was spread by fleas carried on rats.
The scientists were shocked to discover that the two samples were an almost perfect match, meaning the 14th century plague was no more virulent than it is today.
They believe that for such a disease to have spread so quickly and cause so much damage it must have been spread by coughs and sneezes, getting into the lungs of its already weak and malnourished victims.
Dr Tim Brooks from Public Health England in Porton Down where the research was carried out, told the Guardian: 'As an explanation [rat fleas] for the Black Death in its own right, it simply isn't good enough.
However, 25 skeletons recently unearthed in Clerkenwell, London, believed to be of plague victims, have cast doubt on this age-old theory and provided evidence that they deadly disease may have, in fact, been airborne.
The DNA of the remains was compared to samples from an outbreak in Madagascar, in 2012, which killed 60 people.