The research, which examined 25 skeletons unearthed in the Clerkenwell area of London last year, revealed that the previously believed claim that the Black death was caused by a highly contagious strain spread by the fleas on rats may not be true at all, the Guardian reported.
Now evidence reveals that only an airborne infection could have spread so fast and killed so quickly.
Researchers extracted the DNA of the disease bacterium, Yersinia pestis, from the largest teeth in some of the skulls retrieved, and compared it to the strain of bubonic plague preserved there with the one that killed 60 people in Madagascar recently.
They found that, the 14th-century strain, which caused the most lethal catastrophe in recorded history, was no more virulent than today's disease and that the DNA codes were a near perfect match.
According to scientists working at Public Health England in Porton Down, the plague was a pneumonic plague instead of the bubonic plague with infection spreading from human to human, rather than by rat fleas.
The Black Death arrived in Britain from central Asia in the autumn of 1348 and by late spring the following year it had killed six out of every 10 people in London.