India, Oct. 7 -- Researchers have reconstructed the earliest known plague genomes, showing for the first time that early forms of the disease caused deadly outbreaks around 5,500 years ago - long before the Black Death killed up to half of Europe's population.

Plague is commonly associated with rats, overcrowded medieval cities and the devastating epidemics that swept across Europe during and after the Middle Ages.

However, a new study published in the journal Nature shows that the disease was already lethal 5,500 years ago, when it killed people living in small, mobile hunter-gatherer communities - long before the rise of agriculture and cities created the conditions typically associated with large-scale plague epidemics.

An internati...