A new study, featuring Estonian researchers and DNA evidence from Estonia, suggests that Black Death, one of the most ferocious diseases known to man, has literally plagued people for much longer than previously thought. Moreover, it originally spread by human-to-human contact, not fleas.
The study, published in Cell journal on Thursday, analyzed teeth from 101 skeletons from 6 sites from Poland to Siberia, including a Corded Ware culture burial place in Sope, north-eastern Estonia, a source of several neolithic skeletons that have been dated to 2575-2349 BC in the study.
The DNA results show that the bacterium, Yersinia pestis, afflicted humans already more than 5,000 years ago. That is 3,000 years earlier than hitherto believed.
The bacterium was present in seven individuals who lived as long as over five and a half millennia ago. However, six of them were missing key genetic components of modern plague strains, namely the ones that allow the bacteria to be spread by fleas.
The study was led by Professor Eske Willerslev from Cambridge University and included researchers from the University of Tartu's departments of archeology and evolutionary biology.