The Justinianic Plague of the 6th-8th century was almost without a doubt caused by the bacterium Y. pestis, according to new research from Universität Mainz. The research was done by analyzing DNA taken from the skeletons of plague victims in early medieval cemetery of Aschheim in Bavaria.
Doing the last 2000 years there have been repeated and numerous large-scale pandemics, some of which are now referred to as ‘pestilences’. The exact causes behind some of these pestilences have remained somewhat unclear. But that began to change two years ago, when, via the use of DNA taken from plague victims, it was demonstrated that the cause of the infamous “Black Death” during the years of 1346-1351 was the bacterium Y. pestis. After that work was finished, the researchers then moved onto determining the cause of the Justinianic Plague, as that has been the subject of much debate in the scientific community.
“For a long time scholars from different disciplines have intensively discussed about the actual etiological agents of the past pandemics. Only ancient DNA analyses carried out on skeletal remains of plague victims could finally conclude the debate,” said Dr. Barbara Bramanti of the Palaeogenetics Group at the Institute of Anthropology at Johannes Gutenberg University Mainz (JGU).
The analyses of the centuries-old DNA taken from the early medieval cemetery of Aschheim in Bavaria confirmed “unambiguously that Y. pestis was indeed the causing agent of the first pandemic, in contrast to what has been postulated by other scientists recently. This revolutionary result is supported by the analysis of the genotype of the ancient strain which provide information about the phylogeny and the place of origin of this plague. As for the second and third pandemic, the original sources of the plague bacillus were in Asia.”
“It remains questionable whether at the time of the Byzantine Emperor Justinian only one strain or more were disseminated in Europe, as it was at the time of the Black Death,” suggested Bramanti and her Mainz colleague Stephanie Hänsch.
In order to further research this and other questions, Bramanti recently obtained an ERC Advanced Grant for the new project “The medieval plagues: ecology, transmission modalities and routes of the infection” and will be moving to the Center for Ecological and Evolutionary Synthesis at the University of Oslo in Norway.
The new research has been published in the journal PLoS Pathogens.
While Y. pestis was the biological cause of the plague/pandemic, the real cause of large-scale pandemic is almost always trade/migration. With extensive and regular travel/trade , and large-scale migration, the perfect environment is set up for disease emergence and transmission.
Modern antibiotics, which have been around for the last 100 or so years, have, until to now, been successfully limiting the spread of bacteriological diseases/pandemics such as plague. But with the declining effectiveness of available antibiotics, the spread of resistance throughout bacterial communities and the natural environment, and the large-scale migrations that are predicted to occur in the near future as a result of climate change, it remains to be seen if plague will become a major force in the world again. It is a possibility.