An international team of scientists has discovered that two of the world’s most devastating plagues – the plague of Justinian and the Black Death, each responsible for killing as many as half the people in Europe — were caused by distinct Yersinia pestis strains, one that faded out on its own, the other leading to worldwide spread and re-emergence in the late 1800s. These findings suggest a new strain of plague could emerge again in humans in the future.
Burial of plague victims at the early medieval cemetery Aschheim. Foto: © H-P. Volpert
Fig. 2: Plague victim analyzed in the lab.
Using sophisticated methods, researchers from various institutions including McMaster University, State Collection of Anthropology and Paleoanatomy, Munich, Bundeswehr Institute of Microbiology, Munich, Northern Arizona University and the University of Sydney, isolated miniscule DNA fragments from the 1500-year-old teeth of two victims of the Justinian plague, buried in Bavaria, Germany. These are the oldest pathogen genomes obtained to date.
Using these short fragments, they reconstructed the genome of the oldest Yersinia pestis, the bacterium responsible for the plague, and compared it to a database of genomes of more than a hundred contemporary strains.
The results are currently published in the online edition of Lancet Infectious Disease. They show the strain responsible for the Justinian outbreak was an evolutionary ‘dead-end’ and distinct from strains involved later in the Black Death and other plague pandemics that would follow.
“The research is both fascinating and perplexing, it generates new questions which need to be explored, for example why has this particular Y. pestis strain no genetic successors and died out?” questions Holger Scholz, head of the department of Bacteriology and Toxinology at the Bundeswehr Institute of Microbiology in Munich.The findings are dramatic because little has been known about the origins or cause of the Justinian Plague– which helped bring an end to the Eastern Roman Empire – and its relationship to the Black Death, some 800 years later.
The Plague of Justinian struck in the sixth century and is estimated to have killed between 30 and 50 million people— virtually half the world’s population as it spread across Asia, North Africa, Arabia and Europe. The Black Death would strike some 800 years later with similar force, killing 50 million Europeans between just 1347 and 1351 alone.
The third pandemic, which spread from Hong Kong across the globe is likely a descendant of the Black Death strain and thus much more successful than the one responsible for the Justinian Plague.
“We know the bacterium Y. pestis has jumped from rodents into humans throughout history and rodent reservoirs of plague still exist today in many parts of the world. If the Justinian plague could erupt in the human population, cause a massive pandemic, and then die out, it suggests it could happen again. Fortunately we now have antibiotics that could be used to effectively treat plague, which lessens the chances of another large scale human pandemic” says Dave Wagner, an associate professor in the Center for Microbial Genetics and Genomics at Northern Arizona University. However, we should not underestimate the devastating potential of plague, as in recent years strains emerged which are resistant to antibiotics, routinely used in plague therapy, adds Holger Scholz.
The samples used in the latest research were taken from two victims of the Justinian plague, buried in a gravesite in a small cemetery in the German town of Aschheim. The skeletal remains of the early medieval cemetery of Aschheim are examined by researchers of the Munich State Collection of Anthropology and Paleoanatomy since several years”, says Michaela Harbeck, curator of this institution which keeps ten thousands of skeletons, each of them an unique historical and biological source.The skeletal remains yielded important clues and raised more questions.
Researchers now believe the Justinian Y. pestis strain originated in Asia, not in Africa as originally thought.
“This study raises intriguing questions about why a pathogen that was both so successful and so deadly today only infects about 3000 people each year. From our genome analyses we know that Yersinia pestis from both the Black Death and the Justinian plague was not more dangerous than present Y. pestis strains, says Holger Scholz. One testable possibility is that human populations evolved to become less susceptible,” says Holmes. “Another possibility is that changes in the climate became less suitable for the plague bacterium to survive in the wild,” says Julia Riehm of the Bundeswehr Institut of Microbiology.
Scientists hope their research could lead to a better understanding of the dynamics of modern infectious disease, including a form of the plague that still kills thousands every year.
The research was funded in part by the Social Sciences and Humanities Research Council of Canada, Canada Research Chairs Program, U.S. Department of Homeland Security, U.S. National Institutes of Health and the Australian National Health and Medical Research Council.
For more information please contact:PD Dr. Holger C. Scholz
Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory
How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy