Scientists reconstruct evolutionary history of nefarious plague pandemics
For centuries, plague pandemics have wrought havoc around the world; when the Black Death hit Europe in the late 1340s, it killed almost a third of the population. Now a new multinational study has pieced together the global evolutionary history of the deadly disease. The findings, presented in the journal Nature Genetics, could lead to improved trace and preparation measures for potential outbreaks in the future. The team, consisting of academic, industry and government researchers from Europe, China and the US, used historic and phylogenetic comparison of 17 Yersinia pestis (plague bacterium) isolates from international sources to reconstruct the devastating global impact of the bacterium. According to the team, the plague evolved in the vicinity of China more than 2,000 years ago and launched its global attack in a number of pandemics. Relationships between people and pandemic infectious diseases have existed for years, say the experts, adding that these diseases have played a key role in shaping civilisations. Some scientists believe that the plague left the Byzantine (aka Eastern Roman) Empire devastated in the 6th century. The Justinianic plague undermined the empire, both politically and economically, and created the conditions for the empire's ultimate fall. And anyone who thinks the plague is confined to the history books should note that the disease resurfaced in some parts of Africa just a few years ago. In this latest study, headed by Professor Mark Achtman from University College Cork, Ireland, the research team discovered that country-specific plague lineages (populations) could be identified by mutations accumulated in their genomes. 'What I felt was so amazing about the results is that we could link the genetic information so accurately to major historical events,' Professor Achtman remarked. These unique mutations could help researchers better understand future disease events involving plague. DNA (deoxyribonucleic acid) fingerprinting can help characterise natural and man-made plague outbreaks. This is highly significant because people have used plague as a biological weapon. Due to the disease's highly sensitive nature, the researchers worked on 17 complete plague genome sequences and on 933 variable sites in the DNA of the world's biggest plague isolates collection. The information compiled by the team enabled them to track the progress of the historical pandemics worldwide and determine the age of the various wages of this deadly disease. Researchers can now link most of these events to known historical records, according to the experts. 'The sequencing of additional plague bacteria was crucial in identifying subtle, yet important differences in this evolutionary young human pathogen,' explained Dr Mark Eppinger from the Institute for Genome Sciences (IGS) at the University of Maryland School of Medicine in the US, one of the first authors of the paper. For his part, Dr Paul Keim of Northern Arizona University and the Translational Genomics Research Institute in the US said: 'Future epidemiologists can learn from this millennium-scale reconstruction of a devastating disease to prevent or control future infectious disease outbreaks.' Professor Achtman concluded: 'What was so amazing with the results is that it was possible to use present-day genome information to accurately link past plague pandemics to major events in recorded human history.' Experts from France, Germany, Madagascar and the UK also contributed to this study.
Countries
China, Germany, France, Ireland, Madagascar, United Kingdom, United States