(NaturalNews) The two deadliest plagues in the world - the Black Death and the Justinian Plague - wiped out a great deal of Europe's population. A new study shows that they were caused by two different strains of the same bacterium. With funding from a variety of sources from the United States, Australia and Canada, researchers analyzed DNA from people who were victims of those plagues to reach that conclusion.
Yersinia pestis (y pestis) is the bacterium that is the cause of three plague outbreaks of pandemic proportions. The Black Death, also known as the Bubonic Plague, occurred from the 14th and 17th centuries, killing about 500 million people in Europe. During the 19th and 20th centuries, a third pandemic, originating from Hong Kong, occurred. The causes of these two pandemics have been isolated genetically, with many researchers believing that the same strain of the y pestis bacterium is responsible for both.
Mysterious first pandemic
The Plague of Justinian, which occurred during the 6th and 8th centuries, was previously thought to have started in Africa before spreading to Asia, Europe, Arabia and North Africa. Before this study, whose results were recently published in The Lancelet: Infectious Diseases, little was known about the origins and causes of this plague. It is thought to be responsible for the deaths of between 30 and 50 million people.
Answering an age-old question
In order to answer this centuries-old question, researchers set about analyzing the DNA from two people who fell victim to the Justinian plague, and who were, subsequently, buried in an early medieval cemetery in Germany. In performing this analysis, the researchers isolated the DNA from the teeth of the two individuals, screened it for the presence of the specific strain of y pestis that caused the Bubonic Plague and sequenced the DNA. before comparing it to the existing genome database of y pestis bacterium.
Different bacterium strain caused first plague
According to Dave Wagner, coauthor of the study, and an associate professor at Northern Arizona University's Center for Microbial Genetics and Genomics, the study showed that the Justinian Plague and the Bubonic Plague were both caused by the y pestis pathogen, but by different strains. This gives rise to the conclusion as to why the Justinian Plague simply seems to have died out after a period of time while the Bubonic Plague recurred over and over again over a period of hundreds of years.
Though the results of this historic study showed that the two deadliest plagues were not caused by the same strain of the pathogen y pestis, it did emphasize how rats were the reservoir for the spread of the deadly disease. Wagner, the coauthor of the study, pointed out that an outbreak of the plague is still possible today as there are still rats infected with the pathogen.