Triggering plague bacteria identified

Researchers identified the causative bacteria of the plague

30/08/2011

The plague (Latin Pestis = plague) caught up in the Middle Ages about a third of the European population there and formed the most serious pandemic that has experienced humanity so far. Since then, the disease is also called „Black Death“ known and researchers worldwide are still looking for the trigger of the worldwide epidemic. Researchers from Canada and Germany have now been able to identify the plague pathogen.

Although the bacterium Yersinia pestis has long been considered a probable cause of the plague pandemic in the 14th century, but so far could no clear scientific evidence for the bacteria as the trigger of the „black death“ be provided. Researchers at the University of Tübingen and the Canadian McMaster University are now providing this in the current issue of the journal „Proceedings of the National Academy of Sciences“ (PNAS). In their study of 100 skeletons from a mass grave at a plague cemetery in London, the scientists genetically analyzed and searched for traces of the plague pathogens.

Genetics of the plague bacteria decoded
As part of their investigation, the researchers in the skeletons, the genetic material of the pathogen, which had led to the death of those affected, decode and then compare with the current form of bacteria. The result was clear: The bacterium Yersinia pestis, which is still widespread in various regions of the world today, was the cause of the plague pandemic in the 14th century, the scientists report. The assumption that the plague pandemic was possibly a disease similar to the Ebola fever had not been confirmed, according to researchers at the University of Tübingen. Genetic analysis provided a definitive answer, experts said. As the study author Johannes Krause of the University of Tübingen explained „no doubt“ Remember that the pandemic of „black death“ was triggered by the bacteria Yersinia pestis. Although today's Yersinia pestis bacteria are much more harmless than the pathogens of the Middle Ages, but the connection is clear. However, according to the experts, the original, considerably more aggressive form of bacteria no longer exists today. Although people are still getting infected with the pests, but the disease is much slower and far less deadly than in the plague pandemic in the Middle Ages. „This indicates that at least this part of the genetic information of the Pesterreeger has changed little in the last 600 years“, Prof. Dr. Johannes Krause from the University of Tübingen.

According to the World Health Organization, around 100 to 200 people still die every year from black plague. Every year up to 3000 cases are registered, whereby especially in the 3rd world the disease rate is higher. The dangerous germ infecting humans but also animals. The transmission takes place mainly fleas of rats.

Pest spread quickly
The „black death“, as the plague was then called by the people, was the largest pandemic in Europe so far and rampant between the years 1347 and 1353. According to scientific estimates, about 25 million people died as a result of infectious disease. According to previous findings, the pandemic began first in Asia and arrived after some time in Europe. Due to the proliferation of parts of whole areas were depopulated, while other areas were spared or were only partially affected. In the region of today's Germany, it is estimated that nearly one in ten people died as a result of the plague. The worst hit were cities like Cologne, Hamburg or Bremen. Due to poor hygiene and at that time high population density, the pathogen was able to spread quickly.

The plague is still a mystery to the researchers. For a long time, scientists had assumed that the plague pathogen was the bubonic plague. The name „black death“ This could be due to people suffering from internal bleeding on the skin after infection „black spots“ looked. Despite the research, it is still not entirely clear why the plague spread so rapidly in the Middle Ages, while today's plague pathogen can spread much slower, even if there is no medical care available. This must now be determined by further research. (Sb)

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Picture credits: Cornelia Menichelli
Image: Atlas of World History, Roger Zenner, Creative Commons by / sa / de