Bubonic plague Highly dangerous bacteria much older than previously thought

Dangerous infectious disease: So far the oldest genome of bubonic plague decoded

The plague claimed millions of lives, especially in the Middle Ages. Even today, there are epidemics in many regions of the world again and again. The most common form of the plague is the bubonic plague. Researchers have now found that this infectious disease exists much longer than previously thought.

One of the most devastating epidemics in human history

The plague is one of the most devastating epidemics in human history. Especially in the Middle Ages, the "Black Death" claimed millions of lives. Even today, there are epidemics in many regions. The most common form of the plague is the bubonic plague. An international research team led by the Max Planck Institute for Human History in Jena has now found evidence that this infectious disease exists much longer than previously thought.

The plague caused by the bacterium Yersinia pestis has been the cause of some of the deadliest pandemics in human history. Researchers have now found evidence that the pathogen is much older than previously thought. (Image: royaltystockphoto / fotolia.com)

Birth of bubonic plague in the Bronze Age

As stated in a statement from the Max Planck Institute (MPI) for Human History, the researchers reconstructed two Yersinia pestis genomes that indicate a Bronze Age formation of bubonic plague.

According to information, the now identified strain was discovered in two skeletons from a double burial in the Samara region of present-day Russia. The funeral took place about 3,800 years ago.

He is the oldest known strain so far, which has the genes that are characteristic for the bubonic plague.

And according to the researchers, he is the ancestor of today's tribes, which caused the Justinian plague, the black death and the plague epidemics of the 19th century in China.

Cause of some of the deadliest pandemics

The plague caused by the bacterium Yersinia pestis has been the cause of some of the deadliest pandemics in human history, including the Justinian plague, the Black Death and the great epidemics that swept through China and later the rest of the world at the end of the 19th century.

The disease continues to threaten populations around the world, with Madagascar experiencing a plague epidemic last year, with several thousands of patients and numerous deaths.

Other countries were also affected in recent years. According to the World Health Organization (WHO), there were 3,248 cases worldwide from 2010 to 2015, including 584 deaths.

"The three most endemic countries are the Democratic Republic of the Congo, Madagascar and Peru," the organization reported last year on its website.

The origin and age of the disease has not been adequately researched

As the MPI writes, the origin and age of the disease, despite their historical and contemporary significance, are still poorly understood.

In particular, it is unclear when and where Yersinia pestis acquired the genes that allow the pathogen to use fleas as a carrier.

Recent studies of Yersinia pestis genomes of earlier eras have identified an extinct variant of the pathogen and dated to the late Neolithic and early Bronze Age.

However, its genomes do not have the genetic characteristics that make pest exciters particularly efficient - the ability to survive in fleas, which is the major transmission pathway of the disease to humans and other mammals.

The aim of the study now published in the journal "Nature Communications" was therefore to analyze further Yersinia pestis genomes from these epochs in order to find out when and where these crucial adjustments took place.

Probably 1,000 years older

Using data obtained from previous sequencing of Yersinia pestis strains, the team of scientists calculated the age of the newly identified lineage at approximately 4,000 years.

This shifts the presumed age of bubonic plague 1,000 years into the past.

"The line that produced our Yersinia pestis isolates probably originated about 4,000 years ago and had all the genetic properties necessary for the efficient transmission of plague to rodents, humans and other mammals," said lead author Maria Spyrou of the Max Planck Institute for human history.

Two pest lines could be circulating at the same time

Although previous studies have demonstrated a single line of Yersinia pestis throughout the Bronze Age throughout Eurasia, the current study suggests that at least two pest lines circulated simultaneously and that they may have different transmission and infection potentials.

"Whether the lineages in human populations were equally widespread and to what extent human activities contributed to their dissemination are issues that need to be further investigated," explains study leader Johannes Krause of the Max Planck Institute for the History of Humanity.

He adds, "Additional Bronze Age and Iron Age pest genomes could help identify key events that have contributed to the spread of one of humanity's most infamous pathogens." (Ad)