When you buy through our articles links, Future and its syndication partners can earn commissions.
Artist Michel Serre’s view of the Great Marseille Plague in 1721. People have caught plague since the story began. | Credit: Getty Images
Scientists learned how one gene adaptations helped the plague survive for hundreds of years.
Responsible for The mortal pandemic in historythe bacterium causing plague, YersiniaUntil today, it existed in various ancient trunks.
Now scientists have revealed a genetic hint of how the infamous disease has survived for millennia, and over the centuries, outbreaks have been devastated. They published their findings on Thursday (May 29) in the magazine Science;
“This is one of the first studies to directly examine the ancient pathogen we still see today in an attempt to understand what promotes virulence [disease severity]perseverance and (or Hendrik PoinarDirector of Ancient DNA Center McMaster University in Ontaria, Canada, The report says;
Y. pestis Infected people From the story recorded; The most common form of the disease is known as “bubonic” and usually enters the body through bites of infected fleas, although humans may be less likely to catch it directly from infected animals, including rats and cats. When the body enters the body, the bacterium travels to the lymph nodes and replicates. Increased, it causes the formation of painful, pus filled “bubbles” for which the bourbon plague is named.
The plague bacterium can also cause blood infectioncalled the plague of septicemia and lung infection called pneumonic plague.
Related: Oregon 1, bubonic plague tray in 8 years linked to a patient’s domestic cat
The three major plague pandemics are one of the mortal outbreaks in the history of mankind. First pandemic, Justinian Maras (which occurred around 542 to 750) approximately 40% By the end of the sixth century.
The second and saddest outbreak of the disease was in the 14th century. Black death It devastated Europe and the Middle East. The only fatal pandemic was killed by about 25 million people in Europe alone in Europe, from 33% to 50% of its population.
The third, less well -known global plague pandemic began in 1855. In the province of China in the province of China and killed more than 12 million people in India and China. This pandemia was considered active until 1960, after which the death of the plague decreased to a lower level. The plague epidemic continues to this day and the Democratic Republic of Congo, Madagascar and Peru are the most endemic the parties, According to the World Health Organization;
In addition to the stunning calculations of the deaths associated with the pathogen Y. pestis is the longevity of his strains. Justinia’s plague bacteria strains took 300 years to disappear after the first time the outbreaks were recorded, and one of the two lines from the black death resulted in the waves of 500 years before its disappearance and the other became impact of all today’s strains.
To investigate the genetic set of tools Y. pestis to survive so long, researchers performed a plague gene known as Pla over hundreds of samples collected from ancient and modern victims of the disease.
PLA gene encodes an enzyme that helps Y. pestis Move through the body unnoticed by the host’s immune system. Previous studies show that PLA is a major factor that modulates both the mortality of a certain plague strain and its ability to cause human outbreaks. However, one strain of the plague may have a different number of PLA genes than the other, and it was not clear how the number of copies could affect their biology, the researchers noted.
To investigate, they have collected many modern strains Y. pestis from Vietnam, which included a variety of copies in its genomes; By wearing more copies of the gene, bacteria can pull out more copies of the enzyme. By injecting these different plague strains into mice, they found that strains with less PLA copies caused prolonged infections, but reduced the mortality rate of the disease by up to 20%.
Related stories
—Diagnostic dilemma: The scientist caught a plague from bacteria believed to be “non -infectious”
– Has bacteria or viruses or viruses or viruses in the ancient Egyptian mummy have been liberated today?
-Black Death survived persons were resistant to plague resistant to genes that may increase their offspring of autoimmune disease
During the ancient plague genomes, they analyzed, of which 20 dates back to the first plague pandemic and 94 of them from the second, the researchers noted the model when the plague strains lost their copies over time, specifically in the later stages of each pandemic. Among the modern genomes, they found three strains that hint that the same model is revealed today.
They have theoretical that this adaptation most likely caused infections to be less cruel or harmful to the host’s body over time. This indicates that the evolutionary change helped the disease to maintain their hosts – whether they are rats or human – alive longer, thus allowing it to spread more broadly. This adaptation may have been particularly necessary after the outbreaks have been massively killed by the mail host populations.
“PLA decrease can reflect the changing size and density of rodents and human populations,” the poinar said. “It is important to remember that the plague was an epidemic [flea-ridden] Rats that were epidemic and pandemic engines. People were random victims. “
Scientists say that further research on ancient and contemporary plague strains could reveal more extensions and help them better understand how such changes in the germ genome have formed its virulence through history.
These days, Y. pestis Infections can be cured with antibiotics, although some strains have The alarming signs are displayed out of Resistance to antibiotics; To give up the Superbug plague outbreak threat, UK scientists have already started Create a bubble plague vaccine Add to stock.
This article is only for information purposes and is not intended to offer medical advice.