New study finds plague may return

A new study recently gave researchers novel insight into the plague of Justinian and the Black Death and suggested the deadly disease may make another comeback in the present day.

The research was conducted by numerous researchers across multiple universities, including McMaster University, the University of Sydney and Northern Arizona University. Researchers discovered that the plague of Justinian and the Black Death, each of which killed millions of people in the span of a few years, were both caused by different strains of the same pathogen. The Justinian plague faded out on its own, while the Black Death re-emerged years later to kill more than 50 million people.

"The research is both fascinating and perplexing, it generates new questions which need to be explored, for example why did this pandemic, which killed somewhere between 50 and 100 million people die out?" Hendrik Poinar, the associate professor and director of the McMaster Ancient DNA Centre and an investigator with the Michael G. DeGroote Institute for Infectious Disease Research, said.

The study was recently published online in The Lancet Infectious Diseases journal. Researchers were able to study the ancient remains of two people that died from the Justinian Plague around 541 A.D. and complete a genome of the oldest Yersinia pestis, the bacterium which caused the plague. This was then compared to more than a hundred contemporary viral strains, which revealed the relation of this strain to that of the Black Death, which re-emerged 800 years after the Justinian Plague. Researchers also believe the third plague pandemic, which hit Hong Kong, was a likely descent of the Black Death, but were unable to complete a molecular clock.

"We know the bacterium Y. pestis has jumped from rodents into humans throughout history and rodent reservoirs of plague still exist today in many parts of the world," Associate Professor of the Center for microbial Genetics and Genomics at Northern Arizona University Dave Wagner said. "If the Justinian plague could erupt in the human population, cause a massive pandemic, and then die out, it suggest it could happen again. Fortunately we now have antibiotics that could be used to effectively treat plague, which lessens the chances of another large scale human pandemic."

Other questions were recently raised about the origins of the plague. New research points to the Justinian Y. pestis originating from Asia, not Africa, which could mean the Plague of Athens and the Antonine plague may be caused by a completely separate strain of Y. pestis.

Researchers are still unable to answer why the Justinian Plague suddenly died out during the sixth century after killing an estimated 30 to 50 million people, approximately half the world's population at the time.