A new study may change history--that is, black death may have not been caused by rats at all.
Many centuries ago, millions of people died from diseases that had no cure. Black death was one of the fearsome ones as it killed around 200 million people over a course of almost half a century.
The plague, or pandemic, was caused by a bacterium known as Yersinia pestis, which might have come from the fleas that then infested hundreds of rats from Asia. Subsequently the rats boarded the merchant ships traveling to Europe. From there, the fleas moved from the rats to humans, and as they say, the rest is history.
However, a new study conducted by a team from University of Oslo may change that part of history. According to their findings, we need to stop pointing our fingers on these rats but rather on another type of rodent: the gerbils.
Professor Nils Christian Stenseth and his team of researchers revisited the history of black death with the hope they can understand why it just kept on coming back.
By using Europe's tree-ring records covering more than 7,000 outbreaks, they discovered that there's no connection between the weather conditions and the rat infestation. For the transmission to occur, the weather during the times of the outbreak should be warm, most probably during the summer, and the precipitation wasn't severe.
Based on the weather conditions during the time, it looked like another type of rodent, the gerbil, was more likely to thrive. They mentioned that if the conditions were good for gerbil reproduction, it didn't take long before the plague appeared in Europe.
Before, scientists believed that the plague originated in the hot plains of Central Asia. The study concurred that the beginning was in Silk Road, a very famous trading route. During the peak of the plague, trading between the two continents via the Silk Road was vibrant.
Nevertheless, the team is going to put its theory to more tests, including comparing the bacterium DNA found in some of the skeletal remains of the patients.