Perhaps Rats Didn’t Cause the Black Plague After All

For as long as most of us can even remember, the black plague has been blamed on rats. It was believed that they had spread the nasty parasites that carried the plague all through Asia and medieval Europe, and killed millions upon millions of unsuspecting people. Very recently there is a new perspective that has been brought on by an interesting new study. This study has approached the event by through modeling of historical outbreaks and indicates that these little rodents may not have been the cause at all.

New Studies are Saying Otherwise

The study was recently posted in the publication PNAS, is now pointing their bony fingers at the parasites carried by humans. Specifically, they are blaming parasites like body lice and fleas as the main carriers of the deadly plague bacteria throughout the Second Pandemic, which was a series of horrific outbreaks that occurred starting in the 1300s all the way to the early 1800s.

These particular outbreaks included that very well-known Black Death, which killed about a third of Europe’s entire population during the mid-1300s. It wound up with an incredible body count that was in the tens of millions.

“The plague really transformed human history, so it’s really important to understand how it was spreading and why it was spreading so fast,” stated lead author of the study named Katharine Dean. She is also a doctoral research fellow from the University of Oslo’s Centre for Ecological & Evolutionary Synthesis.

One Deadly Bite

Any time these nasty fleas that have been infected with the bacterium Yersinia pestis ever sink their teeth into human beings, the bacteria will often leap right into the bloodstream and collect in their lymph nodes, which are located all over the human body. The infection is known to make lymph nodes swell into terrible “buboes,” which has been the namesakes for the bubonic plague.

However, during the plagues occurring in the late 1800s—which includes the very recent outbreak that occurred in Madagascar during 2017—rats and other nasty old rodents assisted in spreads the disease. If Y. pestis ever infects a rat, the bacterium will easily get picked up by fleas who drink the blood of the rodents. Then after the plague-stricken rat kills over, the parasites that had been living off his body will abandon the rat’s corpse and find some poor human to bite.

Due to the role that rats have played in more modern plagues, and also due to genetic evidence that plague victims from medieval times died from Y. pestis, scientists believe that rats most likely did help spread the plague throughout the Second Pandemic.

There are some diehard historians out there who argue that this Black Death could have spread very differently. For starters, this Black Death ripped across Europe much faster than any of these modern plagues have. And also, rat deaths usually occur prior to modern outbreaks, but during the medieval plague, none of the records ever talk about rats dying off en masse.

“Geneticists and modern historians were putting the rat into the position [of spreading the plague] and were straining bits of evidence,” admits Samuel Cohn, a medieval historian from the University of Glasgow who fiercely criticizing the overall rat-flea theory.