Researchers have long thought that fleas on rats spread the Black Death during medieval times, but a new study suggests it was, instead, fleas and lice on people that transmitted the plague.FLICKR, BAYER CROPSCIENCE UKRats may have gotten a bad rap when it comes to the plague. It was fleas and lice on people, not rats, that spread the disease between the 14th and 19th centuries in Europe, according to a study published today (January 16) in PNAS.
The rodents have long been blamed for spreading the plague, which is caused by the bacterium Yersinia pestis. Researchers thought the bacterium would infect fleas on rats, and when the rats died, the fleas would jump to humans, infecting them. Rats are also thought to be responsible for spreading more recent cases of plague, including the outbreak in Madagascar in 2017.
But the long-held theory that rats spread the plague during the Second Pandemic in the 14th to 19th centuries had a problem—the disease did not spread quickly enough. This discrepancy spurred Katharine Dean, an ecologist at the University of Oslo, and her colleagues to study the patterns of how disease moves through a population. “The plague really transformed human history, so it’s really important ...
