Medieval cities are full of rats and therefore full of fleas. These fleas can carry yersinia pestis, a bacteria believed to be one of the sources of the Black Death in the form of Bubonic plague Infections in the lung could cause pneumonic plague. Scientists still debate the source of the Black Death as the shear speed and scale of the devastation is difficult to attribute to Bubonic plague. Cutting edge investigations, including examinations of DNA in tooth pulp, continue.
What is plague? How many people died from the Black Death and the other plague pandemics? Learn about the bacterium behind the plague disease, how factors like trade and urbanization caused it to spread to every continent except Antarctica, and how three devastating pandemics helped shape modern medicine.