The Guardian
In 1545 disaster struck Mexico’s Aztec nation when people started coming down with high fevers, headaches and bleeding from the eyes, mouth and nose. Death generally followed in three or four days. Within five years as many as 15 million people – an estimated 80% of the population – were wiped out in an epidemic the locals named “cocoliztli” meaning pestilence. Its cause has been questioned for nearly 500 years.