The Cocoliztli Epidemics

1545 and 1576 CE — Mesoamerica, New Spain

Today: Mexico

After smallpox came something worse. Two epidemics the Aztecs called cocoliztli — pestilence — killed perhaps 80% of the survivors of the conquest, with victims bleeding from the nose and eyes and dying within days. Spanish physicians had never seen it and neither had the Nahua. DNA recovered from teeth in a mass grave in 2018 pointed to a strain of salmonella, possibly introduced from Europe and possibly amplified by drought and the forced resettlement and labour the survivors were living under. Mexico's population fell from roughly 20 million to under 2 million within a century of contact.

Worth knowing: Nahua survivors kept records of it in their own language and pictographs, describing symptoms Spanish doctors could not name. The disease was identified 470 years later, from bacterial DNA in the teeth of the dead.

Pattern: Pandemic — A pathogen spreads through a population and reshapes its demography, economy, and beliefs at once.

Entry 158 of 240 in Precedent, a walk through the whole human story in order.