Mexico's Forgotten Plague: 15 Million Dead, 470-Year Mystery Solved in 2018

In 1545 and again in 1576, two waves of an unknown hemorrhagic disease swept central Mexico and killed five to 15 million people. The Aztecs called it cocoliztli, the Nahuatl word for plague. For 470 years, nobody knew what the pathogen was. In 2018, a Max Planck Institute team sequenced bacterial DNA from teeth in a colonial cemetery at Teposcolula-Yucundaa and identified Salmonella enterica serovar Paratyphi C, a strain of paratyphoid fever rare in modern populations. This episode walks through the outbreak, the colonial response, the Aztec descriptions, the salmonella biology, and the paleogenomics breakthrough. Episode eight of the 35-episode series Plagues: How Disease Changed History. Every episode covers the pathogen, the event, and the response. Watch the next video: Episode nine covers the Great Plague of London in 1665. Chapters: 0:00 Mexico, 1545: The Plague Without a Name 7:23 Cocoliztli in Nahuatl, Sahagun, and the Royal Physician 13:36 The Pathogen Mystery and the 2018 Paleogenomics Breakthrough 19:41 The Biology of Salmonella enterica Paratyphi C 25:43 The Colonial Response, the Ticitl, and a Failed Medicine 31:55 The Long Shadow: Demographic Collapse and the Lessons 40:01 Quiz Time 41:48 Key Takeaways #explained #learn #2026 --- Disclosure The avatars and voices in this video are AI-generated. All content -- research, scripts, lesson design, and the custom video engine -- is created by a CISSP, CISM, and PMP certified professional with a Master's in Project Management, a B.S. in Information Technology, and a Doctorate in Business Administration in progress. This channel exists to make learning accessible and straightforward. Educational history-of-medicine series. This channel does not represent any medical institution, public health agency, or academic institution. Every named pathogen, dated outbreak, death-toll estimate, and quoted statistic is sourced from peer-reviewed epidemiology, primary historical documents, and CDC / WHO records. Where death tolls or interpretations are contested by modern scholars, the range is presented honestly. This series presents the historical record — not medical advice. Always consult licensed medical professionals for health decisions.