Mysterious Mexican Disease May Rewrite History of Spanish Conquest

My absolute favourite thing about being a history student is having my previous assumptions about historical narratives dashed. During my first year at Queen’s I quickly learned that what was deemed “fact” in my earlier education is actually just one of many historical narratives to consider – history isn’t as cut-and-dried as I had thought.

I learned this lesson very clearly in my class “The Atlantic World”, during our discussion of the Columbian Exchange – the transfer of ideas, people, plants, animals, and pathogens between the European settlers and the Native populations of the New World. While each of the transfers that occurred in this exchange is fascinating to study, the pathogen transfer generally receives the most attention. By 1600, the vast majority of the Native population in Mexico was decimated due to exposure to European diseases, most famously smallpox. The Natives had not had any exposure to these European diseases and, therefore, their bodies were not equipped to fight them.
Smallpox is almost always credited as the biggest, and sometimes the only, disease that wiped out the Native population; however, research published in 2006 suggests a possible unidentified and deadlier New World disease, the origins of which remain a mystery even today. 

Dr. Rodolfo Acuna-Soto, a Mexican historian, poured through old Spanish records detailing the events of the settlers’ arrival in New Spain, now Mexico, and the epidemics that followed. He noticed something odd; while the first epidemic of 1518 was described in the records using the Native word for smallpox, the disease responsible for the 1545 epidemic was given an entirely different name, cocoliztli. This led Acuna-Soto to suspect that the outbreaks of 1545 and 1576 featured an entirely different disease than that of 1518. Acuna-Soto also translated a text that was written by a Spaniard sent to the New World to record details of the epidemic for the Spanish King. This text detailed several major Mexican epidemics including the epidemic of 1545 that had wiped out 45% of the Native population. The disease was described as having very different symptoms than the full-body rash and pustules that are characteristic of smallpox. According to the text, the casualties of the epidemics of 1545 and 1576 bled from the ears and nose, went insane and died within a week, and when examined post-mortem were found to have blackened internal organs.

The story remains a mystery. Casualties were almost entirely Native youth. Critics question why the European population was not susceptible to cocoliztli if it was a Native disease to which the Europeans had no immunity. How could this disease have bypassed the Spanish population if it did not originate from Europe? Acuna-Soto’s theory is that the disease was carried by rodents who were numerous in the fields where Native youth worked. In discovering that huge rainfalls had hit in the years when cocoliztli broke out, he posited that this would have brought out rodents to the fields, infecting the Native population with the disease.

Medical historians today continue to discuss this mystery, and whether it may prove relevant in the future. If cocoliztli is indeed the largest perpetrator of the decimation of the Mexican Native population in the 1500s, we have identified a pathogen that came out of nowhere only to retreat to obscurity, that we know very little about, and that could very well come back again with unpredictable consequences.

If there is anything I have learned from my experiences working at the Museum of Health Care and as a history student it is that history is not static. Historians are constantly uncovering new evidence and reworking narratives. Counter-histories arise to challenge commonly held truths. History is an ever-changing subject– it is alive and very relevant. In the case of cocoliztli, we will have to wait and see precisely how relevant this alternate historical narrative will be.

Danielle Ruffolo is a fourth year History student at Queen’s University and the summer 2012 Public Program Assistant at the Museum of Health Care.

Acuna-Soto, Rodolfo, Stahle, David. W, et al. “Megadrought and Megadealth in 16th Century Mexico.” Emerging Infectious Diseases Historical Review 4, No. 8. (April 2002). 360- 362.

Chowdhury, Amitava. “The Columbian Exchange”. Lecture in The Atlantic World, offered by Queen’s University Department of History. Queen’s University. Kingston, ON. October 4th 2011.

Sturtz, Bruce. “Megadeath in Mexico”. Discovery Magazine. February 21 2006.

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