How much of Taino depopulation was the result of disease?

By Lindsay Keegan, Betsy Carlson, Michael Pateman and Bill Keegan

Today’s “Talking Taíno” is brought to you by the letters R and N. First R—not the pirate’s favorite letter (which actually is the C)—but R0 (“R naught”), the mathematical term that indicates how contagious an infectious disease is. We invited Lindsay to join us because she wrote her dissertation on R0, and has spent her young career modeling infectious disease transmission, including COVID-19, malaria and zika. The arrival of vaccines will help us to “turn the corner,” but unfortunately, we’re still a long way from the end of the coronavirus pandemic.

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The epidemiologists had warned us. The virologists told us it was lethal, and we had no immunity. The modelers predicted dire consequences. Front-line doctors and nurses showed us overflowing hospital wards; refrigerator trucks were parked out back. And Johns Hopkins kept count: 2,000,000+ deaths worldwide. How could we let this happen? Especially since this isn’t our first rodeo. In fact, the first pandemic in the Americas may date to the arrival of Christopher Columbus. More about Columbus in a bit, but first back to R0.

The density of a population is key to the speed of disease spread. R0 describes that spread if everyone is immunologically naïve (totally susceptible) in the absence of interventions (such as social distancing or mask use). In a nutshell, R0 is the average number of individuals that a contagious individual will infect. Granted, not everyone who is contagious will infect someone else, but there are individuals whose physical response (excessive shedding of the virus) or personal actions (ignoring sanitary behavior) are “superspreaders,” who infect far more than their allotted R0.

For COVID-19, the current pandemic apparently began in Wuhan, China in December 2019 and first appeared in New York in early 2020. Epidemiologists estimate the R0 for the original SARS-CoV-2 virus ranges from 2 to 3 (meaning one individual will infect two to three other individuals). In comparison, the new variants that have emerged recently are 60% more contagious (R0 = 3.2–4.8). Smallpox is estimated to have an R0 = 3.5–6, which means it is 1.75–2 times more infectious than COVID-19 has been. Pandemic influenza, including the 1918 “Spanish flu” (R0 = 1.8–3.6) is on par with COVID-19, while seasonal flu is considerably lower (R0 = 1.2–1.4). In gallows humor, diseases spread because of density and density: Population density—in particular how spatially clustered susceptible people are and the “dense-ity” of the population—or how much they bury their heads in the sand in response to disease.

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This vintage etching depicts the landing of Christopher Columbus.

Back to Columbus, and the phenomenon known as the Columbian Exchange—the transfer of plants, animals, people (and diseases) between the Old and New Worlds. In historian Alfred Crosby’s study of the Exchange, he gave the name “virgin soil epidemics” to diseases in which a population had no previous contact and are therefore immunologically defenseless. In this regard, the politics of disease, what David Jones has called “rationalizing epidemics,” has been used both to blame the source (“China virus”) and absolve those who transmit the disease by blaming the victim (in this case the Native peoples of the Americas) for lacking immunity and being genetically naïve.

By this logic the fault did not lie with the Spanish and other Europeans who came to the New World, even though it was Old World diseases that caused the demise of Indigenous societies. Indeed, accounts from the British settlement of New England in the mid-1600s clearly describe the horrific impact of European diseases, especially smallpox, which decimated the Narragansett, Massachusett, Wapanoag and other Indigenous communities. The colonists’ sentiment was, “God hathe consumed the natives with miraculous plague,” and “cleared our title” to New England.

It is surprising that there are no similar descriptions of Taíno mortality during the initial Spanish invasion. Why not? Were pathogens, unwittingly transmitted by the Spanish invaders, responsible for the rapid collapse of Taíno society? Conversely, did pathogens transmitted by the Taíno cause the death of numerous Spaniards in the early years of Spanish settlement in the Caribbean? To find the answers, we need to examine the different potential diagnoses of the Columbian Exchange with respect to disease symptoms and etiology.

The Columbian Exchange went both ways and sometimes it was the colonizers who got sick. Historically, little attention has been paid to dead Colonial Spaniards, yet die they did and at alarming rates. Within a week of landing at La Isabela, the first Spanish settlement in the New World established on the north coast of the Dominican Republic in 1493, at least one-third of the 1,200 men Columbus brought with him on his second voyage fell sick, half were incapacitated soon after, and an unspecified number died. When newly appointed Governor Nicolas Ovando replaced Columbus in Hispaniola in 1502, the 1,000 men he brought with him fell sick and the majority died. Bartolomé de las Casas (the principal eyewitness chronicler) blamed a new disease—syphilis—but syphilis does not kill quickly, taking on average of 10–30 years from exposure to death. The culprit was certainly not syphilis.

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Fever was the only symptom mentioned at the time. Illness was attributed to the change of climate, diet and hard work; but since more than eleven weeks had passed since they left the Canary Islands, scurvy could be implicated. Scurvy is a debilitating disease caused by a lack of vitamin C in the diet; symptoms can appear in as little as a month and left untreated it can quickly lead to death from infection or bleeding. Or maybe the illness afflicting the Spaniards was an indigenous form of malaria?

Another possibility is a type of influenza that starts in pigs (H1N1). Pigs were first brought to the Americas on Columbus’s second voyage. The close association of pigs and humans in confined ship spaces could implicate “swine flu” as an epidemic agent. (The transmission of disease from infected animals to humans is called “zoonotic spillover.”) It is possible that the Spaniards who died at La Isabela succumbed to the flu, perhaps even a variant of swine flu, which they could have introduced to Hispaniola as early as 1493. We may never know which diseases were introduced by the Spanish, although recent advances in ancient DNA research have identified the genetic signatures of some diseases in human skeletons.

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This illustrated panel depicts a Mesoamerican infected with smallpox.

In recent centuries, modern Indigenous communities in tropical South America have suffered the highest mortality (circa 25%) from measles, malaria and influenza epidemics. However, the first reported case of measles in the Americas dates to 1765, so measles is an unlikely candidate for a late 15th century epidemic. Less virulent strains of malaria were present in the pre-Colonial Americas. If present in the Caribbean, then the Taíno may have developed some level of immunity.

People who live in highly endemic malaria settings develop immunity to symptoms by puberty. Its main symptom is “cyclical” fevers, where the fevers rise and fall as parasites move between the liver and the blood stream to reproduce. This would explain how malaria might have had a greater impact on Spanish health and potentially deaths. Nevertheless, the most deadly malarial parasite (Plasmodium falciparum) was first transported to the Americas with enslaved Africans beginning in the mid-1500s. Here again, malaria is not a good candidate for an earlier epidemic among the Taínos.

Influenza virus, a pathogen with known pandemic potential, was possibly introduced in the early years of Spanish contact. However, the first reliable report of influenza involved transmission from Africa to Europe in 1510, and flu does not spread very well in equatorial regions. We now know that influenza is particularly good at “escaping” our immune system through frequent viral evolution of the part of the virus that interacts with our immune system. Despite recent claims to the contrary, flu is a deadly disease that is today held in check by vaccines, therapies and other medical interventions. In addition, mask wearing and social distancing during the current COVID-19 crisis contributed to a significant decline in influenza and other respiratory infections and deaths this year.

The most stunning example of a deadly flu is the “Great Influenza” of 1918. It occurred before a viral agent had been identified and spurred remarkable scientific efforts to develop a vaccine. Our modern Public Health Service was created to counter its spread. John Barry described how the initial outbreak in an army camp in Kansas blossomed into a global pandemic that killed as many as 100 million people worldwide. Although commonly known as the “Spanish flu,” it did not originate there. Rather, Spain had the only press in which the epidemic was accurately reported. In the United States, where the virus originated, press coverage was tightly restricted at the height of World War I. The first victim in the politics of disease was any “real news” coverage of this pandemic.

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We have saved the most deadly virgin soil pathogen for last: smallpox. Smallpox is estimated to have killed around 500 million people worldwide in the last century alone. Although “completely eradicated” in 1980, it has recently reappeared in some rare cases. With distinctive symptoms (red pustules or “pox”), it is rather unlikely to be misidentified even by non-medical personnel. The first smallpox pandemic in the Americas began in 1517, so it could not have been responsible for initial high mortality among the Taínos. Nevertheless, it was the final nail in their coffin. A recorded Taíno population of 28,000 in 1514 was reduced to only 250 by 1540.

In the British colonies of North America, smallpox is infamous as the first biological weapon, with British colonists infecting local Natives and American soldiers reportedly distributing infected blankets out west. The disease ravaged Native communities in the United States until the 1880s, long after an effective vaccine had become available. In fact, attention to smallpox waned only after it was superseded by tuberculosis as the principal scourge of Native Americans.

The histories of those lethal diseases (smallpox 1517, malaria 1550, measles 1765) show that they could not have been responsible for a virgin soil epidemic during the first decades of European contact. This leaves influenza as the last remaining candidate, but the evidence is not conclusive.

We’ll close this essay with the letter N, a mathematical notation used to indicate the size of a population. Columbus’s brother Bartholomew supposedly counted a Taíno population of 1,100,000 in 1494. Often repeated in 16th century accounts, Las Casas eventually decided that the N was too small for the purposes of his polemic against the mistreatment of the Natives. Within 30 years he first tripled and then quadrupled the N to 4 million souls. Although the numbers were obviously inflated to serve a “moral” agenda, historians felt a need to explain the rapid demise of thriving Caribbean societies, and they did so by proposing virgin soil epidemics caused by Old World diseases.

Bottom line: It is unlikely that disease was the major factor in the depopulation of Hispaniola and demise of the Taínos at the dawn of the 16th century.

In a future essay we’ll explore exciting new genetics research that could dramatically improve our ability to calculate past population numbers. By knowing how many people were susceptible, we can better appreciate the historical impacts of infectious diseases. There is still a lot to be learned about the letters R and N. In the meantime, wear a mask, wash your hands, socially distance and get vaccinated.

Dr. Lindsay Keegan is Research Assistant Professor in the Division of Epidemiology (University of Utah); Dr. Betsy Carlson is Senior Archaeologist at Southeastern Archaeological Research (SEARCH, Inc.) in Jonesville, FL; Dr. Michael Pateman is former Director of the Turks & Caicos National Museum and currently Curator/Lab Director of the AEX Maritime Museum on Grand Bahama; and Dr. Bill Keegan is Curator of Caribbean Archaeology at the Florida Museum of Natural History (University of Florida).