Disease and European Expansion to the Americas 

After Christopher Columbus landed in San Salvador in 1492, Europeans settled and eventually conquered the Americas. How did Europeans overwhelm an Indigenous population that scholars have estimated to be between 60 and 100 million? An essential factor involves the drastic population decrease of Native Americans over the following two centuries. The estimated numbers are staggering, ranging between 70 to 95%!

Scholars cite numerous reasons for this devastation, including superior European technology (e.g., weapons), brutal European tactics, and disease.  Of these factors, diseases carried by Europeans stand as the main culprit of the Native American decimation. Europeans also succumbed to illness but not nearly to the extent of the Indigenous population.

Why did the exchange of germs between Europeans and Native Americans lead to such lopsided results? What gave Europeans a more resilient immune system? To find answers, we need to venture back thousands of years.

Farming and Livestock. Scholars like Alfred Crosby and Jared Diamond argue that Europe’s biological advantage stemmed from the Agricultural Revolution that scholars estimate began c 8000 BC. This gradual transition from hunting and gathering to farming led to significant changes that would facilitate European expansion many centuries later.

Two overarching factors come into play. The first is the domestication of diverse animal species. Alfred Crosby points out that the Old World domesticated a wider range of animals than New World communities. Compare, he writes, “the American assemblage of livestock (dog, lamas, guinea pigs, and some fowl), with that of the Old World: (dogs, cats, cattle, horses, pigs, sheep, goat, reindeer, water buffalo, chickens, geese, ducks, horses and more.” (19)

Ancient Sumerians (c4500-1900BC), residing in the southern part of Mesopotamia, in the flatlands between the Tigris and Euphrates rivers (now south-central Iraq), stood as the eminent domesticators of animals in their time. Animal power allowed people to farm more land than human muscle could muster. Livestock provided a consistent food source – meat and milk – essential during poor cop seasons. Both factors yielded more food, more surplus and facilitated population growth.

More livestock also meant more interspecies exchange of a broader range of microbes. Animals and people died or became quite sick, but sustained contact gradually led to immunity to a comprehensive range of diseases. Smallpox, the flu, influenza, measles, and other ailments evolved from human and livestock interactions. Poxviruses, Crosby points out by way of example, “oscillated back and forth between humans and cattle to produce smallpox and cowpox.” (Crosby, 31) 

Population and “Crowd Disease” Secondly, higher and denser populations exacerbated this interplay of livestock and human. As technologies improved, more people (and animals) could live in smaller areas and encouraged greater microbial spread. The rise of cities further encouraged the spread of germs. More people breathe the same air, spend more time in proximity and are more likely to contact human waste and disease carriers like rodents and insects that thrived in dense human populations.

Of course, these increasingly immunized people from cities and large villages did not stay put. Sumerians and subsequent civilizations traded, travelled, moved, and fought battles and wars, leading to contact with other peoples, including hunter-gathers who lacked sophisticated immune systems. 

Centuries later, when Columbus reached the Americas, Europeans had developed an incredibly resilient immune system that could withstand the likes of smallpox, yellow fever, diphtheria, influenza, chickenpox, and a host of other diseases bred over centuries. Native Americans lacked the immune systems to cope with the microbial onslaught. American populations, new studies show, were higher and denser than previously assumed but still not comparable to European ones. As previously mentioned, a less diverse American livestock inventory meant a narrower field of microbial exchange.  

Disease alone did not decimate America’s Indigenous population, but it seems to be the main culprit. “Far more Americans died,” Jared Diamond writes, “in bed from European germs than on the battlefield from European guns and swords.” (201). Other factors certain exacerbated their impact. Thomas Benjamin points out that diseases “were accompanied and made more deadly by war, exploitation, slavery, and missionaries who brought dispersed people together in a large community.” (321). We must also note that diseases did not uniformly impact the Americas. Denser and higher populations saw higher mortalities. Some Native communities in the northern reaches of Canada did not feel the impact of Old World disease until the 19th and 20th centuries.    

Scholars still debate the topics such as population numbers and whether Europeans, at times, intentionally infected Native people. However, there is a growing consensus that Old World diseases led to the European conquest of the Americas more than any other factor. 


Columbian Exchange. Alfred Crosby coined this term to describe the transcontinental transport and exchange of plants, animals, and diseases. 

Crowd Disease. A disease that can only be exchanged from person to person and therefore thrive in crowded populations.

Influenza. Flu, contagious respiratory disease.

Measles. A viral disease marked by red spots on the skin.

Microbes. A microorganism. Often referring to bacterium causing disease.

Pathogen. An agent that causes disease.

Smallpox. Viral disease became more virulent during the Renaissance (coinciding with Columbus’s voyage to the Americas). Arguably the most devasting disease to Native Americans. 

Selected Bibliography.

Benjamin, Thomas. The Atlantic World: Europeans, Africans, Indians, and Their Shared History, 1400-1900. New York: Cambridge University Press, 2009.

Crawford, Dorothy H. Deadly Companions: How Microbes Shaped our History. Oxford: Oxford University Press, 2017.

Crosby, Alfred W. Ecological Imperialism: The Biological Expansion of Europe, 900-1900. New Edition. New York: Cambridge University Press, 2004.

Diamond, Jared. Guns, Germs, and Steel. The Fates of Human Societies. New York: W.W. Norton and Company, 2017.

Hopkins, Donald R.  The Greatest Killer: Smallpox in History. Chicago: University of Chicago Press, 2002.

Kiple, Kenneth F. ed. The Cambridge World History of Human Disease. Cambridge: Cambridge University Press, 1993.

Martin, Charles. A Short History of Disease: Plagues, Poxes and Civilizations. Harpenden, Herts: Pocket Essentials, 2015. 

Watts, Sheldon. Epidemics and History: Disease, Power, and Imperialism. New Haven: Yale University Press, 1997.

Germans and the Nazi Persecutions (1933-45): Coercion or Complicity?

Complicity. Partnership in a crime or wrongdoing.

Coercion. Persuade or restrain (an unwilling person) by force or threat of punishment.

Introduction. Adolf Hitler and the National Socialist Party gained power in 1933 and would govern Germany until the end of World War Two (1945). By 1934, his Nazi government had become a dictatorship, with Hitler as the Fuhrer. With bolstered state powers, they persecuted  “enemies of Germany,” such as Communist Party members, Social Democrats, and labour groups. Hitler also targeted those deemed unfit according to the Nazi racial hygiene agenda – people of colour, gypsies, criminals, the mentally and physically challenged and above all, Jews. The Nazis dismissed people from their jobs, confiscated property, locked people in prisons and concentration camps, sterilized the “unfit,” and executed millions. 

A Debate. How was it possible for the Nazis to persecute various groups – especially- Jews without significant resistance from German citizens? Many historians have addressed this question. Some scholars argue that German citizens complied with and supported and even initiated the persecution and slaughter of Jews and other groups. Others insist that most Germans disapproved of Nazi domestic persecution and terror but did not speak out for fear of Nazi retribution, including loss of property or career, imprisonment, and execution. 

Nazi Terror and Retribution. When Hitler and the National Socialist Party took power in 1933, they began centralizing control of Germany. According to Richard Evans, the main instrument of coercion was the law. The Nazis passed laws and decrees that broadened what constituted treason and people’s options for freedom of expression. For instance, it became legal to ridicule Hitler, to make derogatory remarks against the Nazi party, or to “discuss alternatives to the political status quo.” (Evans,101)  

Speaking out against Nazi policies or assisting the persecuted could result in severe retribution. In Why? Explaining the Holocaust (2017),  Peter Hayes points out that “overt assistance to Jews constituted sabotage punishable by death”  and cites the example of Nazi Anton Schmidt, who facilitated the escape of at least 100 Jews after witnessing the execution of Jewish infants. After being exposed, he was court-martialed and executed. (145-146).   

Surveillance and intimidation proved effective deterrents to dissent. The Nazi secret police (Gestapo) did not have many men at their disposal but still “infiltrated people’s lives – directly, indirectly and psychologically.”  (Childress, 319).   Gestapo agents performed late-night arrests and interrogations. Germans were encouraged to report transgressions of Nazi law by their peers, neighbours and even family. Those charged faced a dubious legal process through what Richard Evans describes as a “whole system of regional Special Courts, crowned by the National People’s Court, the Volkgerichlen, was created to implement these and similar laws. (Evans, 101)

These historians argue that the Nazis organized an effective program of intimidation and coercion that effectively discouraged Germans from resisting the Nazi racial hygiene program.  

Citizen Complicity. Other scholars believe such interpretations overstate the extent of Nazi control while neglecting the willingness of German citizens to facilitate and even initiate the persecutions. In Hitler’s Willing Executioners: Ordinary Germans and the Holocaust (1997), Daniel Goldhagen acknowledges Nazi government coercion but argues that the main driving force behind the Holocaust was deep-seated, specifically German antisemitism.  

Goldhagen relates a story about Captain Wolfgang Hoffman, “a zealous executioner of Jews” who led “ordinary men” to slaughter tens of thousands of Jews in Poland. (3). Hoffman, he points out, refused to sign a declaration that his group would not plunder and steal from the persecuted Jews. Why did he refuse? Hoffman took offence that he and the men under his charge would steal. Besides the irony that Hoffman enthusiastically killed people, Goldhagen points out that Hoffman was not punished for refusing a direct order. In order words, Hoffman had a choice. By extension, his persecution of Jews came not from fear of retribution but from personal conviction—a willing executioner. 

Goldhagen goes on to argue that historians have focused on the leaders of the Nazi regime while neglecting people like Hoffman who facilitated the execution not from fear of Nazi retribution but out of a conviction that stemmed from “a particular type of antisemitism that led them to conclude that the Jews ought to die.”

Goldhagen’s thesis hinges on pervasive  German-specific antisemitism – a point of controversy among historians.   In Hitler and the Holocaust (2001), Robert S. Wistrich argues that Goldhagen overstates the role of German eliminationist antisemitism in the Holocaust. Germans certainly facilitated the killings, but this didn’t stem from a longstanding eliminationist mindset in the mid 19th century. Before Hitler, Wistrich argues, “racist antisemitism had not made great inroads in Germany” and was “still a state based on the rule of law, where Jews achieved remarkable economic success, were well integrated into society, and enjoyed equal rights.” (4)  

Selective Nazi Terror. In Nazi Terror: The Gestapo, Jews and Ordinary Germans (1999), Eric Johnson agrees with Goldhagen that many ordinary Germans willingly facilitated terror campaigns, persecutions and genocide. He also acknowledges the role of Nazi coercion but disagrees with Evans on the extent of Nazi coercion. He argues that Hitler’s government did not terrorize most Germans but instead focused the terror against “enemies of the state” – especially Jews. Most German citizens were not directly impacted by Nazi terror and “enjoyed considerable space to vent their everyday frustration with Nazi policies and leaders without inordinate fear of arrest or prosecution. (19)

Richard Evans disagrees with Johnson’s presentation of selective Nazi coercion and persecution. Nazi violence focused more on particular groups but “operated across the board.”(199). In 1933-4, for instance, the Nazis targeted the political leaders of the Social Democratic and Communist parties, such as Social Democrat Johann Steller, who “was tortured to death. (93).   Together, Evans notes, “the Social Democrats and Communists had won 131 million votes in the Reichstag election of 1932.” (94). “Hardly,” he points out, “members of a despised minority of social outcasts.”(94)

Self Interest and Opportunism Another historian who does not see antisemitism as the main factor in Holocaust is Joseph D. Bendersky. In A Concise History of Nazi Germany (2014), Bendersky argues that “the Jewish question had not been important to most German” who were more concerned with “moral degeneracy, crime, political subversion, and public order.” (139). Accordingly, the persecution of Communists, sexual deviants, and violent criminals received public support. He places more weight on other factors, including economic self-interest and the “terror of the police state.” (141)  Regarding self-interest, Bendersky notes how although a “Large segment” of German were shocked by Nazi violence, many opportunistically filled the Jewish vacancies in various professions, civil service positions, and businesses as Nazis pushed Jews out of their jobs. “Profit at the expense of the Jews was a temptation too many could not resist.” (139). Like Evans and Hayes, he adds that the Nazi use of terror deterred resistance and many who persisted paid the price. “Countless individuals,” Bendersky writes, paid with their lives for speaking out or for attempting to save others from Nazi tyranny. (141)

Conclusion. The role of German citizens in Nazi persecution, and particularly the Holocaust, remains a contentious topic and one that scholars will grapple with for many years to come. Hitler’s Nazi regime indeed used terror and reward to encourage German complicity. Some Germans, of course, engaged in the persecutions of “German enemies” with horrific enthusiasm. The longstanding question remains. Which factored more, coercion or complicity?


Aly Gotz, Peter Chrousti and Christine Ross. Cleansing the Fatherland: Nazi Medicine and Racial Hygiene. Baltimore: Johns Hopkins University Press, 1994.

Barnet, Victoria J. Bystander: Conscience and Complicity During the Holocaust. Westport, CT: Praeger, 1999

Bendersky, Joseph W. A Concise History of Nazi Germany. New York: Rowman and Littlefield Publishers, Inc. 2014.

Benz, Wolfgang. A Concise History of the Third Reich. Berkeley: University of California Press, 2006

Bergen, Doris L.  Twisted Cross. The German Christian Movement in the Third Reich. Chapel Hill, 1996.

Childress, Thomas. The Third Reich. A History of Nazi Germany. New York: Simon Shuster, 2017.

Marc Dewey, Udo Schagen, Wolfgang U. Eckart & Eva Schoenenberger, “Ernst Ferdinand Sauerbruch and His Ambiguous Role in the Period of National Socialism”, in Annals of Surgery 244 (2006), pp. 315- 321.

Friedlander, Saul. Nazi Germany and the Jews, Vol. 1 The Years of Persecution, 1933-1939. New York: 1997.

Goldhagen, Daniel Jonah.  Hitler’s Willing Executioners. Ordinary Germans and the Holocaust. New York: Random House Inc., 1997.  

Hamerow, Theodore S. On the Road to the Wolf’s Lair. German Resistance to Hitler. London, 1999

Hayes, Peter. Why? Explaining the Holocaust. New York: W.W. Norton Inc. 2017.

Johnson, Eric A. Nazi Terror: The Gestapo, Jews, and Ordinary Germans. New York: Basic Books, 1999.

Lifton, Robert J. The Nazi Doctors: Medical Killing and the Psychology of Genocide. New York, 1986.

Kershaw, Ian. The Nazi Dictators: Problems and Perspectives of Interpretation. (London, 1993).

Proctor, Robert N. Racial Hygiene: Medicine Under the Nazis. Cambridge MA: Harvard University Press, 1998. 

Schmidt. U.H. Karl Brandt: The Nazi Doctor. New York: Continuum, 2007

Shirer, William. The Rise and Fall of the Third Reich. New York: Simon and Shuster, 1960.

Stern, Fritz. Five Germans I have Known. New York: Farar, Straus, and Giroux, 2006. 

Thomas, Gordon and Gary Lewis. Defying Hitler: The German Who Resisted Nazi Rule. New York: Random House, 2019. 

Wistrich, Robert S. Hitler and the Holocaust. London, The Orion Publishing Group, 2001. 

Wistrich, Robert. Who’s Who in Nazi Germany. London, 1995.