The history of human civilization is riddled with course-changing epochs in world history related to the transmission of pathogenic microorganisms such as bacteria and viruses. I learned that important concept in evolutionary medicine when I studied evolutionary biology as a graduate student. Not only did we study the history of evolutionary theory, evidence for evolution, the origin of life, the origins of animals and the Cambrian explosion, genetic evolution, molecular phylogeny versus morphological phylogeny, genetic evolution, natural selection vs sexual selection, microevolution vs macroevolution, species and speciation, and human evolution but we also explored some of the most important evolutionary issues in modern medicine. We learned how medicine is, in fact a form of applied evolution, and the vulnerabilities of human body from an evolutionary perspective, considering disorders ranging from cancer, autoimmune disorders and allergies. We also explored how quickly pathogenic microorganisms can replicate inside and how they can be transmitted from one host to another by studying the evolution of virulence such as the ever-evolving seasonal flu that rapidly evolves each year, and processes such as viral reassortment that give rise to new genotypes. Such is the case with the 1918-1919 influenza that killed at least 50 million people worldwide. Evolutionary biology helps explain why it was so virulent and how scientists can prepare for new pandemics. As people became very mobile, their pathogenic microorganisms have gone along for a ride. Pulitzer Prize-winning author Jared Diamond leaves space for the microbes that swept the Aztec empire at the beginning of the 16th century in his seminal book, Guns, Germs, and Steel:
The importance of lethal microbes in human history is well illustrated by Europeans’ conquest and depopulation of the New World. Far more Native Americans died in bed from Eurasian germs than on the battlefield from European guns and swords. Those germs undermined Indian resistance by killing most Indians and their leaders and by sapping the survivors’ morale. For instance, in 1519 Hernán Cortés landed on the coast of Mexico with 600 Spaniards, to conquer the fiercely militaristic Aztec Empire with a population of many millions… What gave the Spaniards a decisive military advantage was smallpox, which reached Mexico in 1520 with one infected slave arriving from Spanish Cuba. The resulting epidemic proceeded to kill nearly half of the Aztecs, including Emperor Cuitláhuac. Aztec survivors were demoralized by the mysterious illness that killed Indians and spared Spaniards, as if advertising Spaniards’ invincibility. By 1618, Mexico’s initial population of about 20 million had plummeted to about 1.6 million people.
Mr. Diamond also makes a compelling case for the powerful influence of geography and environment in world history. According to him, many discoveries and scientific breakthroughs helped transform kingdoms in western Europe into empires that spanned the globe at the beginning of the 16th century. Some Europeans ventured to distant countries to spread their faith or gain religious freedom, but most went in search for metals and other commodities that would enrich their lives and the monarchs they served. Conquistadores from Spain who ventured to the New World made Spain the world’s largest and richest empire in the 16th century. He also explained that, when conquistadores like Hernán Cortés and Francisco Pizarro arrived in the New World, they brought with them new diseases such as measles and smallpox that were deadlier than their weapons. Their movements have brought diseases to people who were never exposed to them before. In some cases, the encounter has been devastating (Diamond, 1997).
We also learned in our class that, for many centuries, these devastating pathogenic microorganisms and their human hosts in Europe had been in a coevolutionary arms race. As a result, Europeans had some resistance to the disease. But when these pathogens arrived in the New World, they began to infect human populations whose immune systems had not been part of the arms race. Native Americans had no acquired immunity to diseases colonizers introduced, and no horses, firearms, or swords to thwart the invaders. The impact of Europeans on the natives was devastating. They wiped out an estimated 90 percent of the residents of North and South America in the first few decades after first contact with Europeans. If not for the coevolution of humans and pathogens, world history would have taken a different path.
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The Perfect Storm
Four hundred years after Hernán Cortés landed on the coast of Mexico and brought their pathogens for the ride, another virus killed more people than any outbreak of disease in human history that originated from Haskell County, an isolated and sparsely populated county in Kansas, USA. In Collapse: How Societies Choose to Fail or Succeed, Jared Diamond’s 2005 sequel to Guns, Germs, and Steel, he explores several cases to explain the complex interplay of different factors that affect historical outcomes, including environment and government policies, the role of the mass media and intelligentsia, political leadership, etc. The unprecedented fury of the First World War that convulsed the world is an eloquent example of Mr. Diamond’s broader approach to his wide-ranging research.
Every history buff knows that the First World War originated in the Balkans, where the assassination of Austrian Archduke Franz Ferdinand in 1914 by Gavrilo Princip, a 19-year-old Serbian nationalist, caused conflict between Austria-Hungary and Russia, two troubled empire with powerful allies. The conflict pitted the Central Powers against the Allied Powers. When war broke out in 1914, Americans opposed the involvement of US troops, and President Woodrow Wilson declared the country’s neutrality. Whether the sinking of the passenger ship SS Lusitania or the interception of the United States of the “Zimmerman Note” had triggered a cascade of events that led to the United States to join the war, the Congress and President Wilson had to mobilize quickly to rally the soldiers and the citizens behind their war effort with the help of the mass media and the intelligentsia.
In Media Control –The Spectacular Achievements of Propaganda, Noam Chomsky explained that the Wilson administration had to do something about it. When they established the Creel Commission (named after the former Denver Post columnist George Creel, a muckraker who spearheaded the first modern-day propaganda of the Wilson administration) in 1917, he was able to “turn a pacifist population into a war-mongering population.” Among those who participated actively and enthusiastically, Chomsky continues, were the progressive intellectuals, people of the John Dewey circle, who took great pride in having shown that what they called “more intelligent members of the community” namely themselves, were able to drive a reluctant population into a war by terrifying them and eliciting jingoist fanaticism. In Intellectuals and Society, Thomas Sowell describes the propaganda techniques used by these members of the intelligentsia. He contends that the Committee on Public Information, aptly described as “the West’s first modern ministry of propaganda” was created and run by Progressive George Creel, who took it as his mission to turn public opinion into “one white-hot mass” of support for the war, in the name of “100% Americanism,“ with anyone who “refuses to back the President in this crisis” being branded “worse than a traitor.” And, he continues, “while the public was being propagandized on a mass scale – by tens of millions of pamphlets and with ‘war studies’ created in high school and colleges, for example – a Sedition Act was passed which forbade ‘uttering, writing, printing, or publishing any disloyal, profane, scurrilous, or abusive language about the United States government and the military.’”
These factors as well as the unprecedented world travel enabled the explosion and created a perfect storm scenario that enabled the spread of a deadly influenza strain.
How did the flu from Kansas spread across the world?
The “Spanish flu” of 1918-1919, which caused tens of million deaths worldwide, is a misnomer because the outbreak had originated in the United States during World War 1. Countries involved during World War 1 suppressed their press and withheld information from their citizens except Spain. When their king, Alphonse X111, fell ill because of the flu, the pandemic that swept across the world became known as the ‘Spanish Flu.’ However, different epidemiological studies have identified Camp Funston in Kansas as the origin of the influenza outbreak. As the story goes, sometime in 1918, a prominent doctor named Loring Miner started observing an especially severe flu that cropped up among his patients in rural Haskell County, Kansas (Barry, 2005). Miner had seen influenza before, and he knew it well, but this was different and he was shocked by what he saw (Zimmer, 2013):
This virus ravaged his patient’s bodies fast, and it killed, sometimes within a single day. An unusually virulent strain had evolved and begun to spread within the local community. Normally, this kind of outbreak would not get far before disappearing. By killing its hosts too fast, it should have driven itself extinct. But his particular virulent strain did not die out. That’s because America was going to war. The same week that Loring Minor’s patients fell ill, two recruits named Ernest Elliott and Dean Nilson took the train Haskell County to Camp Funston, the second largest training camp in the country. Within a month, thousands of soldiers were hospitalized with the flu and thousands more were treated at infirmaries throughout the base. All the while, troops were being shipped between camps, and from the camps to the European front. Two weeks after that, influenza outbreaks hit other training camps. By that point, the virus had spread with American troops to the trenches; from there it swept across Europe and then China, to New Zealand and Australia, and back again to the United States. As many as 100 million people would die before the 1918 flu pandemic came to an end.
But how did this strain evolve to be so deadly? Wartime conditions changed the nature of selection acting on the influenza virus, permitting the evolution and spread of an extraordinarily deadly strain. Because it was wartime, troops were moving on overcrowded ships to filthy battlefields. Furthermore, President Woodrow Wilson strictly enforced the newly enacted “Sedition Act” that prohibited any news considered “unfavorable to the war effort of the US government and the military.” Normally victims of an epidemic become bedridden in hospitals or home. As a result, they make relatively little contact with healthy people. But at the end of World War 1, wounded soldiers were being put on trains and ships, where they could infect other bedridden hosts (Zimmer, 2013). The viruses could replicate faster because they didn’t have to travel far to infect someone else. If not for the participation of the United States in World War I, the virus would not evolve and become more virulent and the world history would have taken a different path.
How the COVID-19 fares against the world’s deadliest pandemics in history
Too many political pundits, social media influencers, TV host analysts, pseudo- intellectual obscurantists, journalists and modern-day Cassandras surrender to the cognitive bias of assessing the world through memes, anecdotes and images rather than statistical analysis, data and facts when it comes to disseminating information about the COVID-19. The contagion of fear and panic they spread is more virulent that the contagion of virus itself. Fortunately, the virus turned out not to be like the 1918 pandemic because it was relatively mild in terms of virulence and fatality rate. Still, that was little comfort to the families of the estimated 278,000 people (as of March 21, 2020) who have contracted the virus and at least 11,570 who died of the strain, according to a tally by Johns Hopkins University. However, one of the characteristics of viruses is its ability to mutate at a high rate and change the nature of selection, permitting the evolution and spread of an extraordinarily deadly strain from human to human.
For example, subsequent pandemics have evolved every few decades after the reassortment (blending) of the 1918 flu virus such as the “Asian flu” of 1957-58 that killed 1.5 million people and the “Hongkong flu” of 1968-69 that killed 1 million people. These strains continue to circulate today but cause less mortality because human populations have developed immunity to them.
Nowadays, hundreds of thousands of people die each year in the United States alone from influenza but they don’t make worldwide headlines and create worldwide panic. However, the worldwide pandemic we have to worry more about and what experts really are afraid of is a new strain of flu that the human population has not been exposed to before, one that virtually everyone will not have any immunity against—one that scientists believe is worse than the 1918 influenza pandemic that killed tens of millions worldwide. Scientists recently discovered a triple assortant that mixed genes from classic swine flu with genes from bird viruses and human viruses. From our class, we also learned that even the most optimistic scenarios for how the next worldwide flu epidemic (pandemic) might proceed are grim. Experts believe that reassorted influenza virus can affect 20% of the world’s population, with close to 30 million people needing hospitalization, a quarter of whom will die. Pandemics result when a virus to which most people have no immunity, usually an avian strain, acquires the ability to transmit readily from animal to person, and then from person to person. This can happen by the virus mutating so that it can be passed between people, or it could exchange genes with a common human flu strain.
Case in point: In 2002, a mysterious new disease began to spread through China. At first, a Chinese farmer came to a hospital suffering from a high fever and died soon afterward. Other people from the same region of China began to develop the disease as well but didn’t reach the world’s attention until an American businessman flying back from China fell ill on a flight to Singapore and eventually died in Hanoi, Vietnam. The disease was given a new name: SARS or severe acute respiratory syndrome (Zimmer, 2013). The outbreak of SARS almost triggered a global recession. Fear of the virus caused serious financial damage to businesses. During the height of SARS, nobody was going to restaurants and people didn’t want to go shopping. Estimates of economic impact ranged from $40 billion or so. If you’re looking for the economic impact of the current global pandemic, you’re looking at an impact measured in the trillions of dollars. Experts now believe that the odds of a global recession are more likely to happen than it was a month or two ago when the COVID-19 swept across the world. What is scarier is that experts in epidemiology, public health and evolutionary biology had been warning us about a global pandemic for years and we paid a high price for not listening and heeding their advice.
Barry, J. (2005). The Great Influenza: The Story of the Deadliest Pandemic in History. New York: Penguin Publishing.
Diamond, J. (1997). Guns, Germs, and Steel: The Fates of Human Societies. New York: W.W. Norton.
Zimmer, C. and Emlen, D. J., (2013). Evolution: Making Sense of Life. Colorado: Roberts and Company Publishers, Inc.
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