The title of this 4-part course is “How Epidemics Have Shaped the World We Live In.” But our special emphasis will be on the history of epidemics in America.
Over the next 4 weeks, we will have the opportunity to spend a total of six hours together, not nearly enough time to cover the depth and breadth of this topic, but enough to whet your appetite for more, and provide good introduction to the topic and a sense of context.
In our introductory session today, we’ll dive into the historic relationship between “Germs, Conquest, and Warfare.” Epidemics, as we will see, have always been promoted by human behavior, confusion, movement, and misunderstanding. In session 2, we’ll have the opportunity to focus mainly on the 19th century, the emergence of the Sanitary Movement, scientific discover, and social reforms, all of which moderated the course of current and future disease patterns in human populations. Session 3 takes a different tact. Here we’ll explore four case studies of manmade epidemics, vast outbreaks of disease and mortality that were entirely preventable, if not for human avarice and greed. Finally, in Session 4, we’ll explore modern age epidemics, what can be done about them, and the conditions that suggest that microbial chaos is likely to be a constant at least for our immediate futures.
This course represents a single education offering of the Presidents College at the University of Hartford. As such, no recording of representations of any form are permitted. However, a text of this presentation, and those that follow, will be immediately available following each presentation, open source, at www.mikemagee.org under the “resource” navigation bar. So you are free to sit back and enjoy the presentation, knowing that everything I discuss is available in text .
In planning this course, I was acutely aware that the challenge was, as one historian has noted “to avoid an endless listing of repugnant and deadly microbes lined up with dates, mortality figures, and various elements of human mayhem.” To do so would not give the topic its due, would be unduly distressing and ultimately be of limited interest to most.
This is because each epidemic occurs in a specific time and place, engenders a human response that is both individual and societal, creates tension and drama, uncovers structural vulnerabilities, and often unleashes scapegoating and recrimination. In short, epidemics are “social, political, philosophical, medical and above all ecological.” They are also narratives – with a beginning, middle and end, and a range of heroes and villains, both human and microbial.
Over the next hour or so, we’ll meet many of these characters, visit their stories, reveal their unique histories, and draw a range of lessons – often unheeded by future generations.
Let’s begin here. In the late 19th century, orange growers in California reached industrial scale. But in 1888, little white cushions began to appear on the branches of their trees. Within them were tiny, sap-sucking insects that multiplied with alarming speed and damaged the trees production of fruit. The responsible “scale insect”, it was found, was a foreign invader that had arrived that year on a frigate from Australia.
In Australia, the scale insect fed primarily on the native acacia trees. Orange trees were infested as well, but rarely damaged. This was because the insects numbers were naturally controlled by a local orange beetle with black spots called the ladybird beetle. Nobel Laureate ecologist, Australian Macfarland Burnet in 1972 explained that “If the scale insect is particularly plentiful, the ladybird larvae find an abundant food supply, and the beetles in turn become more plentiful. An excessive number of ladybirds will so diminish the population of scale insects that there will be insufficient food for the next generation, and therefore fewer ladybirds.” In Australia, the scale insect and ladybird beetle were in perfect balance most of the time. A truce of ecological sorts had been established.
But in California, there were no ladybird beetles. And so the agricultural leaders in 1889 imported 514 beetles. Prodigious multipliers, they numbered 10,555 by the next year and were distributed to 208 growers. Once they reached adequate numbers in the orchards, the scale beetle “was reduced in importance to a relatively trivial pest.”
Simple, right? Well not exactly. As Burnet explained, “The mutual adjustment is an immensely complicated process, for all the food chains concerned are naturally interwoven, and for every species there will be fluctuations in numbers from time to time, but on the whole, in a constant environment a reasonable approach to a stable balance will be maintained.”
For predators of any shape or size (and that includes bacteria and viruses), “there is less opportunity for enemies…of restricted prey to thrive at their expense.” In the present case with Covid, vaccination, masking, and distancing, in effect, restrict us as potential prey to COVID-19.
Another point. Our ecologists remind us that “Most parasites are restricted to one host species (for their nutrition)…and the main problem that a parasitic species has to solve, if it is to survive, is to manage the transfer of its offspring from one individual host to another.” That often requires intermediate hosts “whose movement or activities will help the transfer to fresh, final hosts…an increased density of the susceptible population will facilitate its spread.”
So with that brief introduction, let us begin where most medical historians would on this topic – with “The Plague.” As Yale historian, Frank Snowden, wrote in his book, Epidemics and Society, “The word ‘plague’ will always be synonymous with ‘terror’.”
That terror played out in three successive waves that extended over Asia, Europe and North America spanning 1400 years. The first wave lasted just over 200 years from 541 to 755 AD, beginning in the Nile Delta. Title the Plague of Justinian after the Byzantine Emperor at the time, Justinian I (541-549 AD), the mysterious disorder took hold in the main port city of Constantinople and from there spread throughout the Mediterranean, top Europe and the Mid-East. The disaster was recorded at the time by court historian, Procopius, who recorded at the time that the Emperor himself had contracted the disease but had recovered completely by 542 AD.
Others were not so lucky. Unconfirmed death rates at the height of the crisis listed deaths per day in Constantinople at 5,000. The source of the disease, the bacterium Yersinia pests, carried by ship rats in vessels transporting grain to Constantinople, would not be uncovered for another millennium. What was suspected at the time was that the disaster traveled along both land and water trade routes, and was rampant in settings that involved filth and overcrowding. The catastrophic human event disrupted the power grab that was underway as Justinian I was just about to claim Rome as his prize, and unite his eastern and western holdings. That never occurred. Total mortality if widely disputed as being anywhere from 15 million to 100 million, and claiming anywhere from 25% to 60% of Europe’s entire human population.
In 2013, DNA studies of Yersinia pestis in human remains, traced the origins of the bacterium to Qinghai, China and the Tian Shan mountain range. It’s initial breakout was probably the result of infected flea infestation of nomadic peoples and their animals traveling along the Eurasian steppe in response to global warming induced food famine. This deadly exodus was magnified by flea carrying rats infesting large granaries and then traveling in transport ships to Constantinople and beyond.
The second major wave occurring from 1346 to 1353 appears to have been launched from Crimea, and was called the “Black Death”accompanied by massive lymph node swellings or “buboes” (thus the term Bubonic Plague) and blackening necrosis of de-vascularized digits. Considered to be the most deadly epidemic in human history, estimated deaths were anywhere from 75 to 200 million in Western Eurasia and North Africa with drops in the world population from 475 million to 350 million, requiring 200 years to recover pre-epidemic population levels.
Yersinia pestis bacterium was commonly present in the guts of the common human flea which in turn housed itself in the fur of ground rodents like rats and marmots. Famine sent the rats on the march, aided by shipping vessels along Mediterranean routes, which were not a barrier, but a highway for disease. The bacterium multiplied at breakneck sped in the fleas, blocking their guts, then forcing starvation on the little creatures, which made them voracious feeders, eventually biting and infecting humans.
Human complacency delayed a response. This is well displayed in Albert Camus’s classic book, The Plague. In it, Camus describes a chance early morning encountered with a brown rat, viewed by many of the time as pets. He writes, “When leaving his surgery on the morning of April 16, Dr. Bernard Rieux felt something soft under his foot. It was a dead rat lying in the middle of the landing. On the spur of the moment he kicked it to one side and, without giving it a further thought, continued on his way downstairs.”
As the crisis grew, local officials in Genoa knew it was “a portable something” that seemed to be timed with the arrival of trade ships in the port. The decision was made to hold arriving ships in port for 40 days to be sure that the ship mates were healthy. From the number 40 was derived the term “Quarantine.” As the crisis expanded, the infected were isolated in “pesthouses”, and safe routes, or “sanitary cordons” were identified and marked. Those felt to be immune were drummed into service to care for the ill and dispose of the dead. Masks were instituted as it began to be clear that transmission could occur by breath and droplets – thus the term “pneumonic plague.”
All of the above was only partially effective, as the plague travelled along the port system and made its way inland for roughly 500 years before yielding control to humans. The final major wave, termed the Modern Plague, began in central China in 1855, had a half century reign of terror attacking nodal cities worldwide killing 20 million global citizens, and especially ravaging London and its colonies in Hong Kong and India.The US was largely spared though 500 did die, mostly in Honolulu and San Francisco
And then, science caught up, in the form of a Pasteur protege, Alexandre Yersin, who visualized and describe his namesake bacterium, and its transport from rat and flea to human. His creation of an anti-serum lowered the mortality rate from 85% to 32%. Once modern antibiotics appeared in 1936, the mortality rate declined to below 10%. Since 1900, approximately 1000 have died in the U.S. of the disease.
As historian Charles Rosenberg observed, “most communities are slow to accept and acknowledge an epidemic. To some extent it is a failure of imagination; perhaps even more it is a threat to interests, to specific economic and institutional interests and, more generally, to the emotional assurance and complacency of ordinary men and women.”
Of course, microbes don’t necessarily play by our rules, and human knowledge can lag infectious catastrophic events by century. A case in point is the recent genomic studies of several hundred 1348 London and Danish victims of the Black Plague. What they discovered was that the presence of a single gene that encoded the protein ERAP2 (endoplasmic reticulum amino peptidase 2) offered a Darwinian natural selection advantage for locals of the time. This is because that protein’s function was to cleave and neutralize the impact of invading viruses and the Yersinia pests bacteria. As a result, modern day British citizens maintain the ERAP2 gene in exaggerated amounts.
On the one hand, that is “good news” because the modern day citizens ancestors were survivors. The “bad news” is that the presence of ERAP2 is also associated with abnormally high levels of autoimmune diseases like Crohn’s Disease, Rheumatoid Arthritis, and Lupus. This study then well illustrates that the line between infectious disease survival and destructive autoimmune chronic disease can be a troublesome human balancing act.
To site a modern example, a certain percentage of fully boosted and immunized Americans were able to be infected by the Omicron variant of Covid and remain asymptomatic carriers and spreaders, especially as they entered dense gatherings where they and unvaccinated and unmasked persons were present in crowds.
In the eyes of an ecologist, all living organisms are survivalists, and there is little difference (except in size) between a parasitic microorganism and a large predatory carnivore. They all need nourishment. As our experts write, whether the bite comes from inside or out, “It is just another method of obtaining food from the tissues of living animals.”
Our current national nemesis, the COVID-19 coronavirus is an organism that is “smaller and less highly differentiated than its host…and gains its nourishment at the expense of the host’s living substances.” Our vulnerability is a relatively recent phenomenon. Until late in the 15th century, the Americas were virgin territory when it came to widespread epidemics. Not so, of course, of Eurasia where humans, rats, fleas and plague bacteria traveled together along Mediterranean trade routes. Yersinia pestis and other bacteria and viruses were chronically embedded in a range of European domestic farm animals including horses, cows, pigs and goats.
We’ll come back to that story in a moment. But for now, let’s focus on a different trade route famously termed the “Columbian Exchange” by University of Texas historian, Alfred Crosby, in 2010. European monarchs in the 15th century supported oceanic exploration as an extension of their power bases. New trade routes and territories carried the promise of the “three G’s” – gold, glory and God. The monarchs, allied with merchants and explorers, and the Catholic Church, willingly opened their coffers seeing the potential to spread Christianity to new lands.
Technologic advances like the astrolabe, the magnetic compass and sea worthy vessels made these ventures still dangerous, but feasible. The death and destruction of the indigenous people followed close behind their arrival. As Alfred Crosby documented, “Indigenous peoples suffered from white brutality, alcoholism, the killing and driving off of game, and the expropriation of farmland, but all these together are insufficient to explain the degree of defeat. The crucial factor was not people, plants or animals, but germs.”
Consider Columbus’s arrival on the island of Hispaniola (now the Dominican Republic and Haiti) in 1492. Documents suggest he was greeted peacefully by the native Taino tribe which numbered some 60,000. By 1548, the numbers had plummeted with less than 500 of the indigenous tribe surviving. What had happened?
The arrival of Columbus and others, and their subsequent movement back and forth between the Old World and the New World led to an unprecedented exchange of plants, manufactured goods and raw materials, tools and technologies, ideas, and microbes.
In the pursuit of wealth, traders and merchants, with financial inducements by their governments, clear cut and developed large plantation farming of cash crops like sugar, tobacco and wheat for export. These crops demand huge workforces for planting and harvesting under brutal and dangerous conditions. The plan initially was to enslave the natives they encountered and maintain a system of forced labor. To assist the effort, they also imported large numbers of domesticated animals from Europe including horses, cows, pigs, goats and sheep. At the time, the only domestic animals on the island were llamas and alpaca.
But the animals carried with them a wide range of infectious diseases including smallpox, chickenpox, measles, mumps and typhus. Over hundreds of years, the Europeans had developed immunities to these diseases. But the native Americans were immunologically naïve. By some estimates, 90% of the indigenous population in South and North America perished. Beyond the human tragedy, their demise created an enormous shortage of labor on the plantations. The solution chosen by the English, Spanish, Portuguese and French conquerors was to begin large scale importation of African slaves.
As journalist Charles Mann outlined in his book “1493: Uncovering the world that Columbus created”, “The scale of the trade was staggering. Between 1492, when Columbus landed, and the early 1800s, more than 2 out of every 3 people who came to the Americas were enslaved Africans. At the time, this human wing of the Columbian Exchange was the biggest migration in history.” Over 10 million enslaved Africans overall were transported to America, with an additional 1.5 million dying in transit.
Warrior conquests and disease have been frequent traveling companions throughout history. In fact, microbes have repeatedly altered the course of human history. In 1789, a Caribbean colony, Saint-Domingue on the western side of the island of Hispaniola, was fast becoming an endless source of wealth for its French conquerors. The eastern portion of the island, current day Dominican Republic, had been awarded to the Spanish. But the French controlled Saint-Dominque (the future Haiti) with its newly established eight thousand plantations producing sugar, coffee, cotton, tobacco, indigo and cacao.
The vast majority of the indentured natives had already died from progressive waves of diseases arriving on the backs of European farm animals. Replacing them were huge numbers of African slaves. The year 1764 marked the importation of more than 10,000 African men, women and children. By 1787, this had grown to 40,000. By July 14,1789, when the French Revolution commenced with the Fall of the Bastille, the tiny island was the home to nearly 500,000 slaves compared to 700,000 in the whole of the United States. The brutal conditions ensured that the average lifespan for survivors of slave ship transport was approximately 5 years, requiring a constant resupply of enforced human labor. This also insured that the slaves never accepted their new lives, with constant uprisings, and deaths regularly exceeding births in the enslaved population.
The contrasts were stark. Historian Frank Snowden describes it this way: “It was said that an acre of land on a Saint-Domingue plantation yielded more wealth than an acre anywhere else on earth. At the same time, the same area enclosed what many regarded the highest concentration of human misery…Men and women who had recently arrived in chains did not regard slavery as natural or permanent.”
To create the plantations, forests had to be cleared which in turn destroyed the natural habitat of insect-devouring birds. The deforestation also created marshes, collections of still water and mounting silt, all of which supported explosive growth of insect populations – most notably the Aedes aegypti mosquito.
This mosquito is the vector of choice for the Flavivirus that causes Yellow Fever. A competitor, the Anopheles mosquito, transmits the protozoa, Plasmodium, that causes malaria. African slaves who had survived these endemic diseases in their homelands often arrived as carriers with the Flavivirus and Plasmodium in their blood.
By the end of the 18th century, revolution was in full swing in the future Haiti led by the dynamic Toussant Louverture, known popularly as “The Black Sparticus.” Out of the ashes of the French Revolution, Napoleon rose to power in a military takeover of the country. While waging war and skirmishes on his own continent, he watched the colonies closely, both as a source of fabulous wealth, but also with significant holdings in North America which included 828,000 squares miles, containing what would become the middle third of the United States. He saw in Louverture a direct competitor, and also a potential massive regional destabilizer. If slavery went down in Saint-Domingue, France’s slave colonies in Guadeloupe, Martinique, Reunion, and Guiana would also likely collapse.
With British and U.S. endorsement, Napoleon took action in 1801, deploying 30,000 soldiers and an armada of 65 ships to the region led by his brother-in-law, General Charles Leclerc. The arrival in February was met, at the direction of Louverture, by surprising non-engagement. The “Black Sparticus” was aware that his African former slaves were largely immune to Malaria and Yellow Fever, and that the Europeans were not. He therefore decided to wait for the summer insect infestation to decimate the French troops. The epidemic that engulfed them eventually killed over 50,000 soldiers, including Leclerc on November 2, 1802, from Yellow Fever.
The bad news didn’t stop there. Napoleon had harbored an interest in establishing a powerful French empire in the Americas. The loss of Saint-Domingue eliminated the forward base for staging additional North American conquests. In his eyes, these far away lands were now “indefensible liabilities.” In 1803, he sold it all – all 828,000 square miles – for $15 million dollars or 4 cents an acre. That land, which would eventually be segmented into 15 new states, was largely the property of native Americans. A study in the Journal of American History calculated the eventual real cost at $2.3 billion. It included “222 Indian cessions within the Louisiana Territory including treaties, agreements, and statutes between 1804 and 1970, …covering 576 million acres, ranging from a Quapaw tract the size of North Carolina sold in 1818 to a parcel smaller than Central Park seized from the Santee Sioux to build a dam in 1958.”
Apparently, Napoleon never fully absorbed the full meaning of this loss. As recounted in Leo Tolstoy’s epic novel, War & Peace, in 1812, at the age of 43, he ventured into the same territory with even more disastrous results. In deciding to venture 1500 miles to invade Russia, he was ambushed coming and going by microbes. On his tortured path to Moscow, he lost 1/3 of his army (120,000 men or 4000 each and every day) to epidemic dysentery caused by drinking water and food soiled with the Shigella bacteria.
If that wasn’t bad enough, in his winter-time retreat from Moscow, he lost most of the remaining troops to a different pathogen. This was not transmitted by human aerosol droplets or fecal contaminants, but by the bites of body lice clinging to the heavy garments that prevented the soldiers from freezing to death on their 83 day march home. The body louse, Pediculus humanus, was the primary carrier of the bacteria Rickettsia prowazekki, and feeds almost exclusively on human blood. While the bacteria’s name may not be familiar, the disease it causes is – Typhus. Over half of those infected died.
As historian Frank Snowden summarized, “Just as yellow fever in Saint-Domingue stopped the western expansion of Napoleon’s empire, so dysentery and typhus halted its advance to the east. Indeed, the two diseases played a major role in causing regime change in France. After the Russian fiasco, Napoleon was permanently weakened and never able again to construct an army of comparable power.”
In a remarkable short period, European aggressors manage to topple a wide range of rich governments, cultures and economies throughout the Americas. In 1519, only 27 years after the arrival of Columbus, the Aztec civilization was gone. It took 40 years of assault beginning in 1532 to eliminate the Inca Empire. In both cases, disease was the final determinant. A similar fate awaited North Americas native Americans, a story we will continue in our second session.
While Native Americans were especially vulnerable due to lack of immunity to microbes arriving with travelers from Europe, Europeans had their own vulnerabilities including lapses of immunity and knowledge. A prime example was Yellow Fever, caused by the transmission of a Flavivirus by the Aedes aegypti mosquito. African slaves, imported to work the Caribbean plantations, were largely immune to the African endemic disease. This made them effective asymptomatic carriers when they arrived at the insect plagued plantation fields. Products from those plantation were carried by ships to the major American cities, and along with the product came swarms of infected mosquitoes.
When Yellow Fever broke out shortly after the arrival of a trading ship from Saint-Dominque, in Philadelphia among colonists with no immunity in 1793, the main response was panic, fear, and mass evacuation from the city. 5000 citizens, roughly 10% of the population, fled including Alexander Hamilton and his wife. Experts were at a loss to explain the cause, and were even more confused how to treat the disease.
More on that next week.