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Plagues, Pox and Pestilence: How pandemics have impacted human history

Updated: May 11, 2020

(Pieter Bruegel the Elder, Triumph of Death (detail), c. 1562, Museo del Prado, Madrid)

Plagues, pox and pestilence: How pandemics have impacted human history

The COVID 19 pandemic is something that most living human beings have not experienced—an infectious disease that has impacted all of us, in one way or another, causing death, debility and widespread economic damage. The latest estimates anticipate well over 100,000 deaths in the U.S. alone. The economic carnage will be the greatest we have seen in this country since the Great Depression.

Although this all may feel strange to most of us, and although the COVID 19 pandemic has interfered with our lives in profound ways, it’s not really an aberrancy when one takes the long-term view of human history. Humanity has dealt with pandemics since prehistoric times. The Bible makes numerous references to plagues and pestilence.

The problem now lies in the management of our expectations. Simply put, over the last century or so, medical science has advanced to the point where we expect a ready cure for everything.

It was not always this way. The history of healing is fraught with discredited pseudo-scientific gobbledygook such as trepanation, blood-letting and the sale of snake oil. That's why prior generations thought that plagues were divine punishment, or the result of magical spells. Human beings were often powerless to do anything to stop them.

But medical science has made great strides in the last century or so. Scientific advances in dealing with disease have given us therapies which are consistently effective, such as antibiotics, vaccination, surgery, endoscopy and advanced imaging. We can do genetic testing for hereditary conditions, transplant organs from one person to another, and can even perform surgery on children still in the womb. Human life expectancy at birth in 1900 was about 47 years of age. It is now 79 years. All of this gives us the collective delusion that we are somehow in control of nature, that we can simply wave our medical magic wands and make everything bad go away in an instant.

But we can’t.

The genesis of pandemics and plague has its roots in the explosion of the human population. The spread of Homo sapiens sapiens from our origins in Africa to span every continent on the globe has resulted in profound changes to our planet—and to us as a species. In many respects, we are now quite literally reaping what we have sown.

Historically, humans lived in small groups of related hunter-gatherers. We are genetically programmed to find whatever resources we need to survive. If resources became scarce in one area, we traveled, usually on foot, to find new places to colonize. Over time, we learned ways to be more efficient. We domesticated animals, began farming, and developed trade. Those things allowed us to become better at food production in one place. Exchange of goods and services between communities became more commonplace, which in turn allowed cities to develop. We came up with technology to allow us to better cope with the world around us, leading to profound leaps in technical expertise in agriculture, animal husbandry, travel and urban living. So we now have large-scale commercial farms producing fruits, vegetables and livestock, an increasing number of people living in cities, and ready travel of both people and goods across the globe.

But these things come with a price.

Crowded cities are incubators for the rapid spread of disease. Travel spreads pathogens to places where people have no immunity, allowing for rapid spread sometimes lethal diseases. Animal farms are breeding grounds for animal pathogens, which can sometimes be spread to humans. Diseases which spread from animals to humans are called zoonoses, and they are a problem for us because we have no immunity to them.

It has been estimated that 70% of the new infectious pathogens seen in humans are of zoonotic origin. SARS CoV-2, the virus which causes COVID 19, is a zoonosis. So are Ebola, HIV, influenza and numerous other plague/pandemic viral and bacterial pathogens. What we are seeing with the coronavirus pandemic is therefore something we have wrought by our own hand. It is not the first time this has happened, and it most certainly will not be the last.

Hopefully, we can learn from the mistakes of the past and be better prepared the next time. Because if history teaches us anything, it is that there will be a next time. It is inevitable.

When one looks back at history, one can see many examples of how plagues and pandemics have affected humanity—and, in many cases, have changed the course of human history. Here are a few of them.

The Athenian Plague

430 B.C.

A pandemic (the first in recorded history) characterized by fever, bloody throat and a reddish skin rash spread through Libya, Ethiopia and Egypt and hit the walled city of Athens during the Peloponnesian War, killing up to two-thirds of its inhabitants. Among those perishing in the plague was Pericles, the leader of Athens. Its leadership fragmented, the Athenians eventually lost the war, shifting the balance of power on the Greek peninsula from Athens to Sparta.

The Antonine Plague

165-180 A.D.

The Greek physician Galen described a disease which spread among Roman troops during the siege of Seleucia in 165-166 A.D. It was characterized by fever, diarrhea and a sore throat, as well as a pustular skin rash. Smallpox, or possibly measles, was felt to be the culprit. The total number of deaths is estimated at 5 million. The disease killed an estimated 10% of the Roman population at the time, infected about a third of the Roman army, and permanently crippled Roman maritime trade. Some have linked this plague to the eventual fall of the Roman Empire.

The Justinian Plague

541 A.D.

This plague, characterized by skin sores and pulmonary symptoms, began in Egypt before spreading through Palestine and the entire Mediterranean basin. Named after Emperor Justinian, the most powerful of the Byzantine Emperors (and the man who built the Hagia Sophia in what is now Istanbul), this was believed to be the first significant appearance of the bubonic plague, caused by a bacterium called Yersinia pestis, which was spread by the fleas on rats. It killed an estimated 25-50 million people (10-20% of the world’s population at the time) and dashed Justinian’s plans to bring the Roman Empire back together.

The Black Death

1346-1353 A.D.

The second large outbreak of the bubonic plague began in Asia, moving west in caravans before entering Europe through the port of Messina, in Sicily. It is estimated to have killed 75-200 million people, or up to half of Europe’s population at the time. The Black Death collapsed the feudal system by making cheap labor harder to find, resulting in the end of serfdom and the advent of better wages for workers—and, ultimately, to the rise of the Middle Class. In England, the Black Death so decimated the population that the nation did not return to its pre-plague levels for 400 years.

The Columbian Exchange Plagues


The arrival of the Spanish into the Caribbean heralded the introduction of such deadly diseases such as smallpox, measles, typhoid, cholera and bubonic plague to the natives of the Americas. Outbreaks resulting from these imported pathogens decimated Native American populations. It has been estimated that 56 million people died in this event, representing up to 90% of the Native American population at the time. The Aztec empire crumbled after 15 million people died in what has recently been identified as a salmonella epidemic (the Cocoliztli plague) in 1545-1550, which closely followed a smallpox outbreak that had killed 5 million Aztecs in 1520. Similar events played out all across the Americas. Hawaii's fate mirrored that of the Americas. There were virtually no viral or bacterial illnesses in the Hawaiian Islands before they were “discovered” by Captain James Cook in 1778. Ultimately, over 90% of the native Hawaiians perished of disease in the same manner as their North and South American counterparts. In May 1824, Hawaii’s King Kameameha II journeyed with his Queen, Kamamalu, to Britain to negotiate an alliance against the United States, who he correctly surmised harbored designs of conquest on his island nation. Unfortunately, both the King and Queen were dead of measles by June of that same year. The U.S. eventually annexed Hawaii in 1898.

Mosquito-borne pandemics


Before 1492, the Aedes aegypti mosquito did not live in the Americas. It came to the New World from West Africa as a hitchhiker on sailing ships, many of which were involved in the trans-Atlantic slave trade. This pesky little insect has a particular affinity for human blood, a trait which makes it an efficient spreader of human disease. Dengue fever, Zika and yellow fever are all mosquito-borne viral illnesses carried by Aedes aegypti. Anopheles, another mosquito species, acts as a similar fashion as the preferred insect carrier for malaria.

As a result of its propensity for carrying such diseases, the lowly mosquito has routinely thwarted the ambitions of empires. For example, malaria so weakened General Cornwallis’s troops during the latter part of the American Revolution that he blamed the disease for the British losing the pivotal battle of Yorktown. A 1793 yellow fever epidemic in Philadelphia (then the U.S. capital) killed 10% of the city’s population, forcing Thomas Jefferson and George Washington to flee the town. Yellow fever epidemics killed hundreds in Savannah in 1820, 1854 and 1876.

Dr. Carlos Finlay of Cuba first proposed in 1881 that the mosquito was the vector for yellow fever, a theory corroborated by subsequent research directed by Dr. Walter Reed of the U.S. Army. Mosquito-borne illnesses were finally brought under control in the early 1900’s after efforts at mosquito eradication were emphasized. The virtual elimination of yellow fever allowed the 1914 completion of the Panama Canal by the United States. The French had originally begun the canal in 1881 but had abandoned the project largely due to the deaths of over 22,000 workers from yellow fever and malaria.

The Cholera Pandemics


There were seven cholera pandemics in the 19th and 20th centuries. Caused by a bacterium called Vibrio cholerae, this illness resulted in a profound diarrheal illness which could dehydrate its victims in a matter of hours. The disease is spread by contaminated food and water.

The first three cholera pandemics originated in India between 1817 and 1860 and followed trade routes to other countries, killing over 15 million people. The next three, between 1865 and 1917, killed 23 million more. Improvements in water purification and sanitation systems have led to a decrease in cholera outbreaks since the early 1900’s, although the seventh cholera pandemic, associated with a new strain of Vibrio cholerae named El Tor, began in 1961. Sporadic outbreaks of this strain of the bacterium have since been reported in areas where food and water sanitation has been compromised, often in India or sub-Saharan Africa. An outbreak in Haiti and the neighboring Dominican Republic, which began in 2010, is still ongoing and has resulted in over 800,000 cases and 10,000 deaths.

The “Spanish” Flu


The worst influenza pandemic of the modern era, the 1918 flu came in two waves just as World War I was ending. Caused by a particularly virulent strain of the influenza virus called H1N1, it infected an estimated 500 million people worldwide, with upwards of 50 million deaths (an estimated 675,000 of whom were in the United States). This version of the flu was devastating, with young people and men being disproportionately affected. Some died within a matter of hours. In fact, more U.S. servicemen died from the flu than died in combat during the First World War.

Interestingly, the “Spanish flu” did not actually originate in Spain, which did not participate in World War I and was therefore merely the first to report it. The first recorded case of this flu outbreak was actually in Kansas.

The 1918 flu may have had an indirect and lasting impact on the rest of the 20th Century, as well. American President Woodrow Wilson was stricken by the flu at the Paris Peace Conference, the conference determining peace terms after World War I. Wilson and British Prime Minister David Lloyd George had been opposed to harsh German reparations after the war, but Wilson’s illness limited his effectiveness as a negotiator. At the urging of French Prime Minister Georges Clemenceau, crippling reparations were imposed on Germany after the war, as spelled out in the Treaty of Versailles. Afterwards, Prime Minister George said that the harsh postwar sanctions on Germany made another war with that nation “inevitable” within 20 years. He was, of course, correct.

There have been other flu pandemics since 1918, but none as severe. The 1957-58 influenza pandemic killed 2 million worldwide, including 70,000 in the U.S. The 1968-69 influenza pandemic killed 1 million worldwide, including 34,000 Americans.

The AIDS pandemic


Acquired Immune Deficiency Syndrome (AIDS), the illness caused by the retrovirus HIV-1, is estimated to currently infect about 38 million people worldwide. Most of the 2.6 million new cases per year are currently in Sub-Saharan Africa (61%). South Africa has the largest population of HIV-positive patients in the world, at about 7 million infected individuals. There are currently about 1 million HIV-infected people in the United States. The disease has killed over 30 million people since it was first described; annual deaths now number around 780,000 worldwide.

Once a veritable death sentence, the morbidity and mortality of AIDS have declined substantially since the illness was first described in 1981. After the HIV virus was identified as the culprit in 1983, anti-retroviral medical therapies were developed which have been quite successful in attenuating the virus’s effects.

It has been found that AIDS most likely originated in Kinshasa, in the Congo, around 1920, likely as a zoonotic infection from people hunting and eating chimpanzees carrying the genetically similar Simian Immunodeficiency Virus (SIV).

COVID 19: Where we stand today

As of this writing, there have been over 4 million cases of COVID 19 worldwide, with nearly 281,000 deaths. The United States is the runaway leader in both total case numbers (1,350,000) and deaths (over 80,000). We are still in the middle of this pandemic, so those numbers are both certain to increase, and likely substantially.

We are now in a phase where the relative benefits of economic “reopening” are being weighed against the associated risks. I wrote extensively about the delicate balance (the “Goldilocks phenomenon”) which must be struck here in this same blog last week.

One thing in this process is certain: As the world's economy is reopened, we must not abandon our vigilance in implementing the tools which we have successfully used so far to “flatten the curve” and decrease some of the stress of COVID 19 on our health care system. There is no vaccine for COVID 19 yet, and we may not have one for some time. We may therefore be living with the threat of this virus for months, and perhaps years. Nevertheless, I have seen some individuals blindly advocate simply “returning to normal,” as though nothing else needs to be done to combat the incredible public health threat posed by this virus. Others have even gone so far as to express their disdain for the social distancing and disinfection measures advocated by our nation’s health experts as a nefarious plot against America, or as a “hoax,” to use a term that is currently popular in social media circles. In so doing, they ignore the preponderance of data acquired about COVID 19 through thousands of peer-reviewed scientific studies.

Let me be very frank here: COVID 19 is not a hoax. It is just “just the flu.” Those individuals who refuse to acknowledge that fact and persist in engaging in high-risk behaviors are not only placing themselves at risk. They are, in fact, hurting all of us.

It is ironic that we live in an era where scientific endeavor has given us so many things to enrich and improve our lives, and yet we often doubt the validity of rigorous scientific research. People prefer instead to believe pronouncements by unqualified celebrities, politicians, or anonymous ignoramuses who post innuendo and hearsay on Facebook, Twitter or Instagram. Medical research has its flaws, to be certain—but it draws on an integral culture of constant self-examination and critical review, with ultimate idea being to peel back the layers of the onion to reveal the kernel of truth hidden someplace within.

As we move forward to extricate our communities, our state, our nation and the world from the enmeshing morass of COVID 19, I would urge people to learn to interpret data critically. Seek out reliable information sources instead of relying on unsubstantiated posts on social media. And try to use some common sense as we work through all of this. Your health, and the health of those you love, may well depend on it.

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