Historical overview of the causes of pandemics and conclusion.

Simon d'Orlaq
11 min readFeb 6, 2021


By deciphering the evolution of epidemics over the past centuries, a significant convergence appears between the manifestation of a pandemic and the growth of the ego within a social group, in this specific case of one or more nations.

It is a question of finding the correlation of these events, i.e. of the emergence of new ever-growing desires of appropriation to the detriment of others with as systematics a signal sent by Nature in order to obviously correct a wandering in the evolutionary process of humanity.

A pandemic (from the ancient Greek πᾶν / pãn “all”, and δῆμος / dễmos “people”) is an epidemic present over a large international geographic area. In the current sense, it affects a particularly large part of the world population.

Signal of a major imbalances

Pandemics occur during major imbalances linked to social and environmental changes throughout history (agricultural revolution, wars and commerce, travel and great discoveries, industrial revolution and colonial empires, globalization …).This summarizes ‘the appetite’ and the desires of monopolization, domination and expansion of some, themselves dominated by an insatiable egoism leading to the various crises that history knows, until the most recent that of Covid19.

The consequences of an uncontrolled pandemic can be very significant, as was the case of the black plague in Europe and Asia, where it killed in a few years tens of millions of people and had a strong impact on the demography, or, more recently, with infection with the human immunodeficiency virus (HIV) which had severely affected sub-Saharan Africa.

In an increasingly globalized world, the transformation of an epidemic into a pandemic is all the easier. These terms are sometimes used for non-infectious diseases. In 1997, after a consultation held in Geneva (3–5 June), the WHO spoke of a “global epidemic” of obesity worldwide. The term pandemic can then apply to addictions, cardiovascular diseases, those linked to old age, etc … or to any emerging phenomenon or behavior becoming very widespread or globalized.

Notable historical pandemics

Antiquity : Settlements and urbanization .

Epidemics became possible from the Neolithic revolution (around 6000 BC in Europe), as soon as human groups reached a sufficient size, with frequent contact between these different groups, hence the importance of sedentarization and urbanization linked to agriculture and trade.

Large epidemics are first rare, then more frequent with commercial links or military conflicts involving a network of cities increasingly populated and connected over long distances. The first “pandemic” described is the plague of Athens in 428 BC. AD, reported by Thucydides. A probable typhus pandemic, it would have come from Ethiopia, hitting Egypt, Persia, and Greece.

Many epidemics are reported in the first half of Roman history, notably by Tite-Live, but they rarely extend beyond neighboring cities. Around the 2nd century BC. AD, the Roman conquest led to the construction of a road network in the direction of the Near East. New epidemics are appearing in Italy, including leprosy. In 65 AD. AD, Tacitus reports another disease — which he does not describe — which, in three months, killed 30,000 in the city of Rome, and spread to Gaul and Germania.

Large epidemics on a European scale occurred until the end of the Roman Empire. The best known are Antonine plague (167–172 AD) or galenic plague (described by Galien) which would be a probable smallpox; the plague of Saint Cyprien (251–256), described by Cyprien de Carthage, of indeterminate nature.

Several epidemics of “pustules” (indeterminate disease, smallpox or anthrax according to the authors) occurred during the 4th century, notably that described by Ammianus Marcellinus , during Perso-Roman wars.

Towards the 5th century, trade decreased with as a corollary the absence of notable epidemics, but some “plagues” can accompany the great invasions. From the sixth to the eighth century two great pandemics struck Europe, one of smallpox, the other of bubonic plague or Justinian plague (541–767) considered to be the first pandemic of plague.

Middle Ages: Trade expansion

Leprosy, which became endemic in late Antiquity, receded in the early Middle Ages, after the year 800, smallpox epidemics became more frequent and the plague disappeared. Three other major epidemics then hit Europe: ergotism, an intoxication from Central Asia, which reached its peak in the 12th century. From the 10th century onwards, large epidemics (interpreted as pandemic flu) occurred once or twice a century; malaria, hitherto confined to the Mediterranean, tends to settle in the marshy areas of northern Europe.

From the central Middle Ages, new contacts with the Middle East revived leprosy. Large epidemics occur in Europe. According to the chronicle of the monk Matthieu Paris, almost 19,000 leper colonies existed in Europe in the 13th century, historians estimate that Europe in 1300 had around 600,000 lepers out of a total population of 75 to 80 million inhabitants.
The bubonic plague reappears with the black plague which makes approximately 25 million deaths in Europe between 1346 and 1350 and probably as much in Asia. It was the explosive start of the second plague pandemic.

Classic period: Wars and trade

In the West, major diseases of the Middle Ages persisted after the Renaissance, such as the plague and smallpox. The second pandemic of plague continued with several major epidemics which ended at the end of the 18th century. Smallpox kills almost 400,000 Europeans each year as the 18th century approaches.
Other scourges are gaining in importance, such as typhus linked to military camps, malaria which spreads from Italy, and tuberculosis in the form of scabs.

The development of human and commercial exchanges, great discoveries and wars favor the spread of infections. Several epidemic diseases are distinguished or rediscovered such as whooping cough, diphtheria, mumps, influenza, measles or scarlet fever.
With the discovery of America, the world is no longer limited to Eurasia. Two new diseases appear: the English suette and syphilis. In return Europe exports smallpox, leprosy, measles, tuberculosis and malaria.
Smallpox and measles decimate the Amerindian civilizations in Mexico, in Central America, and even the Incas. The depopulation is such that the slave trade is necessary to develop the American colonies. With triangular trade, black Africa joins the pandemic circuit between the Americas and Eurasia. It receives diseases from it and exports others such as yellow fever and malaria.

Modern period: Industrial Revolution

From the 18th century, municipal or regional public health regulations were dealt with at government level. Health policies and the fight against epidemics became the business of nation states, and international agreements in the 19th century (International Health Council founded in Constantinople in 1838, International Conference of Paris in 1851, to fight against the plague and the cholera).
International collaboration is growing at the same time as the power of pandemics. This is multiplied by the social changes of the industrial revolution and modern transport using the steam engine.

Plague and cholera

The second plague pandemic ended in the Near East from 1841 in the Ottoman Empire which adopted and severely applied European regulations. The epidemic plague is eliminated in a few years, remaining only in the form of episodic local cases.

A third plague pandemic reappeared in China in the second half of the 19th century. It first claimed several million victims in China and India and spread around the world, but it was blocked at the ports of other continents, causing only a few thousand victims.

Seven pandemics of Asian cholera from India followed one another in the 19th century. The most violent hitting Europe and North America were the second (1829–1837) and third (1840–1860) pandemics. For example, the cholera of 1832 killed more than 500,000 people in England and 100,000 in France.

Mosquito diseases: Colonization and civil war

Malaria declines in Europe, but it reaches its maximum expansion in North America, where it is linked to changes in habitat and agricultural activity it becomes a real threat to colonizers and natives when it first reaches the American continent during slave trade. Malaria wreaks havoc in the Jamestown colony, as well as in the South and Midwest. In 1830, it reached the Pacific Northwest.

During the Civil War, more than 1.2 million cases of malaria were recorded among soldiers from both camps. The southern United States continued to suffer from malaria in the 1930s.

Yellow fever is the cause of several devastating pandemics. American cities such as New York, Philadelphia and Boston have been affected by this pandemic. In 1793, one of the largest American pandemics of yellow fever killed more than 5,000 people in Philadelphia — nearly 10% of the population. Almost half of the residents fled the city, including President George Washington.
In colonial times, West Africa was known as the “White Man’s Tomb” because of the malaria and yellow fever that prevailed there.

Diseases of poverty:Exploitation of human resources

In the 19th century, tuberculosis killed more than a quarter of the adult population in Europe. It is linked to the industrial revolution and housing (urban poverty) . In 1918, one in six deaths in France was caused by tuberculosis. In the 20th century, the disease killed approximately 100 million people. It is one of the most important expanding health complications in the world.
Other pandemics linked to poverty are typhus and relapsing fever. Those related to the hygiene of water (water transmission) and food are gastrointestinal infections, for example cholera, already mentioned, and typhoid fever.

Childhood illnesses:Impoverishment of the working classes

Epidemic diseases strike especially children, they can only be truly combated after identification of the causative agent and passive immunization (serotherapy) or active immunization (vaccines). These epidemics recur regularly and are of varying severity. The most important, both in frequency and in severity, were or are diphtheria, polio, scarlet fever, and measles.
There were 3 to 4 million cases of measles in the United States each year before a vaccine was introduced in 1963. Measles has killed nearly 200 million people worldwide in 150 years.

Influenza and smallpox:Post industrialization

As in previous centuries, major influenza epidemics raged in the 19th century, including that of 1847–1848, the Russian flu of 1889–1890 is considered to be the first well-documented pandemic flu.
The Spanish flu, from 1918 to 1920, was one of the deadliest pandemics in human history, with 20 to 40 million deaths (80 to 100 million according to recent reassessments): after having started in China and Japan, it has spread to Russia, Europe and North America.

The following pandemic flu were more moderate: the Asian flu in 1957 (2 million dead), the Hong Kong flu in 1968 (4 million dead), the Russian flu in 1977, and the A (H1N1) flu in 2009 .
Smallpox persisted in the 19th century, including in industrialized countries, in the form of epidemics of short duration, but sometimes very deadly (France, winter 1870–1871). In the 20th century, the disease would have killed nearly 300 to 500 million people. In the early 1950s, 50 million cases of smallpox were reported each year. Following successful targeted vaccination campaigns during the 19th and 20th centuries, WHO declared smallpox eradicated in December 1979. Smallpox was the only human infection to have been eradicated and one of two deadly viruses had been eradicated.

Last quarter of the 20th century: Demographic transition

If the concept of epidemiological transition remains used (or modified in health transition integrating social factors), , of the diseases infectious, old or new. Among the old, depending on the country, tuberculosis, syphilis, diphtheria, dengue.
Since 1970, more than 1,500 new pathogenic infectious agents have been discovered, 70% of which have been shown to be of animal origin. Many have little public health significance, but many have far-reaching consequences. Among the emerging diseases or new diseases identified at the end of the 20th century, this is notably the case with Lyme disease, legionellosis, Ebola … the most notorious example being HIV / AIDS which comes from from the African continent, then spread to the United States from Haiti between 1966 and 1972.

Beginning of the 21st century: Globalization versus global pandemic

Expansion of the 2019–2020 coronavirus disease pandemic worldwide.

In 2009, the influenza A (H1N1) epidemic, which broke out in Mexico, subsequently developed into a pandemic.

The same year, the new CIA report estimates that “the appearance of a new virulent, extremely contagious human respiratory disease, for which there is no adequate treatment, could trigger a global pandemic”. He considers that this appearance could be linked to “highly pathogenic strains of avian influenza such as H5N1”, as well as “other pathogenic agents, such as the SARS coronavirus and various strains of influenza”, and that ‘it could intervene’ undoubtedly in a densely populated area, with close proximity between humans and animals, as there are in China and in South-East Asia where populations live in contact with livestock .

At the end of 2019, a new coronavirus (SARS-CoV-2) appeared in China, triggering a public health emergency of international scope on January 30, 2020. However, the WHO only spoke in its early days of a significant risk of pandemic. In response to a question on France Info, on March 5, 2020, William Dab, former director general of health, declared: “For epidemiologists, it is obvious that we are in a pandemic.”

Finally, on March 11, 2020, the World Health Organization officially announced that the COVID-19 epidemic has become pandemic. This comes two days after the Italian government decided to quarantine the whole country.

An epidemic is always a moment of testing for a society

What imprints have the great past epidemics such as the Spanish flu of 1918 or the black plague of the 14th century left on societies? Europe at the end of the Middle Ages or at the end of the First World War has little to do with today’s hyper-connected and globalized society. But an epidemic is always a moment of testing for a society and an era, it endangers social ties, can trigger a hidden form of civil war in which everyone is wary of their neighbor. This results in grotesque scenes where supermarket customers fight for the last package of toilet paper. More tragically in Italy, doctors have to choose to save a patient rather than another lack of material, as in a war situation.

Epidemics also lead to the designation of scapegoats, we experienced a small episode of xenophobia against the Chinese at the beginning of the present epidemic. During the great plague epidemic which ravaged medieval Europe between 1347 and 1351, the Jewish populations were the target of exacerbated attacks, sometimes massacres as in 1349 in Strasbourg, where nearly 1,000 Jews were burned. The great episodes of plague also induce ‘epicurean-type reactions’ of flight ahead, of countless expenses: people chose the cabaret or the tavern and lived every day as if it should be the last during the Black Death, 1345–1730 . Others, on the contrary, choose to withdraw from the world, as reported by the Italian writer Boccaccio (1313–1375), who in the Decameron recounts the intentional hatching of ten Florentines out of town to escape the plague.

Sounds the shutdown of the system

The plague takes advantage of this prosperity, puts an end to it and sounds the shutdown of the system :An epidemic is a co-production between nature and society, between microbes and humans. A germ only becomes dangerous in certain circumstances. Thus the black plague ravaged at the end of the XIVth century an Europe in full form where the commercial exchanges was intense, the populous cities, the countryside exploited until saturation. The plague takes advantage of this prosperity, puts an end to it and sounds the end of the serfdom system which founded medieval society.
In 1918, the influenza pandemic had economic consequences ultimately quite low compared to the effects of the war in Europe. An exception because, as a general rule, epidemics have significant economic effects, interrupting trade and redirecting trade to other routes. In medieval times, the repetition of plague epidemics in the Mediterranean basin probably benefited the development of cities in northern Europe. Today, repeated health crises in China, the manufacturing center of the planet, could encourage the diversification of production and supply sites.


We can conclude that at each great turning point throughout the history of our civilization it provide bases for an emerging infectious diseases signifying a major disruption in the process of evolution of humanity, violating the natural laws of creation trying to curb the expansion of the collective ego,conqueror and always more addicted by the monopolization of wealth and pleasures to the detriment of the common good.

It is our duty to understand this and to learn from it before other much more serious signals for the future of humanity may well come on earlier than we thought.