Infectious disease epidemics have occurred throughout human history. Wikipedia lists 235 epidemics between 429 B.C. and 2020, and this list is by no means complete. Rated by the volume of mortality, here are the five most lethal epidemics (ones in which more than 10 million people died).
- Plague of Justinian (Roman emperor during the epidemic), 165–180: Between 25-50 million people perished in Europe, Egypt and West Asia. Cause of the epidemic was plague, which is the name given to diseases caused by the bacterium Yersinia pestis.
- Black Death (also called Bubonic Plague), 1331-1353: Between 75-200 million people died in Europe, Asia and North Africa. Cause of the epidemic was a mutation of the Yersinia pestis bacterium, which is also called plague.
- Cocolizti Epidemic (named by the Aztecs), 1545-1548: Between 5-15 million humans perished in Mexico (80% of the Mexican population). Cause of the Cocolizti Epidemic is uncertain, but it may have been the Salmonella bacterium brought by the Spanish conquerors of Mexico.
- Spanish Flu, 1918-1920: Infected 27% of the world’s population, and up to 100 million people died worldwide. Cause of the Spanish Flu was the Influenza A virus.
- HIV/AIDS, 1920-present. This epidemic is caused by the HIV virus, and it is not over. HIV/AIDS has already killed more than 32 million humans worldwide.
Let us hope that the current Coronavirus pandemic (named COVID 19) does not join this grim list.
Epidemics have had a powerful impact on history. For example, the Plague of Justinian prevented the unification of the eastern and western branches of the Roman Empire. The Cocolizti Epidemic facilitated the European conquest of the Western Hemisphere. The Spanish Flu (which did not originate in Spain) probably shortened World War I and may have affected the outcome.
Epidemics have usually been seriously misunderstood. They routinely generate fear and desperation. Often a strong desire to identify a culprit responsible for the infectious calamity emerges. This can lead to racism, xenophobia and conspiratorial thinking. Jews were repeatedly held responsible for the Black Death, and these attributions sometimes led to massacres of Jews. China was frequently named the source of the Spanish Flu. This induced numerous violations of Chinese civil liberties and also revived the racist label “yellow peril.” Gay men have regularly been designated as the perpetrators of the HIV/AIDS epidemic.
Although epidemics are better understood now than in the past, we still see outbursts of racist and conspiratorial thinking regarding COVID-19. Some politicians in the United States and abroad suggest that COVID-19 was developed by the Chinese government for biological warfare and somehow escaped the laboratory. Actually, COVID-19 is far too infectious and far too unruly for practical use in biological warfare.
About three-quarters of all infectious diseases arise from pathogens that transfer from animals to human beings. It is well established that all forms of the coronavirus originated in animals and subsequently jumped to human beings. The Chinese government can be faulted for withholding information about the initial outbreak of COVID-19 in the city of Wuhan, but the current coronavirus is not a refugee from a Chinese biological warfare lab. And China, it should be noted, has subsequently provided exceedingly useful information about the coronavirus.
The COVID-19 pandemic underscores the essential unity of the human species. We are all in this pickle together and, to quote Benjamin Franklin: “We must, indeed, all hang together or, most assuredly, we shall all hang separately.”
There may even be a silver lining to COVID-19 pandemic. It demonstrates that diverse modern societies are capable of intelligent, energetic and comprehensive action when confronted with an indubitable crisis. If such vigorous and sustained action were directed towards the planetary crisis of climate change, humanity might survive this truly existential emergency.