10 of the Deadliest Global Pandemics of All Time

The Plague of Justinian (541-542)

Estimated deaths: 25 million

The Byzantine Empire, under the reign of Emperor Justinian, was reaching the height of its power and reach when this plague struck. The empire’s borders encompassed all Italy in the West to modern-day Turkey and all of the Holy Lands in the East. It also possessed most of the coastal lands that bordered the southern Mediterranean in north Africa. But for all its power and might, it could not defend itself from the tiniest – and deadliest – enemy it would ever face.

The outbreak was first recorded by the Byzantine historian, Procopius, when the disease first appeared in the port town of Pelusium near modern day city of Suez in Egypt. From there, the plague spread from port to port until it reached Constantinople, the capital of the empire. How exactly did it spread? Looking back, it is believed that the plague bacterium was spread through infected rats that had stowed away on grain transport ships. Grain was needed to feed the growing population of Constantinople and Emperor Justinian’s armies.

Once in Constantinople, the disease wreaked havoc on the large and tightly packed population of the city. It was recorded that an estimated 10,000 people died there daily, but this figure is difficult to verify. This was at a time when the city’s population was about 500,000. The plague was so bad and had spread so fast that there was no place left to bury the dead and so bodies were often left out in the open. Ultimately, it was estimated that 40% of the city’s population had perished. When the plague finally petered out, it was estimated that 25% of the human population of the Eastern Mediterranean was wiped out. The loss of so many people put a strain on Emperor Justinian who, at the time, was conducting military campaigns and paying to build the great Hagia Sophia Church. Procopius recorded Justinian’s ruthless response:

“When pestilence swept through the whole known world and notably the Roman Empire, wiping out most of the farming community and of necessity leaving a trail of desolation in its wake, Justinian showed no mercy towards the ruined freeholders. Even then, he did not refrain from demanding the annual tax, not only the amount at which he assessed each individual, but also the amount for which his deceased neighbors were liable.”

So what was this plague? Well, the mystery would remain until researchers in 2013 examined human remains from the plague and detected the bacteria Yersinia pestis – the same bacteria responsible for the bubonic plague which would strike Europe again six centuries later. Historians consider this the first recorded occurrence of bubonic plague. We will discuss this later outbreak of bubonic plague (better known as the Black Death) in the next section.

The Black Death (1346-1353)

Estimated deaths: 75 – 200 million

There is probably no single event in history that had such a profound impact on the Western world than the infamous Black Death in Europe. When it had run its course, it had decimated up to 60% of the population of Europe. It would take Europe’s population almost three centuries to return to pre-plague levels. That’s how devastating this plague was. But our worries about the plague are unfortunately not contained to the past. Just last year in 2017, an outbreak of pneumonic plague (transmitted by cough) broke out in the island of Madagascar. To date, 171 have been confirmed to have died there according to the World Health Organization.

The plague comes from the bacterium Yersinia pestis, the same bacteria that caused the Plague of Justinian that we mentioned previously. Its origins have been traced back to the plains of Central Asia where rodents carrying the bacteria moved to more populated areas where it spread. From there, the plague bacteria were transported across trade routes – like the famous Silk Road – to various parts of the known world. But it was when it reached Europe that the plague exploded in towns and cities where sanitary conditions were poor and human beings lived in close proximity.

The name Black Death came about due to the visible symptoms that plague victims exhibited on their bodies. Lymph nodes that swelled up after infection and became black in color. The other major visible symptom was the presence of buboes, or localized swellings, in the groin and armpit areas that would ooze pus when opened. If a patient was left untreated, death usually followed within a week. The estimated mortality rate was as estimated to be as high as 80%!

Recent research being conducted at universities in Europe have begun to question the idea that it was rodents that were the main culprits in the spread of the plague. Computer modeling and medical research now seem to indicate that it may have been human-based fleas and lice that were the carriers of the plague bacteria and ultimately the source of the Black Death. If this is accurate then pest eradication may not be enough to prevent a future outbreak. Good personal hygiene and washings may be in order.

The Third Cholera Pandemic (1852-1860)

Estimated deaths: Over 1 million

To date, there have been seven major cholera pandemics in history. But it was the third of these that is considered the deadliest in history. It’s believed origins were in the Ganges River valley area of India, which is also the suspected origins of the first and second cholera pandemics. From there it would eventually spread across Asia, Europe, Africa, and even parts of North America. In Russia, it was claimed to have been the cause for hundreds of thousands of deaths. In 1854, it is blamed for the death of 23,000 in Britain alone.

It was during this pandemic that the famous physician John Snow of Britain made his mark on medical science. At the time, the dominant theory on disease transmission was the “miasma theory” which stipulated that disease transmission is spread through bad or noxious air. Snow was a skeptic of this theory. By talking to local residents in the Soho area of London and plotting infected people’s homes on a street map, he was able to trace the outbreak of cholera there to a public water pump on Broad Street. It was his work that eventually led to the founding of the science of epidemiology.

But what exactly is cholera and what does it do to humans? It is a caused by the bacteria Vibrio cholerae which leads to an infection within the small intestine. The classic symptoms are large and uncontrollable amounts of watery diarrhea that lasts for several days. Other visible symptoms are skin that takes a bluish hue due to dehydration, cold skin, and wrinkling of the hands and feet. What leads to death is the rapid, severe dehydration within the body. Treatment is mainly through continuous rehydration and the administering if antibiotics. Prevention is primarily through proper hygiene, sanitation, and ensuring a clean source of drinking water.

Influenza Pandemic (1889-1890)

Estimated deaths: 1 million

The outbreak of influenza in 1889-1890 was the first pandemic to occur in a world that had become well connected due to the advent of railroad transportation and steam ships. It was commonly called the “Russian flu” because it has been traced back to an area within Russia. Researchers suspect that it may have first appeared in the steppes of Central Asia in mid-1889, but it made its first urban debut in St. Petersburg, Russia in December 1889. Within four to five months it had spread across the northern hemisphere. In the United States, deaths reached a peak in January 1890. From recent analysis, the median time between the first reported case in an area to the highest rates of mortality was about five weeks.

What made this pandemic unique was that this was the first one where the media was able to cover it widely. Newspapers across Europe published the spread of the disease in an almost up-to-the-minute fashion. In some cases, the news of the epidemic reached a given city before the arrival of the first case of influenza there. Although the reporting of the outbreak was mainly informative, the coverage did result in a kind of hysteria within the public about the disease – whether intentional or not. Of course dramatic headlines like the following published in the January 22, 1890 edition of the Polish Gazeta Polska, may not have helped: ‘Influenza, still!… It is no longer laughed at, as when it first arrived. Death strikes time after time.’

This influenza pandemic coincided with the arrival of the field of bacteriology which was heralded by the work of biologists such as Louis Pasteur. Pasteur is noted by making the connection, through his research, between germs and disease. Before then, the theories of the day focused on notions of “bad air” and “spontaneous generation” which was the idea that certain living things could generate from inanimate objects (like the notion that maggots could just arise from dead flesh). He is also credited with the method of pasteurization which is still widely used to sterilize products such as beer and milk.

The Sixth Cholera Pandemic (1899-1923)

Estimated deaths: Over 800,000

The sixth outbreak of cholera also originated in India, as it did with the third cholera pandemic that was presented earlier. From there it spread across the Middle East, North Africa, Eastern Europe, Russia, and briefly in North America. While this eventually killed almost as many people as the earlier one described, the impact was lessened in many areas of the world due to the lessons learned from the earlier pandemic and improvements in medical treatments in many countries – particularly in the United States.

In the United States, government authorities had recognized the need to address any external disease threats before they entered into the mainland. Prior to this cholera outbreak, the government had constructed two small islands near Staten Island, Swinburne and Hoffman, for the quarantine of immigrants. This was just in time as cholera reappeared on the shores of the U.S. when the passenger ship Moltke arrived in New York after sailing from Naples in October 1910. Onboard it was discovered that several passengers were exhibiting signs of cholera. They were subsequently quarantined on Swinburne Island and treated there. These would be the last documented occurrence of cholera in the United States. The success of the program to monitor and quarantine resulted in only 11 cholera deaths in the United States during this pandemic.

Unfortunately, not all countries were as prepared as the U.S. and other countries in Europe where advances in public sanitation and medical facilities had improved greatly since the third cholera pandemic less than a decade earlier. India once again bore the brunt of the epidemic. Between 1918 and 1919, over half a million Indians would perish from cholera. This was at a time in the outbreak when most countries had begun to see a dissipation in the number of cases within their borders.

The Flu Pandemic (1918-1920)

Estimated deaths: 20-50 million

If ever there was an event in modern history that came close to rivaling the Black Death in the speed in which it spread and its mortality rate, it was the great flu pandemic that started in 1918. Sometimes also referred to as the Spanish Flu (which was a misnomer), this flu pandemic was unique in that it seemed to target mainly healthy young individuals. Its origins are still being debated but it is widely believed that the first confirmed case of the outbreak was in the American heartland at Ft. Riley, Kansas. There a young private named Albert Gitchell was diagnosed with a new strain of flu on March 11, 1918. From there it spread like a rushing wave. Actually, it came in three waves.

The first wave was a mild form of the flu that resembled a bad cold. This occurred during the Spring of 1917. However, the second and deadlier wave began in the early Fall of 1917. This version spread to the East coast of the United States and into France, then Spain, Africa, and then continued spreading to the rest of the globe. A third wave of the flu would strike in the Spring of 1918. By the time the pandemic had runs its course the aftermath it had wrought on societies around the globe was astounding.

Maybe the best way to express the impact of this pandemic is by looking at the numbers. It was estimated that one-fifth of the total global population was infected by the flu. In India alone, it was estimated to have killed 17 million people. In Japan, 390,000 perished from the disease. In the U.S., an estimated 28% of the population became infected with the flu. Of those infected, approximately 675,000 would die which was ten times as many American soldiers that were killed on the battlefields of World War I. Up to 20% of those who became infected with the flu would succumb to its lethality.

The Asian Flu Pandemic (1956-1958)

Estimated deaths: 2 million

By the mid-1950s, health organizations globally felt that they were beginning to get a handle on at least better monitoring and warning of disease outbreaks. Vaccinations had been developed to address previous strains of the flu. Things were quiet near the beginning of 1957. However, on April 17, 1957, a Times newspaper article reported that ‘an influenza epidemic has affected thousands of Hong Kong residents.’ This would be the start of the second global flu pandemic of the 20^th century. By mid-May there were 100,000 reported cases of flu in Taiwan and over a million cases in India by the end of June. That same month cases began to appear in the United Kingdom and the United States.

Symptoms for this version of the flu were similar to previous flu outbreaks: fever, body aches, chills, cough, weakness, and loss of appetite. Vaccines would not be available to address this version of the flu until many months later. Before any vaccines could be made though, a second and deadlier, wave of the flu struck around the end of 1957. By then, some 3,550 deaths were reported in the United Kingdom. As the second wave spread, more victims would succumb. At the start of 1958, it was reported that ‘not less than 9 million people in Great Britain had … Asian influenza.’ Near the end of March 1958, it was estimated that 69,800 people had died from the flu in the United States.

When all was said and done, an estimated 2 million people worldwide were confirmed or suspected victims of this strain of flu. However, the response to this flu was far different than in 1918. By this era, medical research was better prepared to study and react to this type of outbreak. A U.S. researcher named Maurice Hilleman of the Walter Reed Army Institute for Research on Infectious Diseases, heard of reports of this strain of flu and soon jumped into action. His team found a sample of the virus from a U.S. serviceman and began to study it. Based on their research and Hilleman’s advocacy, many drug manufacturers worked to produce a vaccine within months of the beginning of the outbreak. Although thousands perished, some health officials believed the death toll in the U.S. could have been as high as 1 million if it were not for Hilleman’s work.

Flu Pandemic (1968)

Estimated deaths: 1 million

Similar to the flu pandemic that struck just a decade earlier, this flu also appeared to originate from Hong Kong. Hence, this flu outbreak is sometimes called the Hong Kong Flu. This was the third flu pandemic to hit the globe in the 20^th century. First appearing in Hong Kong in July 1968, it quickly rippled out and by the end of the same month had reached Vietnam and Singapore. American soldiers returning from the Vietnam War would bring the virus to the United States by the Fall of 1968.

As the world entered 1969, the flu virus migrated to Africa, Europe, South America, India, and Japan. The fortunate trait of this outbreak was the very low mortality rate. Some estimates were as low as 0.1%. The elderly were the primary victims of the disease and had the highest death rate. Another fortunate situation in many Western countries was that the flu hit around winter break which meant that transmission through work and school were greatly reduced. Some medical experts believed that many may have built up some immunity to the flu virus strain after the 1956 outbreak of Asian Flu. Others point to the improved medical system in many countries by this time. Whatever the case, the flu mercifully did not take as many victims as previous ones. Still, an estimated 1 million around the globe would perish from the flu virus.

Like other outbreaks, this too came in waves. The first wave lasted just six months – disappearing as quickly as it had arrived. However, the virus was not done as it returned in 1969, and again in 1970, and finally in 1972. Even though mortality was lower than previous flu outbreaks, the symptoms were still terrible to feel. It produced symptoms of chills, fever, and muscle pain and weakness. These would typically last from four to six days. Something to note is that the H3N2 virus that caused the 1968 pandemic is still in circulation today and is considered to be a strain of contemporary seasonal influenza.

HIV/AIDS Pandemic (Peak years, 2005-2012)

Estimated deaths: 36 million

Many people of a certain age probably remember this photo. It was this image of a young man lying on his bed surrounded by family as his life slipped away that seemed to capture the emotions of the time. It represented the fear and the sorrow of a disease that was badly misunderstood and had affected the social behaviors of entire societies across the globe. The first reported cases of what would eventually be called the acquired immunodeficiency syndrome, or AIDS, was first documented in 1981. Since then tens of millions of people across the planet have been infected by the human immunodeficiency virus, or HIV.

In the beginning of the disease, very little was known about how it was spread. Treatment became difficult as those who were infected were shunned by society and even by the medical community to an extent. In the United States, it had the misnomer of being called the “gay plague” and other misguided stereotypes. Sympathy and awareness began to grow as celebrities either spoke out to help those infected by HIV, like Elton John, or contracted the virus themselves and became symbols for hope and perseverance, like NBA star Earvin “Magic” Johnson in 1991. However, the one major effort that probably made the most difference in the fight against AIDS was the implementation of the $15 billion President’s Emergency Plan for AIDS Relief (PEPFAR) in 2004 under President George W. Bush. It was this effort that had made the biggest governmental monetary commitment to address the AIDS pandemic.

As medical research continued, a new understanding of how the virus was transmitted helped to educate people around the new world and new drugs, such as anti-retroviral (ARV) medication, began to be approved to help those infected with HIV to continue to live normal lives. However, the disease continues to be a pervasive problem in many parts of the world – particularly in sub-Saharan Africa where the prevalence rate is about 5% of the total adult population. There, poor medical infrastructure, stigma against those infected, and even AIDS denialist, allowed the disease to spread rapidly. Thabo Mbeki, South Africa’s president in the early 2000s, gained infamy for his denial of the AIDS crisis. By 2005, 5.5 million South Africans were infected with HIV – or about 12% of the population at the time. Hopefully, new research and government support will one day eradicate this pandemic which still haunts us today.