These Are 20 Of The Deadliest Outbreaks And Pandemics Of All Time

Pandemics and epidemics have been a feature of life since the very dawn of humankind. And of course, their impact can be devastating. For individuals that die, it’s obviously tragic. But the effects of severe disease outbreaks can also shatter societies and even change the course of history. Read on to find out about 20 of the worst epidemics that people have faced over the centuries.

20. Spanish Flu: 1918-1920

Staggeringly, half a billion people around the world are estimated to have come down with Spanish Flu, with some 50 to 100 million dying. The infection got under way in 1918 during the final months of World War I. Strangely, it’s almost certainly the case that the disease didn’t start in Spain. The Spanish label came from the fact that under wartime conditions, other countries were censoring their news outlets. But neutral Spain’s press was free to report it first, giving the country the unenviable but erroneous title of originators.

The first U.S. case was reported at Fort Riley in Kansas, where the unfortunate Private Albert Gitchell fell ill with the virus on the morning of March 4, 1918. By the afternoon, around 100 of his comrades were complaining of symptoms including headache, high temperature and aching throat. The disease spread across the country with alarming speed, taking the lives of around 675,000 Americans. And U.S. soldiers traveling to the front in Western Europe took the infection with them.

19. Black Death: 1346-1353

The Black Death – or the bubonic plague as it’s also known – has perhaps struck more into the hearts of humans than any other disease in history. It’s believed that the plague originated in Asia and then made its way to Europe, where it caused widespread devastation. This outbreak that started in 1346 was one of many that struck countries all around Europe in the following centuries.

The plague was spread by black rats which carried the fleas harboring a bacterium named Yersinia pestis. Researchers believe that more than half of Europe’s population was wiped out by the Black Death, with potentially as many as 50 million deaths. It’s also said that the resulting shortage of labor increased wages and also began a social revolution that brought serfdom to an end.


18. HIV/AIDS: 1981-present

HIV is the human immunodeficiency virus, which destroys cells within the body that normally repel infections. After a time, the virus so weakens a body’s defenses that the sufferer will fall prey to AIDS, or acquired immune deficiency syndrome. This is a disease that’s frequently fatal if left untreated. In the early days after HIV appeared, there was no treatment for the illness. Thankfully, today it can be successfully held at bay with drugs.

Around the world, AIDS has been the cause of some 35 million deaths. Scientists believe that the disease probably came from West African chimpanzees. They carried a version of the virus which mutated and jumped the species barrier as early as the 1920s. Although 40 million people are today living with the disease, the best news about AIDS is that two people have been cured of the disease, one in 2011 and the other in 2020.


17. Prehistoric Chinese epidemic: Circa 3000 B.C.

The ravages of human illness are nothing new, and compelling evidence for this comes from an ancient Chinese village dating back some 5,000 years. The archaeological site – which is known as Hamin Mangha today – is in China’s north-east. Researchers uncovered 27 house foundations in 2011. And what they found in the remains of one of those houses was deeply shocking.

The researchers uncovered the jumbled skeletons of around 100 people in a chaotic mass grave measuring just 210 square feet. A team of anthropologists at Jilin University in the Chinese city of Changchun analyzed the 5,000-year-old human remains. They concluded that the bodies had probably been hurriedly disposed of because of an outbreak of a highly infectious and deadly disease. The researchers theorized that the epidemic had killed so swiftly that proper funerals were impossible.


16. American polio epidemic: 1916

Poliomyelitis, to give the disease its full name, is a viral infection which most usually attacks children of five or under. The majority of polio cases are asymptomatic so that the person contracting it may never even know they’ve had it. But according to the World Health Organization, for every 200 people afflicted by the virus, one will suffer paralysis. Of those people, as many as one in ten will die.

The U.S. was hit by a polio outbreak in 1916. It started in New York City and spread around the nation. Some 27,000 infections were reported, with around 6,000 of those ending in death. Thankfully, experts developed an effective and safe vaccine in 1954. Since then, the prevalence of the disease worldwide has decreased by 99 percent. In 2018 just 33 cases were reported from all over the world, and there have been no cases in the U.S. since 1979.


15. Plague of Athens: 430 B.C.

To get a feel of this terrible epidemic that exploded in Athens some 2,500 years ago, we need look no further than the words of Thucydides. In 2017 a translation of the ancient Greek historian’s work appeared in The History of the Peloponnesian War by Richard Crawley. Here, we can see as Thucydides describes the disease. He records that, “People in good health were all of a sudden attacked by violent heats in the head, and redness and inflammation in the eyes, the inward parts, such as the throat or tongue, becoming bloody and emitting an unnatural and fetid breath.”

Today, it’s difficult to be sure what exactly this horrible affliction actually was, but as many as 100,000 may have died. Experts have speculated that the illness might have been anything from typhoid to Ebola. A Spartan army had Athens under siege at the time, and this may have led to overcrowding within the city walls. This could well have worsened the epidemic, researchers believe.


14. Russian plague: 1770-1772

As seems to happen all too often with epidemics, there was a war underway when this outbreak of bubonic plague hit Russia in 1770. The conflict was the Russo-Turkish War which had started in 1768. The first diagnosed cases were among Russian soldiers stationed in the contested land of Moldova on the Russian Empire’s western fringes.

The plague soon spread through Russia, hitting the capital Moscow with particular ferocity. Although the city had quarantine contingency plans designed to combat just such outbreaks, the measures weren’t activated quickly enough and the plague soon gripped Moscow. Eventually discontented citizens rioted. Three days of violence resulted in many thousands of deaths, adding to the estimated 100,000 Russians killed by the disease.


13. Cocoliztli epidemic: 1545-1548

In the Aztec language the word cocoliztli means pest, and this epidemic was certainly violently pestilent. This epidemic is believed to have killed in the region of 15 million people in the three years that it raged from 1545. The disease was especially devastating since a serious drought had already exhausted the Aztec people.

So, what was it that took this almost unimaginably huge toll on the Aztec people almost four centuries ago? In fact, we do have a likely answer thanks to the modern science of DNA analysis. Studies of genetic material from some of the long-dead Aztecs uncovered evidence of a type of Salmonella. This particular strain of the bacteria causes deadly enteric fever. One of the types of enteric fever that afflicts humans is typhoid, often fatal in the days before antibiotic treatment was available.


12. Philadelphia yellow fever epidemic: 1793

In the year 1793 Philadelphia was the temporary capital of the U.S. However, that distinction did nothing to curtail the dreadful yellow fever epidemic that struck the city. The illness came during the exceptionally hot summer of 1793. Those who could – largely the wealthier sections of the population – fled the city altogether. Many of those left behind were African-Americans.

Thomas Jefferson – then secretary of state and later to become president in 1801 – wrote in a letter, “It is called a yellow fever, but is like nothing known or read of by the Physicians.” In fact, the disease is spread by mosquitoes and today a vaccine protects against it. Symptoms included a yellowing of the skin, high temperatures and stomach disorders. Many of those afflicted didn’t recover and the death toll reached as high as 5,000. The colder weather of the winter brought an end to the epidemic.


11. Plague of Justinian: 541-542

Some 1,500 years ago, a lethal epidemic erupted in the Byzantine Empire – which was effectively the eastern half of what had previously been the Roman Empire. As with so many times and in so many places over the centuries, the disease was the bubonic plague. This was carried by its deadly vector, the black rat and its parasitic fleas.

This epidemic is known as the Justinian as that was the name of the ruling emperor at the time. He was the ruler who built the grand cathedral Hagia Sophia in the great city of Constantinople, which is today the Turkish capital of Istanbul. Justinian himself fell victim to the disease but survived, ruling until his death in 565. Others weren’t so lucky. Hard figures are difficult to come by, but by some estimates as many as 50 million may have perished.


10. Leprosy: 11th Century

Leprosy had been around long before the 11th century. The Gospel of Matthew records an episode in which a leper approaches Jesus saying, “Lord, if You are willing, You can make me clean.” Jesus replied, “I am willing; be cleansed” and the man was cured. But it was from the 11th century onwards that this disfiguring bacterial disease reached its height in Europe.

Lepers were shunned by society, as the disease was often regarded as a punishment from God. Those afflicted with the condition were often forced to live in separate, quarantined enclaves. There was no cure for the condition in the Middle Ages. The disease still strikes today, but thankfully responds to treatment with modern drug treatments.


9. Great Plague of London: 1665-1666

In 1665 it was London’s turn to experience a severe outbreak of bubonic plague. Those that could, including King Charles II, deserted the city and made for the countryside. A hot summer in 1665 increased the severity of the epidemic, allowing the black rats and their infectious fleas to thrive.

Near the beginning of the epidemic the renowned diarist Samuel Pepys recorded that, “Great fears of the Sickenesse here in the City it being said that two or three houses are already shut up. God preserve us all.” The plague went on to claim as many as 100,000 souls. And as if London hadn’t suffered enough, the following year saw the Great Fire incinerating large parts of the city.


8. Broad Street cholera epidemic: 1854

In terms of numbers, this cholera outbreak may appear relatively minor in comparison to other devastating epidemics. But despite the relatively low death toll of 127, it had a very special significance. Broad Street is in central London’s Soho district. People began to fall sick there with cholera in 1854.

At that time, the science of the disease was not understood. But a doctor called John Snow had a theory – formed from his research at Broad Street – that it was transmitted by water polluted with sewage. Later that year, he conducted an experiment whereby one water pump supplied clean water but a second purveyed contaminated water. Those that drank from the clean water remained healthy. Many of those who use the polluted water fell ill with cholera. This was a massively important moment in the growing understanding of how disease spread.


7. H1N1 swine flu pandemic: 2009-2010

H1N1 flu – popularly known as swine flu – erupted in Mexico in 2010. It was a novel flu virus, and so there was no vaccination to counter it. Today, you’ll be glad to hear, there is a vaccine for H1N1. Swine flu spread like wildfire around the world and experts estimate that it infected as many as 1.4 billion people in a period of just 12 months.

Estimates of how many succumbed to swine flu vary widely but the total number of fatalities may have been as high as 575,400. In the U.S. there may have been as many as 18,000 deaths, though various figures have been posited. This particular flu strain tended to infect younger people and some 80 percent of those who died were younger than 65. Usually, the age profile of flu deaths is the exact opposite of that.


6. Encephalitis lethargica pandemic: 1915-1926

The disease Encephalitis lethargica appeared as if from nowhere in 1915. Not only could the scientists of the day not identify its origin, but they were also at a loss in understanding what caused it. The Latin name of the affliction does give a clear clue about the disease’s main symptom. It was Constantin von Economo, a Viennese neurologist, who coined the condition’s name.

Lethargia is the Latin root for lethargy. Appropriately, then, people struck down by the condition were notably sleepy and lacking in energy. Some have claimed that Adolf Hitler may have suffered from the disease in his youth, a putative explanation for his rumored Parkinson’s in later life. In any case, the disease largely disappeared after 1926 with only rare occurrences. But to this day, medics have no clear understanding of the disease.


5. Fiji measles epidemic: 1875

We may perhaps not credit measles with being an especially dangerous disease. But that’s dead wrong. And if you need evidence for the lethal potential of the disease, the outbreak in Fiji in 1875 clearly provides it. During the epidemic that ravaged the island, it’s estimated that a third of the population was wiped out by the disease.

It seems that the disease was brought to Fiji by visitors from Australia. And once it took hold, it spread around the island with terrifying speed. It’s estimated that some 40,000 lost their lives during the outbreak. Today, thankfully, the disease has been almost eradicated from Fiji thanks to an extensive program of vaccination.


4. Iceland smallpox epidemic: 1707-1709

It’s said that passengers aboard a ship from Norway brought the feared disease smallpox to Iceland in 1707. This sparked a severe epidemic that’s perhaps one of the less well-known of history’s devastating disease outbreaks. On his blog Stranger Things Have Happened, author Dave Nichols writes that by 1709, some 12,000 had died. This would have been a quarter of the island’s population at the time.

Nichols points out that, “Smallpox is airborne and highly contagious in confined spaces, like the smoky interiors of Icelandic farmhouses.” And even those who were not killed by smallpox were far from unscathed by the disease. Nichols writes that, “Those who survive usually suffer permanently disfiguring scars on their faces, hands, and feet.” Fortunately, inoculation had eradicated smallpox throughout the world by 1980.


3. Boer War British Army typhoid epidemic: 1899-1902

Wars and epidemics have a habit of appearing together, and the Boer War followed that template precisely. This conflict in South Africa raged from October to May 1902 and was fought between the British and the Boers, settlers of Dutch origin. The Boers fought, ultimately unsuccessfully, for their independence from the British Empire.

The Boers were by all accounts an extremely tough enemy, but even tougher for the British military was the typhoid fever epidemic that ravaged its ranks. The British forces numbered more than 550,000 and nearly 58,000 of them contracted typhoid. Of those, 8,255 died a miserable death since typhoid results in excruciating intestinal pain. By contrast the Boer fighters only succeeded in killing 7,582 of their enemies.


2. The Great Smallpox Epidemic: 1792

When Europeans first traveled to the New World, they often infected the people there with diseases to which they had no natural immunity. One especially harrowing case was the export of smallpox to North America. In 1792 the British explorer Captain George Vancouver cruised up the north-west seaboard of America. Something puzzled the mariner – why were there no people to be seen on land?

The reason for the lack of people turned out to be that most of them had died. And what had killed them was an epidemic of smallpox. Vancouver and his men found abandoned settlements, unburied human remains and a general picture of catastrophe. Uncounted numbers had died. Another disaster had earlier devastated Mexico. A smallpox outbreak there in 1519 and 1520 killed an estimated five to eight million.


1. Asian Flu: 1957-1958

Asian Flu started out in China in 1956 and quickly spread around the world. By the spring of 1957 the virus had reached Singapore and Hong Kong. The first cases were reported in cities around the coasts of the U.S. in the summer of that year. The virus had originated in wild ducks and had mutated and combined with a human strain of flu.

This severe and novel form of flu claimed around 1.1 million lives around the world, with the death toll in the U.S. totaling some 116,000. A vaccine produced in 1957 slowed the spread of the disease, but a second wave appeared in 1958. By 1968 this flu had largely disappeared and scientists believe that it no longer exists in the human population. But it’s a timely warning that novel virus forms can appear without warning.