The second major epidemic of the period is that known as the Antonine plague, which hit the Roman Empire in 166 CE. It probably originated in Seleucia (about 30 kilometres southeast of modern Baghdad) and is also thought to have been smallpox. It marked the beginning of the decline of Rome, which was completed with the third great disaster, the Justinian plague, in Constantinople in 542 CE. Apparently caused by the bacterium Yersinia pestis, it lasted for a year, followed by two whole centuries of new outbreaks, and it is thought to have killed a total of 100 million people.
A few centuries later, during the Crusades, the Christian attacks often failed owing to epidemics of dysentery, typhoid fever or smallpox, diseases the crusaders brought back from foreign lands to their countries of origin in Europe. The opening up of trade routes between Asia and Europe, thanks to the efforts of Marco Polo in the thirteenth century, also made it easier than ever before for microbes to travel between continents. Indeed, most infectious diseases had spread everywhere by the Middle Ages.
It’s all too well known that infections played a key role in the Europeans’ victory over the indigenous peoples of the Americas in the fifteenth and sixteenth centuries. People in the New World had never suffered from many diseases like smallpox or measles which were common in Europe. It’s believed that the reason why these infections didn’t exist in the Americas is that, there, human beings had few domesticated animals, which, as I’ve said, were the origin of many of the European epidemics. In the Americas, people coexisted mainly with ducks, llamas and alpacas, which are not major microbe reservoirs. So, these indigenous peoples had no immunity whatsoever against any of the new pathogens brought in by the invaders, and they began to die in huge numbers as soon as contacts were made. However, the exchange wasn’t wholly unidirectional. It’s believed that the conquistadors took home to Europe other diseases like syphilis and typhus.
Just one victim, tremendous consequences
History has also changed thanks to the premature disappearance of some important figures. For example, Ramses V died of smallpox in 1157 BCE just before his 30th birthday. The leader Pericles, who was eminent enough to have given his name to a whole century of Greek culture, died in the Athens epidemic of 430 BCE. The death of Alexander the Great from an unknown infection in 323 BCE at the age of 33 brought about the fall of his great empire. King Alfonso XI of Castile died in a Black Death epidemic when fighting against Arabs in Gibraltar. Smallpox, which largely wiped out the English Stuart dynasty, also claimed as victims other European monarchs, among them Louis I of Spain, Louis XV of France and Peter II, Tsar of Russia.
In the 120 years after Christopher Columbus arrived in the Americas, about 90 per cent of the indigenous populations died, more because of infection than war. For example, fifty years after Hernan Cortés landed in Mexico, the population had fallen from 30 million to 3 million. Cortés’s victory in the siege of Tenochtitlan in 1521 was possible after only seventy-five days because a smallpox epidemic devastated the city. Apart from his superior arms, the victory of Francisco Pizarro over the Inca empire in 1531 is also thought to have been due to smallpox. This is also why just over 160 men were able to defeat Atahualpa’s army of more than 80,000 soldiers, much to the surprise of both sides.
This difference of immunity between Europe and America, not only defined the future of the continent but also led to the enslavement of whole peoples. The victorious Europeans soon realized that they didn’t have a big enough workforce available, so they resorted to ‘importing’ slaves. Nearly 20 million people from West Africa were abducted and borne off to the New World. So, the whole history of black culture in the Americas began because of deadly epidemics set off by the European conquistadors. This traffic also meant that still other diseases like yellow fever were introduced into the Americas.
A bacterium to blame for a new religion
Some theories hold that an infection might have been the cause of the founding of the Anglican Church. Henry VIII was having problems fathering children with Catherine of Aragon, possibly because he’d had syphilis some years earlier. Since Catholic doctrine wouldn’t permit his divorce, he decided to create a new church with its own rules, including one that said that marriage didn’t have to be for life. So, a bacterium could have been responsible for the changes in sixteenth-century European morality which led to puritanism.
The French tried to construct a canal in Panama in 1880, but a yellow fever epidemic thwarted the project for almost twenty years. In the end, it was finally achieved by the United States in 1913 once the yellow fever was under control. The same disease had killed 10 per cent of the inhabitants of New York at the beginning of the eighteenth century. In 1802, the French army in Haiti lost a good number of its men, including the general, to yellow fever, which made it easier for the slaves to win the island’s independence.
Microbes have fortuitously played a part in many historic decisions. For example, the army of Charles VIII of France had to discontinue its occupation of Naples at the end of the fifteenth century because of a syphilis epidemic, which was more severe in those days than the form of the disease that has survived until the present day. Other diseases like typhus have determined the results of entire wars, for instance when the defeat of the French army prevented Napoleon from conquering the whole of Europe. In fact, it’s believed that, in most wars until the middle of the twentieth century, more people died because of infections than as a direct result of combat.
Rats, fleas, and bacteria
On the list of history’s worst epidemics, plague has a prominent place. It’s caused by Yersinia pestis, a bacterium that lives in rats, which have fleas, and is transmitted to humans by flea bites. It can cause inflammation of lymphatic nodules, forming the typical tumours called buboes (hence the name bubonic plague). Another type can also bring on a general infection and kill in a few hours. A third kind mainly affects the lungs and, left untreated, causes death in 100 per cent of cases. Nowadays, it’s not such a serious disease, as we have a vaccine and antibiotics that can eliminate the bacterium in most cases but, even so, we can’t claim that it’s been eradicated. At the beginning of this century, for example, more than 2,000 cases of plague were still being diagnosed worldwide, most of them in Africa.
Delayed benefits
In the seventeenth century, the small town of Eyam, in the heart of England, was devastated by the Black Death. It’s believed that the disease came from London, in a flea-ridden bundle of cloth. When the townspeople realized what was happening, they closed themselves in their houses to avoid contagion, but it was too late. By the end of the epidemic, 259 of the town’s 350 inhabitants had died.
A few centuries later, Eyam found a way to benefit from this dark episode in its history, by organizing tours of the town and describing all the grisly details of how the plague nearly wiped it off the map.
There have been three significant epidemics of plague: the Justinian plague, that of the Middle Ages, which I’ve already mentioned, and one that broke out in Asia in the nineteenth century and has lasted through to the present day. But plague has almost certainly been with us for millennia. We can find descriptions of what sounds like the bubonic plague in the Bible and, specifically, in the First Book of Samuel, which speaks of the sickness that afflicted the Philistines because they’d captured the Ark of the Covenant. But when the thieves, terrified by what they believed was divine wrath, returned the Ark to its rightful owners, the plague also spread among the Jews, which goes to show that bacteria don’t understand religions.