Epidemics – like wars, floods and famines – feature with dreadful regularity throughout human history. From when we first began living together in settlements, bacteria and viruses were with us, replicating, mutating and jumping species with extraordinary agility.

Doctors have struggled down the ages to diagnose and classify infectious diseases, to understand how and why people fall sick and to try to prevent them from doing so. But despite the advances in microbiology and medicine, we are still engaged in a hard-fought fight against the same pathogens that have dogged us for millennia.

Only forty years ago, many scientists believed that epidemics were about to be confined to history. Infectious diseases were all but conquered, or so the argument went, and there was no more work to be done. This, as we now know to our cost, has turned out to horribly wrong. At the time, it seemed a perfectly reasonable view. Thanks to vaccination and antibiotics, the killer diseases that had rampaged across the world for centuries seemed finally to be on the retreat.

In 1979, smallpox was officially declared eradicated from the globe – but smallpox remains the only human disease to gain this distinction. And while others are tantalisingly close to being conquered, they have proved extraordinarily persistent, with some even staging something of a come-back.

The first major epidemic to be documented is the so-called Plague of Athens, which struck in 430 BC and is said to have killed between 75,000 and 100,000 people, around 25 per cent of the city’s population. As with most epidemics in the ancient world, however, it is impossible to be sure about the death toll, or even which disease was responsible. Typhus is the main contender but an eye-witness account by the Greek historian Thucydides puts several others in the frame, including smallpox, typhoid and bubonic plague.

As with all epidemics, however, the effects of the Plague of Athens went wider than the merely medical. The word epidemic itself comes from the Greek, ‘epi’ meaning ‘upon’ and ‘demos’, ‘the people’, so an epidemic is something that falls upon the masses. And the consequences for those masses – today as well as in the distant past ­– are not only sickness and death but also often devastation to societies and economies. Thucydides describes how law and order broke down, along with societal norms:

‘Men, not knowing what was to become of them, became utterly careless of everything, whether sacred or profane . . . Fear of gods or law of man there was none to restrain them . . . As for the first, they judged it to be just the same whether they worshipped them or not, as they saw all alike perishing; and for the last, no one expected to live to be brought to trial for his offences.’

And there is also some evidence to suggest that the treatment of those known as metics worsened significantly as a result of the epidemic. Metics were foreign residents, including freed slaves, economic migrants and refugees fleeing persecution. They had fewer rights than the indigenous population and were lower down the social scale. When the authorities discovered that many of the surviving metrics were there illegally, there was a backlash against them, with many taken into slavery.

Today pathogens can be halfway around the world in twenty-four hours. But while they previously travelled more slowly, they spread in the same way, relying on the movement of people for trade, exploration – a forerunner of today’s tourism – and colonisation, in order to find new hosts.

The Black Death, which killed an estimated 60 per cent of Europe’s eighty million population and between seventy-five million to two hundred million across the world, is a prime example. The first European cases have been traced to a Mongol attack on an Italian trading station in the Crimea in 1346. Plague broke out among the Mongols and spread into the town. When the Italian merchants fled home, docking at various ports along the way, they took the infected rats with them.

With no knowledge of microbiology and with religion playing a central role in people’s lives, epidemics in ancient and medieval times were often seen as a form of divine retribution. Leprosy in particular holds a special place on the punishment list, to the extent that its victims were sometimes sent to the priest rather than the doctor.

We might see ourselves as more enlightened and educated than our ancestors but people with leprosy, or Hansen’s disease as it is now known, still face huge discrimination in some parts of the world. In the 1980s, HIV/AIDS was dubbed ‘the gay plague’, with some people claiming that it was God’s punishment for what they saw as a dissolute lifestyle.

Today, Donald Trump refers to COVID-19 as ‘the Chinese virus’, and fake news stories on social media claim that the name is short for ‘Nineteenth Chinese-Originated Viral Infectious Disease’. As we can see from history, epidemics have long led to blame games.

When syphilis first struck Europe at the end of the fifteenth century, the French named it the Spanish disease; the English, Italians and Germans called it the French disease; the Russians referred to it as the Polish disease; and the Poles and the Persians, the Turkish disease. The Turks meanwhile took finger-pointing a stage further, dubbing it the Christian disease. As the infection continued to spread around the world, the Tahitians would blame the British; the Indians the Portuguese, and the Japanese the Chinese.

The practice of quarantining, too, is centuries old, and has always been controversial, involving as it does balancing the public interest against the rights of the individual. And of course, there is the practical difficulty of enforcement.

In the Great Plague of London in 1665, victims, along with everyone who lived with them, were ‘shut up’, as it was known, in their homes. This was particularly hard on the poor, as several families often shared one house. Watchmen stood guard to prevent people from leaving and a red cross was put on the door, along with the words ‘Lord have Mercy on us’.

From the start the policy was questioned, with critics arguing that it did more harm than good. Some even suggested that being under house arrest would cause healthy people to become depressed, which would then morph into plague. In a pamphlet setting out six arguments against locking people in, one Londoner wrote:

‘We have known the healthiest men shut up, and with the very thought of a sad and dismal restraint, contracting first a melancholy, and then a fever, and at last (as all diseases turn to that which is most epidemical) a Plague . . . Infection may have killed its thousands, but shutting up hath killed its ten thousands.’

The writer could not have been worried for long, however. It proved impossible to police such large numbers of people, and by the time the outbreak peaked the system had broken down. On 14 September, Samuel Pepys, venturing into the city for the first time in weeks, wrote in his diary: ‘And Lord! To see how I did endeavor all I could to talk with as few as I could, there being now no observation of shutting up of houses infected, that to be sure we do converse and meet with people that have the plague upon them.’

The sudden, shocking appearance of COVID-19 and its rapid sweep across the world is reminiscent of the great epidemics of ancient times, although fortunately, whatever the mortality rate turns out to be, it will not be nearly as high as that of typhus, smallpox or plague.

Our situation is infinitely better than that of the Athenians in 430 BC, but COVID-19 has reminded us in the starkest terms that, despite our huge scientific and technological advances, we are still, like our ancestors, vulnerable to a mass attack, and we are still a long way from eradicating epidemics.

Cover image by Michiel Sweerts (1652–1654), detail from ‘Plague in an ancient city’