The Sword of Damocles — Virus, Bacteria & the History of Pandemics

“In many ways, it is hard for modern people living in First World countries to conceive of a pandemic sweeping around the world and killing millions of people.”

Pandemics | Sheeta Mo

— Charles River Editors, The 1918 Spanish Flu Pandemic: The History and Legacy of the World’s Deadliest Influenza Outbreak

Our generation believed that transmissive diseases were an old and outdated threat. We did not envision our future with a pandemic. Everything changed in 2019. With the Covid-19 outbreak, the terror of transmissive disease rose to the surface again. However, living in a pandemic is nothing new. Our history is tangled and twisted with viruses, bacteria, and pandemics. It is like the sword of Damocles, always hanging on top of human fate.

The Past

Black Death

Death cast its dark cloak over the globe in the 1340s. The disease was carried to Sicily by a ship from Crimea in 1347, where it quickly swept across mediaeval Europe [1]. The Black Death killed about 50 million people, at least a quarter of the world's population [2]. The disease was named after its terrible symptoms – black blotches on patients' skin. Other symptoms included fever, chill, diarrhoea, and vomiting [3]. Patients were asymptomatic and infectious during the incubation period of one to seven days. Infected individuals were described as "poisoner[s]... walking destroyer[s]... who might have ruined those that he would have hazarded his life to save." [3] Medical knowledge and public health measures were not developed at the time. It was widely accepted that diseases were a punishment for sin [4]. Thus, praying was a method of curing. People also believed that the Black Death was caused by breathing in "bad air." Doctors wore birdlike masks as they could fill the long beaks with herbs and perfume, hoping they would sanitise the air [5]. Treatments available included bloodletting, purging, and medicine that contained a large amount of opium (theriac) [6]. Without proper scientific knowledge, humanity had no chance of overcoming the nasty disease. Once infected, there was only one fate: to die. Dead bodies were left on the street since there were not enough people to bury them. People fled from cities, further spreading the Plague. It was a living hell.

In the present day, we know the Plague was caused by Yersinia pestis – the same bacteria which caused the Plague of Justinian in 541 that killed half of the world's population [2]. It was transmitted from the bites of infected fleas, skin contact, and inhalation [7]. Knowledge can be used for both good and evil. Microbiology offers insight into fighting diseases and facilitates the weaponisation of bacteria and viruses. With its high fatality and susceptibility, the Plague was used as a biological weapon several times. During the Second World War, Y. pestis-infested fleas were dropped by Japanese planes over Chinese cities. It killed more than 30,000 people in 1947 as the epidemic persisted for years after the attacks [8]. By the 1960s, the USSR and the US had active programs to weaponise Y. pestis. Models demonstrate that an "international release of 50 kg of aerosolized Y. pestis over a city of 5 million would ... cause 150,000 cases of pneumonic plague and 36,000 deaths." [1]

The ghost from the past had never left us. The Plague also caused several epidemics and the modern pandemic from the mid-19th to1930 that killed more than 12 million people. Currently, an average of 2,500 cases of Plague are reported per year [1]. The impact of the Plague decreased as our sanitation and modern disease control methods improved. Effective antibiotic treatment is also available to save lives.

Smallpox

Day 1 - You felt sick. You had a high fever, and the pain in your back was killing you. It appeared to be just the flu. You went to rest and hope the symptoms will be gone in a few days.

Day 3 - Red spots appear on your face and spread to your body quickly.

Day 5 - The spots become blisters filled with clear liquid, which later turn into pus. You know you had it – smallpox, a variola virus that killed millions of people. You had a 30% chance of dying. Even if you are lucky enough to survive, the deep, ugly scars over your entire body will follow you till your grave. [9]

Smallpox is now a name that no longer triggers terror. The ancient disease that existed for over 3,000 years was eradicated in 1980. This remarkable victory was built upon the first successful vaccine created by Edward Jenner. Thousands of years ago, before vaccines were invented, people in some regions of China, India, Egypt, and Ethiopia collected infected patients' pustules or crusts and put them into healthy people's skin or noses [10]. Inoculation often results in mild illness, but offers protection against severe forms of the disease. Jenner observed from the milkmaids that being infected by cowpox can protect against smallpox. After countless experiments and trials, in 1796, he created the first successful vaccine in human history. Promoting vaccines was not successful in the beginning. Opponents feared that recipients would grow cow-like features on their bodies after being vaccinated with cowpox [10]. The world slowly accepted vaccination in the 1800s as it proved to be effective in eliminating smallpox outbreaks.

In 1967, the World Health Organisation started an Intensified Smallpox Eradication Programme campaigning for mass vaccine coverage globally [11]. It led to triumph as smallpox was eradicated 13 years later, the only disease eradicated by vaccination. The Centre for Disease Control and Prevention, and the Russian State Centre for Research on Virology and Biotechnology keep the remaining virus samples for future studies [12].

The Present and Future

“Globally, as of 5:54pm CEST, 6 September 2022, there have been 603,164,436 confirmed cases of COVID-19, including 6,482,338 deaths, reported to WHO.”

- World Health Organisation [13]

When the first case of Covid-19 was discovered in Wuhan, China in December 2019, the public thought it was an epidemic that would end quickly and quietly. This thought was a naive wish as the WHO declared the outbreak a global pandemic on 11 March 2020. Suddenly, medical jargon became everyday words: SARS-CoV-2, airborne transmission, quarantine, variants, R0, herd immunity. We ride through the emotional cycles, from fear to familiarity. Masks, sanitiser, social distance, and isolation became the new ordinary. We saw empty supermarket shelves, long lines of wait in testing and vaccination, and protests against lockdown and vaccine mandate. We cannot believe history is repeating. Right here, right now, in front of our eyes, except we are the actors, not the audiences. It is August 2022; Covid-19 continues to change our present and future while new threats like monkeypox emerge.

Our relationship with the environment increases the risk of pandemic occurrence. For instance, it was the historical congregation of humans and domestic animals in villages and cities that provided the opportunity for ancestral organisms to switch their hosts to humans and cause human smallpox, measles, and other diseases [2]. The risk of introducing infectious diseases from wildlife directly to human society increases exponentially as our ecological footprint grows. Global warming will also affect the distribution of infectious diseases and potentially increase the severity of animal-borne diseases [14]. Our growing population and urban lifestyle creates an ideal breeding ground for outbreaks. Spreading infectious diseases becomes faster and easier with modern transport systems. There are many unknown challenges ahead of us. Therefore, it is essential to revisit the past. By tracking past pandemic origins and analysing host-virus relationships, we can identify the causes of emerging diseases and predict potential risks [2]. We have the practices and technology accumulated from the past, such as quarantine and vaccines. It all contributes to better prediction, prevention, and control of infectious diseases.

We are currently walking in the mist. We have no idea what the future will be like and where the path will lead us. But we have a lamp in our hands that our ancestors did not hold. It is not bright enough to reveal the entire path but provides guidance. It allows us to light up the surroundings instead of wandering in the dark. The lamp is science. It is merely a tool, and its use depends on the user. We can choose the path of misinformation, speculating with suspension and rumours. Or we can choose to trust knowledge accumulated by years of observation, experience, and practice. Where we walk depends on us.

Sheeta Mo - BSc, Biomedical Science

Sheeta is a first year BSc student specialising in biomedical science. She is immensely interested in neuroscience and genetics and plans to do research in the future.

Random fact about her relating to the article: she was born in China during the SARS outbreak and turned 18 during the COVID-19 pandemic.