Germ warfare: Weaponizing an illness is older than you might think

This column is an instalment in our seriesApocalypse Then, in which cultural historian Ainsley Hawthorn examines the issues of COVID-19 through the lens of the past.

In recent weeks, scientists have called for a renewed investigation into whether the virus that causes COVID-19 was accidentally released from the Wuhan Institute of Virology, a biosafety Level 4 facility in the city where the outbreak began.

The possibility that the novel coronavirus escaped from a lab sparked rumours in North America early in the pandemic that COVID-19 was developed as part of a covert Chinese biological weapons program.

In China, conspiracy theorists accused the U.S. government of importing COVID and releasing it into the country during the World Military Games, which were held in Wuhan in October 2019.

Whether the pandemic began with a lab leak or not, there's no evidence that SARS-CoV-2, the virus that causes COVID-19, was ever intended for use as a bioweapon, by either China or the U.S.

In fact, SARS-CoV-2 lacks many of the widely accepted attributes that a pathogen must have to make it useful in war or terrorism.

A bioweapon needs to be easy to access or manufacture.

Viruses like SARS-CoV-2 are challenging to grow in a lab, making them less practical than, say, anthrax spores, which are easily cultivated.

Diseases don't respect borders

To be weaponized, a pathogen also has to infect most of the people who come into contact with it. COVID-19 is very contagious, but contagion is a double-edged sword.

Diseases don't respect borders or political loyalties, so, in the absence of a cure or vaccine, releasing a contagious illness is a bad bet for an aggressor to make. It's too likely that the illness will return to infect their own population.

Most importantly, to be effective a bioweapon must cause severe illness or death in the majority of cases. A weapon's primary purpose, after all, is to neutralize opposing forces or to destabilize an enemy's society.

Since COVID-19doesn't reliably cause symptoms around 30 per cent of infections are asymptomatic it doesn't have the power to completely overwhelm an opponent.

Although it's unlikely that COVID-19 originated as a bioweapon, one of the most devastating pandemics of all time may well have been set in motion by germ warfare.

In the late Middle Ages, the Republic of Genoa, located on the coast of modern-day Italy, was a maritime trading power so wealthy it was known as la Repubblica dei magnifici, the Republic of the Magnificents.

To support its fleet, Genoa created a network of colonies and way stations in ports around the Mediterranean, and, in 1266, the republic established a trading centre on the Black Sea at a place called Caffa, which became a hub for Genoese merchant ships carrying wares to and from Asia.

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Before the arrival of the Genoese, Caffa was a small fishing village. Less than a century later, it was home to as many as 80,000people not just Genoese merchants, but Venetians, Greeks, Armenians, Jews and Turks.

Caffa, though, existed at the pleasure of the Golden Horde, which governed the northwestern segment of the Mongol Empire, including Caffa and the territory around it.

The relationship between the Muslim Mongol rulers and their Christian Genoese tenants was a tense one. The Genoese considered the Mongols violent and uncivilized; the Mongols saw the Genoese as vain and deceitful.

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In 1343, when a brawl in a town near Caffa between Genoese traders and local Muslims ended in the death of one of the Muslims, it was like the spark that ignited a powder keg.

Khan Janibeg, ruler of the Golden Horde, was incensed. He chased the Genoese back to Caffa and launched a siege that persisted, on and off, for years.

A premature celebration

The tens of thousands of people trapped inside the city walls believed they had received a divine reprieve in 1346 when some sort of mysterious new disease swept through the Mongol camp. No medicine could treat it, and the Mongol soldiers began dying by the hundreds.

But the residents of Caffa celebrated too soon.

According to the second-hand account of Italian notary Gabriela de' Mussis, written only two or three years later, the Mongols, "stunned and stupefied by the immensity of the disaster brought about by the disease, and realizing that they had no hope of escape, lost interest in the siege. But they ordered corpses to be placed in catapultsand lobbed into the city in the hope that the intolerable stench would kill everyone inside."

The corpses that rained down on Caffa seemed to have the desired effect. Disease infected the city, and soon both sides were decimated by it. The Mongols gave up their siege, and the Genoan survivors abandoned Caffa and sailed back to Europe, landing not only in Genoa but in ports like Constantinople, Messina and Venice.

Unbeknownst to the Genoans, they brought the illness that had devastated Caffa with them, and in 1348 it would swell into a pandemic the likes of which Europe had never seen: the Black Death.

The plague would have made it to Europe eventually regardless of the Siege of Caffa; the disease had been creeping across Asia year by year without any assistance from biological warfare.

Still, medieval Europeans blamed the Genoans for unleashing the Black Death upon them, showing that the threat of biological warfare isn't just a modern concern but has played a role in some of history's worst pandemics.

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