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Sabine Hagenauer's avatar

You asked for it! So here’s:

Cholera: the Origin Story

I’ve been amateurishly interested in infectious diseases for a long time and have taken every opportunity to incorporate that interest into my professional life as a teacher - classes about medical history are usually rather a big hit (eww, gross!). Pretty soon, I decided to give cholera the award as the most interesting pandemic-causing disease, because it has had such a fascinating impact on the way we live and is so closely linked with the progress, or lack thereof, of modern history. It hit the world at a time when medical science was just beginning to spread its wings, causing a large number of doctors and scientists to get into public rows about what caused it and how best to treat it.

The microbe behind the swift killer cholera is a strain of plucky little Vibrio cholerae, a bacterium that usually coexists peacefully with tiny copepods in the Sundarbans of Bengal. Sonia Shah, in her excellent book Pandemic: Tracking Contagions, from Cholera to Coronaviruses and Beyond (2020) writes about the microbe’s home:

“This was a netherworld of land and sea long hostile to human penetration. Every day, the Bay of Bengal’s salty tides rushed over the Sundarbans’ low-lying mangrove forests and mudflats, pushing seawater as far as five hundred miles inland, creating temporary islands of high ground, called chars, that daily rose and vanished with the tides. Cyclones, poisonous snakes, crocodiles, Javan rhinoceros, wild buffalo, and even Bengal tigers stalked the swamps. The Mughal emperors who ruled the Indian subcontinent up until the seventeenth century prudently left the Sundarbans alone. Nineteenth-century commentators called it “a sort of drowned land, covered with jungle, smitten by malaria, and infested by wild beasts,” and possessed of an “evil fertility.” “ (p.18)

As long as Vibrio cholerae simply cleaned up the excess chitin left behind by the copepods, it was an innocuous enough little microbe, but then a certain turn of events offered it the chance to become a powerful zoonotic disease because of population pressure. And guess whose fault that was?

“But then, in the 1760s, the East India Company took over Bengal and with it the Sundarbans. English settlers, tiger hunters, and colonists streamed into the wetlands. They recruited thousands of locals to chop down the mangroves, build embankments, and plant rice. Within fifty years, nearly eight hundred square miles of Sundarbans forests had been razed. Over the course of the 1800s, human habitations would sprawl over 90 percent of the once untouched, impenetrable, and copepod-rich Sundarbans.” (p. 19)

Stay away from remote animal habitats, humans! It’s a terrible idea to encroach upon them! By offering to be a new host, you’ll give microbes ideas about evolving into something sinister! Plucky little cholera (I really respect its enterprising nature!) acquired a filament to its tail which allowed it to form large colonies, the better to colonize a human gut with. Even worse, it began to produce a toxin that would upset the human gut spectacularly - reversing the normal function of this organ to leach the body of all fluids, so that victims of a cholera infection would shed copious amounts of highly infectious rice-water diarrhoea and effectively dry up, wither and die within hours.

In the early 1800s, thanks in part to the British Empire, people had become much more mobile than before, and therefore plucky little cholera was able to hitch a ride to almost every corner of the earth within a few decades, causing the first pandemic in Bengal in 1817 and reaching Paris in 1832, where it caused a mad frenzy of cholera parties - immortalized via newspaper reports in Edgar Allan Poe’s The Masque of the Red Death.

In a way, it was the Sundarbans’ revenge for the brutal exploitation of Bengal and the rest of the Indian subcontinent. Except that these things are never intentional, just very predictable.

There’s much more! If anyone wants to hear about the extremely irrational behaviours the various cholera pandemics caused, the frenzied quest to find out what caused it (with a Soho doctor in a starring role as the Sherlock Holmes of cholera research) or the impact it had on cities like London, New York or my own Munich, you need only ask. I’m perfectly capable of tediously droning on for many more pages on the microbe of microbes - plucky little cholera!

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Hilary May's avatar

Random thought that occurred to me - These chapters sum up why I prefer books to films. There is no way I could watch a film of all the death & suffering (I’m far too squeamish for all that blood) and if I did I wouldn’t be able to see the humour of the padre or the grape ‘eyeball’ but reading I can feel both the horror and the humour. Fascinating and I loved the tangents - especially the grapes in Afghanistan- strangely I found that the most fascinating of all.

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