Daily MOS: John Snow Knows Epidemiology

A picture of Jon Snow from Game of Thrones captioned "You know nothing Jon Snow except how to conduct a successful epidemiological study in 19th century England."

Humans figured out science in nonsensical order. We sorted out the theory of gravity and invented calculus while we were still at ‘earth, air, water, fire’ for elements. We understood quarantine long before we understood why it worked.

And in England, during a cholera outbreak when we still thought disease was spread by bad smells, John Snow figured out to take away a pump handle.

Today’s Moment of Science… The Father of Epidemiology.

Disease was obviously caused by miasma if you asked the educated, modern thinking man in the beginning of the nineteenth century. As early as Hippocrates, miasma theory suggested that disease spread via ‘bad air.’ In a time before microscopes, it was kinda reasonable. It was better than religious explanations like ‘shake it more than twice and you’ll go blind.’

John Snow was a physician in London born in 1813. Becoming a doctor was different then. It went a little something like “the boy is fourteen now and practically a man; with his hand-eye coordination and people skills it’s doctor or chimney sweep.”

At merely 18, the cholera epidemic of 1831 was Snow’s first adventure into the world of shit going terribly wrong. And I do mean shit. Cholera gave you a case of diarrhea made you beg for the sweet release of death, and it complied about half the time. No shart you trusted perhaps too boldly compares to cholera. That shit could kill you from dehydration in mere hours. Today, between easy access to antibiotics and IV fluids, cholera is still nasty business but it’s treatable nasty business.

Snow made careful recordings during that epidemic that proved useful in later years. For now, he went off and did some fascinating things with anesthesia. He figured out that dipping a cloth in a random amount of chloroform and throwing it on someone’s face was not the best way to put someone under. Fancy. Studying anesthesia also gave him an expertise on the inhalation of gasses that made him further question miasma theory.

Another cholera epidemic hit in 1848. From conducting patient exams, he now had trouble buying that the illness came from ‘bad air.’ He saw that symptoms were in the gut, and hypothesized the disease spread from there. His seminal work, On the Mode of Communication of Cholera, suggested that cholera was transmitted not via miasma or person to person, but via contaminated water sources.

The medical establishment was like “idk, nah.”

The impact of disease is almost always worse for the poor, which was apparent early in our ability to plumb water through a city. Suggesting that cholera spread via sewage earned him a giant ‘you know nothing John Snow,’ because this meant it wasn’t the fault of the poor with all their immoral ungodly behaviors that obviously made them poor. It was the fault of whoever was running the municipal water supply that they used. And nobody wanted that, because taking responsibility for fucking up lives of poor people with the water supply is so Flint 2014.

Snow had one more shot.

In 1854, another cholera epidemic trickled into London. Comparing patients with their water source, it became stunningly apparent that they were all drinking from the same water pump on Broad Street. Furthermore, he found clusters in the area doing just fine who had their own water supply. Despite a water analysis showing no major contamination, he brought his findings to the local municipal authority. To his surprise, they removed the pump handle.

Contrary to popular belief, this didn’t end the epidemic. It was already waning, and Snow even wrote that it ended because people were fleeing the fuck out away from all the cholera. He’d diligently mapped the water supply to homes of over 600 cholera victims only to have his data plagiarized and his reputation shat upon by The Lancet.

But he was right. They found the well was contaminated by a nearby cesspit.

The important thing to remember about John Snow isn’t that he discovered the microbe that caused cholera, because he did not.
He didn’t really end that epidemic.
Hell, he barely got the city of London to listen to him that one time.

But he did one of the first known real successful investigations into an epidemic to find the source of it, cut off the cause from the people, and gave us an outline for conducting further epidemiological investigations. It’s why we still remember him as the father of epidemiological investigation, and not the guy who thought “maybe I should measure the chloroform.”

This has been your daily Moment of Science, and a humble apology for the GoT reference you knew was coming.

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About SciBabe 375 Articles
Yvette d'Entremont, aka SciBabe, is a chemist and writer living in North Hollywood with her roommate, their pack of dogs, and one SciKitten. She bakes a mean gluten free chocolate chip cookie and likes glitter more than is considered healthy for a woman past the age of seven.

2 Comments

  1. Thank you for your blog. It’s a real joy to read good science, well-written. You write clearly, so the average bloke would understand, but you don’t over-simplify either. There is so little good STEM; I honour your work.

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