The lesson miasma taught us

And why we need to listen to it

The concept of public health is ancient. The Hippocratic Corpus, the foundational medical text written in Greece over a period of 150 years during the 5th and 4th centuries BCE, considered diseases as related to environmental factors rather than divine punishment. While some sadly consider the latter true to this day, it was the first indication that people were moving away from a superstitious etiology.

The first national public health policy in America was the Relief of Sick and Disabled Seaman act in 1798. That established the Marine Hospital Service, the first official public health agency in the states. But I want to look at something that happened a half-century later across the pond, as it helped evolve our understanding of disease.

To understand this story, we have to talk about miasma. From the same ancient times that Hippocrates existed until the late 19th century, the going theory of disease transmission was that it was caused by poisonous vapors, or “bad air,” arising from decomposing organic matter. You could sense it from a foul smell. While this theory had positive impacts, like people cleaning up their environment and sparking scientific interest in decaying matter (which ultimately led to the discovery of microbes as agents of infectious diseases), this mindset perpetuated myths that certain people caused disease due to their smell.

Enter John Snow. The man basically invented the field of anesthesiology by giving doctors the keys to dose levels. His name will forever be remembered, however, as the father of modern epidemiology.

Remembering Broad Street

In 1854, a cholera outbreak struck London's Soho district. Beginning on August 31, over 500 people in the vicinity of Broad Street died within 10 days. Snow had previously speculated that cholera was spread through contaminated water rather than miasma. Outside of his day job putting people under, he saw this as an opportunity to prove his theory.

Snow meticulously mapped the cholera cases and found them clustered around a water pump on Broad Street. He conducted a house-to-house survey, collecting data on the water sources of victims. Harder than it sounds, given the piping system was so elaborate that most residents had no idea which pump was supplying their water. Snow had to test samples from each building with rudimentary equipment to figure out the source.

Snow’s investigation revealed several key findings:

• Most cholera deaths occurred near the Broad Street pump

• A woman who died in Hampstead had water from the Broad Street pump delivered to her

• A nearby workhouse with its own water supply had no cholera deaths

Snow presented his theory to local authorities on September 7, 1854. There was a ton of skepticism and pushback, but he ultimately convinced officials to remove the pump handle, which quickly ended the outbreak. The epidemic subsided within days.

Interestingly, Snow’s main nemesis, Reverend Henry Whitehead, was the only man who had conducted as much groundwork in that neighborhood. A miasmist, Whitehead was highly skeptical of Snow’s waterborne theory. Yet to his credit, he later confirmed Snow's theory when identifying the source of the contamination. A baby, Frances Lewis, had fallen ill with cholera. After she died, her mother disposed of water from washing the child's soiled clothes in a cesspool near the Broad Street well.

Snow and Whitehead remained close friends until Snow’s untimely death in 1858.

Together, these men put a nail in the coffin of miasma theory. In doing so, Snow established a foundation for modern epidemiology and public health practices, including significant improvements in London’s water and sewage systems.

Return of the miasmists

A lot of people weren’t happy about this new etiology, especially miasmists monetizing their theory. Patent medicine makers were the leading advertisers in newspapers around London. They sold untested products like Saunder’s Anti-Mephitic Fluid, which likely contained herbs and alcohol as in so-called medicines of the day.

Here’s the thing: as Snow’s research was bearing fruit, miasmists responded by saying they were really trying to keep their cures out of the hands of the people.

Sound familiar?

Miasma theory hung around for another half-century until the overwhelming evidence of germ theory, along with the growing awareness of interventions like antibiotics and vaccines, put the last nail in its coffin. Even today, a resurgence of “terrain theory” and germ theory denialism has refocused energy on the notion that the environment is the sole cause of disease.

Which really puts this raw milk “scandal” in perspective.