Plumbing the depths of diarrhea etymology

Jun 26, 2024


Hope Randall
Communications Officer, DefeatDD

In London, I spotted the water pump that John Snow famously identified as the true culprit behind cholera. The word “cholera” reflects the previously held belief that the disease is caused by an excess of choler, or yellow bile.


Given that our first social media campaign was the beloved Poo Haiku Challenge, it is probably no surprise that DefeatDD is a team of word lovers. Yet you might be surprised how the worlds of language and science are intertwined. Diarrhea, for example, can be traced to the Greek diárrhoia, meaning to flow through (which, for me, solves the mystery of why the Brits spell the word with an “o:” diarrhoea).

To study etymology, the history of words, is to excavate. Like architecture, words are windows into cultural beliefs, attitudes, and our attempts to make sense of the world around us over time. In science, one of the clearest examples of this is the use of language as taxonomy. “Ella,” for example, is a suffix that categorizes groups of bacteria. What’s the top bacterial cause of diarrhea that ends in “ella”? That’s right: Shigella! Unlocking this taxonomical code allows readers to immediately grasp that Shigella and, for example, salmonella, are types of bacteria.

If you’re wondering who put the “Shig” in Shigella, it would be Japanese physician Kiyoshi Shiga, the first to isolate and characterize the bacteria. Likewise, German physician Theodor Escherich is responsible for the tongue-twister Escherichia coli, often (mercifully) shortened to e. coli (coli is the Latin singular for colon). These are just two examples of a longstanding trend of pathogens being named for their discoverers, cementing their legacy.

By contrast, you won’t find Ruth Bishop’s name immortalized in the wheel-shaped virus she discovered in the 1970s. Instead, the shape gave rise to the name: rota, Latin for wheel, inspired the name rotavirus (see also: rotary phone, named for the circular gadget that rotates a given length based on its corresponding numerical digit).

Photo of a phone
Photo by Pixabay.


Rotavirus photo

That the name rotavirus is based on shape tells us something else, too. Viruses are much smaller than bacteria, and it wasn’t until the invention of the electron microscope in the late 1930s that scientists were able to visualize them for the first time, opening the doors for unprecedented analysis of the organisms that make us sick (and with it, opportunities for more creative name ideas).

Happily, when we talk about rotavirus, we are usually talking about the vaccine that protects against it. While the word immunization has more obvious origins in the word immunity, vaccine comes from the Latin word vacca, meaning cow. The word points to the story of the first vaccine, when Edward Jenner used exposure to cowpox to immunize—vaccinate—a patient against smallpox, providing proof of concept for vaccinology.

Words can also be a time capsule for once widely held beliefs that persist today in name alone. Understanding the word cholera requires going back to medieval medicine’s theory that the imbalance of four humors, or liquids—blood, phlegm, black bile (melancholy), and yellow bile (choler)—was the source of disease. An irritable disposition, and the disease that became known as cholera, was blamed on an excess of yellow bile/choler, which seems unfair because if I had cholera, I would be irritable, too (classic misassignment of cause and consequence).

A sad reality is that, as in science, we run the risk of getting it wrong if we don’t account for our biases. I want Thomas Crapper to be the inventor of the toilet just as much as you do. He’s not, an irony made crueler by the fact that he was a sanitation engineer. The word “crap” pre-dated him (from the Latin word for chaffe/siftings), but it’s unclear how widespread its association with fecal matter was during his career. We’ll never know if his name elicited playful elbow jabs from his fellow plumbers.

Still, he may have inadvertently encouraged the use of the word “crapper” as slang for toilet. American soldiers in London during World War I would have seen his name on sanitation infrastructure and potentially used crapper as shorthand for toilet. The soldiers may have brought the slang back home with them, since it was shortly thereafter, in the 1920s, that the words crapper and toilet became synonymous.

For advocates, the true story of Thomas Crapper may be more inspiring. His innovation was the creation of the bathroom fitting showroom, putting a spotlight on the hidden and unspoken elements of polite society to court new investments. Sounds like an advocate for breaking the poo taboo ahead of his time.

I hope this inspires you to plumb the depths of to explore word origins for terms relevant to your day-to-day. Better yet, if you end up learning about other DefeatDD-related terms, tag us on social media to share what you’ve learned!