Climate, Displacement Lead to Global Cholera Outbreaks

hundreds of thousands fall ill to infection

By Jonny Lupsha, Wondrium Staff Writer

Cholera outbreaks have been reported around the world. Spikes in cholera tend to follow displacement due to extreme weather. An 1854 outbreak in London exemplifies cholera’s toll on a populace.

A picture showing John Snow Pub, named after the public health figure John Snow
The John Snow Pub in London was named after John Snow who was considered one of the fathers of modern epidemiology. Photo by Jamzze / Wikimedia Commons / CC BY-SA 4.0

South Asia, the Middle East, the Caribbean, and Africa have all recently reported outbreaks of cholera. Hundreds of thousands have fallen ill from the bacteria, which often spreads through contaminated water. It is believed that the current outbreak is due to displacement caused by flooding, drought, and armed conflict in the affected regions. The sudden displacement associated with these events often forces people to live in unsanitary conditions. Millions have been displaced in Nigeria and Syria alone.

In 1854, a cholera outbreak struck London. In his video series Understanding Cultural and Human Geography, Dr. Paul Robbins, Director of the Nelson Institute for Environmental Studies at the University of Wisconsin–Madison, revisits the outbreak and what early epidemiologists learned from it.

London in Peril

“The main driver of the outbreak was the underdeveloped sewage system throughout the city, which allowed raw sewage to mix with sources of drinking water,” Dr. Robbins said. “But all of this was totally unknown in the 1850s, since people primarily believed in the ‘miasma theory’ of disease, and that ascribes diseases of this kind to bad air. Modern germ theory, which would have identified the source as bacteria in the drinking water, hadn’t yet overturned miasma theory.”

With a disease running rampant, John Snow, considered to be one of the fathers of modern epidemiology, stepped in. Epidemiology is the study of the patterns, distribution, and effects of diseases. Snow favored germ theory over miasma theory and got to work solving the mystery.

“He was able to track the disease to its source: a single well on Broad Street used by all of the victims of the disease,” Dr. Robbins said. “So, how did he do it? The answer is, unsurprisingly, geography. He did it through careful and rigorous spatial detective work, using grounded observation and the power of mapping to figure out and to communicate what was going on.”

Making Sense of the Data

John Snow took a case history of every single household that had had a cholera encounter. He surveyed members of the household about the identities of victims and how they lived their daily lives. Once he had an idea of which houses were which, he located the troubled water well, performing some experiments on its water that confirmed his suspicions.

“He approached the authorities in the area—the Board of Guardians of St. James’s Parrish—and requested they shut down the pump,” Dr. Robbins said. “And though hesitant to do so, they removed the handle after some persuasion, and cholera in the neighborhood ceased.”

Snow then made his case by showing a map of the epidemic with each of the 13 public water wells marked. He also placed a single black rectangle on each household that had experienced a cholera death, adding corresponding marks for multiple cases per household. The pattern clearly shows a concentration of black bars around the well on Broad Street.

“You can go to the site today and see the wellhead memorialized there,” Dr. Robbins said. “And even a greater honor, in such a city of fine drinking establishments, the John Snow pub can now be found facing the well site.

Understanding Cultural and Human Geography is now available to stream on Wondrium.

Edited by Angela Shoemaker, Wondrium Daily