John Snow - The Cholera Detective

John Snow, a British physician, investigated the 1854 Broad Street cholera outbreak and proved that contaminated water, not bad air, was spreading the disease.

The third cholera pandemic spread worldwide from 1846 to 1860, resulting in over one million deaths in the Russian Empire and 23,000 in Great Britain, not to mention a million more in other parts of the world; it was the harshest pandemic the 19th century had ever seen. Scientists and physicians of the time struggled to contain and understand it, that is, until a young British anesthesiologist, John Snow, began investigating what he believed to be the source of the 1854 Broad Street outbreak: the handle of a public water pump in Soho, London.

Snow was born on March 15, 1813, in York, England, and grew up in one of York’s poorest neighborhoods. The sanitary conditions of much of England in the 19th century were dangerous, with citizens disposing of both human and animal waste either into the street or under their own homes. By the time Snow was nineteen, he had undertaken a medical apprenticeship and was treating cholera victims in the small coal-mining village of Killingworth.

Although Snow was interested in epidemiology and the treatment of cholera (there were multiple epidemics in London throughout his early life), his first contributions to the medical field were centered on anesthesia. After receiving his degree from the University of London and his admittance to the Royal College of Physicians, he founded the Epidemiological Society of London but continued to focus on anesthesia and childbirth. His use of chloroform during pregnancy was monumental in offering laboring mothers pain relief during delivery, and rather than patenting this procedure, he instead published papers and pamphlets for the public to read.

But John Snow would soon learn that the public was not always willing to accept his new medical ideas. At the time of the 1854 Broad Street cholera outbreak, the medical community had two primary and competing views of cholera’s formation and transmission: miasma theory and germ theory. Miasma theory, which took precedent, as it had been widely accepted for decades, stated that cholera was caused by particles in the air. Given the unsanitary conditions of London, this theory was reinforced by scenes of waste lining the streets and the River Thames.

Germ theory, on the other hand, was both new and lacking definitive evidence of a cholera germ cell. However, John Snow believed in this theory, and used it as a point of reference in his investigation of the Broad Street outbreak.

In August of 1854, after multiple outbreaks elsewhere in London, cholera spread rapidly throughout Soho. In just under two weeks, 500 people had died, and the disease reached a mortality rate of almost 13 percent. Given Snow’s medical and epidemiological history, he decided to investigate alongside other medical practitioners. After many conversations with locals, Snow believed that the outbreak had its source at the public water pump. By creating a dot map of known illnesses and deaths surrounding the pump, Snow convinced the local authorities to remove the pump’s handle, effectively disabling the well.

The outbreak quickly subsided, and Snow was given credit for ending cholera’s spread in Soho. His investigation was also responsible for enacting another investigation into the pump, it was discovered that the pump’s well was only a few feet away from an old cesspit that began leaking into its water supply, thus giving contaminated water to all who used it.

Government officials replaced the pump handle, yet both they and the public continued to reject Snow’s germ theory of contamination, however much evidence he had to support it. He lived the rest of his life believing in his theory, and died in 1858 at the age of 45, just eight years before the medical community finally accepted his work as plausible.

References:
“John Snow and the Broad Street Cholera Outbreak.” Policy Navigator, navigator.health.org.uk/theme/john-snow-and-broad-street-cholera-outbreak.
“John Snow.” Encyclopædia Britannica, Encyclopædia Britannica, inc., www.britannica.com/biography/John-Snow-British-physician.
Ruths, Mitali Banerjee. “The Lesson of John Snow and the Broad Street Pump.” Journal of Ethics | American Medical Association, American Medical Association, 1 June 2009, journalofethics.ama-assn.org/article/lesson-john-snow-and-broad-street-pump/2009-06.
Tulchinsky, Theodore H. “John Snow, Cholera, the Broad Street Pump; Waterborne Diseases Then and Now.” Case Studies in Public Health, U.S. National Library of Medicine, 2018, www.ncbi.nlm.nih.gov/pmc/articles/PMC7150208/.

Key words:
Science, Innovation, Courage, Perseverance, Honesty, Responsibility, Make a Difference, Stand Up for Your Beliefs

Image Citation:
Public Domain