John Snow Cholera OutbreakFact or fiction?Take this quiz to see how much you know about John Snow’s historic investigation of cholera in 1854.

1. At the time of the devastating cholera outbreaks in 19th century London, it was a new disease about which little was known.

True?False?

1. At the time of the devastating cholera outbreaks in 19th century London, it was a new disease about which little was known.

FalseAlthough its etiology was unknown, over 700 books and pamphlets dealing with cholera were published in London during the time of the third pandemic (1839-1856). Most adhered to the prevailing thought, known as the miasma theory, that cholera was the result of a noxious form of bad air.

While true that the microscopic organism Vibrio cholerae would not be identified until 1883, British doctors had been treating cholera for hundreds of years. However, it had been seasonal and cases were generally mild and came to be known as cholera nostra (“our cholera”), after the much more virulent “Indian” cholera arrived in the 1830s like a penance for Victorian imperialism.

Vibrio cholera

2. John Snow was a London physician who went door-to-door collecting information about deaths from cholera, which led him to identify water as the likely cause of the outbreak.

True?False?

2. John Snow was a London physician who went door-to-door collecting information about deaths from cholera, which led him to identify water as the likely cause of the outbreak.

FalseSnow’s investigation was guided by his already-developed theory that cholera is a localized disease of the gut and the likely route of transmission in this situation was drinking water.

Snow was focused on the wells from the start, and was told by a community resident that the Broad Street pump had a bad odor during the height of the outbreak. His data – addresses of 89 fatal cases – came from the General Register Office, and he used this to make detailed inquiries during the first phase of his investigation.

1849 Cholera prevention poster

3. Snow noted all the cholera deaths with black horizontal bars on a map of the area, and was able to use this spot map to prove to the Board of Health that the Broad Street pump was the cause of the cholera outbreak.

True?False?

3. Snow noted all the cholera deaths with black horizontal bars on a map of the area, and was able to use this spot map to prove to the Board of Health that the Broad Street pump was the cause of the cholera outbreak.

FalseNot only did Snow not use a map to discover the source of the outbreak, he also did not use a map of any kind in his presentations to the Board of Health. The famous map was created and used several months later as a persuasive illustration for the London Epidemiological Society.

Furthermore, after a decade passed, Dr. Edwin Lankester, who lived in the area and who had instigated a more thorough investigation into the outbreak at the time, said of Snow’s waterborne/pump theory: “He was not believed--not a member of his own profession, not an individual in the parish believed that Dr. Snow was right. But the pump was closed, nevertheless, and the plague was stayed.”

Dr. Edwin Lankester

4. Removing the handle of the Broad Street pump did not stop the cholera epidemic.

True?False?

4. Removing the handle of the Broad Street pump did not stop the cholera epidemic.

TrueDespite myths and urban legends, the cholera epidemic of 1854 was already waning when the Board of Health removed the handle of the Broad Street pump. Snow himself never made any such claims.

Rev. Henry Whitehead, a local cleric who worked with Snow in collecting and analyzing data, presented a paper to the Epidemiological Society of London in 1867. He used a data table that showed the number of fatal attacks had fallen from 142 on September 1, 1854, to 14 on September 8, the day the pump handle was removed.

However, Whitehead explained that removing the pump handle served the important function of preventing a second wave of illness. “…If the removal of the pump handle had nothing to do with checking the outbreak which had already run its course,” he said, “it had probably everything to do with preventing a new outbreak, for the father of the infant, who slept in the same kitchen, was attacked with cholera on the very day on which the pump handle was removed.”

1850s Punch magazine cartoon

5. John Snow did not find the index case – the first person with cholera who initiated the outbreak.

True?False?

5. John Snow did not find the index case – the first person with cholera who initiated the outbreak.

TrueWhile working on an unrelated project, Rev. Henry Whitehead inadvertently came across a report of a 5-month old child who had died on September 2. The cause of death was listed as exhaustion after having diarrhea for 4 days; the onset of her symptoms and the length of her illness meant she was sick before anyone else. Previously it was believed that the epidemic started the night of August 31, when more than a dozen Soho residents came down with symptoms of cholera. Also, this child’s family lived in the house closest to the Broad Street pump.

Whitehead interviewed the child’s mother and discovered that she had rinsed the baby’s diapers in pails of water that she emptied into a cesspool in the front of the house.

Rev. Henry Whitehead

To read more about the historic 1854 cholera epidemic and the community’s efforts to discover the cause, see “Map-Making and Myth-Making: John Snow Didn’t Solve the 1854 Cholera Outbreak with a Map,” at the Practical Playbook.

Sources:

S. P. W. Chave, B.A. HENRY WHITEHEAD AND CHOLERA IN BROAD STREET. Med Hist. 1958 Apr; 2(2): 92-108, 108-1. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1034367/

“John Snow and Cholera,” a blog post at The Sick City Project by Richard Barnett, PhD. https://sickcityproject.wordpress.com/2013/03/11/john-snow-and-cholera/