DataViz History: The Ghost Map: Index Case at 40 Broad Street

40broadstreet_smallDid the index (or first) case of the Broad Street Pump outbreak live at 40 Broad Street, close to the pump? Reverend Henry Whitehead thought so after a detailed investigation of cholera cases in 1854 following the outbreak. [SOURCE]

The woman living at 40 Broad Street (Sarah Lewis, wife of police constable Thomas Lewis) lost both her five-month old child, Frances, and husband to cholera. In the four to five-day interval between her child’s onset of diarrhea on August 28-29, 1854 and subsequent death on September 2, 1854, Mrs. Lewis had soaked the diarrhea-soiled diapers in pails of water. Thereafter she emptied the pails in the cesspool opening in front of her house.

Likely baby Lewis had Vibrio cholerae which contaminated the napkin used to absorb diarrhea. Reverend Whitehead conveyed his suspicion concerning the possible index case to the Medical Committee of the Board of Guardians responsible for the public health of the area. The Board sent a surveyor to assess the situation. He created a diagram of the home and cesspool and reported that decayed brickwork in the cesspool resulted in seepage of fecal debris to the Broad Street pump which was about three feet away (see picture).

house40aThe death certificate for baby Frances was filled out by Dr. William Rogers, a local physician. doctor who had attended baby Frances at 40 Broad Street opined in a detailed letter to Reverend Whitehead that the cause of death was acute diarrhea, not cholera, an opinion that he repeated at a meeting of the London Epidemiological Society. Since Vibrio cholerae was not discovered until 1884, it is doubtful that Dr. Rogers could have accurately distinguished by signs and symptoms alone non-cholera acute diarrhea and cholera diarrhea. Thus Whitehead’s theory is certainly plausible that the infant at 40 Broad Street was the index case.

Thomas Lewis, the baby’s father, came down with a fatal attack of cholera on September 8, 1854, the same day that the Board of Guardians had the Broad Street pump handle removed. Assuming wife Sarah Lewis poured water from his soiled garments into the household cesspool, it is likely that water of the Broad Street pump would have remain a source of further infection, if the handle had not been removed.


Why was the cesspool at 40 Broad Street not maintained? Such neglect was increasingly common in London, due in part to economic circumstances. At the time of the Broad Street pump outbreak, London had about two hundred thousand cesspools. For many years, the contents of the cesspools were sold as agricultural manure to be used as fertilizer in the many farms that surrounded London. The money earned from manure sales would then be used to maintain the cesspools. Yet during the nineteenth century as London’s population grew ever more rapidly, farms were forced to move further from the central city. Transportation costs increased, adding to the expense of acquiring cesspool-based manure. Starting in 1847, another change took place that undercut the sale of cesspool manure. Solidified bird droppings (or guano) were brought in as fertilizer from South America at a price far below cesspool manure.

With no economic incentive to sell their feces, poor people would empty human wastes into the streets, or directly into the London waterways. Most lacked public health understanding of how disease was spread, as did many medical and health officials of the times. In the absence of manure sales, cesspools became expensive to clean. As a result, they were poorly maintained and infrequently emptied. Over time this neglect lead to cracks and crevices, which offered opportunities for the spread of enteric pathogens. Such spread of Vibrio cholerae probably occurred at 40 Broad Street.

Given the diarrhea symptoms of the young infant and the assessment of the cesspool by the surveyor, Reverend Whitehead likely determined the index case that started the infamous Broad Street pump outbreak.


Boylan, D. Personal Communication, 2009.

Brody H et al. The Pharos 62(1), 2-8, 1999.

Chave, SPW. Medical History 11(2), 92-109, 1958.

Halliday, S. The Great Stink of London: Sir Joseph Bazalgette and the Cleansing of the Victorian Metropolis, 1999.

Paneth N. et al. American Journal of Public Health 88(10), 1545-1553, October 1998.

Vinten-Johansen, P et al. Cholera, Chloroform, and the Science of Medicine. A life of John Snow, 2003.

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