Thread by @mendel_random

Must read piece on cholera and COVID by @NeilSinghHQ A brief thread on whether it's true that in Broad Street John Snow “had the handle of the pump removed which led to a sharp decline in cholera cases in Soho”.
theguardian.com/society/2020/m…

1/n When Snow had the Broad Street Pump handle removed the outbreak was almost over.
academic.oup.com/ije/article/31…

2/n The data were published after Snow was dead by his friend the Reverend Henry Whitehead, who accompanied him on his visits to Soho and speculated (with no strong basis) that there may have been a resurgence of the outbreak if the handle had not been removed

3/n Snow’s achievement was not the Pump Handle (though it makes a good, usually mistold - story), it was his study of the water source for houses across London, and how that related to cholera cases, described in his 1854 book that @NeilSinghHQ discusses archive.org/stream/b289852…

4/n However what Snow reported wasn’t all it seemed, as Edmund Parkes' incredibly detailed 1855 review of Snow’s book discussed academic.oup.com/ije/article/42…

5/n Parkes pointed out that whilst Snow made it sound like he had individual level data, this wasn't the case. Parkes discusses what epidemiologists would now call "the ecological fallacy"

6/n It was this “peer review” that led Snow to undertake his definitive show leather epidemiological investigation, demonstrating the importance of individual household level water supply archive.org/stream/b289852…

7/n After the "Great Stink" of 1858 Joseph Bazalgette’s sanitation plan for clean water and efficient removal of sewage was advanced, cleaning up London and protecting against future cholera outbreaks academic.oup.com/ije/article/42…

8/8 Joseph Bazalgette was the great-grandfather of Peter Bazalgette who introduced “Big Brother” @bigbrotheruk
Whilst his ancestor pumped shit out of people’s houses the great grandson pumped shit into them & onto their TVs. Snow and co's whole story: academic.oup.com/ije/article/31…