John Snow

John Snow (1813–1858) was an English physician whose investigation of London's 1854 cholera outbreak helped establish that contaminated water could transmit cholera.

Broad Street cholera outbreak: A severe cholera epidemic in Soho, London, in 1854, centered on households near the Broad Street pump. This outbreak was the central case in Snow's investigation of waterborne transmission.
Cholera map: A spatial representation of cholera cases or deaths used to examine their distribution. Snow used mapped deaths to identify a cluster around the Broad Street pump.
Thomas Wakley: An English surgeon, journalist, and founder of The Lancet medical journal. Wakley's journal published Snow's arguments about cholera and contaminated water.
John Snow's 1855 cholera map: A map in Snow's 1855 book marking cholera deaths in Soho around the Broad Street pump. It became a lasting visual example of using spatial evidence to investigate disease.
Broad Street pump: A public water pump in Soho, London, associated with the 1854 cholera outbreak. Snow's map showed a concentration of deaths near this pump, whose handle was later removed.
Natural experiment: An observational study in which external circumstances create comparison groups without researcher-assigned treatment. The South London water-company comparison let Snow examine health outcomes under different water supplies.
Edwin Chadwick: An English social reformer whose work promoted sanitary improvements in nineteenth-century Britain. Chadwick supported sanitation reform while interpreting disease through miasma theory.
On the Mode of Communication of Cholera: John Snow's 1849 and 1855 publications arguing that cholera spread through contaminated water. These works set out Snow's evidence and reasoning beyond the famous pump investigation.
Cholera: An acute diarrheal disease caused by infection with the bacterium Vibrio cholerae, often spread through contaminated water or food. The disease Snow investigated was understood through its pattern of transmission.
South London water supply experiment: John Snow's comparison of cholera deaths among households supplied by competing South London water companies. This comparison provided evidence linking cholera mortality to the source of household water.

Linked from 27 pages