1854 Broad Street cholera outbreak

The Broad Street cholera outbreak (or Golden Square outbreak) was a severe outbreak of cholera that occurred in 1854 near Broad Street (now Broadwick Street) in Soho, London, England, during the worldwide 1846–1860 cholera pandemic. The Broad Street outbreak, which killed 616 people, is best known for the physician John Snow's study of its causes and his hypothesis that germ-contaminated water was the cause, rather than something in the air called "miasma". This discovery influenced public health and the construction of improved sanitation facilities beginning in the mid-19th century. Later, the term "focus of infection" was used to describe sites, such as the Broad Street pump, where conditions are favourable for transmission of infection. Snow unknowingly took advantage of a natural experiment during his endeavours to identify the cause of cholera transmission.