Maps have the power to change minds, as the 1861 map that convinced Lincoln to end slavery proves. Maps also have the power to save lives. One such map, the John Snow map, single handedly ended a cholera outbreak and revolutionized epidemiology. Dr. John Snow’s cholera map of London charted deaths in the Soho neighborhood during the 1854 cholera outbreak. Snow’s map proved that the outbreak came from contaminated water at the Broad Street Pump.
Cholera in London was a horrifying epidemic, made worse by the fact that London routed its sewage directly into the Thames River, the city's source of drinking water. Victims of cholera suffered from horrific diarrhea, and the mixing of fecal matter and drinking water was a deadly combination.
How did epidemiology start? John Snow, anesthesiologist to Queen Victoria, combined investigative reporting and medical analysis in his cholera map, saving lives and earning himself the title of "father of modern epidemiology." John Snow solved the riddle of cholera as the outbreak struck his own neighborhood.
Cholera Was A Terrifying Epidemic That Could Kill Within Hours
The Working Theory At The Time, The "Miasma Theory," Blamed Cholera On London’s Slums
Doctor John Snow Questioned The Miasma Theory
Death Statistics Pointed Snow Toward A New Theory: Water
In 1854, Snow Tested His Theory When Cholera Broke Out In Soho
Malt Liquor Saved Lives In The Lion Brewery