John Snow and the Broad Street Pump is the classic tale of basic epidemiology, the core science of public health. Prior to identification of Vibrio cholera as the causative agent of cholera, and absent any of the modern laboratory supports or computer analysis, Snow developed a theory of the source of the outbreak. He devised a simple map identifying the number and distribution of cases of the disease in the community and the specific water system serving each house in which disease occurred. On this information (His tables are reproduced on the next slide) he hypothesized that one water pump was responsible for transmission of the disease. Disabling the pump by the simple expedient of removing the handle brought the outbreak of cholera to a close.

Teacher’s Note: