Foundations of Epidemiology
We are going to replicate one of the foundational studies in Epidemiology and the closely related field of Health Geography using modern GIS techniques.
Applying Modern Methods to the 1854 Cholera Outbreak
Dr. John Snow was a physician practicing in London where cholera outbreaks were a frequent occurrence due to poor sanitation practices. Dr. Snow was a skeptic of the miasma theory and a proponent of germ theory. In 1849 he proposed cholera that it was spread by fecal contaminated water, after comparing cholera rates between London districts supplied by different water companies.
- Five years later, during an outbreak in London’s SoHo neighborhood in 1854, Dr. Snow was able to identify the point source of an the outbreak using a hand-sketched map. He recorded each case of cholera in the area using a dash, and recorded each water pump with a circled dot, creating what today would be called a ‘dot map.’ By recording clusters of disease, and conducting interviews, Snow was able to trace most cases of the outbreak to a single water pump, located on Broad st.
- Using this map, Dr. Snow was able to convince the local council to remove the pump handle and the outbreak subsided.
- Despite this, the medical community in London continued to reject the idea that Cholera was caused by fecal contamination for another twenty years.