The turn of the new year during a time of relatively mild weather conditions, at least in Helena, reminds us that we are soon in store for lots of snow. Whatever your thoughts on that (I personally think it should accumulate only in the grassy areas), did you know there is another kind of Snow we should celebrate when pondering our our public health and clinical partnerships?
Dr. John Snow (1913-1958) was an anesthesiologist and obstetrician known as “the father of modern epidemiology”. In 1854, he was able to use his knowledge of disease and its spread, along with a study of the London Soho District and its residents, to ultimately end the deadly cholera outbreak in the city.
Cholera, also known as “blue death”, is caused by some strains of Vibrio cholerae. Its most distinguishing symptom is diarrhea, resembling rice water, which results in rapid dehydration. Successful treatment includes antibiotics and providing oral or intravenous rehydration; without treatment, severe cases can be fatal about half of the time.
Transmission is through the fecal-oral route, especially food or water contaminated with fecal material. Water treatment systems, sanitation policies, and vaccines for travelers can help to reduce the risk for individuals and community members. It is more commonly present in overcrowded, underserved communities where there is poor sanitation and inadequate sewage systems. The London Soho district was just such a community.
The route of transmission is a key factor in this story, because during this time, the popular theory was that this sickness, along with several others, was caused by miasma, the smell in the air. Dr. Snow suspected the water was making people sick, although at that time, “germ theory” was not “a thing”, so he did not necessarily know why.
Dr. Snow knew which neighborhoods got their water from the cleanest vs the dirtiest section of the river, and he plotted the cholera cases on a map. The Soho District was in the area that used the most polluted water. After talking to residents, he was able to deduce which water pump was associated with the highest number of cases. The handle from the (Broad Street) pump was removed so no one could draw water, and the outbreak ultimately ended.
Although he did not live long enough to realize to see it for himself, Dr. Snow’s findings lead to changes in water and waste systems, improving public health in London and around the world. They also supported the germ theory, which says that pathogens cause infections Data such as Dr. Snow’s continues to guide public health decisions today.
As you venture out to enjoy winter activities, remember always, don’t drink from lakes, streams, and especially rivers without treating the water or knowing the best place to capture it. And don’t, please, under any circumstances, eat the yellow snow.
If you choose to stay indoors and learn more about Dr. Snow, you might enjoy The Ghost Map by Steven Johnson, which describes the outbreak and the epidemiological investigation performed by Dr. Snow and Henry Whitehead. You can also read excerpts of his writings in the reference below.
Tulchinsky TH. John Snow, Cholera, the Broad Street Pump; Waterborne Diseases Then and Now. Case Studies in Public Health. 2018:77–99. doi: 10.1016/B978-0-12-804571-8.00017-2. Epub 2018 Mar 30. PMCID: PMC7150208. Available at https://pmc.ncbi.nlm.nih.gov/articles/PMC7150208/pdf/main.pdf. Accessed December 31, 2025.
https://en.wikipedia.org/wiki/John_Snow. Accessed December 31, 2025