clock menu more-arrow no yes

How to trace an outbreak in 1854

It all starts with a pump.

It all starts with a pump.

It all starts with a pump.

In this episode of Vox Almanac, Vox’s Phil Edwards explores the story behind Dr. John Snow’s famous map of the Broad Street pump.

In 1854, news spread about a mysterious new cholera outbreak in London. At the time, doctors and scientists largely believed the disease traveled in a miasma — a floating cloud of sickness. Dr. John Snow suspected bad water might actually be the agent of transmission — and he wanted to prove it in time to stop the outbreak.

Through a mix of personal interviews, clever detective work, and data analysis that included tables and a famous map, Snow managed to stop the outbreak and convince local public health officials, eventually, that cholera could be transmitted through water, not a miasma. Since his breakthrough study, the map has become an iconic piece of epidemiological history — an illustration of keen detective work, analysis, and visual representation that, even today, tells a story.

Watch the above video to learn more. You can find this video and all of Vox’s Almanac series on YouTube.

Further Reading

  • Cholera, chloroform, and the science of medicine : a life of John Snow is a great starting point. This lengthy academic study of John Snow’s life and work follows his career as a pioneering anesthesiologist as well as his work on cholera. It clears up a lot of misconceptions about his influence and work and provides a sense of Snow as a person (he was a teetotaler and vegetarian — both unusual for the time).
  • Cartographies of disease : maps, mapping, and medicine is Tom Koch’s history of disease mapping. It’s a great overview of the discipline, showing how the practice existed before Snow, how Snow’s map changed and influenced the field (and how it didn’t), and how far disease mapping has come since.