John Snow and the broad street cholera epidemic

• Cholera


  A deadly disease that originated in India and was brought back to Britain aboard trading ships
• Cholera was often fatal and provided a very undignified and painful death
• Symptoms of cholera


  1. Severe, often explosive diarrhea

  2. Vomiting

  3. Terrible dehydration

  4. Agonizing cramps

  5. Painful joints

  6. Shrunken, pale face

  7. Coma

  8. Death
• Cholera usually killed in a matter of days, occasionally in hours
• Cities affected by cholera


  • Newcastle
  • Exeter
  • Liverpool
  • London
• Miasma


  The belief that cholera was caused by bad smells
• Cholera was actually caused by sewage getting into drinking water
• Cholera statistics for 19th century epidemics in London


  • 1831-32: 32,000 deaths, 6,536 in London
  • 1848: 62,000 deaths, 14,137 in London
  • 1853-54: 20,000 deaths, majority in London
  • 1866: Last London cholera outbreak declared over
• Edward Chadwick: 'The filth of their dwellings is offensive and so is their personal filth'
• Chadwick believed cholera was caused by the smell of dirty water, not the water itself
• Dr. John Snow


  The first person to correctly identify that cholera was caused by dirty water, during the 1854 Broad Street epidemic
• Dr. John Snow's method

  1. Interviewed people

  2. Mapped cholera deaths around Broad Street pump

  3. Noticed anomalies like Brewery workers not getting sick

  4. Removed pump handle, stopping outbreak
• Dr. John Snow's ideas were not accepted during his lifetime, until Louis Pasteur's germ theory proved him right
• Edwin Chadwick


  Politician who investigated living conditions of the poor and argued disease was caused by filth and dirt, but believed in miasma theory
• Joseph Bazalgette


  Engineer who designed London's new sewer system after the Great Stink of 1858, which helped end cholera by keeping sewage separate from drinking water
• Cholera was a deadly infectious disease that killed thousands in 19th century epidemics
• Cholera was caused by contaminated water, but most people believed it was caused by miasma or bad air
• Dr. John Snow demonstrated cholera was spread by water, but was not widely believed in his lifetime
• Louis Pasteur's germ theory later proved Dr. John Snow was right
• Edwin Chadwick's reports influenced policies to deal with cholera, but he also believed in miasma theory
• Joseph Bazalgette's new sewer system helped end cholera in London, even though he designed it to prevent miasma, not water contamination