John Snow

• Who was John Simpson 


  he was a famous surgeon who worked on broad street London. in 1854 there was an outbreak of cholera and over 700 people died in his area.

  he investigated and through meticulous research, he discovered all people who died were using the same water pump.

  Snow took away the handle and there was no more deaths.

  he investigated further and found that a crack in a street toilet was allowing for waste to contaminate the water supply.

  Snow proved that cholera was spread though contagion and hence disproved the miasma theory
• What was John Snow's short term impact 


  • provided immediate insight into disease transmission
  • increased public awareness about contaminated water
  • improvements in water supplies and sanitation = reducing cholera cases
  • public health responsibility from authorities
• What was John Snows long term impact

  • foundation of epidemiology ( mapping and distribution of diseases)
  • broke the strong miasma theory
  • development of clean water and sewers
• How was John Snow limited 


  • traditional miasma theory
  • political and social factors made the implications of his findings slow