John Snow & Cholera (AQA GCSE History)

The impact of cholera on public health - Summary

Conditions in London in 1832 were perfect for the arrival of a new epidemic disease called cholera. Anyone, rich or poor could catch cholera. However, the disease spread more easily within London’s slums. Overpopulation meant communal facilities like toilets and water pumps could not cope with the demand. Toilets were often overflowing with sewage and water pumps were contaminated. Cholera, as a waterborne illness, thrived in these conditions. 

Similar to the Black Death and Great Plague, cholera epidemics occurred roughly every 10 years. The most severe was in 1848-49 when over 53,000 people across England and Wales died. Like the plague in the Medieval and Renaissance periods, cholera was without a cure.

John Snow’s pioneering work in cholera paved the way to understanding the disease. He presented the government with practical solutions to avoid large-scale outbreaks from occurring again. However, the government refused to accept Snow’s suggestions. They continued to believe miasma spread cholera and wanted to avoid spending large sums of money cleaning up Britain’s water supplies. 

Eventually, the work of Pasteur and Koch provided the scientific backing to Snow’s theory on cholera. This changed how the government reacted to issues of public health and epidemic outbreaks in the 20th and 21st centuries.

What is cholera?

• Cholera was a deadly disease that arrived in Britain in 1831

  • Scientists believe that cholera started in India

  • India was part of the British Empire 

    • It is likely soldiers travelling back to Britain brought the disease with them

Symptoms of cholera

• Symptoms usually lasted for two to five days before the victim died of dehydration

• The two causes were:

  • contact with another person

  • drinking water contaminated with faeces from a cholera victim

Cholera epidemics in Britain

• In February 1832, cholera hit London

  • It mostly affected slums, workhouses, prisons and asylums due to the poor hygiene and crowded conditions

  • Approximately 5,275 people had died in London by the end of 1832

Beliefs about the cause of cholera

• Scientists and the government believed miasma was to blame for cholera

  • They believed that rotting material in the streets released miasma, spreading cholera to anyone who breathed in the bad air

  • To reduce miasma, they attempted to clean up the worst areas of London

Who was John Snow?

• John Snow was a well-respected surgeon and London’s top anaesthetist

  • He was the doctor responsible for giving Queen Victoria chloroform during the birth of her eighth child in 1851

• Snow lived in an area of London called Soho

  • From the mid-18th century, Soho housed many French and Italian immigrants as well as the poor

  • Many wealthier residents moved out of the area

  • Much of Soho’s housing was badly built

    • Landlords and builders did not care about the health and safety of the people who rented their rooms

What did Snow discover?

• During the 1848-49 epidemic, Snow observed the disease and wrote On the Mode of Communication of Cholera. He suggested that:

  • miasma was not responsible for cholera

  • the disease affected the stomach, not the lungs

  • victims caught cholera by drinking contaminated water that contained faeces from another person with cholera

• Snow had no scientific evidence to convince others that his theory on how cholera spread was correct

The 1854 Epidemic

• In August 1854, a cholera outbreak broke out in Snow’s neighbourhood of Soho

  • Snow began to investigate after 93 people died of the disease

• Snow created a spot map in an attempt to discover a pattern

  • On a street map of Soho, he drew a spot to represent each death

    • He placed the spot where the person had lived

  • John Snow concluded that deaths centred around the water pump on Broad Street

• To prove that the pump on Broad Street was responsible for the outbreak of cholera, Snow:

  • investigated the deaths that were outside of Broad Street

    • All the victims had drunk water from the pump

  • asked local residents who were not affected why they had not become ill

    • None of them had drunk water from the Broad Street pump

  • removed the handle from the pump so no one else could use the water

• Inspections of the well underneath the Broad Street pump showed the water was less than a metre away from a cesspit

  • The cesspit had cracked, spreading human waste into the water

Storyboard of John Snow and the Broad Street Pump

Significance of Snow

Short-term significance

• Snow stopped the epidemic of cholera around Broad Street

  • He saved many people from dying in the cholera epidemic

• After Snow presented his findings in 1855, the government did not act

  • The General Board of Health and scientists continued to believe that miasma, not water, was spreading cholera across London

Mid-term significance

• The Great Stink of 1858 motivated the government to dispose of sewage correctly

  • They hired Joseph Bazalgette to create a new sewage system

  • Bazalgette completed this in 1875

• Three years after Snow’s death in 1858, Pasteur released his Germ Theory

  • This discredited the theory of miasma

Long-term significance

• Thirty years after Snow’s death, Robert Koch was able to isolate the bacteria that caused cholera

  • In 1884, he proved that contaminated water contained cholera

• The work of John Snow in cholera proved that the government should intervene in public health

  • They introduced the second Public Health Act in 1875 and released further laws into the 20th century