Geography of health

Map diagrams visualisng John Snow's geographical exploration of deaths from cholera in Soho, London in 1854, which helped him pin down the source of the disease to a single infected pump at the centre of the spread of disease.

How did the 1854 cholera epidemic occur? The following statements may or may not contribute to explaining the findings of Dr Snow. You have to say whether that statement DID or DID NOT help to explain his findings. 1) The weather had been very hot. Foul gases (miasmas) from the decaying rubbish on the streets had caused cholera to break out; 2) Big establishments such as breweries had their own wells; 3) Infected people had moved into the area and they infected the air; 4) The Broad St pump well was polluted by sewage; 5) People drank beer if it was available; they survived, as it was not contaminated; 6) The high population density had caused the disease to spread fast from person to person; 7) People liked the taste of the Broad Street pump water so much that they preferred it to water from their local supply, so they had it delivered; 8) Cholera is a water-borne disease.
Answer 1) This statement does not help explain the findings. In fact, it reflects popular ideas of the day about cholera's transmission by 'miasmas' (foul gases), and does not cover Snow's findings linking the spread of disease with water; Answer 2) This statement helps explain the findings to some extent. The brewery and the workhouse were big enough to have had their own wells. None of their workers were ill. The link with water is clear; Answer 3) This statement does not help explain Snow's findings. It perpetuates the idea that the infection is air-borne; Answer 4) This statement is very useful in helping explain Snow's findings. People noticed the pump water was foul-smelling some days before. Under a microscope, Snow could see the polluting organisms from a leaking sewer in the water. Answer 5) This statement is useful in helping explain Snow's findings. The fermentation process in beer-making kills any organisms. Beer was always safe, the water was not; Answer 6) This statement is of some help but does not make a direct link. A high population density with inadequate sanitation makes disease transmission easier; Answer 7) This statement is very helpful in explaining Snow's findings. The cases in Hampstead and Islington did indeed prefer to drink the Broad Street pump water. This is a very important clue. Answer 8) All the evidence convinced Snow that this was so. Removing the pump handle stopped the epidemic - the case was proved.