In retrospect, Snow made several important contributions to the development of epidemiologic thinking: He proposed a new hypothesis for how cholera was transmitted well and getting cholera. He argued for an intervention which prevented additional cases (removal of the pump handle).
John Snow on the case
DR Snow though the virus was spread by water not air, then he decided to investigate. He started with a map of the soho area, he marked where people had died and he also makes the water pumps in the soho area. He then noticed more deaths their water pumps.
DR Snow convinced the council that the water from the Broad Street pump was the source of the cholera. So the pump was the source of the cholera. So the pump handle was removed. But by then the outbreak was already dying away
The Pump is shut down
So how did the water get infected?
In those days people get water from water pumps, and if the water is polluted bacteria will live in the water. But how did it get infected? There was a leaking cesspool near a water pump so the bacteria goings into the underground well.
Cholera hit London on 31 August 1854,Within three days 127 people had died and slowly more people were died.
At that time no one knew how to treat this virus so DR Snow investigate more and asked the council people to close the water pump as more deaths are near the water pumps as the virus is spread by water from a leaking cesspool.Even though DR Snow didn't invent a cure he investigate and found out the cause of this pandemic!