How did John Snow first discover Cholera and when did he discover it?

August 1854 was when discovered Cholera by John Snow.

He discovered Cholera when there was an outbreak which occurred in Soho. After he carefully investigated the outbreak, by plotting cases of cholera on a map of the area, he was able to identify a water pump in Broad Street as the source of the disease.

He had the handle of the pump removed, and cases of cholera immediately began to diminish.

John snow first discovered cholera by doing a research is a big city in London and he find out that people in those areas were drinking contaminated water and he discovered cholera in 1854.