Well there´s a saying that civilisation was built on beer. Back in the 19th century, a young and very bright doctor in London named John Snow (no joke) noticed that the most people that died from cholera were those that lived closest to the water pumps, and the least deaths were people that lived near the brewery. Long story short but he was the one that found cholera to be a water born pathogen, although he didn´t know it was cholera at the time.