John Snow (March 15, 1813 - June 16, 1858) was an English physician and a leader in the adoption of anesthesia and medical hygiene. He is considered one of the fathers of modern epidemiology, in part because of his work in tracing the source of a cholera outbreak in Soho, London, in 1854. His findings inspired fundamental changes in the water and waste systems of London, which led to similar changes in other cities, and a significant improvement in general public health around the world. Snow suffered a stroke while working in his office. He never recovered, dying in 1858, at the age of 45.