William Budd

William Budd (14 September 1811 – 9 January 1880) was an English physician and epidemiologist known for recognizing that infectious diseases were contagious. He recognized that the "poisons" involved in infectious diseases multiplied in the intestines of the sick, were present in their leaks, and could then be transmitted to the healthy through their consumption of contaminated water. He particularly understood this about the transmission of cholera (as he learned from the work of the physician John Snow) and typhoid fever. Provided by Wikipedia