#37: John Snow
John Snow, a British physician in the 19th century, stands as a towering figure in the history of epidemiology, but his groundbreaking work on cholera faced initial skepticism and disbelief. At a time when the prevailing belief was that diseases spread through “miasma” or foul air, Snow dared to challenge the status quo. During the 1854 cholera outbreak in London, he meticulously mapped cases and traced the source to a contaminated water pump on Broad Street.
His “germ theory” of disease transmission through contaminated water was met with resistance from the medical establishment. However, his persistence led to the removal of the pump handle, effectively halting the outbreak. Snow’s pioneering efforts laid the foundation for modern epidemiology, showing that diseases could be controlled through public health measures.