John Snow (epidemiologist and cartographer)

John Snow was a pioneering epidemiologist known for mapping disease outbreaks. During the 1854 London cholera epidemic, he carefully charted where victims lived and identified a contaminated water pump on Broad Street as the source. His work demonstrated how diseases spread through contaminated water, leading to public health reforms. Snow's approach combined careful data collection, geographical analysis, and scientific reasoning, laying the foundation for modern epidemiology and public health strategies in controlling infectious diseases.