Which statement about John Snow’s cholera work is true?

• A. False.
• B. Maps of cholera outbreaks changed how we saw disease and gave us a model to work with.
• C. It supported miasma theory.
• D. It had no impact on public health practices.

Answer: (B)

Using maps to reveal how an outbreak spreads is key here. John Snow showed that visualizing where cholera cases occur can point to how the disease is transmitted and where to intervene. He plotted cases around the Broad Street pump and found a strong clustering linked to the water source, which argued against the idea that “bad air” caused the illness. This geographic approach gave us a concrete model for investigating outbreaks: gather data, map it, identify the source, and intervene to stop transmission. The pump’s removal led to a drop in cases, illustrating how pinpointing and fixing the source protects public health. Snow’s method helped establish the field of epidemiology and influenced how water and sanitation improvements were implemented.