What action did John Snow take to stop the cholera outbreak?

• A. He removed the handle from the Broad Street Pump
• B. He closed the Broad Street hospital
• C. He quarantined affected houses
• D. He issued a city-wide water purification order

Answer: (A)

Interrupting the transmission route by removing the contaminated water source. John Snow traced the outbreak to the Broad Street pump, showing that people drinking from that tap were getting cholera. By taking the pump handle away, he stopped access to that source, which reduced new infections and provided evidence that the disease was waterborne rather than spreading through the air or via person-to-person contact. The other options wouldn’t address the actual vehicle of transmission: closing a hospital, quarantining houses, or issuing a broad water purification order don’t eliminate exposure to the contaminated water that was driving the outbreak.