Who disproved the Miasma Theory?

• A. John Snow
• B. Ignaz Semmelweis
• C. Edward Jenner
• D. Louis Pasteur

Answer: (A)

Disproving the Miasma Theory hinges on showing a disease is transmitted through a specific mechanism other than foul air. John Snow did this with cholera in London by mapping cases and linking them to a common water source. He found that deaths clustered around the Broad Street water pump and, after removing the pump handle, outbreaks subsided. This provided strong evidence that cholera spread via contaminated water rather than through “bad air,” challenging the idea that disease arose from miasma. While Ignaz Semmelweis highlighted the importance of hand hygiene, Edward Jenner developed vaccination for smallpox, and Louis Pasteur advanced germ theory and disproved spontaneous generation, Snow’s investigation is the classic demonstration that environmental transmission can explain a disease pattern, effectively discrediting the miasma explanation in this context.