Cholera, Miasma, and Germ Theory – Quick Notes

Miasma theory vs. germ theory

• Miasma theory: disease from poisonous vapor; widely accepted.
• By 1840s, cholera outbreaks in London sparked doubt, leading to early germ theory advocates like Dr. John Snow.
• Germ theory: disease from specific microorganisms; data-driven.

John Snow and the cholera investigation

• Dr. John Snow linked cholera to water, challenging airborne transmission.
• Mapped 83 deaths in the first week of the Soho outbreak; 73 lived near the Broad Street pump.
• Proposed shutting down the Broad Street pump, suggesting a "poison in water" idea.

Soho outbreak evidence and pump connection

• Evidence included a widow using Broad Street water despite distance and a nearby workhouse with few infections due to its own well.
• An infant's dirty diapers tossed into a cesspool near the pump implicated contaminated water.

Official response and challenges

• Officials resisted the waterborne hypothesis but shut down the pump as a precaution; new cases then subsided.

Vindication and major germ theory milestones

• 1884: Dr. Robert Koch isolated the cholera-causing bacterium, proving microbial cause.
• Louis Pasteur also contributed to germ theory and vaccine development.

Public health impact and scientific method

• Data-driven challenges to miasma theory revolutionized public health and the scientific approach to disease.

Looking ahead

• Scientists ask: what are the widely held beliefs today that our descendants may find ridiculous?