Evolution of Epidemiology

Toward a Modern Approach

Establishment of Germ Theory

• Studies by Louis Pasteur and Robert Koch firmly established the germ theory.
• Attention and research efforts shifted to biological agents, and away from the environment or host resistance.
• This shift happened in spite of Pasteur’s warning that the role of the environment was more important than that of the agent.
• Snow’s work was not appreciated or expanded upon until the years after World War II.