Which scientist is credited with formulating the concept that many diseases are caused by microorganisms?

Which scientist is credited with formulating the concept that many diseases are caused by microorganisms?

• A. Louis Pasteur
• B. Joseph Lister
• C. John Snow
• D. Christian Gram

Answer: (A)

The main idea being tested is that disease can be caused by microorganisms, the germ theory of disease. Louis Pasteur helped shape and defend this view with key experiments showing that microorganisms drive fermentation, spoilage, and infection, and that they come from the environment rather than arising spontaneously. His work provided strong evidence that specific microbes can be responsible for particular diseases and that controlling or eliminating these organisms can prevent illness, leading to advances like sterile technique and vaccines. While others made important contributions to related areas—such as antiseptic surgery by Joseph Lister, epidemiology by John Snow, or the Gram stain used to identify bacteria—the central concept that many diseases are caused by microorganisms is most closely associated with Pasteur.

The main idea being tested is that disease can be caused by microorganisms, the germ theory of disease. Louis Pasteur helped shape and defend this view with key experiments showing that microorganisms drive fermentation, spoilage, and infection, and that they come from the environment rather than arising spontaneously. His work provided strong evidence that specific microbes can be responsible for particular diseases and that controlling or eliminating these organisms can prevent illness, leading to advances like sterile technique and vaccines. While others made important contributions to related areas—such as antiseptic surgery by Joseph Lister, epidemiology by John Snow, or the Gram stain used to identify bacteria—the central concept that many diseases are caused by microorganisms is most closely associated with Pasteur.