Before the study of microbiology, it was not understood what made people sick or how diseases spread.
The leading theory up through about the 1850s, and the understanding of microorganisms, was called “miasma theory.” Miasma is the bad-smelling air that originates from decaying material, and it was thought that miasma made people sick.
It was not until the advent of the field of microbiology that people started to understand that some diseases are spread by an infection caused by microorganisms. This paradigm shift was proven by the pioneering work of the founders of the field of microbiology, most prominently Antonie van Leeuwenhoek, Louis Pasteur, and Robert Koch.
Now, roughly another 200 years later, we live in an age where the germ theory of disease is widely accepted. For the sake of public health, it is imperative to look toward the future and wonder what the evolution of infectious disease will mean for our civilization.
Specifically, what will be the next plague, and can we prevent it?