Infectious diseases in the bigger picture

Viewing germs through biological and sociological lenses

In 1922, Simon Flexner, the director of the Rockefeller Institute in New York City, observed that “each generation receives its particular impression of epidemic diseases”. After the influenza pandemic of 1918, the postwar medical generation was trying to “define epidemiology in terms wider than those of the microbic incitants of disease alone”, seeking a more complex and biologically informed understanding of patterns of infection.1 With the development of germ theories in the previous century, epidemiology seemed to have dwindled into microbe hunting, leading to neglect of broader biological, environmental and social influences on disease patterns. This would become a common, and perhaps ritualistic, complaint against the status quo, repeated throughout the 20th century. Each generation of epidemiological reformers fancied itself as contending with facile microbe hunters and germ cultivators. Each new epidemiology offered to restore biological or sociological complexity to the disease calculus.2