"To Rid Oneself of the Uninvited Guest": Robert Koch, Sergei Winogradsky and Competing Styles of Practice in Medical Microbiology

Abstract

Does an infectious disease have one, singular pathogenic cause, or many interacting causes? In the discipline of medical microbiology, there is no definitive theoretical answer to this question: there, the conditions of aetiological possibility exist in a curious tension. Ever since the late 19 th century, the "germ theory of disease"-"one disease, one cause"- has co-existed with a much less well known theory of "multifactorality"-"one disease, many interacting causes". And yet, in practice, it is always a singular and never a multifactorial aetiology that emerges once the pathogenic world is brought into the field of medical perception. This paper seeks to understand why. Performing a detailed, genealogical reading of the 2003 severe acute respiratory syndrome (SARS) outbreak, it foregrounds a set of links that connect the practical diagnostic tools at work within contemporary, 21 st century laboratories to the philosophical assumptions at work within late-19 th century understandings of the "germ theory of disease". © 2011 Blackwell Publishing Ltd.