The singular case of SARS: medical microbiology and the vanishing of multifactorality

This thesis is about the politics and the possibilities of aetiology. Firstly, the possibilities. Does an infectious disease have one, single pathogenic cause or many, interacting causes? In the medical microbiological sciences, there is no definitive answer, one way or another, to this question: there, the conditions of aetiological possibility exist in a curious tension. Ever since the birth of the 'germ theory of disease' and the concomitant birth of the singular aetiological object, these conditions have allowed for the co-existence of a very different, and far less well understood kind of object: the multifactorial object. That SARS was caused by one, singular viral agent, a coronavirus (CoV), is now entrenched as microbiological fact. And yet, the curious thing about SARS is that the history of the 2003 outbreak is littered with moments at which the possibility of the multifactorial object presented itself to, and was actively considered by, medical microbiologists. So how did we get here - to SARS-CoV, an infectious disease that could be understood and storied in this, the most singular of ways? And what happened along the way to deny the multifactorial aetiological object any kind of existence at all? In an attempt to grapple with these questions, the thesis seeks to recover the possibility of the multifactorial object through a deep, ethnomethodological reading of the moments at which it flared up precise/y as a possibility for medical microbiologists investigating the outbreak. What emerges from that recovery operation is a sense that the multifactorial object was never actually ruled out or disproved in any way, but rather, was vanished. Put another way, the suggestion is that various medical microbiological practices and interventions, whilst establishing singularity, were serving, at the same time, to create an illusion of multifactorality's non-existence; an illusion behind which the issue of multifactorality, its possibility, could be discarded without ever having to be resolved, one way or the other. In the closing sections of this thesis a move is made towards suggesting that SARS-Co V, the singular disease, was the product of a choice-, a choice that was made to explore one aetiological possibility at the expense of another. And that is where the politics comes in. For if politics, the realm of the political, can be taken to arise in situations where various possibilities exist but not all possibilities can be chosen, then it follows that what this thesis provides is an opportunity to foreground the politics bound up with the practical doing of aetiology. As a result, and based on the experience of attempting to recover the vanished multifactorial object from the 2003 SARS outbreak, the thesis concludes with an attempt to inhabit the present in such a way as to make it possible to think, in a little more detail, about where aetiology, as understood by medical microbiologists, might be heading in the future: might recent shifts in practical, everyday, seemingly innocuous microbiological technique, have begun to make it easier to coax the multifactorial object out into a space of visibility? Might those shifts actually herald the crossing of an epistemological threshold in the medical sciences? And might the conditions of aetiological possibility be changing, and changing in ways that would drastically alter what it meant to speak of a 'disease', an 'infection' and a 'pathogen'?