Until recently, and with a few notable exceptions, social and political histories of Asia had surprisingly little to say about disease. Despite the historical impact of epidemics on human societies in terms of mortality and morbidity, there has been a reluctance to invest such episodes with the significance attached to a war or a dynastic change. Epidemics take center stage only when they cannot be avoided, and even then they are most often invoked as contextual material for narratives that hinge on social, political, and economic developments. This has led to a striking asymmetry: while pages in textbooks on China are devoted to the collapse of the Ming dynasty in the 1640s, only a few sentences are included in passing on the loss of life that resulted from catastrophic epidemics. Similarly, while tomes are written about the First World War, comparatively little attention is paid to the 1918–1919 influenza pandemic in India, which may have killed up to 20 million people – far more than the sum total of those who perished in combat.

One reason for this relegation of epidemics in history has been that they have tended to be viewed as exceptional occurrences. They have been construed as exogenous events, extrinsic to the societies they affect. Like natural disasters, epidemics are understood to crash into communities from without: they belong, accordingly, to a space outside human history. Another reason is that examining the history of infectious disease is deemed to require specialized knowledge and expertise that goes beyond textual scrutiny of the historical archive. How can we write about infections if we have no formal training in, say, epidemiology or microbiology? Because epidemics are intertwined with environmental issues that are vast and complex, they are difficult to grapple with. To engage with such issues and the incommensurable scales they comprise (the very focused and the expansive), history would need to become radically transdisciplinary. It would also involve uncertainty since many questions about the origin and identity of diseases in history cannot be readily answered. William McNeill has expressed this tension succinctly: ‘We all want human experience to make sense, and historians cater to this universal demand by emphasizing elements in the past that are calculable, definable, and, often, controllable as well. Epidemic disease, when it did become decisive in peace or in war, ran counter to the effort to make the past intelligible.