Representations of animals as enemies, antagonists or sources of danger have, in different forms, shapes and degrees, been part and parcel of human interactions with the non-human world across history. It is, however, only at the turn of the nineteenth century that, as a result of bacteriological breakthroughs, non-human animals began to be systematically identified and framed as reservoirs and spreaders of diseases affecting humans. To take one famous example, before the end of the nineteenth century, rats were not believed to be carriers or spreaders of plague or any other infectious disease.⁵ Whereas rats had long been considered to be damaging to human livelihood, due to consuming and spoiling food resources, their only redeeming characteristic was, erroneously, widely believed to be their supposed disease-free nature.⁶ Hence while mid-seventeenth-century plague treatises noted the rat’s destructive impact on fabrics and food, no mention of its connection with the disease was made.⁷ Equally, two centuries later, when in 1849–1850 British colonial officers in India observed that, at the first sight of rat epizootics, Garhwali villagers fled to the Himalayan foothills in fear of the ‘Mahamari’ disease, they dismissed this behaviour as merely superstitious.⁸

However, the bacteriological identification of rats as carriers of plague or mosquitoes as carriers and spreaders of yellow fever and malaria, at the end of the nineteenth century, was itself enabled and indeed complicated by an already-existing stratum of signification which, by the mid-seventeenth century, had led to the introduction of new symbolic, ontological and legal frameworks of thinking about animals as ‘vermin’. Vermin, in Mary Fissell’s definition, ‘are animals whom it is largely acceptable to kill’, not because of some inherent characteristic they possess, but because, in specific historical contexts, ‘they called into question some of the social relations which humans had built around themselves and animals’.⁹ Paraphrasing Fissell, we may say that, arising in early modern Europe, the category ‘vermin’ problematised animals which devoured or destroyed the products of human labour and the means of human subsistence in terms of an agency or intentionality that confounded human efforts to control them. Departing from the structuralist influences of Mary Douglas, which dominated animal studies in the 1980s (see, for example, Robert Danton’s work on the great cat massacre in 1730 France), and from Keith Thomas’ ‘modernisation’ reading of vermin as simply animals that were of no use in an increasingly utilitarian world, Fissell’s discourse analysis of popular texts on vermin from seventeenth-century England was the first to dwell in the social historical reality of the emergence of this notion.¹⁰ However, more recent studies have opposed Fissell’s idea that what made vermin a threat to ‘human civility’ was their perceived ‘greed and cunning’, or their overall ‘trickster’ character.¹¹ Lucinda Cole’s recent monograph Imperfect Creatures argues that, ‘what made vermin dangerous was less their breed-specific cleverness or greed than their prodigious powers of reproduction through which individual appetites took on new, collective power, especially in relation to uncertain food supplies’.¹² The two approaches are not mutually exclusive. Indeed, if approached anthropologically, they point to an entanglement between symbolic and economic aspects of vermin as threats to ‘social integrity’, something that is further supported by the association of vermin at the time with vagrancy and the poor.¹³

Medical historians have in turn noted the association of vermin with miasma in disease aetiologies and public health practices of early modern Eu...