This article’s jumping-off point is the highly incisive but often-ignored claim by the French doctor, Louis-Jacques Tanon, in 1922 that rats acted as plague reservoirs in Paris; in other words, that they harboured the plague bacillus but were refractory to it. This claim partially reframed the fight against this disease in the French capital in the 1920s, which became more centred on surveilling the plague reservoir rather than on destroying rats. Drawing upon Tanon’s hypothesis, this article explores the emergence, evolution, (...) and several iterations of the idea of disease reservoirs in the early twentieth century. On the one hand, it describes the crafting of a range of ideas with which Tanon was directly or indirectly dialoguing, namely, that rats could present a stage called chronic plague, which was especially developed in India; and that human populations, especially children, acted as sources or reservoirs of malaria in Sierra Leone and Algeria. On the other hand, this article shows how Tanon created original reasoning by combining and reformulating some of these ideas and applying them to Paris. Thus, this article contributes to the early history of reasoning in terms of disease reservoirs, as well as presenting a more dynamic history of microbiology by showing how concepts crafted in the “Rest” found their place in Europe. (shrink)

In teasing out the diverse origins of our “modern, ecological understanding of epidemic disease” Greater than the parts: holism in biomedicine, 1920–1950, Oxford University Press, Oxford, 1998), historians have downplayed the importance of parasitology in the development of a natural history perspective on disease. The present article reassesses the significance of parasitology for the “invention” of medical ecology in post-war France. Focussing on the works of microbiologist Charles Nicolle and on that of physician and zoologist Hervé Harant, I argue that (...) French “medical ecology” was not professionally insulated from some major trends in parasitology, especially in Tunis where disciplinary borders in the medical sciences collapsed. This argument supports the claim that ecological perspectives of disease developed in colonial context but I show that parasitologists such as Harant built on the works of medical geographers who had called attention to the dynamic and complex biological relations between health and environment in fashioning the field of medical ecology in the mid-1950s. As the network of scientists who contributed to the global emergence of “disease ecology” is widening, both medical geography and parasitology stand out as relevant sites of inquiries for a broader historical understanding of the multiple “ecological visions” in twentieth-century biomedical sciences. (shrink)

Interactions between microbes and human hosts can lead to a wide variety of possible outcomes including benefits to the host, asymptomatic infection, disease (which can be more or less severe), and/or death. Whether or not they themselves eventually develop disease, asymptomatic carriers can often transmit disease-causing pathogens to others. This phenomenon has a range of ethical implications for clinical medicine, public health, and infectious disease research. The implications of asymptomatic infection are especially significant in situations where, and/or to the extent (...) that, the microbe in question is transmissible, potentially harmful, and/or untreatable. This article reviews the history and concept of asymptomatic infection, and relevant ethical issues associated with this phenomenon. It illustrates the role and ethical significance of asymptomatic infection in outbreaks, epidemics, and pandemics–including recent crises involving drug resistance, Zika, and Covid19. Serving as the Introduction to this Special Issue of Monash Bioethics Review, it also provides brief summaries of the other articles comprising this collection. (shrink)

The Swiss-born medical researcher Karl Friedrich Meyer is best known as a ‘microbe hunter’ who pioneered investigations into diseases at the intersection of animal and human health in California in the 1920s and 1930s. In particular, historians have singled out Meyer’s 1931 Ludwig Hektoen Lecture in which he described the animal kingdom as a ‘reservoir of disease’ as a forerunner of ‘one medicine’ approaches to emerging zoonoses. In so doing, however, historians risk overlooking Meyer’s other intellectual contributions. Developed in a (...) series of papers from the mid-1930s onwards, these were ordered around the concept of latent infections and sought to link microbial behavior to broader bio-ecological, environmental, and social factors that impact hostpathogen interactions. In this respect Meyer—like the comparative pathologist Theobald Smith and the immunologist Frank Macfarlane Burnet—can be seen as a pioneer of modern ideas of disease ecology. However, while Burnet’s and Smith’s contributions to this scientific field have been widely acknowledged, Meyer’s have been largely ignored. Drawing on Meyer’s published writings and private correspondence, this paper aims to correct that lacuna while contributing to a reorientation of the historiography of bacteriological epidemiology. In particular I trace Meyer’s intellectual exchanges with Smith, Burnet and the animal ecologist Charles Elton, over brucellosis, psittacosis and plague—exchanges that not only showed how environmental and ecological conditions could ‘tip the balance’ in favor of parasites but which transformed Meyer thinking about resistance to infection and disease. (shrink)