Many of the biological organisms and processes linked to the spread of infectious diseases are especially influenced by fluctuations in climate variables, notably temperature, precipitation and humidity. Evidently, in its passage from one individual to another, a pathogen is dependent on a specific mode of transmission and a particular configuration of various external factors. Temperature and humidity are crucial with respect to its reproduction, survival and infectiousness.

From colonial medical officers to WHO advisors to Doctors without Borders, border crossers who link medical cultures in disparate parts of the world have recently captured the attention of historians of disease control. By and large, however, those scholars continue to look to the late nineteenth and twentieth century, situating the emergence of border crossers in the rise of modern globalization. This paper challenges this outlook by introducing an overlooked actor from an earlier period: the consul.