The globalisations of disease

Several disciplines - including genetics, bioarchaeology, and documentary history - contribute to the stories we tell of humankind’s major infectious diseases over the past 100,000 years. In some cases, these diseases have dispersed globally because, as obligate pathogens, they have gone wherever their human hosts have gone. Thus, tuberculosis, leprosy, smallpox, syphilis, and HIV/AIDS have traveled along paths (and via technologies) that have moved human populations to all five inhabited continents and Oceania. In other cases, diseases have moved because humans transported microenvironments that brought pathogens along; this would describe the histories of malaria, plague, and cholera. However, many aspects of these narratives are still under debate, including their chronologies and geographic trajectories. This essay will not attempt to settle those debates, but, rather, suggest why the points of debate matter. How does the story change if we alter the chronology by several thousand years, or propose different geographical routes?.