The Evolution and Spread of Major Human Diseases in the Indian Ocean World

Abstract

By placing the Indian Ocean World (IOW) into the larger global histories of five major infectious diseases—malaria, tuberculosis, leprosy, smallpox, and plague—this paper offers a synthetic state-of-the-field assessment of what is now known or postulated about the origins and trajectories of these diseases. Focusing in particular on the mediaeval period, the paper demonstrates the significant value of using an integrated, multi-disciplinary approach in historical epidemiology that blends palaeogenetics with more traditional historical sources to trace the possible connectivities of the five diseases into, across, and from the IOW. It argues that although the IOW has neither been included substantially thus far in global health history, nor has it generated any samples of pathogen ancient DNA (aDNA), it is nevertheless possible to begin to reconstruct the pre-modern histories and conceivable spread of these five major human diseases in and across this region of the world. As archaeology, bioarchaeology, genetics, and document-based history forge stronger alliances, this region of intense historical human activity, migration, and trade—of connectivity—must necessarily be incorporated into wider discussions of the history of global health.