began circa 1970 which has witnessed major developments in human mobility affecting all areas of the world. Understanding this still evolving global migratory context bears importantly upon comprehension of contemporary microbial threats. Health issues comprise a not insignificant dimension of the still emerging field of study of migration and security, a scholarly focus of considerable historical pedigree that reemerged after the Cold War and especially after 9/11 (Castles and Miller, 2009).
To paraphrase Kemal Karpat,4 rarely does migration not figure importantly in the history of humankind. Recent anthropological evidence concerning the late Iron Age in Europe suggests that distinctive societies were much more interconnected and fluid than once thought (Wells, 2001). The prosperity and goods of ancient Greece and Rome fostered trade and myriad other interactions just as the military might of Greece and Rome posed a perceived grave threat to tribes and peoples on the periphery, forcing them to adapt, change, and define their identities. The extensive Viking migrations of the eighth to eleventh centuries gave rise to plunder and violence. But those migrations also involved trade and commerce. Medieval migration of Jews in Europe often was linked to rulers’ efforts to spur economic development and to generate greater tax revenues. Much the same could be said about medieval German migrations eastward (Miller, 2008).
The term international migration, which the United Nations (UN) defines as occurring when a citizen or national of one state moves to another state for a period of at least one year, presupposes the existence of an international system of states. Many students of international relations trace the emergence of the contemporary international or Westphalian system to seventeenth-century Europe and the end of the Thirty Years War5 brought about by the treaties of Westphalia. This embryonic nation-state system then diffused to the rest of the world through processes of colonization and imperialism followed by decolonization and the embrace of the sovereign national state system born of Europe after World War II.
Voyages of discovery, conquest, and trade by Europeans marked the advent of the Modern Age. European domination of the New World ensued as many indigenous people succumbed to European-borne diseases, although European populations also were adversely affected by diseases contracted in non-European areas for which Europeans possessed insufficient or little immunity. In general, with the major exception of the 400-year-long African slave trade, which involved over 15 million Africans, population transfers initially were