While environmental historians have found it tempting to treat diseases as natural entities that have shaped the human past, most diseases so thoroughly entangle the natural and the cultural that consigning them to nature can be reductive and misleading. This article uses the history of yellow fever—a disease whose virus and vector originated in Africa and spread throughout the Atlantic—to tell just such a story of entanglement, to raise larger questions about causation in environmental history, and to argue that we need to see diseases not as intruders into but essential products of history.
