Disease Maps: Epidemics on the Ground by Tom Koch (review)

Maps provide useful visualizations of larger landscapes, allowing us to see connections on a multitude of scales. One thinks of road maps or classroom world maps, but disease maps? Medical geographer Tom Koch argues that “seeing” disease incidence and mortality statistics on a map generates new knowledge or understanding about where and how disease strikes and spreads. He also explores how maps emerge as evidentiary statements in their own right.

The book is divided into three parts. In “Part I: The Idea That Is Disease,” Koch describes early mapping of the body and the world. As sixteenth-century anatomists explored the human body through dissection, they discovered that what they saw in the body did not always match the traditional texts of their venerated medical leaders. Correcting these inaccuracies, Andreas Vesalius published his influential anatomy textbook De Humani Corporis Fabrica in 1543, which, as the first to include detailed illustrations of the body, cultivated knowledge from the experiential and observable. The atlas, another sixteenth-century innovation, promoted visual thinking through its maps of cities and countries and the world. Published in 1570, the Theatrum Orbis Terrarum (Theater of the countries of the world) was the world’s first atlas. The Theatrum compiled, standardized, and arranged maps of various kingdoms, geographical regions, and travellers’ reports to present spatial relationships that allowed readers to “see” lesser-known places and to view the world as more interconnected and alike. By the eighteenth century, society and the state began to view urban diseases such as smallpox, measles, typhus, typhoid fever, influenza, and plague as “diseases of place,” and thus maps made the connection between where people lived and where disease occurred. When yellow fever erupted in New York, physician Valentine Seaman used disease mapping as evidence that a causal relationship existed between yellow fever deaths and odiferous sites in the city, thus supporting the miasmatic theory of disease. But it was cholera in the nineteenth century that really led to the embrace of disease mapping.

Part 2, which contains six of the twelve chapters of this book, focuses on cholera as “the exemplar” in which disease maps outwardly tested ideas about disease. British physician John Snow’s disease map of South London that supported his argument that cholera was a water-borne disease is a well-known story. Visitors to Soho in London can see the historical plaque that outlines Snow’s role in tracing the source of the cholera outbreak of 1854 to the Broad Street pump. What readers may not know, however, is that different disease-map arguments surrounding cholera had been presented before this. In 1831 Polish physicians produced maps arguing that the diffusion of cholera was orderly and predictable, while Dr. John Harnett’s map of the Dantzick cholera proposed that the disease originated from local odours and foul personal habits. The medical journal The Lancet printed a map of cholera to illustrate its method of travel along trade routes, arguing that no locale was necessarily immune from the disease.

The third and final part of the book, entitled “The Legacy and Its Future,” comprises only one chapter, in which Koch suggests mapping cancer in our quest to understand this disease. He cautions us not to see maps as illustrations of statistical data but as tools of graphical analysis in their own right to support new knowledge or ideas about causal elements of disease. The “seeing” is a test of the “knowing,” argues Koch. Perhaps. Mapping clusters of cancer cases (or tuberculosis cases or multiple sclerosis cases) to environmental determinants seems somewhat plausible, yet are all diseases so interchangeable in terms of this approach?

As this is a book about disease maps, it was pleasing to see more than 120 illustrations and maps with good captions. Less pleasing were the errors that an editor should have caught, such as John, not Andrew, Pickstone on page 31, and the year should be 1776, not 1976, on page 83. Still, this is a fine book that will...