A superb thematic map depicting the spread of cholera across Eurasia in the early 19^th century. Separately published, extremely rare, and in its way horrifying.

Perhaps better than any other contemporary map, this work by Carl Ferdinand Weiland (1782-1847) depicts the geographic progress of cholera across Eurasia and the Horn of Africa.  It employs color coding to trace the annual spread of the disease from the year 1817, when it first left Bengal, up to 1831, by which time it had spread to Eastern Europe and parts of Germany.  It also shows vectors by which the disease spread, including a vessel that sailed from Calcutta to Mauritius in 1819 and another from Bombay to the Persian Gulf in 1821, as well as overland trade routes linking India with Russia.  A large inset map at lower left charts the early spread of the disease on the Indian Subcontinent between 1817 and 1820.

This cholera map was published in Germany in 1832, while the pandemic still raged and in an era when the causes of disease were not yet understood. For viewers there it must have conveyed a certain horror to see the disease approaching with the apparent inevitability of a tidal wave.

The Cholera Pandemic
It is no accident that cholera spurred the development of some of the first sophisticated works of medical cartography, as the early 19^th century saw it spread from India to become a global scourge.  It had its origins in the Ganges Delta, where it had recurred since ancient times though historically its spread had been confined to the Subcontinent.  In 1817 however it began to spread from Bengal rapidly across Asia, carried initially by itinerant merchants and British soldiers. As shown on the Cholera-Karte, by 1824 it had reached the far shore of the Caspian Sea as well as the Middle East before playing itself out.

Weiland published his cholera map during the Second Cholera Pandemic (1827-35). This again originated in Bengal but by 1831 had spread to China, Russia, Central Europe and even the North of England, and it eventually crossed the Atlantic to plague Canada and the northeastern United States. This Second Pandemic in particular was a shock to Western society and prompted serious study into the causes, effects and possible treatments. The first significant breakthrough would not occur until 1854, when Dr. John Snow made the connection between contaminated water and the disease.  Subsequent investments in urban sewage infrastructure in the developed world made huge inroads, as did the development of a vaccine toward the end of the century. These however did not come in time to prevent millions of further deaths from a succession of epidemics throughout the 19^th century.

Mapping cholera: pioneering medical cartography
Simple maps locating cases of yellow fever fever in New York City were produced as early as the 1798, but the cholera pandemics catalyzed the first sophisticated works of medical cartography.  While 30 or more cholera maps were published during the early years of the pandemics, the Cholera-Karte stands out for its large size, pan-Eurasian scope, the clarity and detail of its design and the accuracy of its intelligence.  Its excellence was recognized by at least some of Weiland’s contemporaries.  For example a review in an influential German journal opined:

“It’s a very good idea to communicate to the public through one map, the progress and extent of the cholera disease. It has thought of everything that belongs to the convenience of use. For every year special colors are chosen and also the year is also accompanies the colour everywhere… We have no doubt that this map will find the applause of the public and consequently large sales.” (Isis, vol. 4 (1832), p. 444).

Despite the acclaim the great rarity of this cholera map today suggests that it never attained mass circulation.  I am aware of only four institutional examples, all in Germany.

References
OCLC 165458567 (Bayerische Staatsbibliothek, Staats- und Universitätsbibliothek Bremen, and Universitäts- und Landesbibliothek Sachsen-Anhalt) and 312716777 (Universitätsbibliothek Leipzig). Frank A. Barrett, Disease & Geography: The History of an Idea, p. 561. Heinrich Haeser, Bibliotheca epidemiographica sive catalogus librorum de historia morborum (Jena, 1843), p. 138.  Niedersächsisches Landesgesundheitsamt, Den Seuchen auf der Spur: 200 Jahre Infektionskrankheiten in Kartenbild (Exhibition Catalogue, Hannover, 2012), pp. 4-5. Background from Arthur Robinson, Early Thematic Mapping in the History of Cartography, pp. 170-74 and Saul Jarcho, ‘Yellow Fever, Cholera, and the. Beginnings of Medical Cartography,’ Journal of the History of Medicine and Allied Sciences, vol. 25, no. 2 (April 1970), pp. 131-42.

Thanks to Alexander Johnson of Antiquariat Dasa Pahor (Munich), who graciously permitted me to adapt his own work for this description.