Cholera Outbreaks and the Birth of Modern Epidemiology

The cholera outbreaks of the nineteenth century were among the most feared public health disasters in the history of the Industrial Revolution. The disease killed hundreds of thousands of people in the industrial cities, and the response to the outbreaks, including the work of John Snow and the development of modern epidemiology, transformed the understanding of public health.

The Nature of Cholera

Cholera is an acute diarrheal disease caused by the bacterium Vibrio cholerae. The disease is spread by contaminated water and food, and it can kill a healthy person within hours of the onset of symptoms. The disease is characterized by severe diarrhea and vomiting, which lead to rapid dehydration, and the victims often die from shock, kidney failure, or pneumonia.

Cholera was endemic in the Indian subcontinent for centuries, with regular outbreaks in the Ganges Delta and other parts of the region. The disease was not known in Europe or the Americas until the early nineteenth century, when it began to spread along the trade routes from India. The first major outbreak in Europe occurred in 1832, and the disease returned in successive waves in 1848, 1854, and 1866.

The Cholera Outbreaks in the Industrial Cities

The first major cholera outbreak in Britain occurred in 1832, and it killed more than 30,000 people. The disease spread from the port of Sunderland to the rest of the country, and it was particularly severe in the industrial cities of the North, including Leeds, Manchester, and Liverpool.

The second major outbreak occurred in 1848, and it was even more severe than the first. The disease killed more than 50,000 people in Britain, and it was particularly severe in London, where the inadequate sewerage system and the contaminated water supply created ideal conditions for the spread of the disease.

The third and most famous outbreak occurred in 1854, and it was centered in the Soho neighborhood of London. The outbreak killed more than 600 people in a matter of weeks, and it was the occasion for the pioneering work of Dr. John Snow, who demonstrated that the disease was spread by contaminated water, and not, as was widely believed, by “miasma” or bad air.

John Snow and the Birth of Modern Epidemiology

Dr. John Snow (1813-1858) was a London physician who is often considered the father of modern epidemiology. During the 1854 cholera outbreak in Soho, Snow systematically investigated the cases of cholera and identified the source of the outbreak as the public water pump on Broad Street.

The Legacy of the Cholera Outbreaks

The cholera outbreaks of the nineteenth century, and the response to them, transformed the understanding of public health and laid the foundation for the modern public health system.

The Continuing Question

The unresolved historical question about the cholera outbreaks is the one that the miasma-versus-contagion debate put on the public agenda. The traditional answer, going back to the 1830s sanitary reformers and given its modern form in Anthony Wohl’s Endangered Lives (1983), is that the outbreaks were a triumph of the miasma theory: the disease was caused by the bad air of the slums, and the response (sewers, clean water, slum clearance) was the right response. The revisionist answer, going back to John Snow’s 1854 Broad Street pump study and given its modern form in the work of medical historian Christopher Hamlin, is that the miasma theory was wrong, and that the cholera outbreaks were water-borne, and that the public health reforms of the 1840s-1870s worked not because they removed the bad air but because they cleaned up the water supply. The interesting current question, raised in Simon Szreter’s Health and Wealth (2005) and developed in the recent literature on the political economy of public health, is why the British state acted on the miasma theory when Snow had already identified the water-borne mechanism, and why the germ theory of disease (Robert Koch, 1884) was the necessary condition for the post-1860 acceleration of public-health reform. The honest answer, given the historical evidence, is probably: the miasma theory was politically useful because it provided a rationale for sanitary reform that did not require the medical profession or the central government to take responsibility for water quality, and the germ theory, when it finally arrived, made the rationale for sanitary reform more robust but did not change the actual interventions very much.

Selected Sources

Simon Szreter, Health and Wealth: Studies in History and Policy (2005).
Anthony S. Wohl, Endangered Lives: Public Health in Victorian Britain (1983).
John Snow, On the Mode of Communication of Cholera (1849).
Christopher Hamlin, Public Health and Social Justice in the Age of Chadwick (1998).