Beyond The Ghost Map—Exploring Broad Street’s Impact of Public Health
Modern medical technologies and epidemiological surveillance are at the forefront of current disease-mapping efforts within the field of public health. Utilized in crises such as the 2009 H1N1 pandemic and the recent Ebola epidemic in West Africa, infection topography allows communities, governments, and health agencies to better-understand disease outbreaks—information which eventually informs public health education and the prevention of disease incidence. These innovations are often taken for granted given the steep rise in medical discoveries and the increase in collective responsibility for health and human services over the past century. In The Ghost Map, author Johnson, S. (2006) paints a compelling portrait of the intersection of urbanization, public health, and scientific analysis through his account of the 1854 cholera epidemic in London’s Soho neighborhood. Despite the sense of dread that pervaded London’s working class and the lack of understanding faced by concerned laymen and physicians at the time, observation by several key actors led to the source of the outbreak and a new era in the history of public health. Johnson’s uncanny knack for storytelling and his supply of contextual information detailing Victorian London constitute the strengths of The Ghost Map; by reminding readers of the power of ordinary citizens to transform the world, Johnson argues that changes in public health and medicine arise from collaboration and curiosity.
Despite the relative peace and economic growth that characterized Victorian England, London in 1854 would be unrecognizable to visitors today (Johnson, 2006, p. 11). Its lack of sanitation systems stemmed from its outdated “Elizabethan infrastructure” (p. 4) and resulted in the overflow of sewage; cesspools of excrement lined the streets and thus laid the groundwork for London’s most devastating epidemic since the plague (p. 10). A revolting smell engulfed the city, and the palpable division between London’s upper and lower classes confined the worst of its waste management problems to overpopulated communities of individuals marked by low socioeconomic status. London’s General Board of Health, created by Edwin Chadwick and then directed by Benjamin Hall, recognized its sanitation crisis and need for cleanliness (p. 115). Despite these observations, the Board used miasma theory, not the city’s grime, to explain disease transmission. Miasma theory centered on the belief that immoral, unhygienic behavior triggered the spontaneous release of disease-producing miasma—toxic vapors of the air originating from decaying matter (p. 69).
Accumulating waste in London’s water supply transformed it into a successful breeding ground for Vibrio cholerae, which causes cholera. Attaching to the biological receptors of the small intestines and stimulating them to discharge fluid, Vibrio cholerae dehydrates its victims, leading to severe diarrhea, “rice-water” stools, vomiting, and eventual death if left untreated through hydration (pp. 37-38). London’s 1854 cholera epidemic began due to a single action made by a family member of the index case: Sarah Lewis, a resident of Broad Street in the Soho district near Golden Square, discovered her child’s rise-water stools and deposited them into the cesspool in front of her home (p. 22). As a result, Vibrio cholerae seeped into the water supply of the neighborhood, which was frequently accessed via the Broad Street water pump (pp. 179-180). Within hours, London’s death toll rose steeply as water was collected at the Broad Street pump and disease spread throughout the city.
Having investigated and linked previous cholera outbreaks to the water supply, Dr. John Snow, a respected anesthesiologist, decided to collect evidence supporting his hypothesis during the 1854 epidemic (pp. 74-76). Snow went door-to-door throughout the Soho neighborhood, interviewing residents to determine their water source (p. 141). Through his work with William Farr, an accomplished statistician who collected local mortality rates, he noticed that deaths of residents were clustered around the Broad Street pump (pp. 100-101). Moreover, Snow’s collaboration with Priest Henry Whitehead, a Soho native, led to Whitehead’s identification of the Lewis baby as the index case of cholera (pp.178-179). Statistical evidence, a partnership with Farr and Whitehead, and epidemiological surveillance culminated with the discovery of the Broad Street pump as the source of the outbreak; Snow’s convincing argument and authority eventually persuaded Benjamin Hall to remove the Broad Street pump handle (p. 182). Soon after, Snow created a map of households both affected and unaffected by the epidemic while denoting their proximity to the Broad Street pump and the Lewis residence (p. 193). This “ghost map” signaled a shift in belief regarding disease etiology from miasma theory to contagion theory, which Snow supported, by documenting evidence used to determine the source of the outbreak (p. 194). As a result, understanding of the need for a clean water supply heightened, and city officials began to install sewer systems, to clean the filthy River Thames, and to invest in sustainable infrastructure that could support its crowded metropolis and promote urban health (pp. 207-208). Following the epidemic and these innovations, London became the global example of evidence-based health practice and sanitary engineering.
Governmental failure due to preemptive implementation of unsubstantiated health policy during the 1854 cholera epidemic bore the need for observation in the field of public health epidemiology. To gain information regarding cholera and its transmission, Snow, Whitehead, and Farr dedicated themselves to working with affected community members. This persistent surveillance and private investigation differed from the predominant response to epidemics made by the General Board of Health. The Board’s approach to disease centered on action regardless of uncertainty; miasma theory was not scientifically studied by its medical proponents, and mysteries regarding its random manifestations were left uninvestigated. Despite their lack of knowledge, health officials began emptying excrement into the River Thames to combat miasma’s terrors and to rid the city’s streets of miasma-producing sewage. In this way, the “first defining act of a modern, centralized public-health authority… poison[ed] an entire urban population” (p. 120). Had the General Board of Health responded to the cholera outbreak as Snow and his colleagues did—by collecting “samples from the Broad Street pump” (p. 99) and by “think[ing] on the scale of the city, from a bird’s eye view” (p. 98)—their early actions may have had more fruitful, evidence-based repercussions. Snow’s success using this observational method heralded the need for carefully-planned investigations of disease.
Additionally, Snow’s investigation of cholera highlighted the importance of holistic evaluation of observed evidence. Snow recognized that monitoring disease mortality was insufficient proof of his theory that London’s contaminated water supply was the vector of cholera transmission. To convince health officials of contagion theory and his logic, Snow also needed to explain why certain Soho residents were unaffected by the outbreak—“pockets of life where [one] would expect death, pockets of life where [one] would expect death” (p. 140). His observations and questioning of workhouse managers and employees at a local brewery whom were seemingly immune to the cholera epidemic provided him with logical explanations to their survival. In fact, news of the workhouse’s private water supply and the consumption of liquor rather than water at the pub amplified evidence for his empirical claims (p. 142). Snow’s background as “a trained observer of physical symptoms” (p. 146) translated into his infallible epidemiological analysis of the outbreak.
Despite the long-lasting influences of Snow, Whitehead, and Farr’s work during the 1854 cholera epidemic, one cannot forget the mortality that accompanied their emergence as key figures in public health history. As the disease ravaged London, residents also suffered worsened health outcomes as a result of their panic—“whilst pestilence slays in thousands, fear slays its tens of thousands” (p. 84). Confusing messages from medical professionals, city officials, and channels of mass communication to laypersons led to poor decision-making regarding isolation and treatment of the epidemic (p. 83). A lack of progress in disease treatment through analysis of prior outbreaks prevented further advancement in the medical knowledge of cholera and caused communal distress. Fear paralyzed Soho residents into inaction, which promoted cholera’s spread; families remained in their homes and water continued to be collected from the Broad Street pump (p. 86). Fear as a catalyst of disease propagation is not only apparent when reflecting on prior epidemics; uncertainty and poor leadership by health professionals led to worsened health outcomes for citizens of the Western hemisphere when awareness of the Zika virus arose in late 2015 (Santora, 2016). Because of widespread dread regarding Zika’s link to microcephaly, abortion demand and reports of self-induced, unsafe abortions by women in affected countries have increased at a rate that surpasses the real risk of Zika-related child birth defects (Landry, 2016).
As a history-lover, The Ghost Map furthered my understanding of public health history, and its account of Snow, Whitehead, and Farr’s collective leadership reinforced a familiar adage: small groups of committed, enthusiastic individuals are the true change-makers of society. By reading this book, I gained an appreciation for the intricacies of public health epidemiology in a time of crisis and for Snow’s reluctance to conform to the medical community’s established miasmatic theory of disease. Additionally, I found Johnson’s discussion of modern urbanization and its benefits to be extremely thought-provoking. I look forward to recommending The Ghost Map to others who share an interest in health innovations, history, and the retelling of triumphs in the face of adversity.