Public health and development: Infrastructure, social norms, and health behaviours

1 Introduction

Epidemiology is the study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems.

John Snow was an English physician in the nineteenth century. While he was a leader in the development of anaesthesia and medical hygiene, he is also remembered as one of the founding fathers of epidemiology. His findings led to major developments in waste and water management in London and major cities worldwide. Outbreaks of cholera in London were common, and between 1848 and 1854 a series of repeated cholera events caused widespread death.¹ One specific epidemic occurred around Broad Street in Soho, a poor district where industry and housing were crowded and unhygienic. Snow’s investigations showed that most of the deaths were of individuals who drank water from a contaminated water pump on Broad Street. It was later found that the well had been dug close to a cesspit that had begun to leak faecal matter contaminated with cholera. The cholera cases subsided when the authorities closed the pump.

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Replica of Broad Street water pump (London), a memorial to John Snow and the cholera deaths in 1854.

Fast-forward to the twenty-first century, when the 2017 Indian movie Toilet: A Love Story tells the tale of a young wife in an Indian village in Uttar Pradesh who leaves her husband because he refuses to build a toilet in their home. The wife is unwilling to conform to the community customs of practising open defecation (OD), which she considers disgusting. On the other hand, her husband’s family see building a toilet as bringing ‘impurity’ to the living compound. Her husband goes to great lengths to avoid building a toilet, such as using an old, incapacitated lady’s toilet and the train’s toilet during its seven-minute stop at the village station. The film is based on a true story and highlights the widespread practice of open defecation as a massive health hazard that India—mostly its rural population—suffers from. Between 2000 and 2024, the number of people who practice OD worldwide halved, but with 419 million people still practising it, it remains a major public health challenge. OD practices are deeply rooted in some rural areas, and there are major efforts to reduce or eliminate it.

Both stories highlight the pernicious effects of faecal contamination on health. Contaminated water or food or direct contact with faeces is a major cause of diseases worldwide, including cholera. Both in the past and today, major cholera outbreaks cause millions of preventable deaths: from 1990 to 2019, over three million people died from cholera worldwide.² While the link between cholera and contaminated water is a well-established fact today, it was not always the case. To stop contaminated water from spreading diseases, major infrastructure investments were introduced in England after John Snow’s discoveries, such as sewage systems and water chlorination. The plummet in deaths caused by waterborne diseases in OECD countries shows the importance of public investment in this type of infrastructure.

While John Snow’s story points to the relevance of major infrastructure works to achieving health gains, the movie about rural India shows that social norms and culture are also relevant to achieving better health outcomes. Both stories suggest that major investments in infrastructure and behavioural change at the individual level are needed to improve health practices and observe relevant and significant effects on health outcomes.