Context 159 - May 2019

C O N T E X T 1 5 9 : M A Y 2 0 1 9 21 Building services KENT WOODS Civil engineering and the health of a Victorian town The story of the comprehensive redevelopment of Leicester’s sewerage system shows a direct relationship between civil engineering projects and quantitative measures of public health. Mortality rates in Britain began to fall long before there had been significant progress in the treatment of disease, reflecting improvements in nutrition, sanitation and other environmental factors in the 19th century. It is, however, seldom possible to show a direct relationship between specific civil engineering projects and quantitative measures of public health in a defined geographical setting. The case study presented here of the comprehensive redevelop- ment of the sewerage system of Leicester by Joseph Gordon between 1881 and 1891 can plausibly make that claim. The registration of births and deaths began in England and Wales in 1837. These data made possible for the first time a comparison of mortality statistics for the major towns. Infant mortality (the number of deaths before the age of one year, expressed per thousand live births) is a particularly robust metric since it makes no reference to cause of death, which is subject to changes in disease classification and diagnostic accuracy over time. On this measure, Leicester was among the very least healthy of the indus- trial towns throughout theVictorian period, with infant mortality some 35–40 per cent higher than the national average year after year. This unenviable position was the cause of comment in the national medical press and speculation as to the cause. In 1874, a particularly bad year, the then medical officer of health for the town studied the recorded causes of death in the infants. The two (almost equal) leading diagnoses were ‘atrophy and debility’ and ‘diarrhoea’. It is likely that most cases of the former were simply more pro- tracted or recurrent manifestation of the latter. Moreover, the deaths from infant diarrhoea were highly seasonal, almost 90 per cent occurring during the summer months of July, August and September. Medical science of the time offered no adequate explanation.We now know that infant diarrhoea is generally caused by oral ingestion of gut organisms such as the bacterium Escherichia coli through contamination of food or oral fluids by faecal material. This can arise when sewage penetrates the water supply, or by transfer of organisms from faeces to food or drink by the agency of flies – the reason for the seasonal pattern of infant diarrhoea. Diseases now known to be infectious were widely attributed to ‘bad air’ – the miasmatic theory – which dominated thinking almost to the end of the century until the new science of bacteriology succeeded in identifying causative bacteria. The birth of epidemiology The worldwide spread of cholera from the Indian subcontinent, starting in the early 19th century, caused great loss of life. Cholera is caused by the bacterium Vibrio cholerae . Spread by the faecal-oral route, it causes massive loss of water and salts. Without treatment, death can occur within hours from dehydration. It therefore has certain features in common with Seasonal pattern of deaths from infant diarrhoea in Leicester, 1874 Jan Feb Mar Apr May June July Aug Sep Oct Nov Dec 3 1 0 5 0 1 68 82 31 9 6 1 A pub and a replica water pump stand as memorials to John Snow in Broadwick Street in London’s Soho (Photo: Justinc, Wikimedia)