Industry produces infections
How rapid urbanisation caused public health to deteriorate
The invention of the steam engine in the 18th century allowed humans to utilise the power of fossil fuels on an industrial scale for the first time. As industrialisation transformed manufacturing, Britain’s annual economic growth reached an unprecedented 2.5 per cent in the first half of the 19th century, before falling back to 2 per cent. These figures are modest compared with the growth rates experienced by China over the past few decades. But in a world where economic growth had been close to zero since the adoption of agriculture, the impact was extraordinary.
As public-health historian Simon Szreter has pointed out, economic growth didn’t automatically lead to better health. People flooded into the towns from the countryside to work in factories. For most of the 19th century at least, though, British politicians – who were elected by a small number of wealthy voters – weren’t interested in improving water and sanitation in urban slums. Such crowded and insanitary conditions created new habitats in which pathogens thrived. In the mid-19th century, infectious diseases accounted for about
60 per cent of deaths in parts of Liverpool and Manchester. Diarrhoeal diseases, transmitted through drinking water contaminated with faeces, were the major killers.
Between the 1820s and 1870 – a time of unprecedented technological development and wealth creation – average life expectancy in Britain remained stagnant at around 41 years. National figures were dragged down by the new industrial towns. In the central areas of Manchester and Liverpool, life expectancy during that period was around 25 years – lower than at any time since the Black Death. For factory labourers in Manchester and Liverpool, it was just
17 and 15 years, respectively.
Health in towns and cities began to improve only after political reforms in the late 1860s. Suddenly, more than 60 per cent of working-class men could vote in urban local elections. The new voters were far more receptive to city leaders’ ambitious plans to build vast, expensive water and sewerage infrastructure. These projects transformed public health, and deaths from water-borne infectious diseases began to fall. In the 1870s, life expectancy in Britain’s towns and cities finally rose above 1820s levels, and kept rising.
It is only in the past decade that life expectancy has stopped increasing. It has even fallen since 2020, at least partly as a result of Covid-19. But it is too soon to say with any certainty how the most recent pandemic might transform our society, economics and politics.
Jonathan Kennedy is reader in politics and global health at Queen Mary University of London. His new book is Pathogenesis: How
Germs Made History (Torva, 2023)