Cholera in the 19th century was especially terrible because of its fast, violent symptoms, high death rate, and lack of understanding about its cause. The disease hit the poor in crowded, dirty cities the hardest. People suffered severe stomach cramps, vomiting, and diarrhoea, which quickly led to dehydration. Their eyes would sink, their skin would shrivel and turn blue from lack of oxygen. This is why it was called the “blue death.” Many died within a day of getting sick. The speed and horror of cholera made it the most feared disease of its time.

From late June to autumn 1866, a severe cholera outbreak hit London’s East End. This was Britain’s last major urban cholera epidemic and convinced many officials that cholera spread through contaminated water, not “miasma” or “bad air”.

During the 1866 cholera outbreak in London, my great-great-grandfather Frederick Lines, his wife Hannah, and two of their children died.

The main cause was contaminated drinking water.

Registrar-General William Farr and his team studied death rates and the sources of water. They found the outbreak was worst in areas that used water from reservoirs fed by polluted sections of the River Lea and nearby canals, especially the Old Ford reservoir, used by the East London Waterworks Company. Farr’s research showed that the water supply was the main cause, backing up John Snow’s earlier ideas from the 1850s about cholera spreading through water.

Sewage contamination and unfinished sewer systems also contributed.

Fast population growth, industrial waste, and sewage dumping into the Thames and its branches made parts of the Lea and nearby canals dirty, especially during hot weather. When the outbreak began, the East End’s new sewer system and sewage-diversion projects were not finished, so polluted river and canal water could still reach reservoirs and homes.

Social and environmental factors increased the area’s vulnerability.

The East End was crowded and poor, with cramped housing, bad sanitation, and little clean water. These conditions made cholera worse. Poverty did not cause cholera, but it increased the risk of getting sick and made it harder for people to recover from dehydration and illness.

Sources do not all agree on the exact numbers, but the outbreak killed thousands in London’s eastern districts between July and September 1866. Farr’s research is often cited for showing that most deaths occurred in the East London Waterworks area.

The epidemic caused panic, stopped trade and daily life, and overwhelmed local charities and hospitals. Hospitals took in hundreds of cholera patients. At first, many died, but death rates fell as doctors got better at treating severe dehydration.

The evidence from 1866 led most public health officials to stop believing in the miasma theory. Farr’s research helped people accept the waterborne theory and led to quicker changes in laws and city infrastructure, such as stricter rules for water companies, the completion and expansion of sewers, and giving cities greater power to improve sanitation. Joseph Bazalgette’s sewer system and later upgrades to water filtration and supply became even more important after the epidemic.

I can’t imagine how terrifying and grim life must have been for my ancestors at this time, living in constant fear