Hamburg Cholera Epidemic (1892): Robert Koch and Clean Water

The Hamburg cholera epidemic of 1892 was the last major cholera outbreak in western Europe. Between August and October 1892 about 8,600 people died in Hamburg, a rich port city that still supplied its people with unfiltered river water. The disaster, studied on the spot by Robert Koch, became decisive proof that cholera spreads through water and pushed the city into long-delayed reforms.

Background: a wealthy city with old habits

Hamburg was Germany’s largest port and one of the wealthiest cities in Europe, a self-governing city-state within the German Empire. It was run by a Senate drawn from its merchant elite, who favoured low taxes and limited government. Many working people lived in the crowded alleys of the old town, known as the Gängeviertel.

Since the 1840s Hamburg had drawn its drinking water from the river Elbe, upstream of the city at Rothenburgsort. Plans to filter it through sand beds, a method used in London and elsewhere, had been discussed for decades but repeatedly postponed on grounds of cost. The tide could also push polluted water from the harbour back up toward the intake.

Cholera, a severe intestinal infection, had struck Europe repeatedly since the first cholera pandemic spread from India. In 1883-1884 Robert Koch had identified the bacterium that causes it, Vibrio cholerae. But many doctors, including the Munich hygienist Max von Pettenkofer, believed that local soil and groundwater conditions mattered more than the germ itself.

What happened

Cholera appeared in Hamburg in mid-August 1892, during a hot, dry summer when the Elbe was low. Its exact source is unknown. Many contemporaries blamed emigrants from the Russian Empire who passed through Hamburg on their way to America, since cholera was then raging in Russia, but this was never proven.

The first cases were not officially acknowledged for about a week, and the Senate was slow to declare an epidemic for fear of harming trade. By late August the city was reporting around 1,000 new cases a day at the peak. Hospitals overflowed, emergency barracks were built and carts carried away the dead.

The German imperial government sent Robert Koch, who arrived on 24 August. Walking through the slums, he was shocked by the conditions and reportedly told his companions, “Gentlemen, I forget that I am in Europe.” He quickly pointed to the unfiltered water supply as the main cause.

The epidemic declined in September and was largely over by late October. In all, about 16,900 people fell ill and around 8,600 died, out of a population of roughly 640,000.

The Altona contrast

The most powerful evidence came from Hamburg’s neighbour. Altona, then a separate Prussian town on the Elbe, drew its water from the river downstream of Hamburg, where it was even dirtier. But Altona filtered its water through sand beds.

Altona had very few cases. Along the street that formed the border between the two cities, houses on the Hamburg side were struck while those on the Altona side were largely spared. The contrast resembled John Snow’s findings during the Broad Street cholera outbreak in London and convinced many sceptics that clean water was the key.

Key people

Robert Koch (1843-1910) was Germany’s leading bacteriologist, already famous for his discovery of the tuberculosis bacillus. In Hamburg he advised on isolation, disinfection and boiling water, and his authority helped force the city to act.

Max von Pettenkofer (1818-1901) was Koch’s chief opponent. In October 1892, to show that the germ alone did not cause cholera, he drank a culture of cholera bacteria. He suffered only mild illness, which he claimed as a victory, but most scientists did not accept his reasoning.

Consequences

A sand-filtration plant on the island of Kaltehofe, long planned, was rushed to completion and began operating in 1893. Hamburg’s water was safe from then on, and cholera never returned on a large scale.

The epidemic also exposed the city’s political system. Critics blamed the merchant elite for putting cost before lives, and the following years brought a stronger public health administration, slum clearance and housing reform. The disaster strengthened the case for state intervention in health.

There were international effects too. The United States imposed strict quarantine on ships from Hamburg in late 1892, and restrictions on Eastern European emigrants passing through German ports were tightened.

Timeline

• 1883-1884: Robert Koch identifies the cholera bacterium in Egypt and India.
• 1892, mid-August: The first cholera cases appear in Hamburg.
• 1892, 24 August: Koch arrives in Hamburg and blames the unfiltered water supply.
• 1892, late August: The epidemic peaks at around 1,000 new cases a day.
• 1892, 7 October: Max von Pettenkofer drinks a culture of cholera bacteria in Munich.
• 1892, late October: The epidemic is largely over.
• 1893: The Kaltehofe sand-filtration plant begins supplying filtered water.

Why it matters

The Hamburg epidemic showed, in the clearest possible way, that a modern city could kill thousands of its citizens by neglecting its water supply. It settled the long debate over how cholera spreads, vindicated Koch’s germ theory in practice and made filtered water a standard of European public health.