The 19th Century’s Silent Killer: Tuberculosis
Authors: Valentin Charlier, Sophie Vanwambeke
La miseria, 1886, painting by Cristóbal Rojas (© Public Domain)
What did Queen Louise d’Orléans, George Orwell, Frédéric Chopin, Franz Kafka, and Thérèse of Lisieux have in common?
They all died from tuberculosis, the same disease that claimed millions of lives across the world. For centuries, tuberculosis was one of humanity’s deadliest companions, likely the leading cause of death in human history.
In Belgium, tuberculosis was a major killer well into the 19th century, particularly as urbanization and industrialization reshaped living conditions. But were all Belgians affected equally?
Let’s explore how this disease spread and how it was eventually brought under control.
What is tuberculosis?
Tuberculosis in Europe and in Belgium
The Industrial Revolution transformed Europe, and with it, the health of its people. Cities grew rapidly, often without adequate housing or sanitation. Infectious diseases flourished.
Belgium, one of Europe’s early industrial nations, is no exception. People massively moved to cities and industrial areas where they often lived in crowded and unsanitary housing. Infectious diseases thrived in these environments. As shown on the figure below, by the mid-19th century, infectious diseases accounted for roughly 40% of all deaths, and tuberculosis (green) was among the most devastating.
Tuberculosis primarily affected adults and was more lethal among men than women. Mortality began to decline toward the end of the 19th century as living conditions improved and the first public health measures, such as sanatoria and hygiene campaigns, were introduced.
However, progress was uneven. Industrialization brought new risks: fine dust from mechanized mining equipment (like jackhammers) damaged workers’ lungs, and both World Wars temporarily reversed the downward trend in tuberculosis mortality.
By the mid-20th century, tuberculosis became concentrated in specific regions and occupations, such as mining and heavy industry. Today, tuberculosis cases in Belgium are rare and mostly occur among people from countries where the disease remains endemic.
Regional patterns: Flanders and Wallonia
Between 1889 and 1950, tuberculosis mortality was higher in Flanders than in Wallonia. Two main factors help explain this difference:
- Socioeconomic conditions
Flanders remained impoverished until the 1960s, undergoing delayed industrialization following the collapse of the rural linen industry in the 19th century. The arrival of cheap grain from the New World led to widespread unemployment. In contrast, Wallonia experienced considerable prosperity due to the rise of coal and steel industries, positioning it as a major European industrial center until the early 20th century. However, this industrial boom came at a cost to workers’ health and was followed by socio-economic decline after the collapse of heavy industry [Buyst, 2009]. - Health infrastructure and habits
Wallonia developed stronger healthcare networks earlier on. In Flanders, lower breastfeeding rates and poor-quality water may have contributed to weaker immunity and higher vulnerability to infectious diseases [Eggerickx & Tabutin, 1994; Van Rossem et al., 2018].
Despite these differences, tuberculosis eventually declined across both regions as industrial living conditions, healthcare, and nutrition improved. By the mid-20th century, the era of tuberculosis as a major public health threat in Belgium was coming to a close.
On the maps above, we see the evolution of the number of people dying from tuberculosis through four chronological periods
(sum up everything we see: also the absence of tb deaths in certain periods and regions)
During periods X-X the high mortality by tuberculosis in the Walloon industrial basin is visible on the map, and it did concentrate more deaths from tuberculosis in the final years of our analysis – the tail end of tuberculosis as a major cause of death in Belgium.
In Belgium, as in other European countries at the time, before the causes, prevention, and treatment were fully understood, tuberculosis affected the population broadly. But our maps show that some areas were particularly badly affected, which can be related to the agricultural crisis as well as the urban transition related to the industrial revolution.
Tuberculosis and scientific innovation: Koch’s postulates
For centuries, people believed diseases like tuberculosis came from “bad air” (miasma) or divine punishment. The discovery of microbes and the development of germ theory revolutionized that understanding.
In 1882, Robert Koch identified Mycobacterium tuberculosis as the cause of tuberculosis. To prove this, he developed a set of principles known as Koch’s postulates, which laid the foundation for modern microbiology:
- Find it – The germ should always be found in people (or animals) who have the disease, but not in healthy ones.
- Isolate it – Take the germ out of the sick person’s body and grow it in a lab (so you have only that germ, nothing else).
- Test it – Give the germ to a healthy person or animal, and they should get the same disease.
- Prove it – Take the germ out of this newly sick person or animal, it should be the exact same germ you started with.
Although modern science has revealed exceptions (some microbes can’t be cultured or don’t always cause disease), Koch’s approach remains a cornerstone of scientific rigor in infectious disease research.
Conclusion
Tuberculosis was once the leading cause of death in Europe and a defining feature of 19th-century urban life. Its decline , driven by better living conditions, public health reform, and scientific discovery , marks one of humanity’s great public health successes.
Yet the story is far from over. Tuberculosis continues to thrive where poverty, overcrowding, and limited healthcare persist. Understanding its history reminds us how deeply health is shaped by social and economic conditions, and how progress against disease depends not only on medicine, but also on equity.
Sources and Literature
Eggerickx & Tabutin, 1994;
Van Rossem et al., 2018]
WHO 2023
Buyst 2009
