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In the heart of the city of Ghent, under streets where bicycles and tourists circulate today, an unexpected biological file is hidden: the remains of old latrines and burial sites. In them, archaeologists have found more than just structures. They have recovered microscopic traces of medieval daily life, specifically, of their intestinal diseases.
An archaeoparasitological study has analyzed the remains of excrement preserved in latrines and tombs from between the 13th and 18th centuries, comparing samples from the general population with others from the clergy of the Sint-Baafs cathedral. The finding is clear: intestinal parasites affected both social groups equallywithout hierarchical, religious or economic distinction. Neither faith, nor social position, nor the walls of a cathedral were enough to protect from everyday unhealthiness.
Parasites in stone and brick
The analyzed samples come from three different contexts: two latrines from the Oude Schaapmarkt neighborhood, used by ordinary citizens between the 13th and 18th centuries, and a latrine attached to the sacristy of the Sint-Baafs cathedral, used by the clergy between the 16th and 17th centuries.
All samples revealed the presence of intestinal helminths like him whipworm (Trichuris) and the roundworm (Ascaris)along with protozoa that cause severe diarrhea such as Giardia duodenalis and Entamoeba histolytica. According to the authors, these parasites are transmitted mainly by fecal contamination of water and foodindicating poor sanitary conditions that affected the entire city.
“No notable differences were found in the species of parasites found between the clergy and the general population.“, concludes the study. This sentence summarizes one of the most significant findings of the work: social inequality was not reflected in intestinal health.
Between latrines and burials
In addition to the waste preserved in cesspools, the researchers analyzed pelvic sediments from six human burials found in the vicinity of the cathedral. Two of them also showed Trichuris eggs, reinforcing the conclusion that the infection was real in life, and not the result of soil contamination.
The oldest remains analyzed date back to the 13th century, and the most recent to the 18th century. This temporal amplitude allowed us to observe a surprising continuity in parasite typeswithout major changes in the dominant species over more than 500 years.
The researchers also took into account the possibility of differences in the preservation of the remains. The Oude Schaapmarkt latrines were located in lower, more humid areas, which favors the preservation of parasite eggs, while the cathedral sacristy was located on a drier elevation. Even so, The coincidence in the species found is overwhelming..
What do medieval excrements tell us?
One of the most striking aspects of the study is the clear prevalence of parasites transmitted by the fecal-oral routeagainst food parasites, such as those acquired by eating undercooked fish or meat. This is especially striking in the case of the clergy, who followed strict dietary rules and frequently consumed fish.
Despite this, No parasites were found associated with the consumption of raw or undercooked fish.such as fish tapeworm or intestinal fluke. A possible explanation is that in Ghent, both the clergy and the rest of the population cooked the fish in a way that destroyed these parasites, something that is reflected in the medieval recipe books of the region, where there are no references to raw fish.
On the contrary, the protozoa Giardia and Entamoeba were repeatedly identified, both responsible for diarrhea and dysenterydiseases that at the time could be life-threatening, especially in children and malnourished people.
Medieval hygiene, between effort and insufficiency
The city of Ghent was no stranger to hygiene concerns. Starting in the 14th century, there were municipal regulations on street cleaning, food sales and waste management. Urban maintenance teams were created and public wells were built for access to drinking water.
Despite these efforts, the study shows that health measures were not enough to break the cycle of parasitic reinfection. It is likely that one of the main causes was the use of excrement as fertilizer on crops, a common practice that facilitated the transmission of parasites through contaminated fruits and vegetables.
The conclusion is clear: urban advances were not enough to guarantee effective hygienenot even within the most influential religious institutions.
A microscopic window into social history
The results of this work have a value that goes beyond parasitology. In the words of the research team, these analyzes allow “compare the intestinal health of different social groups in the same medieval city”, which turns latrines into an archaeological tool to understand living conditions, inequalities and failures of public hygiene in the past.
Far from being a minor curiosity, the remains preserved in old latrines tell us about infant mortality, chronic malnutrition and daily suffering. They also remind us that biology does not recognize social classesand that true health inequality can only change when material conditions allow it.
References
- Tianyi Wang, Koen Deforce, Janiek De Gryse, Shari Eggermont, Robrecht Vanoverbeke, Piers D. Mitchell. Evidence for parasites in burials and cesspits used by the clergy and general population of 13th–18th century Ghent, Belgium. Journal of Archaeological Science: ReportsVolume 53, 2024, 104394. https://doi.org/10.1016/j.jasrep.2024.104394.
