# Trondheim's medieval waste reuse on fields spread Ascaris parasites, study of 1000–1600 finds

- Published: 2026-11-10 21:14 UTC
- Section: Life & Health › Biology & biochemistry
- Tags: Trondheim medieval sanitation, Nidaros, Ascaris parasites, miasma theory, waste as fertiliser, medieval child mortality, archaeology of sanitation
- URL: https://realtech.media/news/rt-6d2767860753d317df07b992_trondheim_s_medieval/

**Researchers at the Norwegian University of Science and Technology report that fertilising fields with toilet waste returned Ascaris to the food of Nidaros residents.**

![Trondheim's medieval waste reuse on fields spread Ascaris parasites, study of 1000–1600 finds](https://realtech.media/media/2026/11/add2b0264794cdb6.jpg)
*Szilas, Wikimedia Commons, Public domain*

Residents of Trondheim, then called Nidaros, tried to keep the city clean between 1000 and 1600, yet their sanitary measures helped parasites spread. This follows from a new study by the Norwegian University of Science and Technology, reported by science.mail.ru [1]. Townspeople fought rubbish and unpleasant smells, following the miasma theory, which held that odours were a source of disease.

Waste from the city's toilets was carted out of the centre. Farmers mixed it with manure and fertilised fields with it [1]. As a result, parasites of the genus Ascaris got into food and infected the townspeople again. Analysis of the waste indicates that the infection could have affected almost the whole population [1].

Archaeologists found wooden toilets, rubbish containers and drainage channels, which points to an organised sanitation system long before modern sewers [1]. Social inequality strongly affected health. In wealthier districts the diet was more varied, while in the craftsmen's quarters higher child mortality and signs of malnutrition were recorded [1].

## Sources

1. [science.mail.ru](https://science.mail.ru/news/60276-kak-srednevekovaya-uborka-goroda-nezametno-zarazhala-ego-zhitelej)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-6d2767860753d317df07b992_trondheim_s_medieval/