Archaeologists hit pay dirt in medieval latrines

by Mary Caperton Morton
Wednesday, January 16, 2019

Archaeologists digging in Lübeck, Germany, unearthed an unusual source of information about past dietary habits in the city: parasite eggs recovered from 700-year-old latrines.

Researchers excavated fecal samples dating from the 12th through the 17th centuries from latrines in eight medieval houses in the city, which was a busy Baltic Sea trading port in the Middle Ages. Using microscopic techniques and analyses of preserved DNA, they identified parasitic worms in the samples. While they found high counts of roundworm eggs in samples spanning the roughly 500-year period studied, there was a notable shift in the presence of eggs from different types of tapeworms, the team reported in Proceedings of the Royal Society B.

In samples from before about 1300,eggs from Diphyllobothrium latum were prevalent, suggesting that the people of Lübeck were eating a lot of undercooked freshwater fish like carp, perch or whitefish, which are known sources of D. latum. After 1300, however, instead of fish-derived tapeworm eggs, the latrine samples were studded with the eggs of a beef-derived tapeworm called Taenia saginata.

Around 1300, the “people of Lübeck may have stopped eating raw freshwater fish,” or somehow disrupted the life cycle of D. latum, said zoologist Adrian Smith of the University of Oxford in England, a co-author of the study, in a statement. “Interestingly, the shift in eating habits coincides with an increase in tannery and butchery-based industry on the freshwater side of Lübeck, and pollution may have interfered with the fish-derived parasite life cycle,” he said.

The team plans to continue combining archaeological work with DNA sequencing to develop a “molecular archaeoparasitological” map of Europe. “We can use this approach to tell us a lot about specific locations, including levels of sanitation, health status, dietary practices and connectivity of different sites,” Smith said, which “might be of particular importance” in studying past populations for which historical records are lacking.

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