Ancient feces reveal how 'marsh diet' left Bronze Age Fen folk infected with parasites

New research published today in the journal Parasitology shows how the prehistoric inhabitants of a settlement in the freshwater marshes of eastern England were infected by intestinal worms caught from foraging for food in the lakes and waterways around their homes.

The Bronze Age settlement at Must Farm, located near what is now the fenland city of Peterborough, consisted of wooden houses built on stilts above the water. Wooden causeways connected islands in the marsh, and dugout canoes were used to travel along water channels.

The village burnt down in a catastrophic fire around 3,000 years ago, with artefacts from the houses preserved in mud below the waterline, including food, cloth, and jewellery. The site has been called "Britain's Pompeii."

Also preserved in the surrounding mud were waterlogged "coprolites" -- pieces of human faeces -- that have now been collected and analysed by archaeologists at the University of Cambridge. They used microscopy techniques to detect ancient parasite eggs within the faeces and surrounding sediment.

Very little is known about the intestinal diseases of Bronze Age Britain. The one previous study, of a farming village in Somerset, found evidence of roundworm and whipworm: parasites spread through contamination of food by human faeces.

The ancient excrement of the Anglian marshes tells a different story. "We have found the earliest evidence for fish tapeworm, Echinostoma worm, and giant kidney worm in Britain," said study lead author Dr Piers Mitchell of Cambridge's Department of Archaeology.

"These parasites are spread by eating raw aquatic animals such as fish, amphibians and molluscs. Living over slow-moving water may have protected the inhabitants from some parasites, but put them at risk of others if they ate fish or frogs."

Disposal of human and animal waste into the water around the settlement likely prevented direct faecal pollution of the fenlanders' food, and so prevented infection from roundworm -- the eggs of which have been found at Bronze Age sites across Europe.

However, water in the fens would have been quite stagnant, due in part to thick reed beds, leaving waste accumulating in the surrounding channels. Researchers say this likely provided fertile ground for other parasites to infect local wildlife, which -- if eaten raw or poorly cooked -- then spread to village residents.

"The dumping of excrement into the freshwater channel in which the settlement was built, and consumption of aquatic organisms from the surrounding area, created an ideal nexus for infection with various species of intestinal parasite," said study first author Marissa Ledger, also from Cambridge's Department of Archaeology.

See:

Marissa L. Ledger, Elisabeth Grimshaw, Madison Fairey, Helen L. Whelton, Ian D. Bull, Rachel Ballantyne, Mark Knight, Piers D. Mitchell. Intestinal parasites at the Late Bronze Age settlement of Must Farm, in the fens of East Anglia, UK (9th century B.C.E.). Parasitology, 2019; 1 DOI: 10.1017/S0031182019001021

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology