When the University of Cambridge broke ground for a museum renovation in 2017, it discovered the remains of dozens of medieval friars. Dating as far back as 1290, many of the skeletons still sported weathered belt buckles—remnants of ascetic burial robes. They also sported evidence of something even more insidious: the eggs of parasitic worms that potentially wreaked havoc on the friars’ intestines while they were still alive.
Although these men lived a more sanitary existence than city dwellers outside their communities, they were more likely to struggle with parasites, a new study suggests. Their horticultural practices may be to blame.
In medieval Cambridge, many citizens were squatters, living in cramped cottages with cattle and throwing household excrement into communal holes in the ground called cesspits. The city’s Augustinian friars lived the high life by comparison. Within the walls of the friary, gardens produced fresh produce, and toilets were isolated. Many friaries were also provided with running water – a luxury absent even from aristocratic families of the time – to allow the friars to wash their hands. As with many aspects of their lives, their focus on cleanliness brought them closer to God.
This is probably why friars often live longer than normal. But no one noticed whether the friars were less susceptible to insects and other parasites—a common scourge of the time.
So Cambridge palaeopathologist Piers Mitchell and his colleagues set out for a trove of ascetic skeletons in the grounds of their home. To determine whether the remains suffered from parasites such as roundworms and whipworms — which can cause severe damage to the digestive tract and, in extreme cases, stunt growth — the researchers collected sediment around the pelvises of 19 skeletons from the 13th and 14th centuries. .
As a control, they took samples of the friars’ skulls and legs, body parts that should lack any signs of intestinal parasites. They also collected similar samples from 25 non-monastic skeletons at the same time in a rural area a kilometer away from the friary ruins. This parish cemetery served a mainly lower-class congregation between the 12th and 14th centuries.
Back in the lab, the team put samples under a microscope to look for remains of intestinal interlopers. Parasitic worms died out centuries ago. Instead, the researchers sifted through the samples for microscopic worm eggs, which can remain in the sediment for centuries.
Almost 60% of the Cambridge fellows were infested with intestinal worms, the team reported today. International Journal of Paleopathology. They were almost twice as likely to be infected with parasites as their non-monastic neighbors.
Ironically, Mitchell believes, the friars’ good hygiene may be to blame. Because they threw their excrement into the garbage instead of collecting it in the toilet, the priests may have recycled their own waste (or the waste they bought from the townspeople) as fertilizer for their vegetable gardens.
Roundworms lay their eggs in human feces, Mitchell notes, so eggs in the garden can easily get into produce and then into the stomachs of fryers. As the worms hatched and moved through the friars’ digestive tracts, they would cause stomachaches and gut-wrenching bowel movements. And as the worm-infested friars retreated to the latrine block, they helped spread the next generation of roundworm eggs into the fresh manure reservoir.
Little is known about the composting practices of the lower classes in the city. But lack of access to toilets may have made them less likely to use human excrement in their gardens.
However, not all parasitologists are sold that the structures that pocket Friar’s pelvis are medieval worm eggs. Carl Reinhardt, an archaeologist at the University of Nebraska, Lincoln, who studies intestinal parasites preserved in mummy stomachs, notes that many of the eggs the team examined lacked the protective covering typical of roundworms. “There are many ovoid structures in the fungal and plant world that may be parasitic egg mimics in archaic contexts.”
However, according to the Cambridge researchers, intestinal parasites are prevalent in medieval hoards. Skeletons from this period show signs of being destroyed by tapeworms, flukes, and an assortment of single-celled protozoa that cause dysentery.
Although the friar’s remains are centuries old, Mitchell believes the find’s take-home message is timeless: “Don’t be the friar who fertilizes your salad with your manure.”