Far from battlefields and barbarian raids, new research from Hadrian’s Wall shows Roman soldiers and their families were quietly battling something far less visible: intestinal parasites thriving in the very water and sanitation systems meant to protect them.
Hidden threats in the shadow of Hadrian’s Wall
The new study focuses on Vindolanda, a well‑known Roman fort just south of Hadrian’s Wall in what is now northern England. The fort is famous for its wooden writing tablets, leather shoes and remarkably preserved everyday objects.
Now it has yielded another kind of evidence: the microscopic remains of parasites that once infected the people who lived there in the 3rd century AD.
In 2019, researchers from the Universities of Cambridge, British Columbia and Oxford sampled sediments from the main latrine drain at Vindolanda. This drain, connected to a substantial toilet block near the bathhouse and supplied by an aqueduct, was designed as part of a sophisticated sanitation system by Roman standards.
Microscopic analysis of the 1,800‑year‑old latrine sludge showed that the system looked advanced, yet still failed to keep faecal contamination out of everyday life.
The team collected 58 samples along the full length of the drain. They searched for eggs of intestinal worms using microscopy and used a laboratory technique known as ELISA (Enzyme‑Linked Immunosorbent Assay) to look for traces of water‑borne protozoa.
Three parasites tell a story of dirty water and food
The results were stark. The scientists identified eggs from two species of intestinal worms, along with a protozoan parasite passed on through contaminated water.
- Ascaris (roundworm) eggs were found in about 22% of samples.
- Trichuris (whipworm) eggs appeared in around 4% of samples.
- Giardia duodenalis, detected via ELISA, showed up at least once – the first confirmed archaeological evidence of this parasite in Roman Britain.
One sample even contained both Ascaris and Trichuris at the same time, underlining how multiple infections could coexist in the same community.
All three parasites share the same route of transmission: the faecal–oral pathway, where microscopic eggs or cysts move from human waste into food, water or hands, then into another person’s mouth.
What these parasites did to Roman bodies
Ascaris lumbricoides, the roundworm found at Vindolanda, is a strictly human parasite. A single female worm can produce up to 200,000 eggs per day. Those eggs can survive in moist soil for years. Once swallowed, they hatch in the small intestine.
Infections with Ascaris can cause stomach pain, nausea and malnutrition. In heavier cases, worms can migrate through the body, block the intestines or even reach the bile ducts, leading to life‑threatening complications.
Trichuris trichiura, the whipworm, produces fewer eggs – roughly 18,000 a day per female – but causes chronic problems. Whipworm infections often linger for years. They drain energy, contribute to anaemia and can stunt growth in children.
Giardia duodenalis is a single‑celled protozoan rather than a worm. Its presence in Vindolanda’s latrine drain is a clear red flag for contaminated water sources. Giardia is typically caught by drinking or washing with water containing tiny cysts of the parasite.
Giardiasis, the illness it causes, leads to watery diarrhoea, bloating, cramps and weight loss. Without treatment, infections can become long‑term, especially in children, who may suffer from impaired development and learning difficulties.
Life in a Roman fort: advanced plumbing, poor hygiene
Vindolanda was not just a barracks. Archaeologists have uncovered children’s shoes, women’s jewellery and domestic tools alongside military kit. This suggests a mixed community of soldiers, partners, children and civilian workers.
Roman law technically banned soldiers from marrying during service, but texts from Vindolanda – including personal letters on thin wooden tablets – show that families lived around the garrison anyway. Requests for food, clothing and social invitations paint a picture of a bustling settlement rather than a purely martial outpost.
In this cramped environment, a faecal‑oral transmission route had all the conditions it needed. Close quarters, shared latrines, communal bathhouses and limited understanding of hand hygiene would have allowed parasites to circulate continually.
Some sediment samples revealed up to 787 whipworm eggs per gram, pointing to heavy contamination and likely high infection rates.
Modern estimates based on archaeological data suggest that between 10% and 40% of people across the Roman Empire may have carried intestinal worms at any given time. Vindolanda’s figures fit neatly within that range.
Children in particular would have paid the price. Constant exposure to contaminated soil and surfaces, combined with weaker immune systems, made them especially vulnerable to chronic infections that affected growth and cognitive development.
Vindolanda as a microcosm of the Roman Empire’s health problems
The Vindolanda findings match patterns seen at other Roman military sites. Studies at Carnuntum in Austria, Viminacium in Serbia and Bearsden in Scotland also show repeated detection of roundworm and whipworm eggs in ancient latrines and cesspits.
More complex parasites, such as tapeworms and liver flukes, appear less regularly in these military contexts. That consistency hints at shared living conditions and sanitation practices across the Empire’s frontier forts that favoured some parasites over others.
Interestingly, the Vindolanda team did not find clear evidence of zoonotic parasites – those that typically pass from animals to humans – despite strong archaeological proof that pigs were kept and eaten on site.
The contamination at Vindolanda appears to have been largely human in origin, pointing toward people rather than livestock as the main drivers of infection.
Researchers caution that some Ascaris and Trichuris eggs could in theory have come from pigs, since animal and human species look almost identical under the microscope. Yet the overall picture still points to a human‑driven cycle of infection, with faecal matter repeatedly entering water and food.
Why Vindolanda is a goldmine for parasite research
Vindolanda’s damp, oxygen‑poor layers preserve organic material extraordinarily well. Timbers, leather and even ink survive. The same conditions helped preserve fragile parasite eggs and proteins in the latrine sediments.
By taking samples along the entire drain, rather than at a single point, the team could track changes in contamination levels across the structure. This method gives rare insight into how wastewater actually moved through the system, where solids settled and where parasites accumulated.
The study also compared material from the 3rd‑century drain with older features from the 1st century AD. Although parasite levels varied over time, their persistent presence shows that even as infrastructure evolved, exposure to infection remained a basic part of life.
What “faecal–oral transmission” really means in practice
The term faecal–oral transmission can sound abstract. At Vindolanda, it would have played out in very concrete ways:
- Water drawn from a stream upstream of the fort becoming contaminated downstream by waste outflows.
- Latrine splashback or leaking drains leaving parasite eggs on nearby surfaces or soil.
- People cleaning themselves in the bathhouse without soap, then sharing food with unwashed hands.
- Children playing near drainage ditches and then putting their hands in their mouths.
Under those conditions, even an aqueduct and stone‑lined latrines could not guarantee safety. The engineering was impressive for its time, but the underlying understanding of disease transmission was missing.
From Roman latrines to modern public health lessons
For today’s readers, the Vindolanda parasites might feel like a distant curiosity from another age. Yet similar infections remain common in parts of the modern world without reliable clean water or sanitation.
Public health experts still rely on the same basic tools the Romans lacked: safe separation of drinking water from waste, effective sewage treatment and hand‑washing with soap. Where those are absent, Ascaris, Trichuris and Giardia continue to circulate.
The study also shows how disciplines like palæoparasitology – the analysis of ancient parasites – can add a human, bodily dimension to history. Military reports and stone inscriptions tell us about emperors, officers and campaigns. Parasite eggs silently record what happened in the intestines of ordinary soldiers, children and camp followers.
For anyone visiting Hadrian’s Wall today, reconstructed latrines and bathhouses often look clean and orderly. The Vindolanda data invites a different mental picture: a noisy, crowded fort where impressive masonry sat on top of a constant, invisible burden of diarrhoea, stomach cramps and chronic fatigue.
Understanding that tension between advanced engineering and basic hygiene failure gives a sharper sense of life on Rome’s northern frontier – and a reminder that technology alone does not guarantee public health without careful everyday habits to match.
