March 2020

This is a guest blog written by Patrik G. Flammer and Marissa L. Ledger specialists who have been working closely with the Vindolanda Trust analysing samples from the site. They take a closer look at the parasites that can be found and what they tell us about the life, diet and hygiene of the Romans living at Vindolanda.

Searching for Ancient Parasites in Vindolanda's drains.

Throughout history, humans have been afflicted by parasitic worms, and parasite eggs have been found in a variety of archaeological deposits. Many worms that infect humans live in the gastrointestinal tract, particularly the intestines. Some can grow to many meters in length. When these worms reproduce, they release thousands of eggs into the stool. Luckily for archaeologists these eggs survive thousands of years in the soil and can be found in archaeological sites today. Parasite eggs have evolved to survive for prolonged periods of time in the soil and thus show very robust shells. By collecting soil from areas of an archaeological site where human stool would have been deposited we can find preserved parasite eggs and determine what worms may have infected people living in the past. These eggs can be identified by their characteristic shape under the microscope. Aside from looking for preserved eggs under the microscope we can also detect preserved molecules from these parasites. Immunological methods can be used to detect specific antigenic proteins from some parasites and DNA from these parasites can also be recovered.

Roundworm egg (left) and whipworm egg (right) from drain at Vindolanda. (Image credit: Patrik Flammer) 

In the majority of cases, parasitic infections have a very low impact on a person’s health and thus do not interfere with daily life. Different Intestinal parasites have specific infection routes, generally associated with hygiene, contaminated food, or eating raw/undercooked meat or fish. Therefore, these parasites can be used to help us understand human behaviour in the past.

Drain at Vindolanda leading to the latrines.

Soil collected from a drain that connected to a latrine at Vindolanda is being studied to look for evidence of parasites that may have infected Romans who would have used this communal latrine. Often times Roman latrines could be connected to drains running underneath buildings and these latrines would have been ‘flushed’ by channeling water from the baths through the base of the latrine to wash away human excrement into the drain. These Roman drains could often be clogged and would need to have been periodically cleaned, a job that existed in the Roman empire. Luckily for archaeologists there is often quite a bit of soil, preserved organic material, and other refuse in drains which can be studied to learn about diet and disease. 

In the soil collected from the drain at Vindolanda eggs from various types of parasites were found. Two intestinal worms that are transmitted by the faecal-oral route, roundworm (Ascaris sp.) and whipworm (Trichuris sp.), were found. A single roundworm can grow up to 30cm long in the intestines and release more than 200,000 eggs per day in stool. Whipworm is 3-5cm long and releases up to 20,000 eggs per day. Both were fairly common parasites in the Roman period indicating that sanitation and hygiene conditions were not adequate to stop faecal contamination of food. It does not always cause symptoms but it can cause abdominal pain and nutritional deficiencies especially in children.

Taenia sp. Egg (Image credit: Patrik Flammer)

In some cases, tapeworms can be found as well, in the drain from Vindolanda eggs from Taenia (beef/pork tapeworm) were found. These are of particular interest as they are food-transmitted, specifically by the ingestion of raw or undercooked red meat. These provide direct evidence not only about the foods consumed, but also about the preparation of these foods as in order to be infected people must eat undercooked meat.

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Dr Patrik Flammer, Department of Zoology, University of Oxford

During my undergraduate studies in biology and biochemistry I got especially interested in infectious diseases, including their dispersal, genetics and evolution. For my DPhil at the University of Oxford I established a method to use human intestinal parasites (helminths) from archaeological contexts to inform on socio-economic factors of the populations and their interactions with other populations.

Human intestinal parasites have many advantages as a study system. The biology of these parasites allows insight into different aspects of life, from sanitation and hygiene to diet and cultural practices. Genetic research allows not only the exact determination of the species of the infectious agent, but also genetic linkages between parasite populations and thus their human hosts. Our ambition is to build a network of parasite infections throughout time across Europe.

For this network, Vindolanda is a very exciting site. This important fortification at the northern edge of the Roman Empire was the home of many Roman citizens from all over the Empire. They got into close contact with the local population and populations on their way through the Empire to reach Vindolanda. The work on the parasites could provide insight into the lives and origins of the Romans stationed at this fort on Hadrian's Wall.

Marissa Ledger, Graduate Student, University of Cambridge

My research interests are in health and disease throughout human evolution. My PhD research is focused on parasitic infection in the past and the impact of parasitic infection on humans as well as the impact of humans on the spread and evolution of parasites. This research uses techniques including light microscopy and biomolecular identification of parasites from archaeological samples, particularly in the Roman Empire.