Luxurious lavatories have led archaeologists to evidence of a parasite that would have kept the people of ancient Judah “on the throne” for protracted periods.
An international team discovered the earliest known evidence of Giardia infections in humans in soil samples from cesspits in Jerusalem of the eighth to sixth centuries BC. They said that, given its presence at two elite residences, the parasite was likely to have been endemic in the region — bringing diarrhoea, dysentery, joint and eye problems and deadly risks to children.
Lead author Dr Piers Mitchell, of the University of Cambridge’s Department of Archaeology, said: “This is the earliest evidence for Giardia as a cause of dysentery anywhere in the world. Even more exciting is that we found it in the region where people first invented the town and city — which would have then allowed the spread of these infectious diseases. Mix with that the fact that they invented writing in the Middle East — so we have very early medical texts that describe the symptoms of dysentery — and now we can start to put modern biological labels on some of these ancient infectious diseases described in texts.”
Jerusalem in this period was capital of the Kingdom of Judah and a large, vibrant political and religious centre. The cesspits from which the soil samples were taken were only identified thanks to the discoveries of the rare stone toilet seats originally positioned above them.
Mitchell said: “The reason we have the latrines is that they were in swanky houses. They are carved stone latrines that have stood the test of time and were identified because they have a curvy seat for the buttocks and holes for urine and faeces. Most people who had a cesspit would have had a plank with a hole over it. The plank would have decomposed.”
One of the latrines was discovered in a 2019-20 excavation at Armon Hanatziv, just south of ancient Jerusalem. The site has fragments of superb quality architectural stonework and analysis of pollen and seeds hints at a mansion set in pleasure gardens. It dates from the reign of King Manasseh in the seventh century BC and may have belonged to a merchant or noble. Previous research on samples from this cesspit revealed that Judahites were infected by roundworm, whipworm, tapeworm and pinworm.
“The users of both these latrines were heavily contaminated”Dr Piers Mitchell
The site of the second latrine, with a virtually identical seat, was a high-status courtyard house within the city limits, built around the the eighth century BC. The house was destroyed in 586BC when Babylonian ruler Nebuchadnezzar II sacked Jerusalem for a second time, bringing the Kingdom of Judah to an end.
Giardia is spread via contamination of food or water by faeces of an infected person or animal. It exists in the intestine in cyst and motile (trophozoite) forms. The 9-20-micrometer trophozoites attach themselves to the lining of the intestine, causing inflammation and symptoms. The parasite is easily damaged as faeces decompose and therefore very difficult to detect in ancient samples using microscopes. To get round this, the team harnessed a technique called ELISA that uses antibodies to detect proteins that are only produced by this species.
They tested for Giardia and for Entamoeba and Cryptosporidium — other parasites that are among the most common causes of diarrhoea and dysentery in humans. The tests for Giardia were repeatedly positive, the others negative.
Mitchell said: “We were surprised that both latrines were strongly positive across the three times we studied them. A lot of the time when you have ancient remains, you get a weak positive and you test another bit of the sample and may get nothing — because not all of the sample was contaminated by the person or people who had the dysentery. The fact that both latrines were positive all three times we tested, using new samples, suggests this was a big problem and the users of both these latrines were heavily contaminated.”
In their paper, in Parasitology, the team said the large and crowded towns and cities that existed across the Near East around this time would have been fertile grounds for infections. “While they did have toilets with cesspits across the region by the Iron Age, they were relatively rare and often only made for the elite,” they wrote. “Towns were not planned and built with a sewerage network, flushing toilets had yet to be invented and the population had no understanding of microorganisms and how they can be spread.”
Ubiquitous house flies would only have helped to spread the parasite.
As for the implications for the Judahites, Mitchell said Giardia would have caused asymptomatic infections in some, diarrhoea in many others, and additional symptoms such as abdominal cramps, fever and the passing of blood and mucus in stool in numerous dysentery cases.
The parasite was probably a common cause of death for under-fives, he added. “Giardia and other forms of dysentery are most likely to kill children. The reason being that they have less fluid to lose. If you have crashing diarrhoea for a long time, you become dehydrated and can also lose a lot of salt… then you have problems with your heart and your kidneys. That tends to be how how people with dysentery die and adults have more coping strategies and ability to survive.”
Those children who survived infection would have been at risk of stunted growth and impaired cognitive function. Even adult survivors didn’t necessarily return to full health. Mitchell explained: “An interesting thing about Giardia is that quite a lot of people will have chronic longterm problems that may not be related to their guts. So, a proportion who have Giardia go on to have problems with joints — arthritis in their joints and arthralgia — or they have problems with their eyes, for example.”
Other patients experience post-infective irritable bowel, allergies and muscular complications.
The team said there was no proper understanding in the ancient Middle East of the causes of diarrhoea or effective treatments including urgent rehydration. Texts from Mesopotamia (Iraq) from the second and first millennia BC describe diarrhoea affecting infants and children and note incantations that were believed to aid recovery.
Given the new evidence, the researchers said it was likely that Giardia existed in early towns across the wider region and was responsible for at least some of the illnesses described in Mesopotamian sources.
Besides later examples from Roman sites in Italy and Turkey, Giardia has also been found in a single human faeces specimen dating from 600-1BC in Tennessee. Mitchell said: “If that is a genuine positive, and not a mistake, it would suggest that that Giardia must have been spread around the world from a very early period. And either it was in mammals everywhere and then humans started getting it, or it started in Africa, and then humans brought it around the world.”
The photograph at the top of the page shows the stone toilet seat uncovered at Armon Hanatziv, south of ancient Jerusalem. Photo: Yoli Schwartz, The Israel Antiquities Authority