A research team led by the University of Cambridge say it is the oldest example we have of this diarrhoea-causing parasite infecting humans anywhere on the planet. The study is published in the journalParasitology.

"The fact that these parasites were present in sediment from two Iron Age Jerusalem cesspits suggests that dysentery was endemic in the Kingdom of Judah," said study lead author Dr Piers Mitchell from Cambridge's Department of Archaeology.

"Dysentery is a term that describes intestinal infectious diseases caused by parasites and bacteria that trigger diarrhoea, abdominal cramps, fever and dehydration. It can be fatal, particularly for young children."

"Dysentery is spread by faeces contaminating drinking water or food, and we suspected it could have been a big problem in early cities of the ancient Near East due to over-crowding, heat and flies, and limited water available in the summer," said Mitchell.

The faecal samples came from the sediment underneath toilets found in two building complexes excavated to the south of the Old City, which date back to the 7^thcentury BCE when Jerusalem was a capital of Judah.

During this time, Judah was a vassal state under the control of the Assyrian Empire, which at its height stretched from the Levant to the Persian Gulf, incorporating much of modern-day Iran and Iraq. Jerusalem would have been a flourishing political and religious hub estimated to have had between 8,000 and 25,000 residents.

Both toilets had carved stone seats almost identical in design: a shallow curved surface for sitting, with a large central hole for defecation and an adjacent hole at the front for male urination. "Toilets with cesspits from this time are relatively rare and were usually made only for the elite," said Mitchell.

一个来自艾蒙装修极尽奢华房地产ha-Natziv, surrounded by an ornamental garden. The site, excavated in 2019, probably dates from the days of King Manasseh, a client king for the Assyrians who ruled for fifty years in the mid-7^thcentury.

The site of the other toilet, known as the House of Ahiel, was a domestic building made up of seven rooms, housing an upper-class family at the time. Date of construction is hard to pin down, with some placing it around the 8^thcentury BCE.

However, its destruction is safely dated to 586 BCE, when Babylonian ruler Nebuchadnezzar II brutally sacked Jerusalem for a second time after its citizens refused to pay their agreed tribute, bringing to an end the Kingdom of Judah.

Ancient medical texts from Mesopotamia during the first and second millennium BCE describe diarrhoea affecting the populations of what is now the Near and Middle East. One example reads: "If a person eats bread and drinks beer and subsequently his stomach is colicky, he has cramps and has a flowing of the bowels, setu has gotten him."

The cuneiform word often used in these texts to describe diarrhoea was sà si-sá. Some texts also included recommended incantations for reciting to increase the chances of recovery.

"These early written sources do not provide causes of diarrhoea, but they encourage us to apply modern techniques to investigate which pathogens might have been involved," said Mitchell. "We know for sure thatGiardiawas one of those infections responsible."

The team investigated the two-and-a-half-thousand year-old decomposed biblical period faeces by applying a bio-molecular technique called "ELISA," in which antibodies bind onto the proteins uniquely produced by particular species of single-celled organisms.

"Unlike the eggs of other intestinal parasites, the protozoa that cause dysentery are fragile and extremely hard to detect in ancient samples through microscopes without using antibodies," said co-author and Cambridge PhD candidate Tianyi Wang.

The researchers tested forEntamoeba,GiardiaandCryptosporidium: three parasitic microorganisms that are among the most common causes of diarrhoea in humans, and behind outbreaks of dysentery. Tests forEntamoebaandCryptosporidiumwere negative, but those forGiardiawere repeatedly positive.

Previous research has dated traces of the Entamoeba parasite, which also causes dysentery, as far back as Neolithic Greece over 4,000 years ago. Previous work has also shown that users of ancient Judean toilets were infected by other intestinal parasites including whipworm, tapeworm and pinworm.

This research was undertaken through a collaboration between the University of Cambridge, Tel Aviv University, and the Israel Antiquities Authority.