After analyzing 500 years in the Christian quarter of the old city of Jerusalem, researchers found evidence of some species of intestinal parasites that seem to have been “imported” from medieval Europe.

Some of the earliest evidence of a human parasite infection has been unearthed in an ancient burial site in Syria. The egg of a parasite that still infects people today was found in the burial plot of a child who lived 6,200 years ago in an ancient farming community. “The analysis of this fifteenth century latrine in Jerusalem provides a vivid glimpse of the infectious diseases suffered by the people who used it,” reads the study.

The parasites in question are Entamoeba histolytica and fish tapeworm, explains the research published in the International Journal of Paleopathology. The researchers believe long distance travelers had taken these parasites with them as they journeyed to Jerusalem.

Human parasites include various protozoa and worms which may infect humans, causing parasitic diseases. They are divided into endoparasites, which cause infection inside the body, and ectoparasites, which cause infection superficially within the skin. The cysts and eggs of endoparasites may be found in feces which aids in the detection of the parasite in the human host while also providing a means for the parasitic species to exit the current host and enter other hosts. Although there are number of ways in which humans can contract parasitic infections, observing basic hygiene and cleanliness tips can reduce its probability.

The researchers also found quantities of Taenia parasite eggs, indicating pork or beef tapeworm. The Mamluk Period (1250-1516 AD) was Islamic but pigs would have still been consumed in the Christian quarter. Though its effects varied, “a heavy load of these parasites in children, however, can lead to malnutrition, reduced intelligence and stunted growth. This research highlights how we can use preserved parasite eggs in ancient toilets to spot past migrations and the spread of ancient diseases.