Coprolite Parasite Insight

The increased spread of infectious disease during the Neolithic period is attributed to agricultural and population expansion as humans transitioned from hunter-gatherers to farmers and herders. Intestinal parasites in particular are thought to have adapted in response to altering human behavior at that time.

Marrisa Ledger and colleagues honed in on parasite infections in the village of Çatalhöyük, Turkey, by analyzing four samples of coprolite (fossilizes feces) from 6410-6150 BCE (1). The samples were first ground and analyzed by digital light microscopy to confirm the presence of parasite eggs; next, the total lipid extracts of the infected samples were subjected to GC-MS to determine levels of sterols (including those used as faecal biomarker compounds) and bile acids (produced by the organism of origin).

Two of the four samples tested positive for whipworm eggs (Trichuris sp.), most likely human whipworms (Trichuris trichuria), and lipid analysis indicated samples of human origin; sterol profiles were typical of omnivores (high coprostanol, low cholesterol and numerous phytosterols) and bile acid profiles were primarily deoxycholic acid, with few lithocholic acids. The results appear to provide the first evidence for intestinal parasite infection in this region at this time. Additional pelvic soil samples were also collected from nearby burial sites as a control – but all tested negative for parasite eggs.

The researchers plan to use the method to study additional compounds from coprolite samples in studies that go beyond simply confirming the species of origin. “We are developing a more holistic approach,” says investigator Ian Bull. “Many compounds derive from diet, so we hope that we can gain more information about the way people lived, as well as the commodities used.”

How much more information can be uncovered from such samples? The answer is, of course, tied inextricably to the team’s method, which has been evolving in line with instrumental innovation since the early 2000s. “Greater sensitivity is always appreciated but, certainly for us, better workflows and mining of data obtained from time-of-flight and Orbitrap MS systems is now key,” says Bull. “We can already collect vast amounts of information using such platforms – we just need to improve and simplify methods for us to interrogate such datasets. And that moves us very much in the direction of lipidomics and metabolomics.”