Evidence of contact between New and Old World: paleoparasitological and food remains study in the Tagus river population of Sarilhos Grandes (Montijo, Portugal)

The period of European maritime expansion that started in the fifteenth century had a great impact on trading, on human migrations and consequently in the dispersion of infectious diseases. Portugal was at the core of this expansion; however, studies about parasitic infections, especially helminths, are lacking. This study aims to help reduce this gap presenting the results of microscopic analysis of soil sediments collected from the Sao Jorge churchyard of Sarilhos Grandes (Montijo). Consecrated in the fourteenth century AD, it remained as a burial ground until the nineteenth century. Soil samples collected from the pelvic girdle of five adult individuals and samples taken as control were analysed under the microscope after current conventional methodological procedures were undertaken. Eggs from Ascaris lumbricoides were identified. Also eggs of trichostrongyle type species were identified in two individuals and may represent the first report in archaeological European samples. Food remains include potato and rice starches, muscle fibres, bivalves, pollen grains and fungi spores. The stratigraphy interpretation together with potato findings put the oldest skeletons to a chronology around the sixteenth century AD. These results are consistent with historical sources that documented the prominence of Tagus river nearby villages in maritime expansion.