Evaluation of the effect of desiccation and local soils in the recovery of parasites by experimental coprolites

RAMIREZ, DARÍO ALEJANDRO; XAVIER, SAMANTA; FABRA, MARIANA; IÑIGUEZ MAYO, ALENA

Arica

Congreso; VII Congreso de la Asociación de Paleopatología en Sudamérica PAMinSAI; 2017

Paleoparasitological analyses of archaeological sediments of human origin from the Province of Córdoba (Argentina) showed helminth eggs. However, the findings are scarce, especially of human parasites. These results are possibly due to specific taphonomic processes in the region that act negatively on the conservation of the parasites. To test this hypothesis, an experimental coprolite approach using modern faeces was undertaken to evaluate the effects of desiccation of local soil on parasite recovery. Current human faeces (n=8) were divided into 5 different processes: 1) fresh control faeces; 2)experimental coprolites without soil sediment; 3) experimental coprolites with soil sediment; 4) stool controls at -20 °C, and 5) faeces withsoil sediment at -20 °C. The experimental coprolites were desiccated at 37 °C with the dehydration process being controlled weekly, until total desiccation occurred. Using the methods of Lutz and Sheather, parasitological analysis showed eggs of Ascaris sp., Hymenolepis nana and Enterobius vermicularis. A significant loss of egg numbers was observed in experimental coprolites with or without soil sediment. Statistical analysis of ANOVA and T-test revealed that there were significant differences (α=0.05) between the initial number of parasites and those recovered in the experimental coprolites with sediment, as well as in the controls with sediment. There was also a significant difference between coprolites with or without sediments, revealing the importance of the soil incorporation. Finally, the parasitological methods were significantly different, the Lutz method being more informative, as has been reported in paleoparasitological studies. Despite the small number of samples, the aggressive effect of desiccation, especially of the soil and/or the combination of both, on the archaeological remains is evident. This study provides new data for understanding the paleoparasitological results of the region and of paleoparasitology in general.