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THE EFFECTS OF DEHYDRATION AND LOCAL SOIL ON PARASITE RECOVERY: A PRELIMINARY PALEOPARASITOLOGICAL EVALUATION ON EXPERIMENTAL COPROLITES
Ovos de helmintos
Carga de parasitas
Preservação de parasitas
Sedimento
Tafonomia
Affilliation
Instituto de Antropología de Córdoba, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Córdoba, Argentina.
Instituto de Antropología de Córdoba, Consejo Nacional de Investigaciones Científicas y Técnicas, Departamento de Antropología, Facultad de Filosofía y Humanidades, Universidad Nacional de Córdoba, Argentina.
Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratorio de Biologia de Tripanosomatídeos. Rio de Janeiro, RJ, Brasil.
Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratorio de Biologia de Tripanosomatídeos. Rio de Janeiro, RJ, Brasil.
Instituto de Antropología de Córdoba, Consejo Nacional de Investigaciones Científicas y Técnicas, Departamento de Antropología, Facultad de Filosofía y Humanidades, Universidad Nacional de Córdoba, Argentina.
Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratorio de Biologia de Tripanosomatídeos. Rio de Janeiro, RJ, Brasil.
Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratorio de Biologia de Tripanosomatídeos. Rio de Janeiro, RJ, Brasil.
Abstract
Experimental paleoparasitological approaches have been used in order to optimize the methodology previously to the application in archeological
samples. In this study we evaluated the action of dehydration and local soil (Central Argentina) on the loss of parasite eggs in experimental coprolites,
using two parasitological techniques: spontaneous sedimentation and sucrose-flotation. Experimental coprolites comprised fresh human feces, positive
for Hymenolepis nana, Ascaris sp., and Enterobius vermicularis, submitted to controlled artificial dehydration. Experimental coprolites with soil addition
were prepared by mixing archeological sediment with equal mass of fresh feces. Helminth eggs were counted and eggs per gram were estimated in each
subsample. Statistical analyses were applied to compare subsamples before and after desiccation and with and without addition of soil sediment. The
performance of parasitological methods statistically differed, the sucrose flotation technique being the less effective when fresh feces and experimental
coprolites were analyzed. Partial deformation of eggs was observed via both techniques only in subsamples containing H. nana eggs. However, this was
not seen in Ascaris sp. subsamples, possibly due to eggshell composition. We found that sample desiccation significantly decreased the number of eggs
in the experimental coprolites. Mixing archeological sediment with the fecal material also resulted in significantly fewer eggs surviving, independent of
desiccation. This shows that climate and soil in which archeological fecal samples are found can strongly influence the survival of parasite eggs from past
populations. The small amount of parasite evidence often found in paleoparasitological analyses, including Central Argentina, could be attributed to the
action of taphonomic processes rather than to the real absence of infection in these ancient populations. Importantly, the study highlights the role of
local soil, confirmed for the first time by empirical data. The research provides valuable insights into the understanding of the paleoparasitological results
of the region and of general paleoparasitology.
Keywords in Portuguese
CoprólitosOvos de helmintos
Carga de parasitas
Preservação de parasitas
Sedimento
Tafonomia
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