Helmintos, protozoários e algumas idéias: novas perspectivas na paleoparasitologia

The search of parasites in ancient human remains can throw light on such questions as origin and antiquity of parasite-host relationship, general distribution of parasites through time and prehistoric human migrations. It can be a tool in the interpretation of habits and migrations of prehistoric populations. Parasites found in archaeological and paleontological sites can reveal much information about phylogenetic and co-evolution of parasites. The nucleic acid based techniques of parasites found in archaeological material open a new perspective to evolution at a molecular level. We assessed the utility of a commercially available enzyme immunoassay (ELISA) kit for diagnosis of giardiasis in archaeological human remains. The kit is based on a monoclonal antibody to detect the presence of Giardia Specific Antigen 65 in human feces. A total of 83 specimens, previously examined microscopically for parasites were examined. The ELISA detected 3 positive samples, one of the samples as old as 800 years. The immunoassay was superior to direct observation. The results did not show cross reactivity between this protozoa and helminths. The use of ELISA to detect G. duodenalis coproantigen could help the diagnosis of giardiasis in ancient human remains. A review of the paleoparasitological helminth and intestinal protozoa findings available in the literature is also presented. We report the new paleoparasitologic findings from the examination we performed in samples collected in New and Old World archaeological sites. New finds of ancylostomid, Ascaris lumbricoides, Trichuris trichiura, Enterobius vermicularis, Trichostrongylus spp., Diphyllobothrium latum, Hymenolepis nana and Acantocephala eggs are reported. According to the results, A. lumbricoides was originally a human parasite, adapting to pigs after pig domestication. We also discussed alternative routes for human parasite introduction into the Americas. Human ancylostomids, A. lumbricoides and T. trichiura, found in the New World in pre-Columbian times, have not been introduced into the Americas by land via Beringia.