Are immunoenzymatic tests for intestinal protozoans reliable when used on archaeological material?

Intestinal protozoans found in ancient human samples have been studied primarily by microscopy and immunodiagnostic assays. However, such methods are not suitable for the detection of zoonotic genotypes. The objectives of the present study were to utilize immunoenzimatic assays for coproantigen detection of Cryptosporidium sp., Giardia duodenalis, and Entamoeba histolytica/Entamoeba dispar in sixty ancient human and animal samples collected from 14 archaeological sites in South America, and to carry out a critical analysis of G. duodenalis according to results obtained from three diagnostic methodologies: microscopy, immunodiagnostic tests (immunoenzymatic and immunofluorescence), and molecular biology (PCR and sequencing). More than half (31/60) of the samples analyzed using immunoenzymatic tests were positive for at least one of the intestinal protozoans, with 46.6% (28/60) corresponding to G. duodenalis, 26.6% (16/60) to Cryptosporidium sp., and 5% (3/60) to E. histolytica/E. dispar. Cryptosporidium sp. and G. duodenalis coinfection was observed in 15% (9/60) of the samples, whereas all three protozoans were found in 5% (3/60) of samples. In the Northeast Region of Brazil, by immunoenzymatic tests there is evidence that G. duodenlais and Cryptosporidium sp. have infected humans and rodents for at least 7150 years. However, for G. duodenalis, the results from the three diagnostic tests were discordant. Specifically, despite the efficiency of the molecular biology assay in the experimental models, G. duodenalis DNA could not be amplified from the ancient samples. These results raise the following question: Are all ancient samples positive for coproantigen of G. duodenalis by immunoenzymatic tests truly positive? This scenario highlights the importance of further studies to evaluate the sensitivity and specificity of the immunoenzymatic method in the archaeological context.

Studies on protozoa in ancient remains--a review.

Paleoparasitological research has made important contributions to the understanding of parasite evolution and ecology. Although parasitic protozoa exhibit a worldwide distribution, recovering these organisms from an archaeological context is still exceptional and relies on the availability and distribution of evidence, the ecology of infectious diseases and adequate detection techniques. Here, we present a review of the findings related to protozoa in ancient remains, with an emphasis on their geographical distribution in the past and the methodologies used for their retrieval. The development of more sensitive detection methods has increased the number of identified parasitic species, promising interesting insights from research in the future.

Studies on protozoa in ancient remains - A Review

Paleoparasitological research has made important contributions to the understanding of parasite evolution and ecology. Although parasitic protozoa exhibit a worldwide distribution, recovering these organisms from an archaeological context is still exceptional and relies on the availability and distribution of evidence, the ecology of infectious diseases and adequate detection techniques. Here, we present a review of the findings related to protozoa in ancient remains, with an emphasis on their geographical distribution in the past and the methodologies used for their retrieval. The development of more sensitive detection methods has increased the number of identified parasitic species, promising interesting insights from research in the future.