Ancient Human Parasites in Ethnic Chinese Populations

Whilst archaeological evidence for many aspects of life in ancient China is well studied, there has been much less interest in ancient infectious diseases, such as intestinal parasites in past Chinese populations. Here, we bring together evidence from mummies, ancient latrines, and pelvic soil from burials, dating from the Neolithic Period to the Qing Dynasty, in order to better understand the health of the past inhabitants of China and the diseases endemic in the region. Seven species of intestinal parasite have been identified, namely roundworm, whipworm, Chinese liver fluke, oriental schistosome, pinworm, Taenia sp. tapeworm, and the intestinal fluke Fasciolopsis buski. It was found that in the past, roundworm, whipworm, and Chinese liver fluke appear to have been much more common than the other species. While roundworm and whipworm remained common into the late 20th century, Chinese liver fluke seems to have undergone a marked decline in its prevalence over time. The iconic transport route known as the Silk Road has been shown to have acted as a vector for the transmission of ancient diseases, highlighted by the discovery of Chinese liver fluke in a 2,000 year-old relay station in northwest China, 1,500 km outside its endemic range

Some microDNAs are shared between and within drug groups.

<p>Number of genes where from microDNA derived shared between drug groups (Sensitive: S; Resistant: R; Treated: T; Non-Treated: NT) (<b>A</b>) Observed numbers per drug <b>Top</b>: MTX <b>Bottom</b>: ASP (<b>B</b>) Observed <i>vs</i>. expected numbers of microDNA-derived genes per group. Expected numbers were computed by generating 1000 random new microDNAs with lengths corresponding to those we identified. <b>Top</b>: MTX <b>Bottom</b>: ASP. p<0.01 (estimated by chi-square) for the difference between observed and expected numbers in all cases except MTX R_NT group.</p

MicroDNA generation in relation to treatment.

<p>Percentage (%) of unique microDNAs generated from LCL samples when treated <i>vs</i>. non-treated with (<b>A</b>) Methotrexate (MTX) or (<b>B</b>) Asparaginase (ASP). Treated <i>vs</i>. non-treated samples: <b>Left</b>, regardless of sensitivity/resistance status; <b>Center</b>, in resistant cells; <b>Right</b>, in sensitive cells. Numbers on the graph represent the number of unique microDNAs generated in each group.</p

MicroDNA length and periodicity.

<p>Size distribution in base pairs (bp) of all identified microDNAs (<b>A</b>) regardless of drug used for treatment. Vertical lines depict the 190 bp periodicity. (<b>B</b>) per drug (ASP: Asparaginase, MTX: Methotrexate) and per sensitivity status (resistant: R, sensitive: S, treated: T, non-treated: NT).</p

Percentage of shared entities between samples.

<p><b>Left</b>: Gene intersects, microDNA derivied for the same gene, shared between ≥ 2 samples. <b>Right</b>: Cluster intersects, microDNA derived from the same genomic position shared between ≥ 2 samples with > = 1 bp overlap. The number/total and (%) of intersects per drug group are indicated. Difference between groups was assessed using a two-tailed Chi-square test.</p

MicroDNA are significantly enriched in coding and active genomic regions.

<p>Fold enrichment is calculated as the ratio of the observed by expected number. Expected numbers were computed by generating 1000 random new positions with lengths corresponding to those of identified microDNAs and outputting the median. The dotted line shows a hypothetical situation where expected number would be equal to the observed number. <b>Top</b>: Methotrexate (MTX). <b>Bottom</b>: Asparaginase (ASP). Statistical significance was assessed using Fisher's Exact test (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0184365#pone.0184365.s009" target="_blank">S3 Table</a>).</p