Scholarlink

Background <p><i>Endolimax nana is a</i> common intestinal archamoebid within Evosea (Amoebozoa), alongside genera such as <i>Entamoeba</i>, <i>Iodamoeba</i>, and <i>Mastigamoeba</i>. Despite its frequent colonization of humans, it has received limited attention as a presumed non-pathogenic commensal, and its genetic diversity and host-associated distribution remain poorly resolved. Here, we define the molecular diversity, subtype structure, and host-associated distribution of <i>E. nana</i>.</p> Methods <p>Cross-sectional surveys were conducted in Wainyapu Village, Sumba Island, Indonesia. A total of 315 stool samples were collected from humans (<i>n</i> = 144) and animals (<i>n</i> = 171), including rats, pigs, dogs, ducks, chickens, horses, buffaloes, and goats between 2015 and 2016. Samples were screened by PCR targeting the 18S rRNA gene, followed by direct sequencing and sub-cloning. Sub-cloning was performed for 26 samples with ambiguous chromatograms. Phylogenetic relationships were inferred using Bayesian inference, Neighbor-Joining, and Maximum Parsimony methods. In human, the association between <i>E. nana</i> colonization and diarrheal stool form was evaluated using logistic regression analysis.</p> Results <p><i>E. nana</i> was detected in humans (42.4%, 61/144), rats (12.0%, 6/50), pigs (11.1%, 5/45), dogs (7.7%, 2/26), ducks (20.0%, 1/5), and chickens (3.6%, 1/28). Sequencing yielded 127 sequences (1252–1283&#xa0;bp) comprising 118 unique 18S rRNA haplotypes. Phylogenetic analyses resolved two major subtypes (ST1 and ST2), each consistently recovered monophyletic clusters and further subdivided into distinct subclusters. Subtype distribution revealed clear host-associated structure: ST1-1 and ST2-2 were predominantly human-associated, ST1-2 was shared between humans and pigs, and ST2-1 was distributed across humans, pigs, and rats. Notably, no subtype was restricted to animal hosts, indicating that all subtype lineages include human-associated populations. No association was observed between <i>E. nana</i> colonization and diarrheal stool form.</p> Conclusions <p>We provide the first molecular characterization of human-derived <i>E. nana</i>, defining its subtype structure and host-associated distribution. The absence of animal-restricted subtypes suggests that <i>E. nana</i> circulates primarily within human-associated transmission networks. No association was observed between <i>E. nana</i> colonization and diarrheal stool form in the present dataset. However, these findings should not be interpreted as definitive evidence regarding the commensal or pathogenic nature of the organism.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Intraspecies genetic diversity and host-associated distribution of Endolimax nana in Sumba Island, Indonesia

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年8月4日

查看全文
  • A. A. Mustamir,
  • S. A. Lacante,
  • T. Mizuno,
  • X. Bi,
  • D. Syafruddin,
  • P. B. S. Asih,
  • H. Afzan,
  • N. R. Norton,
  • Y. Sun,
  • M. Tokoro

摘要

Background

Endolimax nana is a common intestinal archamoebid within Evosea (Amoebozoa), alongside genera such as Entamoeba, Iodamoeba, and Mastigamoeba. Despite its frequent colonization of humans, it has received limited attention as a presumed non-pathogenic commensal, and its genetic diversity and host-associated distribution remain poorly resolved. Here, we define the molecular diversity, subtype structure, and host-associated distribution of E. nana.

Methods

Cross-sectional surveys were conducted in Wainyapu Village, Sumba Island, Indonesia. A total of 315 stool samples were collected from humans (n = 144) and animals (n = 171), including rats, pigs, dogs, ducks, chickens, horses, buffaloes, and goats between 2015 and 2016. Samples were screened by PCR targeting the 18S rRNA gene, followed by direct sequencing and sub-cloning. Sub-cloning was performed for 26 samples with ambiguous chromatograms. Phylogenetic relationships were inferred using Bayesian inference, Neighbor-Joining, and Maximum Parsimony methods. In human, the association between E. nana colonization and diarrheal stool form was evaluated using logistic regression analysis.

Results

E. nana was detected in humans (42.4%, 61/144), rats (12.0%, 6/50), pigs (11.1%, 5/45), dogs (7.7%, 2/26), ducks (20.0%, 1/5), and chickens (3.6%, 1/28). Sequencing yielded 127 sequences (1252–1283 bp) comprising 118 unique 18S rRNA haplotypes. Phylogenetic analyses resolved two major subtypes (ST1 and ST2), each consistently recovered monophyletic clusters and further subdivided into distinct subclusters. Subtype distribution revealed clear host-associated structure: ST1-1 and ST2-2 were predominantly human-associated, ST1-2 was shared between humans and pigs, and ST2-1 was distributed across humans, pigs, and rats. Notably, no subtype was restricted to animal hosts, indicating that all subtype lineages include human-associated populations. No association was observed between E. nana colonization and diarrheal stool form.

Conclusions

We provide the first molecular characterization of human-derived E. nana, defining its subtype structure and host-associated distribution. The absence of animal-restricted subtypes suggests that E. nana circulates primarily within human-associated transmission networks. No association was observed between E. nana colonization and diarrheal stool form in the present dataset. However, these findings should not be interpreted as definitive evidence regarding the commensal or pathogenic nature of the organism.