Ubiquity and diversity of human-associated Demodex mites

PLoS One. 2014 Aug 27;9(8):e106265. doi: 10.1371/journal.pone.0106265. eCollection 2014.

Abstract

Demodex mites are a group of hair follicle and sebaceous gland-dwelling species. The species of these mites found on humans are arguably the animals with which we have the most intimate interactions. Yet, their prevalence and diversity have been poorly explored. Here we use a new molecular method to assess the occurrence of Demodex mites on humans. In addition, we use the 18S rRNA gene (18S rDNA) to assess the genetic diversity and evolutionary history of Demodex lineages. Within our samples, 100% of people over 18 years of age appear to host at least one Demodex species, suggesting that Demodex mites may be universal associates of adult humans. A phylogenetic analysis of 18S rDNA reveals intraspecific structure within one of the two named human-associated Demodex species, D. brevis. The D. brevis clade is geographically structured, suggesting that new lineages are likely to be discovered as humans from additional geographic regions are sampled.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Animals
  • Female
  • Genes, rRNA*
  • Genetic Variation
  • Hair Follicle / parasitology
  • Humans
  • Male
  • Middle Aged
  • Mite Infestations / epidemiology*
  • Mites / classification
  • Mites / genetics*
  • Phylogeny*
  • Prevalence
  • RNA, Ribosomal, 16S / genetics*
  • RNA, Ribosomal, 18S / genetics*
  • Sebaceous Glands / parasitology
  • United States / epidemiology

Substances

  • RNA, Ribosomal, 16S
  • RNA, Ribosomal, 18S

Grants and funding

DJF, RRD, and MST were supported on a NASA Biodiversity grant (ROSES NNX09AK22G), www.nasa.gov/, and NSF Career grant (0953390), www.nsf.gov/, during this work. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.