Giardia lamblia miRNAs as a new diagnostic tool for human giardiasis

PLoS Negl Trop Dis. 2019 Jun 17;13(6):e0007398. doi: 10.1371/journal.pntd.0007398. eCollection 2019 Jun.

Abstract

Background: Giardia lamblia is a very common cause of gastrointestinal symptoms worldwide. There are several methods for the diagnosis of Giardia infection, however none are ideal. We aim to find a new, microRNA-based method that will improve the currently available diagnostic methods for giardiasis.

Methods: Deep-sequence profiling of Giardia small-RNA revealed that miR5 and miR6 are highly expressed in Giardia. These miRNAs were tested by qRT-PCR in duodenal biopsies of patients with giardiasis who were positive by microscopic pathological evaluation. The gastric biopsies of the same patients served as negative control tissues. Additionally, these miRNAs were evaluated in stool samples of patients with proven giardiasis.

Results: All histologically proven duodenal biopsies of patients with Giardia infection were positive for Giardia miR5, with a mean threshold cycle (Ct) of 23.7, as well as for Giardia DNA qPCR (16S-like gene, mean Ct 26.3). Gastric biopsies which were tested as a control all were negative. Stool evaluation of miR6 in patients with giardiasis showed 90% specificity but only 66% sensitivity, and a lower accuracy rate was obtained with miR5.

Conclusion: Giardia miR5 testing in duodenal biopsies may be a new method for the diagnosis of giardiasis. It seems to be more sensitive when compared with testing for Giardia DNA by qPCR in duodenal biopsies. It will be important to investigate the contribution of routine Giardia miRNA testing in duodenal biopsies from patients with persistent abdominal symptoms.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biopsy
  • Duodenum / parasitology*
  • Feces / parasitology*
  • Female
  • Giardia lamblia / genetics*
  • Giardiasis / diagnosis*
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • MicroRNAs / analysis*
  • RNA, Protozoan / analysis*
  • Sensitivity and Specificity

Substances

  • MicroRNAs
  • RNA, Protozoan

Grants and funding

The research was funded by grant from the The Israel Science Foundation (ISF) I-CORE program number 41/11 to Ben-Dov Z. Iddo. In addition the research was funded by grant from the Sheba Medical Center internal grant, titled: Identifying MicroRNAs in the stool as a diagnostic tool for human Giardiasis to Avni Dror and Schwartz Eli. We declare that the funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.