Abstract
Dientamoeba fragilis, an intestinal trichomonad, occurs in humans with and without gastrointestinal symptoms. Its presence was investigated in individuals referred to Milad Hospital, Tehran. In a cross-sectional study, three time-separated fecal samples were collected from 200 participants from March through June 2011. Specimens were examined using traditional techniques for detecting D. fragilis and other gastrointestinal parasites: direct smear, culture, formalin-ether concentration, and iron-hematoxylin staining. The presence of D. fragilis was determined using PCR assays targeting 5.8S rRNA or small subunit ribosomal RNA. Dientamoeba fragilis, Blastocystis sp., Giardia lamblia, Entamoeba coli, and Iodamoeba butschlii were detected by one or more traditional and molecular methods, with an overall prevalence of 56.5%. Dientamoeba was not detected by direct smear or formalin-ether concentration but was identified in 1% and 5% of cases by culture and iron-hematoxylin staining, respectively. PCR amplification of SSU rRNA and 5.8S rRNA genes diagnosed D. fragilis in 6% and 13.5%, respectively. Prevalence of D. fragilis was unrelated to participant gender, age, or gastrointestinal symptoms. This is the first report of molecular assays to screen for D. fragilis in Iran. The frequent finding of D. fragilis via fecal analysis indicated the need to include this parasite in routine stool examination in diagnostic laboratories. As the length of amplification target correlates to the sensitivity of PCR, this assay targeting the D. fragilis 5.8S rRNA gene seems optimal for parasite detection and is recommended in combination with conventional microscopy for diagnosing intestinal parasites.
Highlights
Dientamoeba fragilis, an intestinal trichomonad, occurs in humans with and without gastrointestinal symptoms
Microscopic analysis Examination by direct microscopy, formalin-ether concentration, and culture and staining techniques revealed 69 (34.5%; 95% CI: 28.3%–41.3%) participants infected with at least one of the species of intestinal protozoon detected: Dientamoeba fragilis, Blastocystis sp., Giardia lamblia, Entamoeba coli, and Iodamoeba butschlii (Table 2)
Dientamoeba fragilis was detected in ten (5%; 95% CI: 2.7%–9.0%) and two (1%; 95% CI: 0.3%–3.0%) subjects by modified iron-hematoxylin staining and culture methods, respectively; while no D. fragilis infection was found by direct microscopy or formalinether concentration methods (Table 2)
Summary
Dientamoeba fragilis, an intestinal trichomonad, occurs in humans with and without gastrointestinal symptoms. Specimens were examined using traditional techniques for detecting D. fragilis and other gastrointestinal parasites: direct smear, culture, formalin-ether concentration, and iron-hematoxylin staining. (Monocercomonadidae, Sarcomastigophora) is a trichomonad parasite infecting the gastrointestinal tract of humans and other vertebrates, including sheep, pigs, and birds [1,2]. The sensitivity of diagnostic techniques and the expertise of testing laboratories affect the reported prevalence rate of D. fragilis [14,16]. Common methods such as direct smear and culture are challenging and require experience to distinguish D. fragilis from other gastrointestinal parasites [17].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
