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Parasitology Research Apr 2018It remains controversial whether Dientamoeba fragilis is a commensal parasite or a pathogen. The objective of this systematic review was to establish the strength of the... (Review)
Review
It remains controversial whether Dientamoeba fragilis is a commensal parasite or a pathogen. The objective of this systematic review was to establish the strength of the evidence that Dientamoeba fragilis would cause diarrhea. A search was performed for studies that reported either the association between D. fragilis detection in stools and diarrhea or diarrhea outcomes with D. fragilis therapy or challenge. Data from seven studies of specific populations reported that 22% had D. fragilis in stools of which only 23% had diarrhea. Eleven studies of stool samples submitted to laboratories reported that 4.3% of individuals had D. fragilis of which 54% had diarrhea. Twelve studies reported that D. fragilis was detected from 1.6% of individuals with diarrhea and 9.6% of diarrheal stools. Five studies analyzed the prevalence of D. fragilis in individuals with and without diarrhea; the two with a statistically significant difference between groups had discordant results. The only cohort study with an appropriate control group reported diarrhea in a higher proportion of children with D. fragilis than in controls. No D. fragilis treatment studies included diarrhea as an outcome. There were only two challenge studies involving one person each. In conclusion, the evidence that D. fragilis would cause diarrhea or that treatment would hasten diarrhea resolution is inconclusive.
Topics: Child; Cohort Studies; Diarrhea; Dientamoeba; Dientamoebiasis; Feces; Humans; Prevalence
PubMed: 29404747
DOI: 10.1007/s00436-018-5771-4 -
Journal of Clinical Microbiology Sep 2016Dientamoeba fragilis is a single-celled protozoan, closely related to the trichomonads. Reported worldwide as causing human gastrointestinal symptoms, D. fragilis is... (Review)
Review
Dientamoeba fragilis is a single-celled protozoan, closely related to the trichomonads. Reported worldwide as causing human gastrointestinal symptoms, D. fragilis is very common and is second only to Blastocystis spp. Dientamoebiasis equals or exceeds the incidence of giardiasis. This minireview includes diagnostic options, clinical relevance, therapy, an animal model, the confirmed cyst stage, and sequencing data. The development of a rodent model, fulfilling Koch's postulates, and the confirmation of a cyst stage have clarified transmission routes, including fecal-oral transmission. The prevalence of D. fragilis varies between 0% to over 82%; results depend on the geographic location, group studied, and diagnostic methods used.
Topics: Animals; Antiprotozoal Agents; Dientamoeba; Dientamoebiasis; Disease Models, Animal; Humans; Incidence; Intestinal Diseases, Parasitic; Neglected Diseases; Prevalence
PubMed: 27053676
DOI: 10.1128/JCM.00400-16 -
Journal of Travel Medicine Feb 2023Blastocystis sp. is a worldwide-distributed protist colonizing the guts of humans and a great variety of animals. It is unclear whether it is just a commensal or an... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Blastocystis sp. is a worldwide-distributed protist colonizing the guts of humans and a great variety of animals. It is unclear whether it is just a commensal or an infectious parasite that prompts eradication.The main objective of this study was to evaluate the usefulness of metronidazole in patients with gastrointestinal symptoms harbouring only Blastocystis sp. In addition, we explored whether Blastocystis subtype or concomitant parasitic infection detected by polymerase chain reaction (PCR) may influence treatment outcome.
METHODS
We included adults with persistent gastrointestinal symptoms (>14 days) visiting a primary care physician and in whom stool microscopy revealed only Blastocystis sp. Eligible patients were randomized to receive 10 days of metronidazole or placebo, followed by a crossover if still symptomatic. The primary outcome was normal stool consistency. Secondary outcomes were the changes in other abdominal symptoms (bloating, flatulence, abdominal pain, number of daily bowel movements) and general wellbeing. After the clinical phase of the study, Blastocystis subtypes were determined by PCR sequencing and stool samples were tested for 11 other protozoa with an in-house PCR.
RESULTS
We screened 581 outpatients for inclusion, of which 50 met the eligibility criteria. There was no difference in the primary outcome, nor any of the secondary outcomes between the subjects treated with metronidazole and placebo.The most frequent Blastocystis subtypes were ST4 (11/36) and ST2 (10/36). The in-house PCR was positive for other protozoa in 25% (10/40) of the patients. We identified Dientamoeba fragilis in 5, Entamoeba dispar in 3 and Cyclospora cayetanensis in 2 patients. Stratified analysis according to Blastocystis subtype or the presence of other protozoa showed no significant difference in treatment outcome with metronidazole or placebo.
CONCLUSIONS
Among patients infected with Blastocystis sp., metronidazole, compared with placebo, was not better in improving gastrointestinal symptoms, irrespective of subtype or microscopically undetected coinfection with other protozoa.
Topics: Adult; Animals; Humans; Blastocystis; Blastocystis Infections; Metronidazole; Pilot Projects; Gastrointestinal Diseases; Feces
PubMed: 36440639
DOI: 10.1093/jtm/taac143 -
Virus Evolution 2022Metagenomic techniques have facilitated the discovery of thousands of viruses, yet because samples are often highly biodiverse, fundamental data on the specific cellular...
Metagenomic techniques have facilitated the discovery of thousands of viruses, yet because samples are often highly biodiverse, fundamental data on the specific cellular hosts are usually missing. Numerous gastrointestinal viruses linked to human or animal diseases are affected by this, preventing research into their medical or veterinary importance. Here, we developed a computational workflow for the prediction of viral hosts from complex metagenomic datasets. We applied it to seven lineages of gastrointestinal cressdnaviruses using 1,124 metagenomic datasets, predicting hosts of four lineages. The , strongly associated to human gum disease (periodontitis), were predicted to infect , an oral pathogen itself involved in periodontitis. The , originally linked to fatal equine disease, were predicted to infect a variety of parabasalid protists, including in humans. Two viral lineages observed in human diarrhoeal disease (CRESSV1 and CRESSV19, i.e. pecoviruses and hudisaviruses) were predicted to infect spp. and respectively, protists responsible for millions of annual human infections. Our prediction approach is adaptable to any virus lineage and requires neither training datasets nor host genome assemblies. Two host predictions (for the and CRESSV1 lineages) could be independently confirmed as virus-host relationships using endogenous viral elements identified inside host genomes, while a further prediction (for the ) was strongly supported as a virus-host relationship using a case-control screening experiment of human oral plaques.
PubMed: 36325032
DOI: 10.1093/ve/veac087 -
Revista Do Instituto de Medicina... 2021In order to provide additional data on the prevalence and genetic diversity of Dientamoeba fragilis in human populations, we conducted a study in children from...
In order to provide additional data on the prevalence and genetic diversity of Dientamoeba fragilis in human populations, we conducted a study in children from low-income communities in Sao Paulo State, Brazil. Fecal samples from daycare center attendees up to 6 years old (n=156) and staff members (n=18) were submitted to PCR and sequencing of D. fragilis as well as to microscopic examination for the presence of other intestinal parasites. All children assessed were asymptomatic and 10.3% (16/156) were positive for D. fragilis. No worker was found to be positive. An association between Dientamoeba and coinfection with other intestinal parasites was observed. Concerning the genetic diversity, 14 and only two isolates were genotype 1 and genotype 2, respectively. Our findings outline interesting aspects: (1) asymptomatic children as carriers of Dientamoeba in communities in which environmental conditions ensure parasite transmission and, (2) association between Dientamoeba infection in young children and coinfection with other enteric parasites, reinforcing its transmission via the fecal-oral route.
Topics: Brazil; Child; Child, Preschool; Dientamoeba; Dientamoebiasis; Feces; Humans; Intestinal Diseases, Parasitic; Prevalence
PubMed: 33978095
DOI: 10.1590/S1678-9946202163039 -
Pathogens (Basel, Switzerland) Jun 2023We aimed to assess the performance of the Novodiag Stool Parasites (NSP) assay in the diagnosis of the most common intestinal protozoan and microsporidia infections.
OBJECTIVES
We aimed to assess the performance of the Novodiag Stool Parasites (NSP) assay in the diagnosis of the most common intestinal protozoan and microsporidia infections.
METHODS
A panel of 167 selected stool samples was retrospectively analysed with the NSP assay and compared to routine microscopy and qPCR methods for the detection of pathogenic protozoa and microsporidia.
RESULTS
Whereas specificity was high for all protozoa and microsporidia, NSP sensitivity was strongly dependent on the comparative method used as reference. When compared to microscopic methods, NSP sensitivity was high (96.7 to 100%) for , and but was lower for (85.2%) and ≤50% for and . In comparison to conventional qPCR, the NSP assay demonstrated lower sensitivity characteristics dependent on parasite loads, reaching 60 to 70% for , , spp. and Sensitivity was 100% for , but none of the five samples containing spp. were detected.
CONCLUSIONS
The overall performance of the NSP assay in the diagnosis of gastrointestinal protozoa and microsporidia seems to be better than or equivalent to that observed with microscopic methods but inferior to that obtainable with classical targeted qPCR.
PubMed: 37513736
DOI: 10.3390/pathogens12070889 -
PloS One 2022The increasing interest to perform and investigate the efficacy of fecal microbiota transplantation (FMT) has generated an urge for feasible donor screening. We report...
BACKGROUND
The increasing interest to perform and investigate the efficacy of fecal microbiota transplantation (FMT) has generated an urge for feasible donor screening. We report our experience with stool donor recruitment, screening, follow-up, and associated costs in the context of clinical FMT trials.
METHODS
Potential stool donors, aged between 18-65 years, underwent a stepwise screening process starting with an extensive questionnaire followed by feces and blood investigations. When eligible, donors were rescreened for MDROs and SARS-CoV-2 every 60-days, and full rescreening every 4-6 months. The costs to find and retain a stool donor were calculated.
RESULTS
From January 2018 to August 2021, 393 potential donors underwent prescreening, of which 202 (51.4%) did not proceed primarily due to loss to follow-up, medication use, or logistic reasons (e.g. COVID-19 measures). 191 potential donors filled in the questionnaire, of which 43 (22.5%) were excluded. The remaining 148 candidates underwent parasitology screening: 91 (61.5%) were excluded, mostly due to Dientamoeba fragilis and/or high amounts of Blastocystis spp. After additional feces investigations 18/57 (31.6%) potential donors were excluded (mainly for presence of Helicobacter Pylori and ESBL-producing organisms). One donor failed serum testing. Overall, 38 out of 393 (10%) potential donors were enrolled. The median participation time of active stool donors was 13 months. To recruit 38 stool donors, €64.112 was spent.
CONCLUSION
Recruitment of stool donors for FMT is challenging. In our Dutch cohort, failed eligibility of potential donors was often caused by the presence of the protozoa Dientamoeba fragilis and Blastocystis spp.. The exclusion of potential donors that carry these protozoa, especially Blastocystis spp., is questionable and deserves reconsideration. High-quality donor screening is associated with substantial costs.
Topics: Humans; Adolescent; Young Adult; Adult; Middle Aged; Aged; Fecal Microbiota Transplantation; Donor Selection; SARS-CoV-2; COVID-19; Feces; Clostridium Infections
PubMed: 36264933
DOI: 10.1371/journal.pone.0276323 -
Parasitology International Aug 2024Blastocystis sp. and Dientamoeba fragilis are intestinal protists, which are common worldwide, but the pathogenic role of these organisms in gastrointestinal diseases is...
Blastocystis sp. and Dientamoeba fragilis are intestinal protists, which are common worldwide, but the pathogenic role of these organisms in gastrointestinal diseases is still controversial. This study aimed to investigate the frequency of Blastocystis sp. and D. fragilis in stool samples from adult patients with celiac disease (CD) by using conventional and molecular methods. A total of 75 patients with CD and 75 healthy individuals were included in this study. Fresh stool specimens collected from each individual were analyzed by conventional and molecular methods. The overall prevalence of Blastocystis sp. and D. fragilis was 41.3% (31/75) and 24% (18/75) in patients with CD, and 46.7% (35/75) and 13.3% (10/75) in healthy controls, respectively. There was no statistically significant difference in the prevalence of Blastocystis sp. and D. fragilis between CD patients and healthy individuals. Blastocystis sp. subtypes were identified in 20 CD and 16 control patients and the overall subtype distribution was observed as ST1 13.9%, ST2 30.6%, and ST3 55.6%. The prevalence of Blastocystis sp. and D. fragilis in adults with CD is similar to the prevalence of protozoa in healthy adults. In this study, the most prevalent Blastocystis subtype was ST3 and the most frequent allele was a34 in both CD patients and healthy individuals. No significant difference was found between the two groups in terms of the detection rates of Blastocystis sp. and D. fragilis, and it is thought that both protists may be colonisers of the intestinal microbiome.
Topics: Humans; Blastocystis; Dientamoeba; Celiac Disease; Blastocystis Infections; Adult; Dientamoebiasis; Male; Female; Feces; Middle Aged; Prevalence; Young Adult; Adolescent; Aged
PubMed: 38499283
DOI: 10.1016/j.parint.2024.102888 -
Travel Medicine and Infectious Disease 2022
Topics: Dientamoeba; Feces; Humans; Pruritus
PubMed: 35364300
DOI: 10.1016/j.tmaid.2022.102319 -
Enfermedades Infecciosas Y... May 2019The characteristics of D. fragilis infection are described, with special focus on the clinical and epidemiological aspects.
INTRODUCTION
The characteristics of D. fragilis infection are described, with special focus on the clinical and epidemiological aspects.
MATERIALS AND METHODS
A retrospective and descriptive study was performed, including all the patients with Dientamoeba fragilis infection who attended a specialized unit between January 2012 and December 2017. PCR was used to diagnose D. fragilis. Patients were treated with metronidazole or paromomycin and reviewed at four and eight weeks post-treatment. Cure was defined as the negativization of all parasitological tests, in absence of symptoms.
RESULTS
163 patients were diagnosed. The most frequent symptoms were abdominal pain (36.2%), chronic diarrhoea (12.3%), anal itching (10.4%), abdominal discomfort (9.2%), skin disease (8%), acute diarrhoea (4.3%) and vomiting (4.3%). Fifty patients were asymptomatic. Forty-two patients had eosinophilia in blood. Thirty-eight cases (23.3%) had a coinfection by Enterobius vermicularis. One hundred and seven patients received treatment, sixty-one of them with metronidazole and the rest with paromomycin. Ninety-nine patients (91%) were cured. The rate of cure was 100% in the paromomycin group versus 86.8% in the metronidazole group (p=0.005; OR: 1.173 [1.057-1.302]). The absence of cure was associated with E. vermicularis coinfection (p=0.014; OR: 6.167 [1.432-26.563] and with longer duration of the symptoms (175 [±159SD]) versus 84 [±88SD] days, p=0.014) but multivariable analysis did not confirm these associations.
CONCLUSION
Dientamoeba fragilis is an important and underestimated cause of gastrointestinal disease in both the autochthonous and immigrant or traveller population. More studies are needed to clarify its optimal treatment and the role played by E. vermicularis in its transmission and maintenance.
Topics: Adult; Antiprotozoal Agents; Dientamoebiasis; Female; Humans; Male; Metronidazole; Middle Aged; Paromomycin; Retrospective Studies; Young Adult
PubMed: 30274823
DOI: 10.1016/j.eimc.2018.07.008