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Current Opinion in Gastroenterology Jan 2015To highlight new findings on the relevance of gastrointestinal protozoan infections to global public health in low-income and middle-income countries and suggest new... (Review)
Review
PURPOSE OF REVIEW
To highlight new findings on the relevance of gastrointestinal protozoan infections to global public health in low-income and middle-income countries and suggest new large-scale interventions.
RECENT FINDINGS
New disease burden assessments and epidemiological studies highlight the role of the major intestinal protozoa as important etiologic disease agents in low-income and middle-income countries. Despite their prevalence and adverse health impact, such information has not yet translated to the implementation of large-scale interventions as exist for helminth infections and other neglected tropical diseases. There are also several key research and development questions that must be addressed for intestinal protozoan infections and the potential need for new tools, for example, drugs, diagnostics, and vaccines. Additional studies have identified new and emerging species of intestinal protozoa relevant to global public health such as Dientamoeba fragilis and Blastocystis hominis and how they too might emerge as important gastrointestinal pathogens in the coming years.
SUMMARY
New and emerging information on intestinal protozoa are reviewed with emphasis on aspects considered relevant to global health policymakers including prospects for scaling up interventions against intestinal protozoan infections in resource-poor countries.
Topics: Blastocystis Infections; Communicable Diseases, Emerging; Cryptosporidiosis; Developing Countries; Dientamoebiasis; Dysentery, Amebic; Global Health; Humans; Intestinal Diseases, Parasitic; Protozoan Infections
PubMed: 25394233
DOI: 10.1097/MOG.0000000000000135 -
Parasitology Research Sep 2017Irritable bowel syndrome (IBS) is globally one of the most prevalent gastrointestinal disorders with a negative impact on quality of life and socio-economic status of... (Meta-Analysis)
Meta-Analysis Review
Irritable bowel syndrome (IBS) is globally one of the most prevalent gastrointestinal disorders with a negative impact on quality of life and socio-economic status of patients. Recently, controversial evidences suggest that Blastocystis sp. and Dientamoeba fragilis infections may be implicated in the development of IBS. We performed a systematic review and meta-analysis to examine the possible association regarding this issue. PubMed, ScienceDirect, Scopus, Web of Science, and Cochrane electronic databases were searched (up to February 2017) to identify the relevant studies. Pooled odds ratio (OR) and 95% confidence intervals were estimated using a random effects meta-analysis model on data from included studies. A total of 17 studies including 5882 participants (2527 patients and 3310 controls) met the eligibility criteria. Individuals with Blastocystis infection were found to have a positive association with IBS (OR, 2.19; 95% CI, 1.54-3.13), while this association was not observed for D. fragilis infection (OR, 1.13; 95% CI, 0.22-5.72). In subgroup analysis for Blastocystis infection, the pooled ORs were OR 2.29, 95% CI 1.55-3.41; OR 1.70, 95% CI 0.83-3.44; and OR 3.83, 95% CI 2.34-6.27 for hospital-based, healthy volunteers, and combined controls, respectively. Considering the subtypes, meta-analysis result demonstrated significant positive ORs for ST1 (OR, 4.40; 95% CI, 2.81-6.90) and ST3 (OR, 1.94; 95% CI, 1.36-2.77) to be potential risk factors for IBS. Our results support the existence of a positive association between Blastocystis sp. and IBS. Further studies with more sample size should be performed to better investigate the real impact of these parasites on the occurrence of IBS.
Topics: Blastocystis; Blastocystis Infections; Dientamoeba; Dientamoebiasis; Feces; Humans; Irritable Bowel Syndrome; Middle Aged; Prevalence; Quality of Life; Risk Factors
PubMed: 28668983
DOI: 10.1007/s00436-017-5535-6 -
Archives of Disease in Childhood Jul 2019To study the association between colonisation and faecal calprotectin to see whether the parasite is a harmless commensal or a gut pathogen.
OBJECTIVE
To study the association between colonisation and faecal calprotectin to see whether the parasite is a harmless commensal or a gut pathogen.
DESIGN
Cross-sectional study of previously collected stool samples.
SETTING AND PATIENTS
Two hundred stool samples originated from children aged 5-19 years with chronic abdominal pain and diarrhoea, who were seen in paediatric clinics in the Netherlands and Belgium and in whom somatic gastrointestinal disorders were excluded. Another 122 samples came from a healthy community-based reference population of the same age. All stool samples were analysed with real-time PCR for the detection of and with an ELISA for calprotectin-a biomarker of gastrointestinal inflammation.
MAIN OUTCOME MEASURES
Prevalence of colonisation and results of stool calprotectin testing.
RESULTS
was detected in 45% (95% CI 38% to 51%) of patients and in 71% (95% CI 63% to 79%) of healthy children. Median (IQR) concentrations of calprotectin in patients and healthy children with a positive PCR result were not different from those with a negative PCR result (40 (40-55) μg/g vs 40 (40-75) μg/g, respectively).
CONCLUSION
Since colonisation is most prevalent in healthy children and is not associated with an increase in faecal calprotectin concentration, our data do not support the inference that is a pathogenic parasite. Routinely testing for in children with chronic abdominal pain should therefore be discouraged.
Topics: Abdominal Pain; Adolescent; Belgium; Child; Child, Preschool; Cohort Studies; Cross-Sectional Studies; Dientamoeba; Dientamoebiasis; Feces; Female; Humans; Male; Netherlands; Prevalence; Prospective Studies; Real-Time Polymerase Chain Reaction; Retrospective Studies; Young Adult
PubMed: 30798256
DOI: 10.1136/archdischild-2018-316383 -
Parasitology Research Apr 2024Dientamoeba fragilis and Blastocystis sp. are single-celled protozoan parasites of humans and animals. Although they are found in the intestines of healthy hosts, the...
Dientamoeba fragilis and Blastocystis sp. are single-celled protozoan parasites of humans and animals. Although they are found in the intestines of healthy hosts, the pathogenicity of them is still unclear. To date, there is no report on D. fragilis and only two studies (without subtyping) on the occurrence of Blastocystis sp. in Musca domestica. In this study, fly samples were collected from livestock farms and their surroundings in the Kirsehir province (Central Anatolia Region) of Türkiye from May to August 2023. A total of 150 microscopically identified M. domestica samples were analyzed for the detection of D. fragilis and Blastocystis sp. molecularly. The overall prevalence of Blastocystis sp. and D. fragilis in M. domestica was determined to be 3.3% (5/150) and 8.0% (12/150), respectively. The SSU rRNA gene sequences of the isolates indicated genotype 1 of D. fragilis. Eleven isolates were identical and represented a single isolate (KAU-Dfrag1). BLAST analysis of KAU-Dfrag1 indicated identity with the isolates reported from humans, cattle, sheep, and budgerigars. The other isolate (KAU-Dfrag2) was polymorphic at two nucleotides from KAU-Dfrag1 and three nucleotides from known genotypes from GenBank and represented a variant of genotype 1. The Blastocystis sp. isolates were found to be identical and represent a single genotype (KAU-Blast1). BLAST analysis revealed that the KAU-Blast1 genotype belonged to the potentially zoonotic subtype 5 (ST5) and exhibited the highest genetic identity (ranging from 99.4 to 99.6%) with pigs, cattle, and sheep from different countries. Our study provides the first data on the molecular prevalence, epidemiology, and genotypic characterization of D. fragilis and Blastocystis sp. in M. domestica.
Topics: Humans; Animals; Sheep; Cattle; Swine; Blastocystis; Dientamoeba; Houseflies; Blastocystis Infections; Muscidae; Genotype; Feces; Prevalence; Nucleotides
PubMed: 38622363
DOI: 10.1007/s00436-024-08202-4 -
Parasites & Vectors Nov 2023Lactiplantibacillus plantarum HEAL9 and Lacticaseibacillus paracasei 8700:2 positively affect the fecal bacteriome in children with celiac disease autoimmunity after 6... (Randomized Controlled Trial)
Randomized Controlled Trial
Effects of Lactiplantibacillus plantarum and Lacticaseibacillus paracasei supplementation on the single-cell fecal parasitome in children with celiac disease autoimmunity: a randomized, double-blind placebo-controlled clinical trial.
BACKGROUND
Lactiplantibacillus plantarum HEAL9 and Lacticaseibacillus paracasei 8700:2 positively affect the fecal bacteriome in children with celiac disease autoimmunity after 6 months of supplementation. The aim of the present investigation was to study the effects of Lactiplantibacillus plantarum HEAL9 and Lacticaseibacillus paracasei 8700:2 on the single-cell parasitome, with a primary focus on Blastocystis.
METHODS
Stool samples were collected from 78 Swedish children with celiac disease autoimmunity participating in a randomized, double-blind, placebo-controlled clinical trial to either receive a mixture of supplementation with L. plantarum HEAL9 and L. paracasei 8700:2 (n = 38) or placebo (n = 40). A total of 227 stool samples collected at baseline and after 3 and 6 months of intervention, respectively, were retrospectively analyzed for Blastocystis by quantitative real-time PCR and subtyped by massively parallel amplicon sequencing. Other single-cell parasites were detected by untargeted 18S rDNA amplicon sequencing and verified by real-time PCR. The relation between the parasites and the bacteriome community was characterized by using 16S rDNA profiling of the V3-V4 region.
RESULTS
Three different single-cell protists were identified, of which the highest prevalence was found for Dientamoeba fragilis (23.1%, 18/78 children), followed by Blastocystis (15.4%, 12/78) and Entamoeba spp. (2.6%, 2/78). The quantity of the protists was stable over time and not affected by probiotic intervention (P = 0.14 for Blastocystis, P = 0.10 for D. fragilis). The positivity of the protists was associated with increased bacteriome diversity (measured by multiple indices, P < 0.03). Bacterial composition was influenced by the presence of the protists: positivity of Blastocystis was inversely associated with Akkermansia (at the levels of the genus as well as its family, order, class and phylum); P < 0.002), Faecalibacterium (P = 0.003) and Romboutsia (P = 0.029); positivity of D. fragilis was inversely associated with families Enterobacteriaceae (P = 0.016) and Coriobacteriaceae (P = 0.022) and genera Flavonifractor (P < 0.001), Faecalibacterium (P = 0.009), Lachnoclostridium (P = 0.029), Ruminococcus (P < 0.001) and Granulicatella (P = 0.018).
CONCLUSIONS
The prevalence of single-cell protists is low in children with celiac disease autoimmunity. The colonization was stable regardless of the probiotic intervention and associated with increased diversity of the fecal bacteriome but inversely associated with some beneficial bacteria.
Topics: Humans; Child; Lacticaseibacillus; Lacticaseibacillus paracasei; Autoimmunity; Celiac Disease; Retrospective Studies; Feces; Blastocystis; Bacteria; Probiotics; Double-Blind Method; DNA, Ribosomal
PubMed: 37946274
DOI: 10.1186/s13071-023-06027-1 -
Biology Nov 2022The human gastrointestinal microbiota contains a diverse consortium of microbes, including bacteria, protozoa, viruses, and fungi. Through millennia of co-evolution, the... (Review)
Review
The human gastrointestinal microbiota contains a diverse consortium of microbes, including bacteria, protozoa, viruses, and fungi. Through millennia of co-evolution, the host-microbiota interactions have shaped the immune system to both tolerate and maintain the symbiotic relationship with commensal microbiota, while exerting protective responses against invading pathogens. Microbiome research is dominated by studies describing the impact of prokaryotic bacteria on gut immunity with a limited understanding of their relationship with other integral microbiota constituents. However, converging evidence shows that eukaryotic organisms, such as commensal protozoa, can play an important role in modulating intestinal immune responses as well as influencing the overall health of the host. The presence of several protozoa species has recently been shown to be a common occurrence in healthy populations worldwide, suggesting that many of these are commensals rather than invading pathogens. This review aims to discuss the most recent, conflicting findings regarding the role of intestinal protozoa in gut homeostasis, interactions between intestinal protozoa and the bacterial microbiota, as well as potential immunological consequences of protozoa colonization.
PubMed: 36552252
DOI: 10.3390/biology11121742 -
PLoS Neglected Tropical Diseases Oct 2021The clinical significance of Blastocystis sp. and Dientamoeba fragilis in patients with gastrointestinal symptoms is a controversial issue. Since the pathogenicity of...
Investigation of neglected protists Blastocystis sp. and Dientamoeba fragilis in immunocompetent and immunodeficient diarrheal patients using both conventional and molecular methods.
INTRODUCTION
The clinical significance of Blastocystis sp. and Dientamoeba fragilis in patients with gastrointestinal symptoms is a controversial issue. Since the pathogenicity of these protists has not been fully elucidated, testing for these organisms is not routinely pursued by most laboratories and clinicians. Thus, the prevalence of these organisms and the subtypes of Blastocystis sp. in human patients in Turkey are not well characterized. This study aimed to determine the prevalence of Blastocystis sp. and D. fragilis in the diarrheic stool samples of immunodeficient and immunocompetent patients using conventional and molecular methods and to identify Blastocystis sp. subtypes using next generation sequencing.
MATERIAL AND METHODS
Individual stool specimens were collected from 245 immunodeficient and 193 immunocompetent diarrheic patients between March 2017 and December 2019 at the Gazi University Training and Research Hospital in Ankara, Turkey. Samples were screened for Blastocystis sp. and D. fragilis by conventional and molecular methods. Molecular detection of both protists was achieved by separate qPCRs targeting a partial fragment of the SSU rRNA gene. Next generation sequencing was used to identify Blastocystis sp. subtypes.
RESULTS
The prevalence of Blastocystis sp. and D. fragilis was 16.7% and 11.9%, respectively as measured by qPCR. The prevalence of Blastocystis sp. and D. fragilis was lower in immunodeficient patients (12.7% and 10.6%, respectively) compared to immunocompetent patients (21.8% and 13.5%, respectively). Five Blastocystis sp. subtypes were identified and the following subtype distribution was observed: ST3 54.4% (n = 37), ST2 16.2% (n = 11), ST1 4.4% (n = 3), ST6 2.9% (n = 2), ST4 1.5% (n = 1), ST2/ST3 11.8% (n = 8) and ST1/ST3 8.8% (n = 6). There was no statistically significant difference in the distribution of Blastocystis sp. subtypes between immunocompetent and immunodeficient patients.
CONCLUSION AND RECOMMENDATION
Our findings demonstrated that Blastocystis sp. and D. fragilis are commonly present in immunocompetent and immunodeficient patients with diarrhea. This study is the first to use next generation sequencing to address the presence of Blastocystis sp. mixed subtypes and intra-subtype variability in clinical samples in Turkey.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Blastocystis; Diarrhea; Dientamoeba; Feces; Female; High-Throughput Nucleotide Sequencing; Humans; Immunocompetence; Male; Middle Aged; Primary Immunodeficiency Diseases; Turkey; Young Adult
PubMed: 34613993
DOI: 10.1371/journal.pntd.0009779 -
Pediatrics International : Official... Jun 2016The aim of this study was to investigate the frequency of intestinal parasites in patients with chronic diarrhea and clarify the importance of these parasitic pathogens...
The aim of this study was to investigate the frequency of intestinal parasites in patients with chronic diarrhea and clarify the importance of these parasitic pathogens in such cases. A total of 60 pediatric patients with chronic diarrhea between June 2012 and October 2014 were enrolled in the study. Out of 60 stool samples, five were positive for Giardia lamblia, two, Dientamoeba fragilis, and one, Blastocystis hominis. One stool sample was positive for Entamoeba hartmanni and B. hominis, another one was positive for G. lamblia and B. hominis, another, G. lamblia and E. hartmanni and one sample was positive for Enterobius vermicularis, D. fragilis and B. hominis together. Parasitic infection, which decreases quality of life and increases susceptibility to other infections, should not be neglected, particularly in patients with chronic diarrhea. Accurate diagnosis decreases morbidity and mortality in patients with parasite infection.
Topics: Animals; Child; Child, Preschool; Chronic Disease; Diarrhea; Feces; Female; Humans; Incidence; Intestinal Diseases, Parasitic; Male; Parasites; Retrospective Studies; Turkey
PubMed: 27322863
DOI: 10.1111/ped.12959 -
Tropical Parasitology 2022() diagnosis is an intestinal protozoan parasite globally found in rural and urban areas and is attracting a growing interest. Its prevalence in stool varies from 0.2%...
INTRODUCTION
() diagnosis is an intestinal protozoan parasite globally found in rural and urban areas and is attracting a growing interest. Its prevalence in stool varies from 0.2% to more than 19% depending upon the population studied.
MATERIALS AND METHODS
This study was based on the examination of 100 stool samples of randomly referred cases in a rural area in Motobus district, Kafr El-Sheikh governorate, Egypt. Our aim was to investigate the presence of in stool of the examined individuals using conventional polymerase chain reaction (PCR) compared to wet mount and trichrome stain with confirmation of infection by transmission electron microscopy.
RESULTS
was detected in 13/100 of the stool samples examined using wet mount smears, while trichrome stain detected 17/100. Conventional PCR diagnosed 41 cases of in the studied group. A very good agreement was found between wet mount and trichrome stain for diagnosing , while there was fair agreement between conventional PCR and both microscopy methods. Transmission electron microscope was performed on pooled positive samples that revealed the internal structures of trophozoite with its characteristic nucleus.
CONCLUSIONS
PCR technique was superior to microscopy for the detection of . Trichrome stain remains vital for microscopic diagnosis.
PubMed: 36643979
DOI: 10.4103/tp.tp_93_21 -
Trends in Parasitology Oct 2016The trichomonads are a remarkably successful lineage of ancient, predominantly parasitic protozoa. Recent molecular analyses have revealed extensive duplication of... (Review)
Review
The trichomonads are a remarkably successful lineage of ancient, predominantly parasitic protozoa. Recent molecular analyses have revealed extensive duplication of certain genetic loci in trichomonads. Consequently, their genomes are exceptionally large compared to other parasitic protozoa. Retention of these large gene expansions across different trichomonad families raises the question: do these duplications afford an advantage? Many duplicated genes are linked to the parasitic lifestyle and some are regulated differently to their paralogues, suggesting they have acquired new functions. It is proposed that these large genomes encode a Swiss army knife of sorts, packed with a multitude of tools for use in many different circumstances. This may have bestowed trichomonads with the extraordinary versatility that has undoubtedly contributed to their success.
Topics: Evolution, Molecular; Gene Duplication; Gene Expression Regulation; Genome, Protozoan; Host-Parasite Interactions; Trichomonas
PubMed: 27312283
DOI: 10.1016/j.pt.2016.05.014