Dientamoeba Research Articles

A prospective analysis of clinical and parasitological outcomes after treatment or a wait-and-see approach of Dientamoeba fragilis infection in an adult general practice population.

Dientamoeba fragilis is a protozoan frequently encountered in stool samples globally. It is debated whether Dientamoeba fragilis carries pathogenic capacities. This study prospectively analyses clinical and parasitological outcomes after treatment or a wait-and-see approach of Dientamoeba fragilis infection in a general practice adult population. In this prospective observational cohort study 113 adult patients with a positive Polymerase Chain Reaction (PCR) test result for D. fragilis (T0) in a primary care setting, were followed-up longitudinally with a control PCR-test and microscopic stool examination at 30 days (T1) and 90 days (T2) after inclusion. Standardized patient-reported questionnaires including treatment details and the adjusted Irritable Bowel Syndrome-Severity Score (IBS-SS) were retrieved at T0, T1 and T2. Parasitology and questionnaires were retrieved from 87 participants at T0 and T1, and 74 at T2. Treated patients(n = 64) more often tested PCR negative at T1 (64.1% vs. 16.4%, p < 0.001) and T2 (67.3% vs. 5.3%, p < 0.001) compared to untreated patients. No difference in decline in IBS-SS was seen comparing the treatment and non-treatment groups at T1 (p = 0.403) or T2 (p = 1.00). A short and long term increased parasitological clearance is shown with treatment of clioquinol or metronidazole compared with no treatment. A clear and significant correlation between parasitological cure and decline of clinical complaints as reported by the participants could not be established.

High rates of Dientamoeba fragilis and Blastocystis species in children’s stool but minor clinical significance

ObjectiveThe aim of this study was to describe the epidemiology and the clinical significance of dientamoeba fragilis (DF) and blastocystis (Bs) in pediatric stool samples. MethodsA historical cohort study of children under 18 years of age who underwent stool multiplex PCR for bacteria and parasites. DF and Bs results were not routinely reported. We assessed the frequency of various stool microorganisms and analyzed a composite of symptoms occurring within 14 days before testing and four post-test composite outcomes (symptoms, further medical evaluation, prescriptions of symptomatic treatment or antibiotics). Comparisons were made between children mono-infected with DF or Bs, those with negative PCR results, and those positive for microorganisms with established pathogenicity. ResultsOf 36,008 eligible children, 32.5% were positive for DF and 7.9% for Bs. Children positive for DF or Bs did not exhibit higher odds for pre- or post-test composite outcomes compared to those with all-negative PCR results, except for increased rates of abdominal pain and referrals for anti-TTG testing among DF-positive children. Antibiotic prescription was significantly more common among those positive for microorganisms of known pathogenicity. ConclusionsWhile DF and Bs are frequently detected in pediatric stool samples, their clinical significance appears to be limited.

Protozoan intestinal invasions in military personnel of the Northern region of Ukraine

Objective — to study the prevalence and spectrum of intestinal parasitic infestations (IPI) agents in groups of military personnel of the Northern region of Ukraine, which differed according to the criteria of having symptoms of gastrointestinal disorders and passing the serving in a combat zone. Materials and methods. From February to November 2023, the study covered 302 servicemen during inpatient medical care at the Military Medical Clinical Center of the Northern Region of Ukraine. Detection and identification of intestinal parasites in samples of feces (SF) was carried out by classical methods of microscopy using the enrichment procedure (formalin‑ethyl acetate sedimentation) and the preparation (from each enriched sediment) of four smears: two thick wet with 50% aqueous solution of glycerol and D’ Anthony iodine solution; two thin, fixed, permanently stained with Whitley’s modified trichrome (mWT) or Heidenhain’s iron hematoxylin (HIH) and the modified Ziehl‑Neelsen acid method (mZN). Smear microscopy results were evaluated according to the criteria of the US Clinical and Laboratory Standards Institute. Results. It was established that the level of prevalence of IPI among the examined servicemen reached 10.6% with variation in the value of this indicator in different groups of soldiers from 2.2% to 12.6%. A specific share of protozoan monoinvasions in soldiers reached 65.6%, and mixed invasions (with two parasites at the same time) — 34.4%. Soldiers with symptoms of gastrointestinal diseases had significantly higher rates of IPI than did asymptomatic. In addition, the infestation rates among soldiers were higher in the cold season (October‑February) with a seasonality index of 1.9. All cases of IPI in servicemen (n=32) were caused by protozoan parasites (n=39), in the etiological spectrum of which the vast majority (84.6%) were pathogenic species (Blastocystis sp., Dientamoeba fragilis, Giardia lamblia), and a smaller proportion (15.4%) were commensal species (Chilomastix mesnili, Iodamoeba butschliі). Among pathogenic protozoa (n=33), Blastocystis sp. (51.5%) and D. fragilis had the highest proportion (42.4%), G. lamblia (6.1%) had significantly less one. Conclusions. Optimizing the management tactics of military medicine to reduce the negative impact of IPI on the health and combat capacity of servicemen requires knowledge about the prevalence and spectrum of pathogens of invasions among specific groups of soldiers. A necessary condition for increasing the efficiency of microscopic detection/identification of protozoan parasites (primarily D. fragilis) in the SF is the production of permanently stained (mWT or HIH) smears. Microscopic examination of such smears at high resolution (100ґ objective, oil immersion) provides an increased incidence of detection/identification of Blastocystis sp. by 47.1% and D. fragilis by 100%.

Evaluation of the Allplex GI Parasite and Helminth PCR Assay in a Belgian Travel Clinic.

Recently a number of broad-range stool parasite PCR assays have been developed. However, there is ongoing disagreement regarding their diagnostic performance, as various studies have produced contradictory results. In this study, we compared the diagnostic accuracy of the Seegene Allplex GI-Parasite and Allplex GI-Helminth assays (SA) with the conventional methods used at the travel clinic of the Institute of Tropical Medicine (ITM) including microscopy, antigen testing, and molecular detection in order to provide insights into the strengths and limitations of this diagnostic tool which may be crucial to select the most appropriate diagnostic tools for the suspected pathogen. A total of 97 native stool samples from 95 patients with suspected gastrointestinal illness were analyzed, including 26 from a frozen collection and 71 prospectively collected samples. The diagnostic performance of SA was notably superior to the conventional workflow in detecting Dientamoeba fragilis (sensitivity 100% vs. 47.4%) and Blastocystis hominis (sensitivity 95% vs. 77.5%). SA had a comparable performance with the conventional workflow in detecting pathogenic protozoa (sensitivity 90% vs. 95%). In contrast, SA had a much lower diagnostic performance in detecting helminths (59.1%) compared to the conventional workflow (100%). We conclude that the Seegene Allplex GI-Parasite assay may be useful for protozoa screening in low-endemic industrialized countries. However, the Allplex GI-Helminth assay is not recommended due to its suboptimal performance compared to microscopy.

The Low Genetic Diversity of Dientamoeba fragilis Isolates in Southwest Turkey and Analysis of Clinical Findings.

Dientamoeba fragilis (D. fragilis) is a common intestinal protozoan with a global distribution. In the present study, we aimed to determine genetic diversity of D. fragilis isolates with multilocus sequence typing (MLST) in the southwest of Turkey and analyse the clinical findings. The study included faecal samples from 200 individuals in Aydin, Turkey. The positivity of D. fragilis was determined with 18S rRNA gene-based PCR assay. Six nested-PCR reactions were set to amplify partial D. fragilis housekeeping genes in the positive samples. The sequences were aligned with the references from GenBank to detect nucleotide polymorphisms and haplotypes. Additionally, the clinical findings and demographic characteristics of patients were statistically analysed between D. fragilis-infected and non-infected cases. The positivity of D. fragilis was 16% (32 out of 200 cases) with 18S rRNA based-PCR, and all were classified as "genotype 1". The analysis of six MLST loci revealed different haplotypes only at one locus; the remaining five loci exhibited no polymorphisms. The haplotypes in the present study were identical to at least one previously reported reference, except the locus "large subunit of RNA polymerase II" locus. There were no significant differences in any of the clinical findings or demographic characteristics between the infected and non-infected groups. Our study revealed a low genetic diversity of D. fragilis isolates from Turkey, like other countries including Italy, Denmark, the UK, Australia, and Brazil. The high degree of sequence similarity in housekeeping genes indicated the clonal distribution of D. fragilis.

Impact of &lt;i&gt;Tritrichomonas&lt;/i&gt; spp. on the immune system of Muc2&lt;sup&gt;–/–&lt;/sup&gt; mice after antibiotic therapy

While pathogenic protists inhabiting the reproductive tract are well studied, the gastrointestinal (GI) tract contains a constitutive protist microbiota that is an integral part of the vertebrate microbiome. Currently, the effect of protozoan infections on the host immune system and their potential contribution to disruption of mucosal immune homeostasis are not well understood. Protists, along with bacteria and viruses, are permanent representatives of the human microbiota. The main attention of researchers is focused on studying their pathogenic role in gastrointestinal diseases. However, their role in symbiotic relationships with hosts is relatively little studied. It was previously shown that the closest human ortholog of mouse Trichomonas (Tritrichomonas spp.) is Trichomonas Dientamoeba fragilis, which can cause symptoms of inflammatory bowel disease. It is currently unclear whether Dientamoeba fragilis and other protist species such as Enteromonas spp., Entamoeba dispar are commensals, pathobionts, or pathogens of the human intestinal tract. Thus, information about the mutualistic relationships between protists, the gastrointestinal microbiota, and the immune system of mice can be used to understand host-protozoan relationships in humans. The data obtained allow us to evaluate the potential contribution of commensal protozoa in the formation of protective mechanisms of the mucous membrane of animals and humans. We have previously shown that antibiotic therapy leads to an increase in the number of Tritrichomonas spp. along with a reduction in bacteria in the gut of mice with a mutation in the Muc2 gene. A mutation in this gene leads to impaired formation of the intestinal mucosa in mice. Mice with a mutation in the Muc2 gene can be used as model to study human inflammatory bowel diseases (IBDs). In this work, we conducted a comparative study of the immunological status of Muc2–/– mice harboring Tritrichomonas spp. after antibiotic therapy for 2 weeks followed by gavage of Lactobacillus johnsonii into mice and mice without introduction of probiotic microorganisms (self-recovery). Analysis of the main populations of lymphocytes in the blood, spleen and lymph nodes showed that the introduction of Lactobacillus johnsonii after antibiotic therapy leads to a significant increase in the population of T-lymphocytes in the blood and spleen, and an increase in the number of helper T cells in the lymph nodes of Muc2–/– mice compared to mice without the addition of probiotic microorganisms.

A cross-sectional survey of Blastocystis sp. and Dientamoeba fragilis in non-human primates and their caregivers in Czech zoos

Intestinal protists in the gut microbiome are increasingly studied, but their basic epidemiology is not well understood. We explored the prevalence, genetic diversity, and potential zoonotic transmission of two protists colonizing the large intestine - Blastocystis sp. and Dientamoeba fragilis - in 37 species of non-human primates (NHPs) and their caregivers in six zoos in the Czech Republic. We analyzed 179 fecal samples (159 from NHPs, 20 from humans) by qPCR. Blastocystis sp. was detected in 54.7% (98/179) of samples, in 24 NHP species and in 57.2% of NHP samples (prevalence ranged between 36 and 80%), and in 35% of human samples (prevalence ranged between 0 and 67%). Using next generation amplicon sequencing, nine Blastocystis subtypes (ST1-ST5, ST7, ST8, and two novel subtypes) were identified. The two new Blastocystis subtypes (named ST47 and ST48) were described using Nanopore sequencing to produce full-length reference sequences of the small subunit ribosomal RNA gene. Some subtypes were shared between NHPs and their caregivers, suggesting potential zoonotic transmission. Mixed subtype colonization was frequently observed, with 52% of sequenced samples containing two or more subtypes. Dientamoeba was found only in NHPs with a prevalence of 6%. This study emphasizes the critical role of molecular diagnostics in epidemiological and transmission studies of these protists and calls for further research to better understand their impact on public health.

Clustering of Gastrointestinal Microorganisms in Human Stool Samples from Ghana.

The study was conducted to identify cluster patterns of enteric microorganisms with potential etiological relevance for infectious gastroenteritis in stool samples of individuals from Ghana, which is a known high-endemicity setting for infectious gastroenteritis. These patterns were compared to previous observations with specimens from Colombian indigenous people in order to assess potentially stable clustering for temporally and spatially distinct populations from high-endemicity regions. By doing so, the study aimed to identify stable clusters as markers of microbial interaction with potential importance for etiological relevance assignment in cases of multiple enteric pathogen detections. Stool samples from 1569 Ghanaian individuals (875 from HIV patients, 30 from HIV-negative control adult patients, and 644 from children < 2 years of age) were assessed for enteric microorganisms by applying real-time PCR. As a result, nucleic acids of bacterial microorganisms were most frequently detected, followed by protozoa, microsporidia, and helminths. Interestingly, the cluster assessment confirmed interaction patterns known from the previous analysis with Colombian indigenous people, demonstrating a high likelihood of Blastocystis hominis for clustering with other microorganisms and a prominent, potentially mediating role of Dientamoeba fragilis for microbial interactions within the clusters. In conclusion, the assessment confirmed conserved clustering of enteric microorganisms with potential etiological relevance for human infectious gastroenteritis over geographically distinct high-endemicity settings. Furthermore, the composition of abundant microorganisms is more important than regional factors for the determination of the interplay of enteric microorganisms in the human gut. Thereby, some microbial pathogens and commensals seem more susceptible to a changing microbial composition in the human gut than others.

Food and Drinking Water as Sources of Pathogenic Protozoans: An Update

This narrative review was aimed at collecting updated knowledge on the risk factors, illnesses caused, and measures for the prevention of protozoan infections transmitted by food and drinking water. Reports screened dated from 2019 to the present and regarded global prevalence in food handlers, occurrence in food and drinking water, impact on human health, and recently reported outbreaks and cases of severe infections attributable to the dietary route. Cryptosporidium spp., Cyclospora cayetanensis, Entamoeba histolytica, and Cystoisospora belli were the protozoans most frequently involved in recently reported waterborne and foodborne outbreaks and cases. Blastocystis hominis was reported to be the most widespread intestinal protozoan in humans, and two case reports indicated its pathogenic potential. Dientamoeba fragilis, Endolimax nana, and Pentatrichomonas hominis are also frequent but still require further investigation on their ability to cause illness. A progressive improvement in surveillance of protozoan infections and infection sources took place in developed countries where the implementation of reporting systems and the application of molecular diagnostic methods led to an enhanced capacity to identify epidemiological links and improve the prevention of foodborne and waterborne protozoan infections.

Occult Amebiasis among Pediatric with Enterocolitis in National Referral Hospital in Indonesia.

Enterocolitis and gastroenteritis remain major health problems, particularly in children living in developing countries. Intestinal protozoa, such as Entamoeba histolytica, Blastocystis, and Cyclospora, are frequently associated with these conditions. Amebic colitis can cause serious complications, including fulminant necrotizing colitis, toxic megacolon, extraintestinal amebiasis, and stunting in children. The diagnosis of amoebiasis is challenging, relying on microscopic examination, which cannot distinguish E. histolytica from the nonpathogenic E. dispar and E. moshkovskii. Therefore, this study aimed to identify intestinal parasites, particularly Entamoeba, their prevalence, and the clinical characteristics of patients admitted for enterocolitis and gastroenteritis at a tertiary-referral hospital. A cross-sectional, retrospective study was conducted at a national, tertiary-referral government hospital, in Jakarta. Of the 111 retrieved medical records from hospitalized patients with enterocolitis and gastroenteritis, for which parasitology feces were examined, 54 fecal samples (48.6%) were still available in the parasitology laboratory storage. All fecal samples underwent the following tests: 1) direct stool examination, after staining with 1% Lugol's solution, and using the water-ether concentration method; 2) modified acid-fast staining for coccidian parasites; 3) Jones' culture medium to detect Blastocystis; 4) copro-antigen assay to detect Cryptosporidium and Giardia; and 5) a polymerase chain reaction (PCR) assay to identify Entamoeba. Clinical and demographic data were obtained from the medical records. Largely, patients (44.1%) were from the cohort of young children ≤5 years old, followed by adults aged 19-60 years old (24.3%). Both cohorts exhibited polyparasitism. Intestinal parasites were detected in 17 out of the 54 samples (31.4%). These included 6 (11.1%), 2 (3.7%),5 (9.2%), 3 (5.5%), 2 (3.7%), and 1 (1.8%) samples that were positive for Blastocystis, E dispar, E. histolytica, E. moshkovskii, Cryptosporidium, and Dientamoeba fragilis, respectively. PCR analysis revealed that 10 samples were positive for Entamoeba infection, eight of which originated from pediatric patients. At a national tertiary-referral hospital in Indonesia, Entamoeba infection was the most prevalent parasite among pediatric patients with enterocolitis. E. histolytica and E. moshkovskii were the two main species identified by PCR. Therefore, PCR assays and fecal occult-blood tests are recommended in cases of enterocolitis and gastroenteritis.

Zarażenia pasożytami jelitowymi u polskich żołnierzy rozmieszczonych w Kosowie

Introduction and objectiveSoldiers of the Polish Military Contingents currently stationed in foreign countries serve under difficult environmental conditions. Military service abroad is associated with the risk of importing infectious pathogens back to soldiers’ home country. The aim of the study was to assess the current prevalence of infections caused by intestinal parasites in soldiers from the Polish Military Contingent Kosovo serving as part of the Kosovo Force operation in the Balkans.Material and methodsParasitological diagnostics was carried out in June 2023 in a group of 221 soldiers from the Polish Military Contingents Kosovo stationed in several military camps across the country. Each participant was asked to provide three stool samples collected at 2–3-day intervals. Faecal examinations were performed using three different light microscopy testing methods (direct smear, decantation, flotation) at the Department of Epidemiology and Tropical Medicine at the Military Institute of Medicine – National Research Institute.ResultsIntestinal parasites, all of protozoan aetiology, were found in 28 out of 221 Polish soldiers taking part in the Kosovo Force operation in Kosovo included in the study (0.9% participants were infected with &lt;i&gt;Giardia intestinalis&lt;/i&gt; and 11.7% with potentially pathogenic parasites, &lt;i&gt;Blastocystis&lt;/i&gt; spp. and &lt;i&gt;Dientamoeba fragilis&lt;/i&gt;). There were no infections with nematodes, cestodes or trematodes among the study participants. No correlation was found between the detection of a parasitic infection and the presence of diarrhoea or other gastrointestinal symptoms within six months prior to the study. The analysis demonstrated that infections with protozoa were most often found in soldiers aged 35–45 years old. As for the military ranks, the rate of infections in each corps (privates, non-commissioned officers, and officers) was similar.ConclusionsCases of intestinal parasitic infections in soldiers from the Polish Military Contingent Kosovo could be associated with the effects of environmental conditions (poor standards of sanitation in the areas of deployment) and failure to comply with disease prevention principles (food and feed hygiene).

Collider Bias Assessment in Colombian Indigenous Wiwa and Kogui Populations with Chronic Gastroenteric Disorder of Likely Infectious Etiology Suggests Complex Microbial Interactions Rather Than Clear Assignments of Etiological Relevance.

Multiple microbial detections in stool samples of indigenous individuals suffering from chronic gastroenteric disorder of a likely infectious origin, characterized by recurring diarrhea of variable intensity, in the rural north-east of Colombia are common findings, making the assignment of etiological relevance to individual pathogens challenging. In a population of 773 indigenous people from either the tribe Wiwa or Kogui, collider bias analysis was conducted comprising 32 assessed microorganisms including 10 bacteria (Aeromonas spp., Campylobacter spp., enteroaggregative Escherichia coli (EAEC), enteropathogenic Escherichia coli (EPEC), enterotoxigenic Escherichia coli (ETEC), Salmonella spp., Shiga toxin-producing Escherichia coli (STEC), Shigella spp./enteroinvasive Escherichia coli (EIEC), Tropheryma whipplei and Yersinia spp.), 11 protozoa (Blastocystis spp., Cryptosporidium spp., Cyclospora spp., Dientamoeba fragilis, Entamoeba coli, Entamoeba bangladeshi/dispar/histolytica/moshkovskii complex, Entamoeba histolytica, Endolimax nana, Giardia duodenalis, Iodamoeba buetschlii and Pentatrichomonas hominis), 8 helminths (Ascaris spp., Enterobius vermicularis, Hymenolepis spp., Necator americanus, Schistosoma spp., Strongyloides spp., Taenia spp. and Trichuris spp.), microsporidia (Encephalocytozoon spp.) and fungal elements (microscopically observed conidia and pseudoconidia). The main results indicated that negative associations potentially pointing towards collider bias were infrequent events (n = 14), while positive associations indicating increased likelihood of co-occurrence of microorganisms quantitatively dominated (n = 88). Microorganisms showing the most frequent negative associations were EPEC (n = 6) and Blastocystis spp. (n = 3), while positive associations were most common for Trichuris spp. (n = 16), Dientamoeba fragilis (n = 15), Shigella spp./EIEC (n = 12), Ascaris spp. (n = 11) and Blastocystis spp. (n = 10). Of note, positive associations quantitively dominated for Blastocystis spp. In conclusion, collider bias assessment did not allow clear-cut assignment of etiological relevance for detected enteric microorganisms within the assessed Colombian indigenous population. Instead, the results suggested complex microbial interactions with potential summative effects. Future studies applying alternative biostatistical approaches should be considered to further delineate respective interactions.

Clinical Characteristics, Investigations and Treatment in Children with Chronic Urticaria: An Observational Study.

Background and Objectives: The guidelines for chronic urticaria in children contain recommendations that are often based on adult studies. The diagnostic pathway has not been standardized and the effectiveness of anti-H1, omalizumab, montelukast, and systemic glucocorticoids is rarely reported in the pediatric population. There is a wide variation in the rate of remission of chronic urticaria between studies. The aim of this study is to enhance our understanding of pediatric chronic urticaria. Materials and Methods: This study enrolled 37 children with chronic urticaria aged from 0 to 18 years. Demographic parameters, medical history, clinical features, laboratory data and treatment information were collected. Children were treated with the recommended dosage of second-generation H1-antihistamines, which was increased by up to twofold. Omalizumab was added for refractory anti-H1 patients. A three-day course with systemic glucocorticoids was administered for severe exacerbations. Montelukast was administered to some children. Results: Wheals without angioedema were common. Chronic urticaria was spontaneous in 32 children (86.48%), inducible in 2 (5.41%), induced by a parasite in 1 and vasculitic in 2. Treatment of the potential causes of chronic urticaria was of no benefit, except for eradication of Dientamoeba fragilis. Chronic urticaria was resolved within three years in 45.9% of cases. Allergic diseases were present in nine children (24.32%) and autoimmune diseases were present in three (8.11%). All children were treated with anti-H1 at the licensed dose or at a higher dose. A partial or complete response to anti-H1 was observed in 29 (78.38%) patients. Montelukast showed no benefit. All children treated with omalizumab responded. Systemic glucocorticoids were successfully used to treat exacerbations. Conclusions: Our findings indicate that laboratory tests should not be routinely performed in children with chronic urticaria without clinical suspicion. However, comorbidities such as thyroid autoimmune disease and coeliac disease are suggested to be monitored over the chronic urticaria course. These clinical conditions could be diagnosed from the diagnostic framework of chronic urticaria. Increasing the dosage of anti-H1 and omalizumab was effective in children resistant to standard treatment but we still need further studies to generate a standard patient-centered treatment.

A tale of two studies: is peripheral eosinophilia associated with Dientamoeba fragilis detection in adult stool samples?

The protozoan parasite Dientamoeba fragilis is a frequently isolated stool organism and postulated cause of gastrointestinal symptoms. Peripheral blood eosinophilia has been described. This is the first study amongst the Australasian adult population to assess the relationship between organism detection and eosinophilia. A case-control study took place over 7 years at a single Sydney laboratory site, evaluating patients with D.fragilis identified on stool using real-time PCR with a recent full blood count, to control groups with Giardia spp. and sequential negatives with neither organism. A nested study compared those with microscopic evidence of D.fragilis as a marker of disease burden, to molecular diagnosis alone. Sixty-four D.fragilis, 30 Giardia spp., and 94 sequential controls were enrolled. Only 60.1% of samples were preserved in sodium acetate-acetic acid formalin (SAF) fixative, indication mostly not documented. The major co-organism detected amongst all participants was Blastocystis sp., particularly in the D.fragilis cohort (37.2%). The most common pathogen amongst sequential controls was Campylobacter spp. (7.4%). Patients with D.fragilis were more likely (12.5%) to have a clinically significant eosinophilia (>0.5×109/L) compared to those with Giardia spp. (3.3%) or sequential controls (4.3%) (p=0.03). A significant difference was also noted in the overall median eosinophil count of those with D.fragilis versus all controls (0.2 vs 0.1×109/L, p=0.01); however, this was within the reference interval (where up to >0.5×109/L is accepted in healthy individuals within a typical population). No eosinophil difference was found between those with molecular versus additional microscopic detection of D.fragilis (0.1 vs 0.1×109/L). These results support an association between the identification of clinically significant peripheral blood eosinophilia and D.fragilis presence, which may impact the diagnostic approach to the patient with unexplained eosinophilia. Further prospective trials may help assess any significance further and the implication of co-carriage with other enteric organisms. The importance of clinical indication and need for appropriate fixative media in diagnostic parasitology are also highlighted.

Molecular detection and genotyping of Dientamoeba fragilis and Blastocystis sp. in housefly Musca domestica (Diptera: Muscidae): first report for Dientamoeba fragilis.

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.

Detection of positive test for Trichomonas vaginalis in oropharyngeal exudate from а patient with pharyngitis by amplification of nucleic acids: clinical case

Trichomoniasis is the most common infectious and inflammatory disease that is mainly sexually transmitted. Trichomonads are a group of flagellated protozoa. Four species of them infect humans: Trichomonas vaginalis, Trichomonas tenax, Dientamoeba fragilis and Pentatrichomonas hominis. Among them, only Trichomonas vaginalis is considered pathogenic, while the pathogenicity of other species is debatable. According to the WHO, more than 180 million cases of urogenital trichomoniasis are reported annually. Epidemiology of urogenital trichomoniasis has not been studied enough, but the prevalence of this infection, unlike gonorrhea and urogenital chlamydia, increases in older age groups. In women with pelvic inflammatory disease, trichomonas are detected in 5.6—20.6 % of cases, in pregnant women — in 0.98—32 %, in patients with infertility — in 19.5 %, in men with inflammatory genital diseases — in 0.2—8.5 % of cases. The only reliable evidence of trichomonas etiology of the lesion is laboratory detection of the pathogen in biological materials.We describe a clinical case of a patient K., aged 29 years, with symptoms of pharyngitis, in whom urogenital trichomonads were detected in the pharyngeal and tonsillar exudate by polymerase chain reaction. During a thorough anamnesis, patient K. reported her participation in unprotected oral sex with a partner who had been diagnosed with urogenital trichomoniasis. In view of the above, patient K. was offered an oropharyngeal exudate test for sexually transmitted infections. Pharyngeal and tonsillar exudate obtained with the ThinPrep Non Gyn non-gynecological test gave a positive result for Trichomonas vaginalis using the nucleic acid amplification test. Test results for HIV, syphilis, tuberculosis, chlamydia and gonorrhea were negative. The results of the culture testing for opportunistic pathogens were also negative. The oropharyngeal swab with nucleic acid amplification test was positive for Trichomonas vaginalis. Conclusions. Careful collection of the anamnesis of sexual life and examination of swabs from the oropharynx with the help of nucleic acid amplification test made it possible to detect Trichomonas vaginalis in the oral cavity. The patient and her sexual partner were successfully treated. This case indicates that Trichomonas vaginalis can be transmitted orally after unprotected oral sex with a partner who has been diagnosed with urogenital trichomoniasis.Given that the clinical case presented by us and the results of the diagnostic tests are not consistent with the existing recommendations of the Center for Disease Control and Prevention, further clinical and laboratory studies are advisable to determine the possibility of oral transmission of Trichomonas vaginalis during unprotected oral sex, as well as the likelihood of these pathogenic unicellular parasites being involved in the development/maintenance of inflammatory processes of the oropharyngeal mucosa.

Blastocystis spp. and Other Intestinal Parasites in Polish Soldiers Deployed to Lebanon and Iraq.

Intestinal parasitic infections are one of the most common infectious diseases worldwide, particularly in developing countries. A distinct group at increased risk of infection is military personnel deployed overseas for extended periods, typically six months at a time. The aim of this study was to determine the prevalence of Blastocystis spp. and other intestinal parasites in Polish military personnel returning from deployments to Lebanon (n = 206) and Iraq (n = 220). In this group of subjects, we found Blastocystis spp. (13.6%), Dientamoeba fragilis (3.3%), Entamoeba coli (0.9%), and Endolimax nana (0.5%). Entamoeba histolytica sensu lato and Chilomastix mesnili infections were detected only in one soldier returning from Lebanon and Iraq, respectively. Blastocystis subtype (ST) 3 was predominant in soldiers returning from Lebanon, followed by ST2 and ST1. ST1 infection was predominant in soldiers returning from Iraq, followed by ST3 and ST2. Our study affirms that, deployment abroad is of no influence of the prevalence of parasitic protozoa. However, it would be worth to monitor parasite infection in military personnel returning from tropical zone even if they have no actual symptoms. In addition, it is very important to determine the subtypes of Blastocystis-this may help to clearly define their pathogenicity, especially considering the scarcity of studies on Blastocystis genotypes in Iraqi and Lebanese residents.

Detection of Blastocystis sp. and Dientamoeba fragilis using conventional and molecular methods in patients with celiac disease

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.

Evaluation of the Use of Singleplex and Duplex CerTest VIASURE Real-Time PCR Assays to Detect Common Intestinal Protist Parasites

Cryptosporidium spp., Giardia duodenalis and Entamoeba histolytica are species of protozoa- causing diarrhoea that are common worldwide, while Entamoeba dispar, Dientamoeba fragilis and Blastocystis sp. appear to be commensal parasites whose role in pathogenicity remains controversial. We conducted the clinical evaluation of five singleplex and one duplex CerTest VIASURE Real-Time PCR Assays against a large panel of positive DNA samples (n = 358), and specifically to Cryptosporidium spp. (n = 96), G. duodenalis (n = 115), E. histolytica (n = 25) E. dispar (n = 11), Blastocystis sp. (n = 42), D. fragilis (n = 37), and related parasitic phylum species such as Apicomplexa, Euglenozoa, Microsporidia and Nematoda. DNA samples were obtained from clinical stool specimens or cultured isolates in a national reference centre. Estimated diagnostic sensitivity and specificity values were 0.94–1 for Cryptosporidium spp., 0.96–0.99 for G. duodenalis, 0.96–1 for E. histolytica, 1–1 for E. dispar, and 1–0.99 for D. fragilis in the evaluated singleplex assays. In the duplex assay for the simultaneous detection of Blastocystis sp. and D. fragilis these values were 1–0.98 and 1–0.99, respectively. Measures of diagnostic precision for repeatability and reproducibility were found to be under acceptable ranges. The assays identified six Cryptosporidium species (C. hominis, C. parvum, C. canis, C. felis, C. scrofarum, and C. ryanae), four G. duodenalis assemblages (A, B, C, and F), and six Blastocystis subtypes (ST1-ST5, and ST8). The evaluated singleplex and duplex VIASURE Real-Time PCR assays provide sensitive, practical, and cost-effective choices to the molecular diagnosis of the main diarrhoea-causing intestinal protists in clinical microbiology and research laboratories.

Observations on the transmission of Dientamoeba fragilis and the cyst life cycle stage.

Little is known about the life cycle and mode of transmission of Dientamoeba fragilis. Recently it was suggested that fecal–oral transmission of cysts may play a role in the transmission of D. fragilis. In order to establish an infection, D. fragilis is required to remain viable when exposed to the pH of the stomach. In this study, we investigated the ability of cultured trophozoites to withstand the extremes of pH. We provide evidence that trophozoites of D. fragilis are vulnerable to highly acidic conditions. We also investigated further the ultrastructure of D. fragilis cysts obtained from mice and rats by transmission electron microscopy. These studies of cysts showed a clear cyst wall surrounding an encysted parasite. The cyst wall was double layered with an outer fibrillar layer and an inner layer enclosing the parasite. Hydrogenosomes, endoplasmic reticulum and nuclei were present in the cysts. Pelta-axostyle structures, costa and axonemes were identifiable and internal flagellar axonemes were present. This study therefore provides additional novel details and knowledge of the ultrastructure of the cyst stage of D. fragilis.