Clinical significance of enteric protozoa in the immunosuppressed human population

Parasitic infections: what do paediatricians need to know?

Parasitic infections and the medications used to treat them may be unfamiliar to many paediatricians. Parasitic infections, however, are not uncommonly seen in children in the UK. We summarise infections which are commonly seen, currently recommended treatment and practical guidance on formulations, adverse effects and treatment choice.

High Prevalence of Enterocytozoon bieneusi Genotype BEB6 in Wild Boars in Lorestan Province, Iran: Potential Source of Zoonotic Transmission

Background

We aimed to investigate the prevalence of Enterocytozoon bieneusi and the circulating genotypes in wild boar in the western regions of Iran.

Methods

Fifty-two fecal samples were collected from wild boars in Lorestan province, Iran. After DNA extraction, the presence of E. bieneusi was evaluated by real-time PCR. A nested PCR targeting the internal transcribed region (ITS) was employed to characterize genotypes. The PCR products were sequenced, and the genetic diversity and relationships among the genotypes were identified using MEGA X and DnaSp (V5) software.

Results

Sixteen (30%) samples were positive for E. bieneusi using real-time PCR, and 11 (21%) were positive for nested PCR, which was sequenced. All 11 positive samples were identified as the BEB6 genotype (Group 2). The haplotype diversity was noted to be 0.182, and the nucleotide diversity, calculated using DnaSp, was 0. 00085.

Conclusion

The findings highlight the high prevalence of the genotype BEB6 in wild boars. The presence of this genotype suggests the circulation of E. bieneusi between domesticated animals and wild boars in Iran.

Cryptosporidiosis in a Zoonotic Gastrointestinal Disorder Perspective: Present Status, Risk Factors, Pathophysiology, and Treatment, Particularly in Immunocompromised Patients

Cryptosporidium infection is highly prevalent among immunocompromised patients with Acquired Immunodeficiency Syndrome, cancer, primary immunodeficiency, and organ transplant recipients. Comprehensive knowledge about Cryptosporidium infection provides the means for efficient diagnosis, treatment, and prevention. Therefore, with the objective of providing an in-depth analysis of Cryptosporidiosis in immunocompromised patients, this review presents a comprehensive understating of the prevalence, risk factors, pathophysiology of Cryptosporidium infection, clinical presentation in the immunocompromised, the immune response of the host, diagnostic methods performed in laboratory settings, possible treatments, and prevention methods, which can be used for further studies. Peer-reviewed, published, original articles on cryptosporidiosis in immunocompromised patients were searched using specific key-words on PubMed, ResearchGate, Google Scholar, and ScienceDirect databases. Articles which were accessible to the date of 18th of August 2023, were included in this comprehensive review. We analyzed reports on Cryptosporidium in immunocompromised patients with human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS), cancer, primary immunodeficiency, and organ transplant recipients. 134 Articles describing epidemiology, related risk factors, clinical presentation, diagnosis, and possible treatments in the light of pathogenesis, pathophysiology, and virulence factors of Cryptosporidium and immunology of the host are summarized in this study. Effective treatments to be administered, importance, and ways of prevention were identified. Cryptosporidium infection was found to be highly prevalent among immunocompromised in Asia, Africa, Europe, and North America. The immunity of the host and the decrease in CD4+ T-cell count were found to the main factors which decide the susceptibility and the severity of infection. Drugs that activate host immunity and suppress Cryptosporidium growth, along with supportive therapy, is an effective treatment. But prevention is the most effective strategy for immunocompromised patients; thus, a better understanding about the disease would lead to effective prevention.

Multiplex PCR for gastrointestinal parasites in stool: Benchmarking against direct microscopy and simplex PCR

PURPOSE

To develop and validate a multiplex conventional PCR assay to simultaneously detect Cryptosporidium spp., Entamoeba histolytica, and Giardia lamblia in diarrheal samples as a rapid, cost-effective, and sensitive diagnostic tool for prevalent co-infections for improved diagnostic accuracy and efficiency in resource-limited settings.

METHODS

Stool samples collected from patients with gastrointestinal symptoms after taking written consent, processed via wet mount, iodine mount, and PCR assays. Cohen's kappa statistical analysis was done to test agreement.

RESULT

Among 240 patients, 28.75% showed intestinal protozoa via Microscopy; Single-plex and multiplex PCR demonstrated 100% concordance, detecting 27.9%; confirmed by sequencing. Highest parasite positivity was observed in transplant and immunocompromised patients, with moderate to almost perfect agreement between microscopy and molecular methods.

CONCLUSION

Multiplex-conventional PCR offers superior sensitivity and specificity over microscopy and 100% concordance with single-plex PCR, enabling rapid, cost-effective diagnosis of multiple parasites from single stool sample. Its adoption could revolutionize parasitic infection management in routine diagnostics.

Comparative performance evaluation of four different methods for diagnosing Giardia infection in dogs and zoonotic assemblages' identification

Giardia duodenalis (syn. G. intestinalis or G. lamblia) is a parasitic protozoan that infects the upper intestinal tract of a broad range of hosts, including humans and domestic animals. Thus, it has raised concerns about the public health risk due to companion animals. Recently, with the improvement of living standards and increasing contacts between pets and humans, the zoonotic transmission of Giardia has dramatically increased. From a genetic point of view, G. duodenalis should be viewed as a complex species that includes eight different species-specific genetic assemblages. The laboratory diagnosis is mainly based on the finding of microscopic cysts in stool samples by coprological examination. Other methods include the detection of antigens, immunoassays or PCR protocols, which allow the identification of Giardia assemblages. The study aimed to compare the performance of Direct Fluorescence Antibody test (DFA), zinc sulfate flotation technique (ZnSO4), rapid diagnostic test (RDT), end-point PCR amplification (PCR) for the detection of Giardia and to identify the concerning assemblages in a canine population from Central Italy. Direct fluorescence antibody test is the reference standard for laboratory diagnosis of Giardia in fecal samples from dogs, despite the microscopic examination after flotation remains the most useful method in many veterinary diagnostic centers. The present findings demonstrate the high performance of DFA and ZnSO4 in detecting Giardia, while RDT may be useful as alternative or complementary method to the DFA and ZnSO4. PCR performance was low, but it allowed determining Giardia B zoonotic assemblage in 25% of the PCR-positive specimens (15 out of 60), while the remaining PCR-positive isolates belonged to the dog-specific assemblage C. The 26% prevalence of G. duodenalis detected by DFA in owned dogs and the identification of potentially zoonotic assemblages underline the potential risk for public health and indicate frequent cross-species transmission of the parasite between humans and dogs.

Protozoan Infections in Cancer Patients: A Case Series

Intestinal parasitic infections can cause significant morbidity and mortality in individuals with cancer. Despite this, they are often self-limiting in healthy individuals. Entamoeba histolytica is an anaerobic parasite that causes amebiasis in infected individuals. Poor sanitary conditions and endemic areas increase the risk of contracting amebiasis. Furthermore, giardiasis is a parasitic infection of the small intestine that is caused by Giardia duodenalis, a flagellated protozoan. In both cases, the disease burden is greater and the timeline is longer among immunosuppressed patients. Due to this, we aimed to more thoroughly characterize disease progression and treatment efficacy of these intestinal parasitic infections in cancer patients by presenting a case of intestinal amebiasis and enterocolitis due to Entamoeba histolytica, as well as two giardiasis cases, while also providing a review of the literature.

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.

[Feline and canine giardiosis: An Update]

Giardia duodenalis is a facultative pathogenic intestinal parasite. Giardiosis in dogs and cats may appear with or without clinical signs. Typical signs include diarrhea with or without vomiting. The prevalence in young animals is high and may amount to up to 50%. There are 8 different genotypes (A - H), which are called assemblages. Assemblages C and D are most common in dogs and assemblage F most frequent in cats. However, animals may also be infected with the zoonotically effective assemblages A and B or exhibit mixed infections. The immunofluorescence test (IFA), the enzyme-linked immunosorbent assay (ELISA) and fecal centrifugation using zinc sulphate solution are currently recommended as diagnostic methods. Polymerase chain reaction (PCR) may be used to determine the corresponding assemblage. Approved treatments for giardiosis include fenbendazole and metronidazole. In addition, undertaking specific hygiene measures is warranted. Only animals showing clinical signs or those living in the same household with high-risk patients (e. g. immunosuppressed humans) are recommended to receive medication. The aim of treatment is clinical improvement of the diseased dogs and cats. Frequently, complete elimination of Giardia is not attained.

Genotyping and epidemiological distribution of diarrhea-causing isolates of Giardia duodenalis in southeastern part of West Bengal, India

The prevalence and genetic diversity of the protozoan pathogen Giardia duodenalis have been extensively studied worldwide. There is currently a lack of data regarding the genetic variability of the organism in eastern India. Understanding the circulating genotypes and associated risk factors is crucial for effective planning and implementing control measures. Therefore, the objective of the study was to conduct an epidemiological study to determine the prevalence and identify the various genotypes present. This survey adds to our knowledge on the occurrence and distribution of Giardia genotypes in the studied region. The overall prevalence was found to be 6.8%. This parasitic infection was significantly associated with two age groups, i.e., >0-5 years and >5-12 years. Using a multilocus genotyping method, we genotyped 52 human Giardia isolates that were obtained from diarrheal patients. Two distinct assemblages were found in the population-30.8% belonged to assemblage A; 63.5% belonged to assemblage B, prevalent in the population; and 5.7% belonged to a combined assemblage A+B. Sub-assemblage AII was found in 17.3% of the cases, followed by sub-assemblage AI (13.5%). High levels of genetic diversity were found within the population of assemblage B undergoing balancing selection. Overall, the high prevalence of the parasite observed, particularly among children, raises a major concern and necessitates implementation of robust control measures. Furthermore, we report the presence of numerous unique genotypes, circulating in this limited geographical boundary, which can be useful dataset for future studies.

Microsporidia in HIV-Positive and HIV-Negative Pediatric Patients with Diarrhea at a Tertiary Care Hospital

Background  Human microsporidiosis presents as an important and rapidly emerging opportunistic infection. However, the exact burden of this infection especially in the pediatric population of Northern India remains unknown. In this study, we investigated the prevalence of microsporidia among human immunodeficiency virus (HIV)-positive and HIV-negative pediatric patients who presented with diarrhea. Methods  A total of 263 children were recruited consisting of 98 HIV seropositive with diarrhea and 165 HIV seronegative but with diarrhea. Morning stool samples were collected and both direct and formol ether concentrated samples were examined for the presence of intestinal parasites. The modified acid-fast staining was done for coccidian parasites and trichrome stain for microsporidia detection. Further, the species were detected using a real-time polymerase chain reaction (PCR) targeting a conserved region of the small ribosomal subunit rRNA gene of Enterocytozoon bieneusi , Encephalitozoon hellem , Encephalitozoon intestinalis , and Encephalitozoon cuniculi . Results  Overall, one or more parasites were detected in 52.04% (51/98) of HIV seropositive and 53.33% (88/165) of seronegative children ( p  = 0.8391). However, coccidian parasites were detected in a significantly huge number of HIV seropositive children (21.43% [21/98]) as compared with HIV seronegative children (4.24% [7/165]). Microsporidial DNA could be detected in HIV seropositive with diarrhea children (17.35% [17/98]) by PCR. A significant correlation between low CD4 count (≤ 200/μL) and intestinal parasite positivity could be established. Conclusion  Microsporidia is a significant cause of diarrhea in HIV seropositive pediatric patients and should be kept in mind as one of the differential diagnoses in such patients.

Diarrhoeal pathogens in the stools of children living with HIV in Ibadan, Nigeria

Introduction

Diarrhoea can be debilitating in young children. Few aetiological investigations in Africans living with human immunodeficiency virus (HIV) have been performed since antiretrovirals became widely available.

Methods

Stool specimens from children with diarrhoea living with HIV, and HIV-uninfected controls, recruited at two hospitals in Ibadan, Nigeria, were screened for parasites and occult blood, and cultured for bacteria. Following biochemical identification of at least five colonies per specimen, diarrhoeagenic Escherichia coli and Salmonella were confirmed by PCR. Data were line-listed and comparisons were made using Fisher's Exact test.

Results

Only 10 children living with HIV could be enrolled during the 25-month study period and 55 HIV-uninfected children with diarrhoea were included for comparison. The most common pathogens overall were enteroaggregative E. coli (18/65, 27.7%), enteroinvasive E. coli (10/65, 15.4%), Cryptosporidium parvum (8/65, 12.3%) and Cyclospora cayetanensis (7/65, 10.8%). At least one pathogen was detected from seven of ten children living with HIV and 27 (49.1%) HIV-uninfected children. Parasite detection was associated with HIV positive status (p=0.03) with C. parvum specifically recovered more commonly from children living with HIV (p=0.01). Bacterial-parasite pathogen combinations were detected in specimens from four of ten children living with HIV but only 3(5.5%) HIV-uninfected children (p=0.009). Stools from five of ten children living with HIV and 7(12.7%) HIV-negative children (p = 0.014) contained occult blood.

Discussion

Even though children living with HIV present infrequently to Ibadan health facilities with diarrhoea, their greater propensity for mixed and potentially invasive infections justifies prioritizing laboratory diagnosis of their stools.

Extensive testing of a multi-locus sequence typing scheme for Giardia duodenalis assemblage A confirms its good discriminatory power

BACKGROUND

The flagellated parasite Giardia duodenalis is a major and global cause of diarrhoeal disease. Eight genetically very distinct groups, known as assemblages A to H, have been recognized in the G. duodenalis species complex, two of which (assemblages A and B) infect humans and other mammalian hosts. Informative typing schemes are essential to understand transmission pathways, characterize outbreaks and trace zoonotic transmission. In this study, we evaluated a published multi-locus sequence typing (MLST) scheme for G. duodenalis assemblage A, which is based on six polymorphic markers.

METHODS

We genotyped 60 human-derived and 11 animal-derived G. duodenalis isolates collected in Europe and on other continents based on the published protocol. After retrieving previously published genotyping data and excluding isolates whose sequences showed allelic sequence heterozygosity, we analysed a dataset comprising 146 isolates.

RESULTS

We identified novel variants at five of the six markers and identified 78 distinct MLST types in the overall dataset. Phylogenetic interpretation of typing data confirmed that sub-assemblage AII only comprises human-derived isolates, whereas sub-assemblage AI comprises all animal-derived isolates and a few human-derived isolates, suggesting limited zoonotic transmission. Within sub-assemblage AII, isolates from two outbreaks, which occurred in Sweden and Italy, respectively, had unique and distinct MLST types. Population genetic analysis showed a lack of clustering by geographical origin of the isolates.

CONCLUSION

The MLST scheme evaluated provides sufficient discriminatory power for epidemiological studies of G. duodenalis assemblage A.

Comparison of Intestinal Parasites in Native and Refugee Patients Admitted to a Territory Hospital in Turkey

OBJECTIVE

This study aimed to evaluate the distribution of intestinal parasites in refugee and native patients who applied to a territory hospital in Turkey.

METHODS

A total of 17911 patients who were admitted to our hospital between January 2018 and January 2019 were evaluated retrospectively in terms of intestinal parasites. The patients' stool samples were investigated for the existence of intestinal parasites by direct wet mount preparation, formalin ether concentration technique and cellophane tape method. The data obtained were compared between patient groups according to the examination method.

RESULTS

The overall prevalence of E. vermicularis in refugee children was found twice higher than that in native patients and the most common symptom was abdominal pain in these patients. Intestinal parasite detection rates were significantly higher in the stool concentration method than in the direct wet mount examination. Cutaneous complaints and protein energy malnutrition/growth retardation were the most common clinical conditions besides gastrointestinal symptoms in patients with intestinal parasitosis.

CONCLUSION

In our study, the prevalence of Blastocystis sp. in refugees was found to be higher than in the normal population. Intestinal parasitic infections should be investigated with proper diagnostic methods especially in children with PEM/GR and cutaneous symptoms in addition to gastrointestinal problems.

Evaluation of a Novel Commercial Real-Time PCR Assay for the Simultaneous Detection of Cryptosporidium spp., Giardia duodenalis, and Entamoeba histolytica

Cryptosporidium spp., Giardia duodenalis, and Entamoeba histolytica are the most common diarrhea-causing protozoan species globally. Misdiagnosis is a concern for asymptomatic and chronic infections. Multiplexing, i.e., the detection of more than one parasite in a single test by real-time PCR, allows high diagnostic performance with favorable cost-effectiveness. We conducted a clinical evaluation of the VIASURE Cryptosporidium, Giardia, & E. histolytica real-time PCR assay (CerTest Biotec, San Mateo de Gállego, Spain) against a large panel (n = 358) of well-characterized DNA samples positive for Cryptosporidium spp. (n = 96), G. duodenalis (n = 115), E. histolytica (n = 25), and other parasitic species of the phyla Amoebozoa (n = 11), Apicomplexa (n = 14), Euglenozoa (n = 8), Heterokonta (n = 42), Metamonada (n = 37), Microsporidia (n = 4), and Nematoda (n = 6). DNA samples were obtained from clinical stool specimens or cultured isolates in a national reference center. Estimated sensitivity and specificity were 0.96 and 0.99 for Cryptosporidium spp., 0.94 and 1 for G. duodenalis, and 0.96 and 1 for E. histolytica, respectively. Positive and negative predictive values were calculated as 1 and 0.98 for Cryptosporidium spp., 0.99 and 0.98 for G. duodenalis, and 1 and 0.99 for E. histolytica, respectively. The assay identified six Cryptosporidium species (Cryptosporidium hominis, Cryptosporidium parvum, Cryptosporidium canis, Cryptosporidium felis, Cryptosporidium scrofarum, and Cryptosporidium ryanae) and four G. duodenalis assemblages (A, B, C, and F). The VIASURE assay provides rapid and accurate simultaneous detection and identification of the most commonly occurring species and genetic variants of diarrhea-causing parasitic protozoa in humans. IMPORTANCE Thorough independent assessment of the diagnostic performance of novel diagnostic assays is essential to ascertain their true usefulness and applicability in routine clinical practice. This is particularly true for commercially available kits based on multiplex real-time PCR aimed to detect and differentiate multiple pathogens in a single biological sample. In this study, we conducted a clinical evaluation of the VIASURE Cryptosporidium, Giardia, & E. histolytica real-time PCR assay (CerTest Biotec) for the detection and identification of the diarrhea-causing enteric protozoan parasites Cryptosporidium spp., G. duodenalis, and E. histolytica. A large panel of well-characterized DNA samples from clinical stool specimens or cultured isolates from a reference center was used for this purpose. The VIASURE assay demonstrated good performance for the routine testing of these pathogens in clinical microbiological laboratories.

Prevalence of Intestinal Parasites among Immunocompromised Patients, Children, and Adults in Sana'a, Yemen

Intestinal parasite infection (IPI) is still a very important public health issue. The severity of the parasitic disease has been reported as a high infection in immunocompromised patients and children. Hence, this study aimed to investigate the prevalence of intestinal parasites among immunocompromised patients and children with various gastrointestinal system complications in Sana'a city, Yemen, with different variables, including genus and age, and explore the risk factors associated with parasitic intestinal infections. The study socioeconomic data and certain behavioral and environmental risk factors and stool samples were collected from immunocompromised adult and children's patients, including children (one to eight years old), pregnant women, diabetes mellitus patients, cancer patients, HIV patients, and older adults. Out of 436 fecal samples, the overall prevalence rate of IPIs among immunocompromised patients and children in Sana'a was 51.8%. In contrast, the rate of infection in children (26.1%) was higher than that in old patients (25.7%) and in females (38.5%) and higher than that in males (13.3%). The protozoa (44.5%) have been shown more than intestinal helminths (7.3%) in samples, and the most common intestinal protozoan was Giardia lamblia and Entamoeba histolytica (13.8% and 12.8%), respectively. The most common intestinal helminthiasis was Hymenolepis nana with 1.8%. Concluding that the rate of infection was high for several reasons, including lack of commitment to hygiene as not handwashing after using the toilet (88.9%), eating uncovered food (56.3%), poor sanitation as lack of water sources (59.5%), reduced health education, and presence of other family members infected by parasites (61.3%). Interventions are required to reduce intestinal parasites, including health education on personal hygiene for patients, increasing awareness, and improving the environment and healthcare system.

Conserved metabolic enzymes as vaccine antigens for giardiasis

Giardia lamblia is a leading protozoal cause of diarrheal disease worldwide. Infection is associated with abdominal pain, malabsorption and weight loss, and protracted post-infectious syndromes. A human vaccine is not available against G. lamblia. Prior studies with human and murine immune sera have identified several parasite antigens, including surface proteins and metabolic enzymes with intracellular functions. While surface proteins have demonstrated vaccine potential, they can exhibit significant variation between G. lamblia strains. By comparison, metabolic enzymes show greater conservation but their vaccine potential has not been established. To determine whether such proteins can serve as vaccine candidates, we focused on two enzymes, α-enolase (ENO) and ornithine carbamoyl transferase (OCT), which are involved in glycolysis and arginine metabolism, respectively. We show in a cohort of patients with confirmed giardiasis that both enzymes are immunogenic. Intranasal immunization with either enzyme antigen in mice induced strong systemic IgG1 and IgG2b responses and modest mucosal IgA responses, and a marked 100- to 1,000-fold reduction in peak trophozoite load upon oral G. lamblia challenge. ENO immunization also reduced the extent and duration of cyst excretion. Examination of 44 cytokines showed only minimal intestinal changes in immunized mice, although a modest increase of CCL22 was observed in ENO-immunized mice. Spectral flow cytometry revealed increased numbers and activation state of CD4 T cells in the small intestine and an increase in α4β7-expressing CD4 T cells in mesenteric lymph nodes of ENO-immunized mice. Consistent with a key role of CD4 T cells, immunization of CD4-deficient and Rag-2 deficient mice failed to induce protection, whereas mice lacking IgA were fully protected by immunization, indicating that immunity was CD4 T cell-dependent but IgA-independent. These results demonstrate that conserved metabolic enzymes can be effective vaccine antigens for protection against G. lamblia infection, thereby expanding the repertoire of candidate antigens beyond primary surface proteins.

Evaluation of Intestinal Parasites and Some Clinical Symptoms in Children with Diarrhea

OBJECTIVE

This study aimed to determine the frequency of intestinal parasites in children who were presented to health centers with a complaint of diarrhea and to reveal the importance of these parasites.

METHODS

The study was conducted on children within the age range of 1-16 who were presented to Iğdır State Hospital and Private Bulut Hospital between 2020 February-April 2020 with a complaint of diarrhea. A total of 300 children comprising 141 girls and 159 boys were enrolled in the study. The control group was composed of 100 children (girls=50, boys=50) without any chronic disease and diarrhea. Stool samples were evaluated by the native-Lugol method and the modified acid-fast staining method.

RESULTS

Intestinal parasite positivity was found in 105 (35%) out of the 300 children in the patient group and in 17 (17%) out of the 100 children in the control group. In terms of parasitic positivity, a statistically significant difference was found between children with diarrhea and the healthy control group (p=0.001). Blastocystis hominis (13%), Cryptosporidium spp. (3%), and Giardia intestinalis (2%) were found in the patient group. Intestinal parasitic positivity was found in 30.2% and 40.4% of the boys and girls in the patient group, respectively, whereas it was found in 14% and 20% of the boys and girls in the control group, respectively. When evaluated statistically according to gender, a significant difference (comparison for boys: p=0.008; comparison for girls: p=0.004) was noted between the patient group and control group for each gender. In terms of the relationship between the frequency of parasites and some living conditions of the patients, a statistically significant relationship was found in the comparison of "whether or not livestock" (p=0.004) and "whether there is a sewerage network" (p=0.002). Additionally, a significant difference was found between parasitic positivity and abdominal pain (p=0.008) and nausea (p=0.003).

CONCLUSION

The present study concludes that children with clinical symptoms, such as diarrhea, abdominal pain, and nausea, should be evaluated for intestinal parasites. Furthermore, it has been understood that intestinal parasites remain an important health problem among the pediatric cohort.

Association between Blastocystis sp. infection and immunocompromised patients: a systematic review and meta-analysis

The significance of opportunistic infections in immunocompromised patients and the enigmatic pathogenicity of Blastocystis directed us to conduct the first global systematic review and meta-analysis on Blastocystis prevalence, odds ratios (ORs), and subtypes distribution in various immunocompromised patients (HIV/AIDS, cancer and hemodialysis patients, as well as transplant recipients). The systematic searching procedure was done in Web of Science, PubMed, Scopus, and Google Scholar databases for relevant published literature until November 11, 2020. Random-effects model was utilized to calculate the weighted estimates and 95% confidence intervals (95% CIs). The computed pooled prevalence of Blastocystis inferred from 118 papers (128 datasets) on immunocompromised patients was 10.3% (95% CI: 8.7-12.2%), with 16.1% (95% CI: 11.3-22.2%), 12.5% (95% CI: 8.5-18%), 8.4% (95 % CI: 6.6-10.6%), and 6% (95% CI: 2.6-13.3%) for hemodialysis patients, cancer patients, HIV/AIDS patients, and transplant recipients, respectively. Based on 50 case-control studies (54 datasets), the highest ORs were associated with cancer [2.81 (95% CI: 1.24-6.38, P = 0.013)] and hemodialysis patients [2.78 (95% CI: 1.19-6.48, P = 0.018)]. The most frequent subtype being found in immunocompromised patients was ST3 [41.7% (95% CI: 31.4-52.7%)], followed by ST1 [31.7% (95% CI: 23.2-41.8%)] and ST2 [23.1% (95% CI: 14.8-34.1%)]. Also, the weighted frequency of Blastocystis in various subgroups (publication year, WHO regions, geographical distribution, continents, and country income) was analyzed separately. In total, the results of the present meta-analysis highlighted that one's immunodeficiency status is probably associated with an increased Blastocystis infection, underpinning strict preventive measures to be taken.

Prevalence of Gastrointestinal Pathogens Detected by Multiplex Polymerase Chain Reaction in a Prospective Cohort of Men Who Have Sex With Men Taking Human Immunodeficiency Virus Preexposure Prophylaxis-New York City, 2019-2020

Multiplex polymerase chain reaction testing for gastrointestinal pathogens was performed on a longitudinal cohort of 110 men who have sex with men taking human immunodeficiency virus preexposure prophylaxis. At least 1 pathogen was detected among 50 (45%) participants, with some participants testing positive for the same pathogen on multiple consecutive visits over a period of months.

Diagnóstico molecular de parasitosis intestinales

Infections causes by parasites of the gastrointestinal tract are a global public health problem. In industrialised countries, their particular epidemiological (low general prevalence of enteroparasites), economic (high labour costs) and clinical characteristics (constant increase in the number of samples and diagnostic determinations to be performed) have led molecular techniques to progressively replace conventional microscopy as the first-line diagnostic method of these pathogens in modern clinical laboratories. PCR-based techniques, particularly those developed for the simultaneous detection of the various agents that can cause the same infectious disease (syndromic diagnosis), already represent a cost-effective option that allow process automisation, workflow optimisation, and comparison of results among different laboratories, and facilitate accreditation of diagnostic procedures. This review clearly and concisely discusses the current situation of the molecular diagnosis of the main species of intestinal parasites in humans, particularly the enteric protozoans causing diarrhoea (Cryptosporidium spp., Giardia duodenalis, Entamoeba histolytica), the most important members the Microsporidia phyla (Enterocytozoon bieneusi) and Stramenopiles phyla (Blastocystis sp.), as well as the helminths transmitted by soil (Ancylostoma spp., Ascaris lumbricoides, Necator americanus, Strongyloides stercoralis and Trichuris trichiura) and food (Anisakis spp., Clonorchis sinensis, Fasciola spp., Taenia solium, and Trichinella spiralis). Special attention is paid to the description of available techniques and formats, to their diagnostic benefits and the most widely used genetic markers for their detection, both in clinical laboratories and genotyping in referral and research centres.

Parasite-derived microRNAs as a diagnostic biomarker: potential roles, characteristics, and limitations

MicroRNAs (miRNAs), a subclass of small regulatory RNAs that present from ancient unicellular protozoans to parasitic helminths and parasitic arthropods. MiRNAs' mode of action has attracted wide attention as a result of their unique functional importance. MiRNAs play a role in diverse physiological and pathological processes ranging from organ development, immune function to apoptosis and cancer at the post-transcription gene expression. Thus, miRNAs are known to be targets for clinical treatment and therapy. The discovery of the high stability of circulating miRNA in various types of host body fluids, such as whole blood, serum, plasma, saliva, and urine has increased great interest among researchers in the potential of circulating miRNA as a prognosis/diagnosis of infectious. Some circulating miRNAs biomarkers advanced to clinical applications related to human diseases. However, this idea starts to come only in the fields of infectious disease. The goal of this review is to enhance the current understanding of these molecules and their applicability in the field of medicine. A detailed review of the available literature consulting tools performed in online repositories such as NCBI, PubMed, Medline, ScienceDirect, and UpToDate. This review summarizes an overview of preclinical studies using circulating miRNAs biomarkers against infectious diseases affecting humans. The use of miRNA as a safe and potential tool is encouraging news, considering that until now, guidelines for the use of miRNA in clinical practice are still lacking.

Toxoplasmosis, cryptosporidiosis, and isosporiasis in HIV-negative immunocompromised patients: A single-centre study, Ottawa, Ontario, Canada

BACKGROUND

Historically, patients with HIV have been at the highest risk of infection with opportunistic protozoans such as Toxoplasma, Cryptosporidium, and Isospora. Among patients with HIV who are compliant with antiretroviral therapy, the likelihood of acquiring an opportunistic infection is low. The risk of infection is harder to mitigate in the growing number of HIV-negative immunodeficient patients, such as people with hematological malignancies or those who are post-transplantation.

METHODS

We conducted a retrospective case series of patients with documented Toxoplasma infections between 2008 and 2017 and with Cryptosporidium and Isospora infections between 2014 and 2017 at the Ottawa Hospital.

RESULTS

During the study period, there were 10 confirmed cases of toxoplasmosis, 20 cases of cryptosporidiosis, and 2 cases of isosporiasis. Cryptosporidiosis (95%) and toxoplasmosis (60%) occurred more frequently among HIV-negative patients, whereas isosporiasis cases were limited to HIV-positive patients. Among patients with cryptosporidiosis, the most common underlying cause of immunosuppression in HIV-negative individuals was solid organ transplantation (15.79%), followed by diabetes (10.53%), end-stage renal disease (5.26%), and hematologic malignancy (5.26%). Seventy percent of patients had no known cause of immunosuppression. The most common underlying condition associated with toxoplasmosis was hematological malignancy (50%), followed by solid organ transplantation (33.33%), and solid tumours (16.66%).

CONCLUSIONS

This study's results suggest that Cryptosporidium infections are more common among immunocompetent patients in Ottawa, whereas Toxoplasma infections are more common among HIV-negative patients with acquired immunodeficiencies. As the demographics of immunocompromised individuals continue to evolve, screening for protozoal infections in high-risk populations may become clinically important.

Profile of intestinal parasitic infections in human immunodeficiency virus/acquired immunodeficiency syndrome patients in Northeast India

Introduction:

Diarrhea is one of the major complications occurring in over 90% of human immunodeficiency virus (HIV)-infected individuals in developing countries. Coccidian group of parasitic infections remain the standout opportunistic pathogens in many parts of the world.

Aim:

The objective was to understand the profile of diarrheagenic parasites in HIV/AIDS patients along with analysis of the changing trends in the profile of parasitic diarrhea with special context to coccidian parasitic infections.

Methodology:

A cross-sectional study was performed at “ID CENTRE FOR NORTHEAST,” Shillong, from January 2014 to October 2017. Stool samples collected were observed microscopically for parasites both on direct and concentrated stool samples under ×10 and ×40 magnification. Modified acid-fast staining was used for the detection of coccidian parasites. All statistical analyses were performed using IBM SPSS software, Version 24.0.

Results:

The prevalence of intestinal parasitic infections was 40.99%, coccidian parasitic infection accounted for 85.13% of total intestinal parasitic infections. Cryptosporidium parvum was the most common cause of diarrhea (70.64%), followed by Cystoisospora belli (23.81%) and Cyclospora spp. (5.55%). Trend analysis of coccidian etiology during the study revealed a significant rise in the positivity of Cryptosporidium spp. and a decrease in the Cystoisosporiasis belli infection. The common noncoccidian parasites identified include hookworm (8.1%) followed by Ascaris lumbricoides (4.7%).

Conclusion:

The magnitude of parasitic infections is considerably high among the HIV/AIDS patients in Northeast India, and it is essential for screening and periodic monitoring of all the HIV patients for coccidian parasites by stool microscopy.

30 years of parasitology research analysed by text mining

Bibliometric methods were used to analyse the major research trends, themes and topics over the last 30 years in the parasitology discipline. The tools used were SciMAT, VOSviewer and SWIFT-Review in conjunction with the parasitology literature contained in the MEDLINE, Web of Science, Scopus and Dimensions databases. The analyses show that the major research themes are dynamic and continually changing with time, although some themes identified based on keywords such as malaria, nematode, epidemiology and phylogeny are consistently referenced over time. We note the major impact of countries like Brazil has had on the literature of parasitology research. The increase in recent times of research productivity on 'antiparasitics' is discussed, as well as the change in emphasis on different antiparasitic drugs and insecticides over time. In summary, innovation in parasitology is global, extensive, multidisciplinary, constantly evolving and closely aligned with the availability of technology.

Opportunistic parasitic infections in patients with human immunodeficiency virus/acquired immunodeficiency syndrome: A review

The number of human immunodeficiency virus (HIV) cases increases annually, and Indonesia has become the country with the fastest HIV/acquired immunodeficiency syndrome (AIDS) epidemic spread among the five Southeast Asian countries. Indonesia entered the critical phase of HIV/AIDS infections after 5 out of the 33 provinces, namely, Papua, Jakarta, Bali, West Java, and East Java, reported HIV/AIDS epidemic since 2004. In AIDS pathophysiology and immune-suppression are severe, thus, opportunistic intestinal parasitic infections that cause diarrhea in HIV infection may be fatal. Several studies have suggested that Cryptosporidium parvum, Isospora belli, and Blastocystis hominis are the most common intestinal protozoan parasites categorized as AIDS associated illness. Diarrhea caused by parasites is considerably suspected in the cases of chronic and persistent diarrhea in adults, in an era of increasing HIV/AIDS cases nowadays. The present review highlights the current advances in etiologic agents of HIV/AIDS opportunistic infections among countries, epidemiology and prevalence, lifecycle, risk factors, examination methods, and treatment.

Multilocus genotyping of Giardia duodenalis in Southwestern Iran. A community survey

Giardia duodenalis is one of the main enteric pathogens associated with diarrheal disease. In developing countries, giardiasis is a major public health concern, particularly in children under five years of age. This study aimed to evaluate the occurrence and genetic diversity of G. duodenalis causing human infections in Shushtar County, Southwestern Iran. Individual faecal specimens were collected from 1,163 individuals (male/female ratio: 0.9; age range 2-75 years) with (n = 258) and without (n = 905) gastrointestinal symptoms living in rural and urban settings during the period 2017-2018. Conventional (sucrose flotation and microscopy) methods were used for the initial detection of G. duodenalis cysts in faecal specimens. Microscopy-positive samples were confirmed by PCR amplification and sequencing of the small subunit rRNA (ssu rRNA) gene of the parasite. A multilocus genotyping (MLG) scheme targeting the triose phosphate isomerase (tpi), the glutamate dehydrogenase (gdh), and the beta-giardin (bg) genes was used for genotyping purposes. Giardia duodenalis cysts were detected in 7.7% (90/1,163) of samples by microscopy, of which 82 were confirmed by ssu-PCR. Successful amplification and sequencing results were obtained for 23.2% (19/82), 9.8% (8/82), and 8.5% (7/82) of the confirmed samples at the tpi, gdh, and bg loci, respectively. MLG data for the three loci were available for two samples only. Out of the 24 samples genotyped at any loci, 50% (12/24) were identified as assemblage A and the remaining half as assemblage B. Overall, AII was the most prevalent sub-assemblage detected (41.7%, 10/24), followed by BIII (25.0%, 6/24), discordant BIII/BIV (5/24) or AII/AIII (2/24) sequences, and BIV (1/24). No significant correlation was demonstrated between a given assemblage/sub-assemblage and the occurrence of clinical symptoms. No genotypes adapted to animal hosts other than humans (e.g. assemblages C-F) were found circulating in the investigated human population, suggesting that transmission of human giardiasis in this Iranian region is primarily of anthroponotic nature. Further molecular-based studies are needed to confirm and expand these results, and to ascertain the presence and public health relevance of the parasite in environmental (e.g. drinking water) samples.

Microscopic examination after concentration techniques for Blastocystis sp. detection in serial faecal samples: How many samples are needed?

Objective

Blastocystis sp. is one of the most frequently observed intestinal parasites in humans. It is suggested that sensitivity of classical parasitological tests for the Blastocystis sp. diagnosis increases when increasing the number of investigated samples, although there is a lack of information. The aim of the study is to evaluate the sensitivity of classical parasitological tests for the Blastocystis sp. diagnosis depending on the number of investigated samples and to determine risk factors associated to high parasite burden.

Methods

Retrospective study where patients in whom three consecutive stool samples were examined for parasitic diagnosis through microscopic examination at Vall d'Hebron University Hospital (Barcelona, Spain) from January to April 2019 were included. To determine risk factors associated to high parasite burden, a case-control study was performed including patients with at least one positive stool sample for Blastocystis sp.: cases were those patients with only one or two positive stool samples, and controls were those with all three stool positive samples). Clinical records were reviewed from included patients to collect clinical and demographic information.

Results

In 2771 patients three consecutive stool samples were examined for parasitic diagnosis, with an overall prevalence of Blastocystis sp. detection of 23.3%. The proportions of positive cases depending on the number of investigated samples were: 22.3% when taking into account the first sample, 22.9% when taking into account the first and second samples, and 23.3% when taking into account the three samples, with no statistically significant differences among them. For the case-control study we finally included 63 cases and 133 controls. No differences were found regarding clinical and demographic characteristics among groups.

Conclusion

Prevalence of Blastocystis sp. infection was high in our study (23.3%). The sensitivity of classical parasitological methods for Blastocystis sp. diagnosis did not increase when increasing the number of investigated samples, and no risk factors associated to high parasite burden were identified.

Intestinal Protozoan Parasitic Infections in Immunocompromised Child Patients with Diarrhea

Intestinal protozoan parasites are common causes of infectious diarrhea in children receiving anticancer therapy or undergoing transplantation. Additionally, immunosuppression therapy in such patients may exacerbate the symptoms related to these parasitic infections. The aim of this study was to evaluate the prevalence and diagnostic importance of parasitic protozoan infections in children treated for malignancies or undergoing transplantation, and to highlight the control of intestinal parasitic infections for immunosuppressed patients at a hospital in İzmir, Turkey. In total, 82 stool samples from 62 patients were analyzed by microscopic examination and polymerase chain reaction (PCR) for the presence of coccidian parasites. Our results showed that Cryptosporidium, Cyclospora, and Cystoisospora were present in 22.5% (14/62), 9.6% (6/62), and 3.2% (2/62) of the cases using either method, respectively. The prevalence of these coccidian parasites identified with both methods was 35.4% (20/62). Other intestinal parasites (Blastocystis, Giardia, and Entamoeba coli) were detected in 10 patients. PCR analysis showed the presence of all coccidian parasites in the same stool sample for one patient. Finally, both PCR and microscopic examination of the stools revealed that there is a higher prevalence of Cryptosporidium, Cyclospora, and Cystoisospora in immunocompromised children. These examinations allowed an early start of appropriate antibiotic treatments and led to an increased percentage of correctly treated patients.

Risk factors for Blastocystis infection in HIV/AIDS patients with highly active antiretroviral therapy in Southwest China

Background

Blastocystis is a widespread zoonotic protozoan of mammalian species, especially in HIV/AIDS individuals. The aim of this study was to analyze the prevalence and risk factors related with Blastocystis infection among HIV/AIDS patients in Southwest China.

Methods

The cross-sectional study was performed in 311 HIV/AIDS cases in Tengchong City, Yunnan Province from July 2016 to March 2017. For each subject, stool specimen was collected to detect the Blastocystis, and the blood sample was used to detect HIV virus load and CD4⁺ T cell count, in addition, structured questionnaire was used to collect the basic information and risk factors.

Findings

The result showed that the detection rate of Blastocystis was 3.86% (95% CI: 2.22–6.62) among HIV/AIDS patients. Both raising animal (OR = 12.93, 95% CI: 1.54–108.36) and drinking un-boiled water (OR = 8.17, 95% CI: 1.76–37.90) were risk factors for Blastocystis infection in HIV/AIDS individuals. In addition, the interaction of CD4⁺ T cell count and HIV virus load was also contribution to Blastocystis infection (P = 0.007).

Conclusions

A high prevalence of Blastocystis infection was found in HIV/AIDS patients in Tengchong. Poor hygienic habits, the interaction of HIV virus load and CD4⁺ T cell count were identified as main risk factors for infection. These results will help us to develop efficient control strategies to intervene with and prevent the occurrence of Blastocystis among HIV-infected individuals.

Parasites in Human Stool: To Ignore or Not To Ignore?

Human stool contains a myriad of microorganisms, of which the vast majority are nonpathogenic and represent an important component of the healthy microbiome. The increasing use of molecular techniques has allowed the rapid identification of bacteria, viruses and parasites in human stool. This review focuses on the 3 main classes of parasite responsible for human disease, helminths, protozoa and ectoparasites, and highlights the importance of differentiating between pathogenic and nonpathogenic parasites.

Cryptosporidium Sp. Findings and Its Symptomatology among Immunocompromised Patients

BACKGROUND

Cryptosporidium sp. is an apicomplexan protozoa, and it is related to an immunocompromised state. As it develops diverse clinical manifestations, mild to life-threatening conditions, administration of anti-parasitic medication and its management remain problematic.

AIM

The study aimed to provide Cryptosporidiosis symptomatology and its prevalence among HIV-infected patients in a tertiary referral hospital, Haji Adam Malik General Hospital, Medan, Indonesia.

MATERIAL AND METHODS

Symptomatology was noted using short-questionnaire, and laboratory findings were obtained from the hospital medical record registry on the same day of admission. We enrolled 24 patients were suffered from HIV infection for a certain period and more than one-week diarrhoea including 18 males and 6 females. Routine faeces examination using wet mount, Kinyoun-gabet, and trichrome staining was performed for all samples in Parasitology Department, Faculty of Medicine, Universitas Sumatera Utara, Medan, Indonesia. Numerical data were evaluated using the Mann-Whitney test while Fisher Exact test was used to determine any association between categorical variables.

RESULTS

Our study found that 8 of 24 patients were positive with Cryptosporidium sp. while its symptomatology including abdominal cramp (66.7%), nausea and vomiting (70.8%), and fever (62.5%) is prevalent from our study. We obtained significant association between CD4 cell count (p = 0.006), diarrhea duration (p = 0.007), abdominal pain (p = 0.005), and nausea and vomiting (p = 0.021) with cryptosporidiosis.

CONCLUSION

High consideration of several symptoms related to cryptosporidiosis leads a clinician to initiate prompt management particularly in a high-risk population.

Health Considerations for HIV-Infected International Travelers

PURPOSE OF THE REVIEW

International travel continues to steadily increase, including leisure travel, travel to one's country of origin to visit friends and relatives, travel for service work, and business travel. Travelers with HIV may have an increased risk for travel-associated infections. The pre-travel medical consultation is an important means of assessing one's risk for travel-related health issues. The aim of this review is to provide an update on key health considerations for the HIV-infected traveler.

RECENT FINDINGS

Like all travelers, the HIV-infected traveler should adhere to behavioral precautions, including safety measures with food and water consumption, safe sexual practices, and arthropod bite avoidance. HIV is a risk factor for venous thromboembolism and patients should be educated regarding this risk. Most pre-travel vaccines are safe and immunogenic in HIV-infected individuals, though live vaccines should be avoided in patients with low CD4 counts. Malaria chemoprophylaxis is strongly recommended in patients with HIV traveling to endemic areas and no significant interactions exist between the commonly used prophylactic anti-malarial agents and anti-retroviral therapy (ART). Travelers with HIV, particularly those who are not on ART or who have low CD4 cell counts, may have increased risk for tuberculosis, malaria, enteric infections, visceral leishmaniasis, American trypanosomiasis, and endemic mycoses such as histoplasmosis, talaromycosis, and coccidioidomycosis. The immune status of the HIV-infected traveler should be assessed prior to travel along with the duration, itinerary, and activities planned during travel in order to carefully consider individual risk for travel-related health issues.

Immune response markers in sera of children infected with Giardia duodenalis AI and AII subassemblages

In this study, we evaluated serum markers of immune responses in children infected with G. duodenalis and compared them with the characterized parasite isolates. The reactivity indexes (RI) of IgG (1.503 ± 0.819) and IgA (2.308 ± 1.935) antibodies were significantly higher (P < 0.001) in infected children than in non-infected children. There were also statistically significantly higher serum levels (P < 0.05) of IFN-γ (393.10 ± 983.90 pg/mL) as well as serum (30.03 ± 10.92 μmol/L) and saliva nitric oxid derivatives (NO_x) (192.4 ± 151.2 μmol/L) in children infected with G. duodenalis compared to the group of non-parasitized children (127.4 ± 274.30 pg/mL; 25.82 ± 7.74 μmol/L and 122.5 ± 105.90 μmol/L, respectively). Regarding the characterized genetic variants of G. duodenalis and the immune response profiles, no differences were observed in terms of antibody reactivity or levels of serum cytokine and NO_x among children infected with AI or AII subassemblages. The elevated levels of IFN-γ and NO_x indicate that G. duodenalis intestinal infection in humans induces a cellular immune response detectable at the systemic level. Moreover, no significant differences in the antibody reactivity profile or the cytokine and NO_x production in the sera of children infected with AI or AII G. duodenalis variants were observed, suggesting that subtypes of the parasite do not influence the immune response profile.

Giardia lamblia infection: review of current diagnostic strategies

Giardiasis has a global distribution and it is a common cause of diarrhea in both children and adults and is transmitted via the fecal-oral route through direct or indirect ingestion of cysts. The laboratory diagnosis of Giardia spp. is mainly based on demonstration of microscopic cyst or trophozoite in stool samples but several immunological-based assays and molecular methods are also available for giardiasis diagnosis. The aim of this study was to conduct a review of the applied methods in medical laboratory and to highlight pitfalls and challenges of them for diagnosis of giardiasis. In this article we have evaluated the Giardia diagnostic methods with a broad review of literature, electronic databases and books. The search has covered the articles and some textbooks that have published up to 2018. It has been concluded that traditional microscopy combination with stool concentration method should still be held in the routine medical laboratory due to economical and high sensitivity and immunological-based assay and molecular methods which are recommended to use as a complementary test to the traditional technique.

Lactoferrin and lactoferricin endocytosis halt Giardia cell growth and prevent infective cyst production

Lactoferrin (LF) is an 80 KDa iron-binding glycoprotein that plays a significant role in the innate immune system and is considered to be an important microbicide molecule. It has been suggested to be effective in the treatment of giardiasis, an intestinal disease caused by the protozoan parasite G. lamblia. However, the molecular mechanisms by which LF exerts its effect on this parasite are unknown. Most of the microbicidal activity of human or bovine LF (hLF or bLF) has been associated with the N-terminal region of the mature LF - lactoferricin (LFcin). LFcin is produced by pepsin cleavage of the native protein in vitro and likely in vivo. In this work, we analyse the participation of the endocytic machinery of G. lamblia in the internalization of bLF and bLFcin and their effects on cell homeostasis. Our results show that, when bLF or bLFcin are internalized by receptor-mediated endocytosis, cell growth stops, and morphological changes are produced in the trophozoites, which ultimately will produce immature cysts. Our findings contribute to disclose the fine mechanism by which bLF and bLFcin may function as an antigiardial molecule and why they have therapeutic potential to eradicate giardiasis.

Prevalence of non-pathogenic types of gastrointestinal protozoa in population in Slovakia and their potential importance in the aspect of public health

The aim of the research was to determine the prevalence of non-pathogenic protozoa circulating in the human population of Slovakia. We particularly focused on the socially deprived areas with poor sanitation conditions, as they are one of the factors affecting the transmission of these infections. Within this study, 2760 people were coprologically screened for the presence of protozoan cysts. The analyzed group comprised 1173 men and 1587 women from different regions of Slovakia. The total prevalence (2.03%) of non-pathogenic protozoa species was determined. The prevalence of Entamoeba coli was 0.80%, the prevalence of Endolimax nana 0.58%, and the prevalence of Blastocystis hominis was 0.65%. The presence of non-pathogenic protozoa was more frequent in women than that in men, in all age groups. The highest incidence of Entamoeba coli was found in children aged one month - seven years (0.79%), the lowest in the age group of 19-88 years (0.66%). Endolimax nana was most frequent in 8-18 year-olds (0.95%), where the statistical significance was found (p<0.05). The prevalence of Blastocystis hominis by the age group ranged from 0.39 to 0.95%. We did not find any statistical significance (p>0.05) for Entamoeba coli, and similarly for Blastocystis hominis associated with the sex and age. Although the circulation of non-pathogenic protozoa in the human population is far from being limited to the developing countries, their occurrence is also frequent in the population of developed countries. Despite their controversial pathogenicity, they should not be neglected, particularly in the patients with gastrointestinal symptoms.

Mouse macrophages capture and kill Giardia lamblia by means of releasing extracellular trap

Giardia lamblia is one of the most prevalent parasites residing in the duodenum of human and many other mammals throughout the world which is transmitted via ingested cysts through contaminated food or water. The severity of disease may depend on multiple parasite and host factors. Commonly, children and immunologically compromised persons like AIDS patient exhibit severe diarrhea, malabsorption and weight loss, however, there are also some infected people who are asymptomatic or only exhibit mild clinical symptoms and can shed the Giardia cysts in the environment. Although many studies have indicated that the innate immune system is important for Giardia defense, however, whether the innate immune responses such extracellular traps (ETs) could be induced by G. lamblia is still unclear. In recent years, macrophage extracellular traps (METs) have been described as an effective defense mechanism against invading microorganisms. In the present study, the formation of METs triggered by G. lamblia trophozoites was investigated. The formation of METs induced by G. lamblia trophozoites of mouse macrophage was observed with Scanning Electron Microscopy (SEM). The main components DNA, H3 histone and MPO were confirmed by Sytox orange staining, DNase1 digestion, immunofluorescence staining and fluorescence confocal microscopy. Inhibitor assays suggested that G. lamblia trophozoites triggered METs formation through ERK1/2 and p38 MAPK signal pathways and was Store-operated Ca²⁺ entry (SOCE) dependent. In addition, the process of METs formation triggered by G. lamblia trophozoites was also time and dose-dependent. Furthermore, the production of Reactive Oxygen Species (ROS) in macrophages stimulated with G. lamblia trophozoites significantly increased whereas no significant changes were observed about LDH activity.

Socio-Behavioral Risk Factors Associated with Cryptosporidiosis in HIV/AIDS Patients Visiting the HIV Referral Clinic at Cape Coast Teaching Hospital, Ghana

Objective:

To identify the socio-behavioral risk factors associated with cryptosporidiosis among HIV/AIDS patients with chronic diarrhea symptoms visiting the HIV referral clinic at Cape Coast Teaching Hospital, Ghana.

Methods:

A cross-sectional study was conducted among 50 HIV/AIDS patients with recurrent diarrhea. Questionnaires were administered to collect social and behavioral risk factors associated with Cryptosporidium and other opportunistic protozoan parasitic infections in HIV patients. Stool samples were collected for the diagnosis of enteric protozoan pathogens using modified Ziehl-Neelsen and acid-fast staining methods. CD4⁺ cells counts of study subjects were obtained from patients clinical records. The data obtained were analyzed using Pearson chi-square and multivariate-adjusted statistics tool on SPSS 16 for Windows.

Results:

Twenty-seven (54%) of the subjects were infected with enteric protozoan pathogens. The prevalences of Cryptosporidium, Cyclospora and Microsporidium infections were 46%, 32% and 16%, respectively. Cryptosporidium infection was significantly associated with drinking water (ײ=13.528, p<0.001), Cyclospora was associated with the type of drinking water (ײ=14.931, p<0.001) and toilet facilities used by the study subjects (ײ=12.463, p<0.01), whiles Microsporidium infection was associated with hand washing behavior (ײ=12.463, p<0.01). Enteric protozoans were frequently encountered among subjects with CD4+ T-cell count <200 cells/mm³. However, coinfection of Cyclospora spp & Cryptosporidium spp was not observed in CD4⁺ cell count <200 and >500 cells/mm^3. Multivariate analysis showed that the risk factor for Cryptosporidium infection among HIV/AIDS patients was the source of drinking water (pipe borne water 76.2% prevalence: sachet water 25%; OR=0.10, 95%CI: 0.03-0.39, p<0.001).

Conclusion:

We report the risk factor for exposure of Cryptosporidium infection among HIV/AIDS patients for the first time in Ghana. The contamination of drinking water by protozoan parasites should be a public health concern. These results provide the stepping block to understand the transmission dynamics of Cryptosporidium and other opportunistic pathogens in HIV/AIDS infected patients in Ghana.

Molecular detection of Enteropathogens from diarrheic stool of HIV positive patients in Gondar, Ethiopia

Background

Infectious diarrhea is a common problem in the developing world, especially among people living with HIV/AIDS. Traditional diagnostic methods such as stool culture and microscopic examination are limited by resources and poor sensitivity. The use of molecular diagnostics for enteropathogen detection in this region of sub-Saharan Africa has not been fully explored. We sought to identify risk factors and characterize enteropathogens from diarrheic stools of HIV-positive patients in Gondar, Ethiopia using multiplex molecular panels targeting key infectious agents.

Methods

A cross-sectional study of 100 stool samples was performed. Samples were collected consecutively from HIV- positive patients presenting with diarrhea at University of Gondar Hospital clinic, a major center in NW Ethiopia. Genomic DNA was extracted from stool and processed using a multiplex molecular panel Allplex™ [Seegene, Canada]. Correlations between patient characteristics, symptoms, public health risk factors, and enteropathogen type (s) were studied. Eighty-six samples were successfully analyzed by molecular methods.

Results

The mean age was 35 with 43% male. Eighty percent lived in an urban area, 18% had access to well water only, and 81% practiced proper hand hygiene. The majority of patients (72%) were receiving HAART with a median CD4 cell count of 362/μL. Multiple pathogens were detected in 94% of specimens, with an average of 5 enteropathogens per sample. Common bacteria, viruses, and parasites detected were Shigella spp./enteroinvasive E. coli (80%), enterotoxigenic E. coli (73%), Norovirus (16%) and B. hominis (62%). CD4 cell count < 500/ μL was associated with the presence of viruses (p = 0.004) and the absence of STEC (p = 0.010). The use of HAART or CD4 levels was not associated with the number of enteropathogens detected.

Conclusions

Diarrheic stool from HIV-positive outpatients in Gondar, Ethiopia had on average 5 enteropathogens present in their stool. Shigellaspp./enteroinvasive E. coli and enterotoxigenic E. coli are the major pathogens, not dissimilar to immunocompetent individuals in low income countries.

Practical Guidance for Clinical Microbiology Laboratories: Laboratory Diagnosis of Parasites from the Gastrointestinal Tract

This Practical Guidance for Clinical Microbiology document on the laboratory diagnosis of parasites from the gastrointestinal tract provides practical information for the recovery and identification of relevant human parasites. The document is based on a comprehensive literature review and expert consensus on relevant diagnostic methods. However, it does not include didactic information on human parasite life cycles, organism morphology, clinical disease, pathogenesis, treatment, or epidemiology and prevention. As greater emphasis is placed on neglected tropical diseases, it becomes highly probable that patients with gastrointestinal parasitic infections will become more widely recognized in areas where parasites are endemic and not endemic. Generally, these methods are nonautomated and require extensive bench experience for accurate performance and interpretation.

Host specificity in the Giardia duodenalis species complex

Giardia duodenalis is a unicellular flagellated parasite that infects the gastrointestinal tract of a wide range of mammalian species, including humans. Investigations of protein and DNA polymorphisms revealed that G. duodenalis should be considered as a species complex, whose members, despite being morphologically indistinguishable, can be classified into eight groups, or Assemblages, separated by large genetic distances. Assemblages display various degree of host specificity, with Assemblages A and B occurring in humans and many other hosts, Assemblage C and D in canids, Assemblage E in hoofed animals, Assemblage F in cats, Assemblage G in rodents, and Assemblage H in pinnipeds. The factors determining host specificity are only partially understood, and clearly involve both the host and the parasite. Here, we review the results of in vitro and in vivo experiments, and clinical observations to highlight relevant biological and genetic differences between Assemblages, with a focus on human infection.

2017 Infectious Diseases Society of America Clinical Practice Guidelines for the Diagnosis and Management of Infectious Diarrhea

These guidelines are intended for use by healthcare professionals who care for children and adults with suspected or confirmed infectious diarrhea. They are not intended to replace physician judgement regarding specific patients or clinical or public health situations. This document does not provide detailed recommendations on infection prevention and control aspects related to infectious diarrhea.

Protozoan parasites in irritable bowel syndrome: A case-control study

AIM

To investigate the putative role of protozoan parasites in the development of irritable bowel syndrome (IBS).

METHODS

The study included 109 IBS consecutive adult patients fulfilling the Rome III criteria and 100 healthy control subjects. All study subjects filled a structured questionnaire, which covered demographic information and clinical data. Fresh stool samples were collected from patients and control subjects and processed within less than 2 h of collection. Iodine wet mounts and Trichrome stained smears prepared from fresh stool and sediment concentrate were microscopically examined for parasites. Blastocystis DNA was detected by polymerase chain reaction, and Cryptosporidium antigens were detected by ELISA.

RESULTS

A total of 109 IBS patients (31 males, 78 females) with a mean age ± SD of 27.25 ± 11.58 years (range: 16 -60 years) were enrolled in the study. The main IBS subtype based on the symptoms of these patients was constipation-predominant (88.7% of patients). A hundred healthy subjects (30 males, 70 females) with a mean ± SD age of 25.0 ± 9.13 years (range 18-66 years) were recruited as controls. In the IBS patients, Blastocystis DNA was detected in 25.7%, Cryptosporidium oocysts were observed in 9.2%, and Giardia cysts were observed in 11%. In the control subjects, Blastocystis, Cryptosporidium and Giardia were detected in 9%, 0%, and 1%, respectively. The difference in the presence of Blastocystis (P = 0.0034), Cryptosporidium (P = 0.0003), and Giardia (P = 0.0029) between IBS patients and controls was statistically significant by all methods used in this study.

CONCLUSION

Prevalence of Blastocystis, Cryptosporidium and Giardia is higher in IBS patients than in controls. These parasites are likely to have a role in the pathogenesis of IBS.

Integrating Household Water Treatment, Hand Washing, and Insecticide-Treated Bed Nets Into Pediatric HIV Care in Mombasa, Kenya: Impact on Diarrhea and Malaria Risk

Introduction:

In developing countries, HIV-infected children are at higher risk of morbidity and mortality from opportunistic infections than HIV-uninfected children. To address this problem, the Healthy Living Initiative (HLI) in Mombasa, Kenya distributed basic care packages (BCPs) containing improved water storage vessels, water treatment solution, soap, and insecticide-treated bed nets to prevent diarrhea and malaria in children, and had community health workers (CHWs) make bimonthly home visits to encourage adherence to HLI interventions and antiretroviral (ARV) medicine use.

Methods:

To evaluate HLI, we enrolled 500 HIV-infected children from Bomu Hospital. In the implementation phase, from February to August 2011, we conducted surveys of caregivers, then provided free BCPs. In the evaluation phase, from September 2011 to August 2012, CHWs recorded observations of BCP use during home visits. We abstracted hospital data to compare diarrhea and malaria episodes, and pharmacy data on ARVs dispensed, between the 12-month preimplementation baseline phase (February 2010–January 2011) and the evaluation phase.

Results:

The retention rate of children in HLI was 78.4%. In a multivariable logistic regression model adjusting for demographic characteristics, number of CHW home visits, distance to clinic, orphan status, and number of ARVs dispensed, children in HLI had 71% lower risk of diarrhea (relative risk 0.29, P < 0.001) and 87% lower risk of malaria (relative risk 0.13, P = 0.001) during the evaluation phase than the baseline phase; there was no independent association between ARV use and illness.

Conclusions:

HIV-infected children in HLI were less likely to experience diarrhea and malaria during the evaluation phase than the baseline phase.

PCR-based verification of positive rapid diagnostic tests for intestinal protozoa infections with variable test band intensity

Stool-based rapid diagnostic tests (RDTs) for pathogenic intestinal protozoa (e.g. Cryptosporidium spp. and Giardia intestinalis) allow for prompt diagnosis and treatment in resource-constrained settings. Such RDTs can improve individual patient management and facilitate population-based screening programmes in areas without microbiological laboratories for confirmatory testing. However, RDTs are difficult to interpret in case of 'trace' results with faint test band intensities and little is known about whether such ambiguous results might indicate 'true' infections. In a longitudinal study conducted in poor neighbourhoods of Port Elizabeth, South Africa, a total of 1428 stool samples from two cohorts of schoolchildren were examined on the spot for Cryptosporidium spp. and G. intestinalis using an RDT (Crypto/Giardia DuoStrip; Coris BioConcept). Overall, 121 samples were positive for G. intestinalis and the RDT suggested presence of cryptosporidiosis in 22 samples. After a storage period of 9-10 months in cohort 1 and 2-3 months in cohort 2, samples were subjected to multiplex PCR (BD Max™ Enteric Parasite Panel, Becton Dickinson). Ninety-three percent (112/121) of RDT-positive samples for G. intestinalis were confirmed by PCR, with a correlation between RDT test band intensity and quantitative pathogen load present in the sample. For Cryptosporidium spp., all positive RDTs had faintly visible lines and these were negative on PCR. The performance of the BD Max™ PCR was nearly identical in both cohorts, despite the prolonged storage at disrupted cold chain conditions in cohort 1. The Crypto/Giardia DuoStrip warrants further validation in communities with a high incidence of diarrhoea.

An overview of parasitic infections of the gastro-intestinal tract in developed countries affecting immunocompromised individuals

In both developed and developing countries, parasitic infections continue to be a frequent cause of mortality and morbidity. Due to the globalization of the world, doctors must be fully prepared to deal with a plethora of parasitic infections. More commonly the gastrointestinal (GI) tract is infected and in developed countries protozoans are more likely to be the cause of infection compared to helminths. These GI protozoa are progressively becoming recognized as important pathogens in patients that are immunocompromised. The number of immunocompromised patients is increasing and therefore the likelihood of similar infections will also increase. This paper aims to highlight the key GI parasites affecting immunocompromised individuals in developed countries, discussing diagnosis, treatment options and also prevention. Cryptosporidium parvum may be the most common GI parasite found in the immunocompromised host closely followed by Cyclospora, however, Giardia duodenalis is the most common GI parasite found in developed countries. The pathogenesis of parasitic infection is not clear, poorly understood and diagnostic testing remains difficult with management continuing to be a challenge.