Molecular identification of giardia intestinalis in patients with dyspepsia

Gastrointestinal parasites in Africa: A review

Data on human gastrointestinal parasites (GIP) infections in the african sub-regions and countries are mainly lacking in terms of prevalence and population stratification by afflicted age group, symptomatology, multi-parasitism, and diagnostic methods. This study aims to describe the GIP reported in african countries and discuss the extent of the burden in the african context. Only 68.42% (39/57) of african countries reported human cases of GIP with helminths (45%, CI: 40-50%, I²: 99.79%) as the predominant parasitic group infecting the african population. On a regional scale, Central Africa had the highest pooled prevalence for GIP (43%, CI: 32-54%, I²: 99.74%), while the Central African Republic led all countries with a pooled prevalence of 90% (CI: 89-92%, I²: 99.96%). The vulnerable population (patients who are minorities, children, old, poor, underfunded, or have particular medical conditions) was the most affected (50%, CI: 37-62%, I²: 99.33%), with the predominance of GIP in the 6 to <20 years age group (48%, CI: 43-54%, I²: 99.68%). Reports on multi-parasitism (44%, CI: 40-48%, I²: 99.73%) were almost double the reports of single infections (43%, CI: 27-59%, I²: 99.77%) with combined molecular and non-molecular techniques demonstrating the best performance for GIP identification. The current review spans more than 40 years of GIP reports from the african continent. Geographical characteristics, environmental factors, habits of its inhabitants, and their health status play a crucial role in GIP modulation and behaviour in its captive hosts. Strategies for regular and enhanced surveillance, policy formation, and high-level community awareness are necessary to identify the true incidence in Africa and the transmission of the pathogens via water and food.

Helicobacter pylori Pathogenicity Islands and Giardia lamblia Cysteine Proteases in Role of Coinfection and Pathogenesis

Helicobacter pylori is a well-known human-specific stomach pathogen that infects more than half of the world’s population. The infection with this bacterium can cause a variety of gastrointestinal problems, including chronic gastritis, peptic ulcers, and even cancer. H. pylori is a highly infectious bacterium. H. pylori causes an increase in gastric mucosa pH or gastric mucosa intestinal metaplasia. These modifications in the stomach environment are necessary for G. lamblia colonization to occur. Giardia lamblia is a flagellate protozoan parasite that can cause giardiasis in humans and other mammals. It dwells in the duodenum and upper jejunum. Globally, over 280 million cases of human giardiasis are predicted to occur each year. Simultaneous human colonization by G. lamblia and H. pylori is a typical occurrence since the viruses’ predisposing factors are similar in both groups. Giardiasis is a parasitic infection that affects both children and adults worldwide. Infection with Giardia is more common in underdeveloped countries. Globally, more than 200 million cases of giardiasis are detected each year. In contrast, the presence of G. lamblia in the host body triggers an immunological response comparable to that of H. pylori, with lymphocytes strongly polarized towards Th1. As a result, their combined presence exacerbates host tissue damage. The major goal of this seminar is to describe the pathophysiology, immunology, and clinical aspects of G. lamblia and H. pylori coinfection using a comprehensive search of PubMed, Lancet, and Google Scholar sources. Upper gastrointestinal problems such as upper abdominal pain, abdominal bloating, nausea, vomiting, epigastric pain/burning, and belching are all caused by both organisms. Differentiation by physical examination is impossible in people infected with both bacteria. For this coinfection distinction, a laboratory diagnosis is required. G. lamblia and H. pylori, when present together, have a synergistic effect on the host and can cause serious damage. As a result, researchers should delve deeper into the mechanics underlying this potential microbial interaction.

Association of Helicobacter pylori and parasitic infections in childhood: impact on clinical manifestations and implications

The association of Helicobacter pylori (H. pylori) infection and parasitic infections including Giardia lamblia (G. lamblia), especially in childhood, is widely recognized to be high in developing communities. We aimed to study the impact of concomitant intestinal parasitic and H. pylori infections on the different clinical presentation of infected children and whether this coinfection could in turn cause any alteration in the clinical manifestations of each other. This cross-sectional study included 150 children of both sexes with their age ranging from 1 to 15 years, having gastrointestinal complaints, throughout 8 months duration. All cases were subjected to full history taking, clinical examination and stool analysis by direct wet smear and formalin-ethyl acetate concentration technique, permanent staining with cold acid fast stain in addition to H. pylori coproantigen detection in stool. Parasitic infection was recorded in 58.6% of patients, with G. lamblia the most detected parasite (35.2%). Cases infected with H. pylori were 63 cases (42%) of which 61.9% of cases showed associated parasitic infection. Diarrhea was the most frequent complaint (63.2%) in cases infected with intestinal parasites, while it was less frequently recorded in co-infected cases (35.8%) and in cases with H. pylori infection only (29.1%) (P value 0.0008). On the other hand, vomiting was less recorded in coinfected cases than cases with H. pylori infection. Coinfection with intestinal parasites (including G. lamblia) and H. pylori could modulate the clinical manifestation of each other especially diarrhea in parasitic infections and vomiting in H. pylori infection.

Role of Polymerase Chain Reaction in Stool and Duodenal Biopsy for Diagnosis of Giardiasis in Patients with Persistent/Chronic Diarrhea

BACKGROUND

Giardia duodenalis is a common cause of chronic diarrhea especially in tropical countries. Diagnosis is based on microscopy (three stool samples) for trophozoites/cysts. Role of stool or duodenal biopsy PCR as a diagnostic method needs to be defined. We conducted a prospective study to determine the diagnostic characteristics of G. duodenalis stool and duodenal biopsy PCR in comparison to stool microscopy (reference standard). Later, we compared other techniques with stool PCR, considering it as new reference standard and characterized the type of Giardia assemblage.

METHODS

G. duodenalis stool nested PCR was first evaluated using 40 positive controls and 50 negative controls considering stool microscopy as reference standard. Patients with chronic diarrhea (n = 100) were evaluated by stool microscopy and nested PCR. In 30 patients in whom upper gastrointestinal endoscopy was performed, duodenal biopsy samples were obtained and evaluated by histopathology, imprint cytology, and nested PCR. The type of Giardia assemblage was detected by assemblage-specific PCR.

RESULTS

Stool nested PCR was found to have sensitivity and specificity of 100% and 94%, respectively, compared to stool microscopy. In patients with chronic diarrhea, 48% had evidence of Giardia infection. Stool microscopy detected 65%, stool PCR detected an additional 27%, and duodenal biopsy PCR detected an additional 8% of cases. The commonest assemblage found was assemblage B. Clinical and demographic characteristics were similar in patients harboring either assemblage A or B.

CONCLUSION

Stool PCR is more sensitive than stool microscopy. By utilizing stool microscopy, stool nested PCR, and duodenal biopsy PCR in sequential manner, diagnostic yield can be increased.

Giardia intestinalis and Fructose Malabsorption: A Frequent Association

Nowadays, scientific studies are emerging on the possible etiological role of intestinal parasites in functional digestive disorders. Our study was carried out with healthy individuals (control group; n = 82) and symptomatic patients with lactose or fructose malabsorption, including positive (malabsorbers; n = 213) and negative (absorbers; n = 56) breath test, being analyzed for the presence of intestinal parasites. A high parasitic prevalence was observed in malabsorbers (41.8%), exclusively due to single-cell eukaryotes but not helminths. Giardia intestinalis was the predominant parasite in cases of abnormal absorption (26.5%), significantly associated with fructose malabsorption and doubling the probability of developing this pathology. Within controls, Blastocystis sp. (13.4%) was almost the only parasite, being the second among patients (12.6%), and Cryptosporidium parvum, the last species of clinical relevance, was detected exclusively in two malabsorbers (0.9%). The consumption of ecological food and professions with direct contact with humans arose as risk factors of parasitism. A diagnosis of carbohydrate malabsorption in adulthood is the starting point, making the search for the primary cause necessary. Accurate parasitological diagnosis should be considered another tool in the clinical routine for patients with recurrent symptoms, since their condition may be reversible with adequate therapeutic intervention.

Multilocus genotyping of Giardia duodenalis isolated from patients in Egypt

Human giardiasis is a common waterborne/foodborne parasitic disease worldwide, especially in developing countries. Prevalence and molecular identity of Giardia parasites are largely controversial. The present study was conducted to determine the occurrence of Giardia parasites and the genetic profile of circulating assemblage(s) in patients attended the outpatient clinic at Kafrelsheikh University hospital, Kafr El Sheikh Province, Egypt. A total of 318 patients, of different age and sex, referred to the clinic were subjected to fecal examination. Microscopic results revealed that 181/318 (56.9%) were positive for Giardia parasites. Multilocus genotyping by PCR/sequencing of beta-giardin (bg), triose phosphate isomerase (tpi), and glutamate dehydrogenase (gdh) genes of representative number of positive samples (65) revealed that assemblages A, B and mixed infections (A + B) occurred in 26/65 (40.0%), 32/65 (49.2%) and 10.8% (7/65) of the analyzed isolates, respectively. MLGs analysis indicated that assemblage A sequences clustered in two novel types of AII sub-assemblage. In assemblage B sequences, BIII was the predominant (22/23, 95.7%) sub-assemblage compared to BIV (1/23, 4.3%). Collectively, assemblage B MLGs displayed greater levels of genetic diversity compared to assemblage A. Our data indicate that assemblages A and B of G. duodenalis circulate in humans at Kafr El Sheikh Province, Egypt, and that high genetic diversity exists at the assemblage and/or sub-assemblage levels.

Giardia lamblia miRNAs as a new diagnostic tool for human giardiasis

Background

Giardia lamblia is a very common cause of gastrointestinal symptoms worldwide. There are several methods for the diagnosis of Giardia infection, however none are ideal. We aim to find a new, microRNA-based method that will improve the currently available diagnostic methods for giardiasis.

Methods

Deep-sequence profiling of Giardia small-RNA revealed that miR5 and miR6 are highly expressed in Giardia. These miRNAs were tested by qRT-PCR in duodenal biopsies of patients with giardiasis who were positive by microscopic pathological evaluation. The gastric biopsies of the same patients served as negative control tissues. Additionally, these miRNAs were evaluated in stool samples of patients with proven giardiasis.

Results

All histologically proven duodenal biopsies of patients with Giardia infection were positive for Giardia miR5, with a mean threshold cycle (Ct) of 23.7, as well as for Giardia DNA qPCR (16S-like gene, mean Ct 26.3). Gastric biopsies which were tested as a control all were negative. Stool evaluation of miR6 in patients with giardiasis showed 90% specificity but only 66% sensitivity, and a lower accuracy rate was obtained with miR5.

Conclusion

Giardia miR5 testing in duodenal biopsies may be a new method for the diagnosis of giardiasis. It seems to be more sensitive when compared with testing for Giardia DNA by qPCR in duodenal biopsies. It will be important to investigate the contribution of routine Giardia miRNA testing in duodenal biopsies from patients with persistent abdominal symptoms

Giardiasis is a major cause of diarrheal disease throughout the world. It is more common in areas with poor sanitation such as in many low-income countries, but it occurs in high-income countries as well. It is the most commonly identified intestinal parasite in the United States and it is endemic in other industrialized countries. The causative agent is the flagellate protozoan Giardia lamblia, and transmission is mainly by the fecal-oral route. The basic method of diagnosis is stool examination. It is usually found through stool microscopy examination which should be performed on fresh stool and repeated in 3 days. Despite some newer diagnostic methods, Giardia is still difficult to detect, often leading to misdiagnoses.

In this study we show that using Giardia microRNA (miR5) as a marker for Giardia infection in duodenal biopsies may be a new method for diagnosis of giardiasis. It appears to be more sensitive than histological diagnosis and also more sensitive than Giardia DNA testing in duodenal biopsies. Interestingly, in our patients, duodenal biopsies were done for persistent abdominal symptoms and the finding of Giardia in their biopsy was unexpected. Thus, testing duodenal biopsies for Giardia miRNA in patients with persistent abdominal symptoms might contribute to diagnosis and prompt treatment for those with giardiasis.

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.

Overview in the clinical management of patients with seronegative villous atrophy

Differential diagnosis and management of enteropathies found in the context of seronegative villous atrophy (VA) are still a clinical challenge. Although seronegative coeliac disease may be the most frequent cause of serology-negative VA, other conditions must be taken into account in the differential diagnosis of seronegative VA. The rarity of these enteropathies with frequent overlapping of histological features may result in misclassification of such patients as affected by a seronegative or a refractory form of coeliac disease with consequent inappropriate treatments and long-term morbidity. The aim of this review is to summarize the current knowledge and to provide an evidence base and practical algorithmic approach for the investigation and management of seronegative VA.

Cytopreparation of duodenal biopsy fixative improves detection rate of giardia in clinically suspected cases

INTRODUCTION

Giardia intestinalis is a flagellated protozoan, frequently documented as an agent for enteric illness worldwide. Laboratory procedures for diagnosis include stool examination, antigenic detection assays and, at times, mucosal biopsy. We hypothesised that the formalin fixative used as a preservative for mucosal biopsy can be a good diagnostic sample for detecting surface mucosal and luminal infective agents such as giardia. The aim of the study was to find out the utility of processing the remaining formalin fixative as a complementary diagnostic method for detecting giardia.

METHODS

This study included 200 cases of duodenal biopsies sampled over 6 months. The biopsies were picked up using clean forceps and the remaining fixative was processed using standard cytospin protocol. The cytospin preparation and formalin-fixed paraffin-embedded tissue sections were examined by two pathologists independently blinded to each others findings.

RESULTS

On cytology, trophozoites of giardia were detected in 23 out of 200 cases (11.50%). The cytomorphology of pear-shaped organism with paired flagella and nuclei is very diagnostic. One case also showed presence of cryptosporidium spores. No other intestinal parasite was seen. Out of the 23 positive cytology samples, only 12 (6%) corresponding formalin-fixed paraffin-embedded tissue sections showed presence of giardia.

CONCLUSION

Concurrent examination of duodenal biopsy and the formalin fixative cytopreparation in cases with high index of clinical suspicion of giardiasis proved to be a useful adjunct to biopsy diagnosis of giardiasis, which was statistically significant (P < .0001). This approach adds negligible cost and effort but with good diagnostic yield. We recommend that the formalin cytopreparation be used as a complementary technique to biopsy for cases suspected of intestinal parasitic infection.

Co-infection of intestinal parasites and Helicobacter pylori among upper gastrointestinal symptomatic adult patients attending Mekanesalem Hospital, northeast Ethiopia

OBJECTIVE

Intestinal parasites and H. pylori are well-known for their high prevalence worldwide. Thus, the objective of this study waste assess risk factors and co-infection of intestinal parasites and H. pylori among adult patients with upper gastrointestinal complaints. A hospital-based cross sectional study was conducted among 363 consecutive adult patients from December 10, 2015 to February 30,2016. Stool and venous blood were collected for analysis of Intestinal parasites and H. pylori infection, respectively. Data was analyzed using SPSS version 16 and logistic regression analysis was carried out to assess predictors of co-infection. A p ≤ 0.05 was considered as statistically significant.

RESULTS

Helicobacter pylori IgG and intestinal parasites were detected in 70.25-38.3% of participants, respectively while G. lamblia accounted 22.3%. G. lamblia prevalence was significantly higher among H. pylori infected participants (COR: 2.76; 95% CI: 1.46-5.23), but E. hystolytica/dispar infection didn't show significant variation (p = 0.15). H. pylori and intestinal parasites concomitant co-infection was associated with male sex (AOR: 1.61; 95% CI: 1.01-2.56), consumption of river water (AOR: 1.85; 95% CI: 1.11-3.07) and ground/spring water (AOR: 4.10; 95% CI: 1.97-8.52). Thus, besides H. pylori investigation, upper gastrointestinal symptomatic patients should be screened for G. lamblia infection and other intestinal parasites.

Cytology Preparations of Formalin Fixative Aid Detection of Giardia in Duodenal Biopsy Samples

Giardiasis is the most common intestinal parasitic infection in the United States. The organism elicits no, or minimal, inflammatory changes in duodenal biopsy samples, so it can be easily overlooked. We performed this study to determine whether Giardia could be isolated from the formalin fixative of biopsy samples, and to evaluate the value of fluid analysis in the assessment for potential infection. We prospectively evaluated duodenal biopsy samples from 92 patients with a clinical suspicion of giardiasis or symptoms compatible with that diagnosis (ie, diarrhea, bloating, or abdominal pain) Biopsy samples were routinely processed and stained with hematoxylin and eosin. Histologic diagnoses included giardiasis (5 cases, 4%), normal findings (64 cases, 70%), peptic injury/active duodenitis (12 cases, 13%), and intraepithelial lymphocytosis with villous blunting (10 cases, 12%). Fifteen cases (13%) showed detached degenerated epithelial cells or mucus droplets in the intervillous space that resembled Giardia. Cytology slides were prepared from formalin in the biopsy container using the standard Cytospin protocol and reviewed by a cytopathologist blinded to the biopsy findings. Cytologic evaluation revealed Giardia spp. in all 5 biopsy-proven cases, and identified an additional case that was not detected by biopsy analysis. Organisms were significantly more numerous (mean: 400 trophozoites; range, 120 to 810) and showed better morphologic features in cytology preparations compared with tissue sections (mean: 129 trophozoites; range, 37 to 253 organisms; P=0.05). Our findings suggest that cytology preparations from formalin fixative can resolve diagnostically challenging cases and even enhance Giardia detection in some cases.

Molecular seasonality of Giardia lamblia in a cohort of Egyptian children: a circannual pattern

Giardia lamblia (G. lamblia) is the most worldwide prevailing intestinal parasite, notorious for its broad range of seasonal and age-related prevalence. The potentially lethal nature of giardiasis makes it essential that the seasonality, the groups at risk, and other potential risk factors are identified. The present molecular epidemiological study was designed to determine the genetic diversity of G. lamblia infection, taking into account seasonal peaks, age distribution, and associated symptoms in a cohort of Egyptian diarrheic patients. Stool samples were collected from 1187 diarrheic patients attending outpatient clinics of Cairo University hospitals, of all age groups over a 12-month period. The patients were examined microscopically for fecal G. lamblia cysts, and/or trophozoites, and for copro-DNA detection using nested polymerase chain reaction (nPCR) assays targeting beta giardin gene. PCR-positive samples were characterized molecularly by nPCR restriction fragment length polymorphism (RFLP) to determine Giardia assemblages. The findings revealed circannual prevalence of Giardia, with a seasonal pattern peaking in mid-summer and late winter, with the summer peak preceded by a peak in temperature. Infection was prevailing in 224 (18.9 %) cases, mainly assemblage B (81.2 %) followed by assemblage A (18.8 %). There were statistically significant associations between the detection of Giardia and flatulence, persistent diarrhea, vomiting, and abdominal pain, while gender and intermittent diarrhea showed no association. The pre-school age group was the most vulnerable. This is the first study of molecular characterization of Giardia to determine its circannual prevalence in Egypt, a finding which carries promising potential for the diagnosis, treatment, and elimination of the disease.

Giardia duodenalis assemblages in Egyptian children with diarrhea

Giardia duodenalis is considered the most common cause of parasitic diarrhea worldwide. Genetic studies revealed that at least eight assemblages (A-H) exist. Of these assemblages, A and B are found primarily in human beings and occasionally in animals. The association between clinical symptoms and G. duodenalis assemblages is controversial. The aim of the present study was to determine the assemblages of G. duodenalis prevalent among Egyptian children with diarrhea. Therefore, 96 positive stool samples for Giardia by light microscopy were subjected to multilocus genotyping targeting the triose phosphate isomerase (tpi), β-giardin (bg), and glutamate dehydrogenase (gdh) genes. Amplified polymerase chain reaction (PCR) products were then purified, sequenced, and aligned with reference strains to determine the assemblages of the Giardia isolates. Out of the 96 microscopically positive stool samples for Giardia, 77 (80 %) were successfully amplified and sequenced at least at one locus. Of these, 21 (27.3 %) were shown to be assemblage A, 54 (70.1 %) assemblage B, while discordant sequence typing results were observed in 2 (2.6 %) samples. AII was the predominant subassemblage of assemblage A, while it was generally difficult to further classify assemblage B. It was concluded that infection with assemblage B was more common than that with assemblage A. No associations between epidemiological information and assemblage were detected, except with age. Although infections with assemblage B were more frequently associated with abdominal pain and acute diarrhea than with assemblage A, the difference was not statistically significant.