Predominance Of Assemblage Research Articles

Molecular appraisal of Giardia intestinalis from Western India: A prospective observational study.

Giardia intestinalis is an intestinal protozoan which commonly causes parasitic gastroenteritis globally. It is a species complex consisting of at least eight assemblages (genotypes). In India, Giardia is mostly underreported and missed in asymptomatic cases. The aim of this study was to genotype the G. intestinalis isolates from stool samples of patients at a tertiary care center in Rajasthan, India, and to clinically correlate it. This prospective pilot cross-sectional study was conducted from 2019 to 2021 in a tertiary care center in western India. Patients who were microscopically positive for giardiasis were enrolled. DNA was extracted from their stool samples and amplified by polymerase chain reaction (PCR) using 4E1-HP as the target sequence. Anthropometric measurements and analysis were done for children by using Anthrocal application. A total of 50 patients were enrolled. Diarrhea was present in 18 patients (36%). Among these, 6 were immunocompromised and had different comorbidities. Among the children <12 years of age, 55.17% (n = 16/29) were stunted (<-2 S.D.), and among <5 years, 44.4% (n = 4/9) showed wasting (<-2 S.D.). A PCR product corresponding to assemblage B of G. intestinalis was amplified in 47 stool specimens. Only three stool samples were negative for both assemblages A and B and posed an interesting enigma. In this study, a predominance of assemblage B of G. intestinalis was detected in 94% of the isolates. Furthermore, the possibility of zoonotic transmission could not be ruled out.

Giardiasis in symptomatic children from Sharkia, Egypt: genetic assemblages and associated risk factors.

Giardia intestinalis (G. intestinalis) is a common enteric protozoan parasite worldwide and in Egypt. Identification of true prevailing Giardia assemblages helps in identification of the sources of infection. The study's aim was to determine the true prevalence of Giardia assemblages in Egyptian children from Sharkia governorate presenting with gastrointestinal symptoms and to investigate their association with molecularly detected Giardia. A total of 617 stool specimens were collected from children presenting with gastrointestinal symptoms in Alquraeen, Sharkia governorate, Egypt for 17months. All stool specimens were microscopically examined by wet mount smear before and after stool concentration to recover parasitic stages. Giardia copro-DNA was amplified from microscopically detected stool specimens using Copro-nPCR targeting the tpi gene for Giardia, followed by sequencing products of nPCR. The molecular prevalence of Giardia among symptomatic children was 9.88%, 83% of which were assemblage B and 17% were assemblages A. Giardia affected both sexes and all ages and wasmost prevalent in preschool children. Abdominal pain was the most common GIT symptom followed by diarrhoea. However, none of the patients' demographic variables (sex, age, weight and height) nor clinical symptoms showed significant association with molecular detection of Giardia. Giardia was common among symptomatic children from Sharkia, Egypt, with the predominance of assemblage B, which suggests the possibility of sharing common transmission source and route. Giardia had age, sex and clinical symptom distributions without statistical significance. The results necessitate further genomic studies targeting multiple gene targets for a better understanding of the ecology, dynamics of transmission, pathogenicity and clinical impact of Giardia infection, to improve its management and strategic control.

Molecular Characterization of Giardia lamblia: First Report of Assemblage B in Human Isolates from Rio de Janeiro (Brazil).

BackgroundDespite the high prevalence of giardiasis, the genetic characterization of Giardia lamblia has been poorly documented in Brazil and molecular epidemiology research has only been conducted in the last few years. The aim of this study was to determine the prevalence of different G. lamblia assemblages and detect mixed infections among patients with giardiasis.Methods and Principal FindingsThe cross-section survey was conducted among patients attending the FIOCRUZ in Rio de Janeiro. In order to discriminate the genetic assemblages/sub-assemblages, G. lamblia isolates were characterized by PCR-RFLP and qPCR using four loci genes (bg, gdh, tpi and orfC4). Of the 65 positive samples, 41 (63.1%) were successfully amplified by nested-PCR of bg and gdh genes. Among them, 16 were typed as sub-assemblage AII, 7 as BIII, 4 as BIV and 8 as a mixture of BIII and BIV. After the analysis by qPCR assay, a total of 55 (84.6%) samples were amplified using at least one locus: bg gene was amplified in 38 (58.5%) samples, gdh in 41 (63.1%), tpi in 39 (60%), and orfC4 in 39 (60%). Multilocus genotyping results showed that 29 (52.7%) samples belonged to Assemblage A and 26 (47.3%) samples belonged to Assemblage B. In 2011 and 2012, 20 (74.1%) samples belonged to Assemblage A and 7 (25.9%) belonged to Assemblage B. In subsequent years (2013–2015) there was a predominance of Assemblage B, 19 (67.9%) versus 9 (32.1%) Assemblage A.ConclusionsThis is the first time that Assemblage B of G. lamblia was reported in human clinical samples from Rio de Janeiro (Brazil) and is the first report about genetic characterization using four genes. The qPCR assemblage-specific showed no mixed infections by Assemblages A and B. A switch in genetic profile over the years was observed, firstly predominance of Assemblage A and lastly of Assemblage B.

Molecular characterization of Giardia duodenalis in children from the Cufada Lagoon Natural Park, Guinea-Bissau

Molecular characterization of Giardia duodenalis in African countries is relatively scarce. The global understanding of Giardia epidemiology is reinforced when more data are available from highly endemic countries. In the present study, 50 fecal samples collected from children from Guinea-Bissau were screened for Giardia infection. Amplification of the Giardia ssu-rRNA fragment was achieved for 28 samples (28/50, 56.0 %) of which 23 (23/50, 46.0 %) positive samples for Giardia were detected through microscopy. Eighteen samples previous amplified for the ssu-rRNA locus were amplified for the bg gene fragment. Sequence analysis was performed in 26 and 17 samples for the ssu-rRNA and bg gene fragment, respectively. Our results revealed a predominance of assemblage B (22/26, 84.6 %), sequences with high genetic polymorphism among isolates belonging to this assemblage, making impossible the subassemblage determination. Assemblage A was identified in three isolates (3/26, 11.5 %), and our results strongly suggest that two isolates belong to subassemblage A2. This study provides information about G. duodenalis genotypes in a rural area of Guinea-Bissau and may contribute for a better understanding of giardiasis epidemiology in this country.

High Prevalence of Giardia duodenalis Assemblage B Infection and Association with Underweight in Rwandan Children

Background Giardia duodenalis is highly endemic in East Africa but its effects on child health, particularly of submicroscopic infections, i.e., those below the threshold of microscopy, and of genetic subgroups (assemblages), are not well understood. We aimed at addressing these questions and at examining epidemiological characteristics of G. duodenalis in southern highland Rwanda.Methodology/Principal FindingsIn 583 children <5 years of age from communities and health facilities, intestinal parasites were assessed by triplicate light microscopy and by PCR assays, and G. duodenalis assemblages were genotyped. Cluster effects of villages were taken into account in statistical analysis. The prevalence of G. duodenalis as detected by microscopy was 19.8% but 60.1% including PCR results. Prevalence differed with residence, increased with age, and was reduced by breastfeeding. In 492 community children without, with submicroscopic and with microscopic infection, underweight (weight-for-age z-score <−2 standard deviations) was observed in 19.7%, 22.1%, and 33.1%, respectively, and clinically assessed severe malnutrition in 4.5%, 9.5%, and 16.7%. Multivariate analysis identified microscopically detectable G. duodenalis infection as an independent predictor of underweight and clinically assessed severe malnutrition. Submicroscopic infection showed respective trends. Overall, G. duodenalis was not associated with gastrointestinal symptoms but assemblages A parasites (proportion, 13%) were increased among children with vomiting and abdominal pain.Conclusions/SignificanceThe prevalence of G. duodenalis in high-endemicity areas may be greatly underestimated by light microscopy, particularly when only single stool samples are analysed. Children with submicroscopic infections show limited overt manifestation, but constitute unrecognized reservoirs of transmission. The predominance of assemblage B in Rwanda may be involved in the seemingly unimposing manifestation of G. duodenalis infection. However, the association with impaired child growth points to its actual relevance. Longitudinal studies considering abundant submicroscopic infections are needed to clarify the actual contribution of G. duodenalis to morbidity in areas of high endemicity.

Molecular characterization ofGiardia duodenalisisolated from Semai Pahang Orang Asli (Peninsular Malaysia aborigines)

This study was conducted to determine the genotypes of Giardia duodenalis isolated from human faecal samples at Pos Betau, Pahang, Malaysia. Faecal specimens were collected and examined for G. duodenalis cysts using Trichrome staining techniques. Molecular identification was carried out by the amplification of a region of the small subunit of the nuclear ribosomal RNA (SSU rRNA) gene using nested PCR and subsequent sequencing. The sequences from 15 isolates from G. duodenalis were subjected to phylogenetic analysis (including appropriate outgroups) using the neighbor-joining and maximum parsimony methods. The trees identified G. duodenalis assemblages A and B, with a predominance of assemblage B. The predominance of anthroponotic genotypes indicates the possibility of anthroponotic transmission of these protozoa in this Semai Pahang Orang Asli community.

Detection and genotyping of Giardia duodenalis in wastewater: Relation between assemblages and faecal contamination origin

Among the seven assemblages identified in Giardia duodenalis species, only assemblages A and B infect humans and numerous other mammals as well. On the other hand, assemblage E is considered to be host restricted to livestock. The aim of the present study was to compare the presence of G. duodenalis assemblages A, B and E in wastewater samples from two municipal treatment plants ( n=24) and one slaughterhouse ( n=12). Thus, PCR assays targeting the tpi gene were developed to detect specifically these three G. duodenalis assemblages. Assemblages A and B were detected in urban wastewater with a predominance of assemblage A, especially for one treatment plant. Concerning slaughterhouse wastewater, assemblage A was found in 58% of the samples, whereas assemblage B was not detected. Assemblage E was not detected in urban wastewater, but was found in 92% of the samples from slaughterhouse. Thus, combination of assemblages A and B seemed to indicate a human contamination origin, while combination of assemblages A and E appeared to correspond to a livestock contamination origin.