Refractory Giardiasis in an Immunosuppressed Patient in Turkey

Giardiasis is an infection of the small intestine caused by the protozoan parasite Giardia duodenalis. In immunocompetent patients the infection is usually self-limited and no treatment may be needed. Immunodeficiency, however, is a predisposing factor for the development of severe Giardia infection. In this report, a case of recurrent giardiasis refractory to nitroimidazoles and nitazoxanides presented. A 28-year-old male patient with hypogammaglobulinemia admitted to our hospital because of chronic diarrhoea. Microscopic examination of stool revealed a high number of Giardia trophozoites and cysts. Treatment with higher doses and a longer course of metronidazole, trimethoprim-sulfamethoxazole, ornidazole and albendazole failed. Administration of nitazoxanide, which has been reported to be effective against Giardia duodenalis refractory to nitroimidazoles, was commenced, but his symptoms persisted and stool samples demonstrated Giardia trophozoites and cysts again.

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Giardia duodenalis and Its Secreted PPIB Trigger Inflammasome Activation and Pyroptosis in Macrophages through TLR4-Induced ROS Signaling and A20-Mediated NLRP3 Deubiquitination

Cells ◽

10.3390/cells10123425 ◽

2021 ◽

Vol 10 (12) ◽

pp. 3425

Author(s):

Lin Liu ◽

Yongwu Yang ◽

Rui Fang ◽

Weining Zhu ◽

Jingxue Wu ◽

...

Keyword(s):

Nlrp3 Inflammasome ◽

Defense Mechanisms ◽

Giardia Duodenalis ◽

Protozoan Parasite ◽

Global Scale ◽

Inflammasome Activation ◽

Giardia Infection ◽

Immune Effector ◽

Nlrp3 Inflammasome Activation ◽

Innate Immune Effector

The extracellular protozoan parasite Giardia duodenalis is a well-known and important causative agent of diarrhea on a global scale. Macrophage pyroptosis has been recognized as an important innate immune effector mechanism against intracellular pathogens. Yet, the effects of noninvasive Giardia infection on macrophage pyroptosis and the associated molecular triggers and regulators remain poorly defined. Here we initially observed that NLRP3 inflammasome-mediated pyroptosis was activated in Giardia-treated macrophages, and inhibition of ROS, NLRP3, or caspase-1 could block GSDMD cleavage, IL-1β, IL-18 and LDH release, and the cell viability reduction. We also confirmed that Giardia-induced NLRP3 inflammasome activation was involved in its K63 deubiquitination. Thus, six candidate deubiquitinases were screened, among which A20 was identified as an effective regulator. We then screened TLRs on macrophage membranes and found that upon stimulation TLR4 was tightly correlated to ROS enhancement, A20-mediated NLRP3 deubiquitination, and pyroptotic signaling. In addition, several Giardia-secreted proteins were predicted as trigger factors via secretome analysis, of which peptidyl-prolyl cis-trans isomerase B (PPIB) independently induced macrophage pyroptosis. This was similar to the findings from the trophozoite treatment, and also led to the TLR4-mediated activation of NLRP3 through K63 deubiquitination by A20. Collectively, the results of this study have significant implications for expanding our understanding of host defense mechanisms after infection with G. duodenalis.

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Intestinal coccidian parasites as an underestimated cause of travellers’ diarrhoea in Polish immunocompetent patients

Acta Parasitologica ◽

10.1515/ap-2017-0077 ◽

2017 ◽

Vol 62 (3) ◽

Cited By ~ 5

Author(s):

Matylda Kłudkowska ◽

Łukasz Pielok ◽

Krystyna Frąckowiak ◽

Małgorzata Paul

Keyword(s):

Gastrointestinal Symptoms ◽

Chronic Diarrhoea ◽

Microscopical Examination ◽

Coccidian Parasite ◽

Gastrointestinal Infections ◽

Food Borne ◽

Coccidian Parasites ◽

Potential Risk Factors ◽

Stool Samples ◽

Immunocompetent Patients

AbstractIntestinal coccidian parasites are intracellular protozoa most frequently transmitted during food-borne and water-borne infections. This group of parasites is responsible for acute diarrhoeal illnesses especially among immunocompromised patients. However, they are more frequently detected in immunocompetent individuals including travellers, and they should also be considered as important etiologic factors of travellers’ diarrhoea. We examined 221 immunocompetent patients hospitalized due to acute or chronic diarrhoea and other gastrointestinal symptoms after returning from international journeys to hot climates. A basic microscopical examination and acid – fast staining of stool samples was performed. Each patient was also a part of the epidemiological investigation to define potential risk factors of tropical gastrointestinal infections. Intestinal coccidiosis was confirmed in 12 out of 221 successively hospitalized patients (5.4%). The most common coccidian parasite was

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Gastrointestinal parasites of sheep, municipality of Lajes, Rio Grande do Norte, Brazil

Revista Brasileira de Parasitologia Veterinária ◽

10.1590/s1984-29612012000100015 ◽

2012 ◽

Vol 21 (1) ◽

pp. 71-73 ◽

Cited By ~ 6

Author(s):

Maria de Fátima de Souza ◽

Manoel Pimentel-Neto ◽

Rízia Maria da Silva ◽

Albeísa Cleyse Batista Farias ◽

Marcos Pezzi Guimarães

Keyword(s):

Small Intestine ◽

Large Intestine ◽

Haemonchus Contortus ◽

Giardia Duodenalis ◽

Rio Grande ◽

Gastrointestinal Parasites ◽

Ovis Aries ◽

Eimeria Spp ◽

Stool Samples ◽

Gastrointestinal Parasitism

This study investigated the gastrointestinal parasitism by helminths and protozoa in sheep (Ovis aries) Santa Inês breed, municipality of Lajes, Rio Grande do Norte. Monthly, from April 2005 to August 2007, stool samples were collected from two tracer lambs in the first day of the experiment and performed a necropsy of these animals in 44th day. A total of 64 lambs were sampled, but only 62 lambs were slaughtered. The fecal samples were examined by sedimentation in water. The contents of the abomasum, small intestine and large intestine were examined for the recovery of helminths. The parasitological examination revealed eggs of the following groups of helminths: Strongyloidea, Strongyloides sp., Trichuris sp., and Moniezia sp. Also were found oocysts of Eimeria spp., cysts of Entamoeba ovis and Giardia duodenalis. The helminths identified from examining the contents were: Haemonchus contortus, Cooperia pectinata, Cooperia punctata, Trichostrongylus colubriformis, Moniezia expansa, Oesophagostomum sp. Skrjabinema ovis and Trichuris sp.

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Multilocus Genotyping of Giardia duodenalis in Mostly Asymptomatic Indigenous People from the Tapirapé Tribe, Brazilian Amazon

Pathogens ◽

10.3390/pathogens10020206 ◽

2021 ◽

Vol 10 (2) ◽

pp. 206

Author(s):

Pamela Carolina Köster ◽

Antonio F. Malheiros ◽

Jeffrey J. Shaw ◽

Sooria Balasegaram ◽

Alexander Prendergast ◽

...

Keyword(s):

Triosephosphate Isomerase ◽

Gastrointestinal Symptoms ◽

Giardia Duodenalis ◽

Protozoan Parasite ◽

Indigenous Communities ◽

Brazilian Amazon ◽

Epidemiological Survey ◽

Small Subunit ◽

High Genetic Diversity ◽

Cross Sectional

Little information is available on the occurrence and genetic variability of the diarrhoea-causing enteric protozoan parasite Giardia duodenalis in indigenous communities in Brazil. This cross-sectional epidemiological survey describes the frequency, genotypes, and risk associations for this pathogen in Tapirapé people (Brazilian Amazon) at four sampling campaigns during 2008–2009. Microscopy was used as a screening test, and molecular (PCR and Sanger sequencing) assays targeting the small subunit ribosomal RNA, the glutamate dehydrogenase, the beta-giardin, and the triosephosphate isomerase genes as confirmatory/genotyping methods. Associations between G. duodenalis and sociodemographic and clinical variables were investigated using Chi-squared test and univariable/multivariable logistic regression models. Overall, 574 individuals belonging to six tribes participated in the study, with G. duodenalis prevalence rates varying from 13.5–21.7%. The infection was positively linked to younger age and tribe. Infected children <15 years old reported more frequent gastrointestinal symptoms compared to adults. Assemblage B accounted for three out of four G. duodenalis infections and showed a high genetic diversity. No association between assemblage and age or occurrence of diarrhoea was demonstrated. These data indicate that the most likely source of infection was anthropic and that different pathways (e.g., drinking water) may be involved in the transmission of the parasite.

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Re-Discovery of Giardiavirus: Genomic and Functional Analysis of Viruses from Giardia duodenalis Isolates

Biomedicines ◽

10.3390/biomedicines9060654 ◽

2021 ◽

Vol 9 (6) ◽

pp. 654

Author(s):

Gianluca Marucci ◽

Ilaria Zullino ◽

Lucia Bertuccini ◽

Serena Camerini ◽

Serena Cecchetti ◽

...

Keyword(s):

High Throughput Sequencing ◽

Diarrheal Disease ◽

Current Knowledge ◽

Biological Significance ◽

Giardia Duodenalis ◽

Protozoan Parasite ◽

Protein Translation ◽

Mass Spectrometry Analysis ◽

Animal Origin ◽

Spectrometry Analysis

Giardiasis, caused by the protozoan parasite Giardia duodenalis, is an intestinal diarrheal disease affecting almost one billion people worldwide. A small endosymbiotic dsRNA viruses, G. lamblia virus (GLV), genus Giardiavirus, family Totiviridae, might inhabit human and animal isolates of G. duodenalis. Three GLV genomes have been sequenced so far, and only one was intensively studied; moreover, a positive correlation between GLV and parasite virulence is yet to be proved. To understand the biological significance of GLV infection in Giardia, the characterization of several GLV strains from naturally infected G. duodenalis isolates is necessary. Here we report high-throughput sequencing of four GLVs strains, from Giardia isolates of human and animal origin. We also report on a new, unclassified viral sequence (designed GdRV-2), unrelated to Giardiavirus, encoding and expressing for a single large protein with an RdRp domain homologous to Totiviridae and Botybirnaviridae. The result of our sequencing and proteomic analyses challenge the current knowledge on GLV and strongly suggest that viral capsid protein translation unusually starts with a proline and that translation of the RNA-dependent RNA polymerase (RdRp) occurs via a +1/−2 ribosomal frameshift mechanism. Nucleotide polymorphism, confirmed by mass-spectrometry analysis, was also observed among and between GLV strains. Phylogenetic analysis indicated the occurrence of at least two GLV subtypes which display different phenotypes and transmissibility in experimental infections of a GLV naïve Giardia isolate.

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Molecular Characterization of Giardia duodenalis in Children and Adults Sampled in Algeria

Microorganisms ◽

10.3390/microorganisms9010054 ◽

2020 ◽

Vol 9 (1) ◽

pp. 54

Author(s):

Salem Belkessa ◽

Daniel Thomas-Lopez ◽

Karim Houali ◽

Farida Ghalmi ◽

Christen Rune Stensvold

Keyword(s):

Real Time ◽

Molecular Characterization ◽

Real Time Pcr ◽

Intestinal Parasites ◽

Giardia Duodenalis ◽

Specific Pcr ◽

Stool Samples ◽

Pcr Targeting ◽

Assemblage B

The molecular epidemiology of giardiasis in Africa remains unclear. A study was carried out across four hospitals in Algeria. A total of 119 fecal samples from 55 children, 37 adults, and 27 individuals of undetermined age, all scored positive for intestinal parasites by microscopy, and were screened by real-time PCR for Giardia. Molecular characterization of Giardia was performed by assemblage-specific PCR and PCR targeting the triose phosphate isomerase gene (tpi). Of the 119 samples, 80 (67%) were Giardia-positive by real-time PCR. For 48 moderately-highly real-time PCR-positive samples, tpi genotyping assigned 22 samples to Assemblage A and 26 to Assemblage B. Contrary to Assemblage A, Assemblage B exhibited substantial genetic diversity and allelic heterozygosity. Assemblage-specific PCR proved to be specific for discriminating Assemblage A or B but not as sensitive as tpi genotyping. We confirmed that real-time PCR is more sensitive than microscopy for detecting Giardia in stool samples and that robust amplification and sequencing of the tpi gene is feasible when moderate-to-strongly real-time PCR-positive samples are used. This study is one of the few performed in Africa providing genotyping data on Giardia infections in humans. Both assemblages A and B were commonly seen and not associated with specific sociodemographic data.

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Highly sensitive and specific detection of Giardia duodenalis, Entamoeba histolytica, and Cryptosporidium spp. in human stool samples by the BD MAX™ Enteric Parasite Panel

Parasitology Research ◽

10.1007/s00436-017-5720-7 ◽

2017 ◽

Vol 117 (2) ◽

pp. 447-451 ◽

Cited By ~ 11

Author(s):

Marijo Parčina ◽

Ingrid Reiter-Owona ◽

Frank P. Mockenhaupt ◽

Valerija Vojvoda ◽

Jean Bosco Gahutu ◽

...

Keyword(s):

Entamoeba Histolytica ◽

Giardia Duodenalis ◽

Specific Detection ◽

Cryptosporidium Spp ◽

Highly Sensitive ◽

Stool Samples ◽

Human Stool

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New Associated Structures of the Anterior Flagella of Giardia duodenalis

Microscopy and Microanalysis ◽

10.1017/s1431927613013275 ◽

2013 ◽

Vol 19 (5) ◽

pp. 1374-1376 ◽

Cited By ~ 9

Author(s):

Claudia Maia-Brigagão ◽

Ana Paula Rocha Gadelha ◽

Wanderley de Souza

Keyword(s):

Electron Microscopy ◽

Structural Organization ◽

Giardia Duodenalis ◽

Protozoan Parasite ◽

Filamentous Structure ◽

Marginal Plates ◽

Favorable Conditions ◽

And Behavior ◽

Crossing Point ◽

Scanning Electron

AbstractGiardia duodenalis is a protozoan parasite that causes intestinal disorders. The trophozoites present four pairs of flagella. Here we further analyze the structural organization of the anterior flagella associated structures of G. duodenalis. High resolution scanning electron microscopy of detergent-extracted trophozoites revealed novel aspects of the interaction of the anterior flagella axonemes with the marginal plates. Images of the marginal plates showed that it was located in the anterior region of the parasite, above the crossing point of the anterior flagella axonemes toward the periphery of the cell. Two well distinguished structures were seen associated with the anterior flagella. The first one corresponds to the “dense rods”, located just below the axoneme. The second one is a system of filaments located in the upper portion of the flagellum, facing the marginal plates and connecting these two structures. The thickness of the filaments is around 18 nm and they are spaced at intervals of 4–32 nm (average 18 nm). The length of the filaments may vary from 33 to 240 nm. We suggest that this filamentous structure of Giardia may help the dynamics and behavior of the anterior flagella of trophozoites during protozoan motility and adhesion, providing favorable conditions for the establishment of parasitism.

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Assemblages A and B of Giardia duodenalis reduce enteric glial cells in the small intestine in mice

Parasitology Research ◽

10.1007/s00436-018-5853-3 ◽

2018 ◽

Vol 117 (7) ◽

pp. 2025-2033 ◽

Cited By ~ 2

Author(s):

Mariana Felgueira Pavanelli ◽

Cristiane Maria Colli ◽

Renata Coltro Bezagio ◽

Marcelo Biondaro Góis ◽

Gessilda de Alcântara Nogueira de Melo ◽

...

Keyword(s):

Small Intestine ◽

Glial Cells ◽

Giardia Duodenalis ◽

Enteric Glial Cells

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14C-Cobalamin Absorption from Endogenously Labeled Chicken Eggs Assessed in Humans Using Accelerator Mass Spectrometry

Nutrients ◽

10.3390/nu11092148 ◽

2019 ◽

Vol 11 (9) ◽

pp. 2148 ◽

Cited By ~ 2

Author(s):

Garrod ◽

Rossow ◽

Calvert ◽

Miller ◽

Green ◽

...

Keyword(s):

Mass Spectrometry ◽

Accelerator Mass Spectrometry ◽

Human Volunteers ◽

Physiological Limit ◽

Stool Samples ◽

Vitamin B 12 ◽

Chicken Eggs ◽

Higher Doses ◽

Cobalamin Absorption

Traditionally, the bioavailability of vitamin B-12 (B12) from in vivo labeled foods was determined by labeling the vitamin with radiocobalt (57Co, 58Co or 60Co). This required use of penetrating radioactivity and sometimes used higher doses of B12 than the physiological limit of B12 absorption. The aim of this study was to determine the bioavailability and absorbed B12 from chicken eggs endogenously labeled with 14C-B12 using accelerator mass spectrometry (AMS). 14C-B12 was injected intramuscularly into hens to produce eggs enriched in vivo with the 14C labeled vitamin. The eggs, which provided 1.4 to 2.6 μg of B12 (~1.1 kBq) per serving, were scrambled, cooked and fed to 10 human volunteers. Baseline and post-ingestion blood, urine and stool samples were collected over a one-week period and assessed for 14C-B12 content using AMS. Bioavailability ranged from 13.2 to 57.7% (mean 30.2 ± 16.4%). Difference among subjects was explained by dose of B12, with percent bioavailability from 2.6 μg only half that from 1.4 μg. The total amount of B12 absorbed was limited to 0.5–0.8 μg (mean 0.55 ± 0.19 μg B12) and was relatively unaffected by the amount consumed. The use of 14C-B12 offers the only currently available method for quantifying B12 absorption in humans, including food cobalamin absorption. An egg is confirmed as a good source of B12, supplying approximately 20% of the average adult daily requirement (RDA for adults = 2.4 μg/day).

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