Giardia Infection Research Articles

Myeloid Cells in the Immune Response to Giardia

Abstract Infection with the protozoan parasite, Giardia, produces symptoms associated with intestinal distress, but does not induce intestinal inflammation. Long-term sequellae of this infection include malnutrition, Irritable Bowel Syndrome and Chronic Fatigue Syndrome. Previous work indicates that T-cells are critical for clearance of this parasite; however, it is unclear which cells are responsible for the activation of T-cells. As such, our goal was to examine the contribution of myeloid cells to Giardia immunity as possible T-cell activators, effector cells and/or immune regulators. Small intestinal lamina propria cells were isolated from Giardia-infected wild-type or CCR2 deficient mice. Flow cytometry was used to determine cell phenotypes and to monitor cytokine response. EdU labeling was used to examine in situ proliferation of resident macrophages. Lastly, wild-type mice were treated with an anti-CSF1R monoclonal antibody to deplete macrophage populations. Flow cytometry demonstrated that CD11b+, F4/80+, CD11cint, MHCII+, Ly6Cint, CX3CR1int cells accumulate in the small intestine and express ARG1 and NOS2 during infection. Intracellular cytokine staining revealed an increase in IL-10 with a concurrent decrease in TNF-α. Macrophage accumulation was the same in wild-type and CCR2-deficient mice, and EdU labeling suggested in situ proliferation of resident macrophages rather than recruitment of inflammatory monocytes. Mice treated with anti-CSF1R eliminated the parasites as well as control mice. This study demonstrates that macrophages with a regulatory phenotype accumulate in the small intestine during Giardia infections and may explain why intestinal inflammation is not present during Giardia infections.

Effects of Water, Sanitation, Handwashing, and Nutritional Interventions on Child Enteric Protozoan Infections in Rural Bangladesh: A Cluster-Randomized Controlled Trial

We evaluated effects of individual and combined water, sanitation, handwashing (WSH), and nutritional interventions on protozoan infections in children. We randomized geographical clusters of pregnant women in rural Bangladesh into chlorinated drinking water, hygienic sanitation, handwashing, nutrition, combined WSH, nutrition plus WSH (N+WSH), or control arms. Participants were not masked. After approximately 2.5 years of intervention, we measured Giardia, Cryptosporidium, and Entamoeba histolytica prevalence and infection intensity by multiplex real-time polymerase chain reaction of child stool. Analysis was intention-to-treat. Between May 2012 and July 2013, we randomized 5551 pregnant women. At follow-up, among 4102 available women, we enrolled 6694 children into the protozoan assessment. We analyzed stool from 5933 children (aged ~31 months) for protozoan infections. Compared with 35.5% prevalence among controls, Giardia infection prevalence was lower in the sanitation (26.5%; prevalence ratio [PR], 0.75 [95% confidence interval {CI}, .64-.88]), handwashing (28.2%; PR, 0.80 [95% CI, .66-.96]), WSH (29.7%; PR, 0.83 [95% CI, .72-.96]), and N+WSH (26.7%; PR, 0.75 [95% CI, .64-.88]) arms. Water and nutrition interventions had no effect. Low prevalence of E. histolytica and Cryptosporidium (<2%) resulted in imprecise effect estimates. Individual handwashing and hygienic sanitation interventions significantly reduced childhood Giardia infections, and there were no effects of chlorinated drinking water and nutrition improvements in this context. Combined WSH interventions provided no additional benefit. To reduce Giardia infection, individual WSH interventions may be more feasible and cost-effective than combined interventions in similar rural, low-income settings. NCT01590095.

Protease Activated Receptor‐2 Mediates Giardia‐Induced Disruptions of the Intestinal Mucus Barrier

BackgroundGiardia duodenalis has been associated with disruptions of the mucus layers of the small and large intestines, in part via Giardia's cysteine proteases. Disruption of the intestinal mucus barrier has been implicated in a variety of intestinal disorders, but mechanisms currently remain unclear.HypothesisGoblet cell function and mucus disruptions are modulated by activation of protease activated receptor 2 (PAR2), which is highly expressed through the gastrointestinal tract and is known to regulate mucus production in the airway and stomach. Giardia's cysteine proteases cleave and activate PAR2 on intestinal goblet cells.MethodsMUC2 mucin and PAR gene expression were assessed in the human colonic epithelial cell line LS174T using quantitative PCR (qPCR). LS174T were pre‐treated with the PAR2 antagonist p2Pal‐218S pepducin, and incubated with Giardia trophozoites or the PAR1 and PAR2 agonist peptides TFLLRN and 2fLIGRLO, respectively. Ability of Giardia to cleave PAR1 and PAR2 at the N‐terminal domain was determined using CHO cells transformed with N‐luciferase tagged PAR1 or PAR2. Following incubation with Giardia, culture supernatant was collected, reacted with luciferin, and luminescence was measured. Wild‐type and PAR2 deficient mice were infected with Giardia trophozoites. Thickness of the mucus layer was measured by fluorescently staining mucus with fluorescein‐coupled WGA, and expression of Muc2 and Muc5ac genes were determined in the colon and jejunum via qPCR.ResultsLS174T cells express functional and responsive PAR2, but little or no PAR1. Treatment of cells with 2fLIGRLO PAR2 agonist, but not TFLLRN PAR1 agonist, increased MUC2 gene expression. Incubation of cells with Giardia trophozoites increased MUC2 mRNA production, and this increase was abolished by pre‐treatment of cells with a PAR2 antagonist. Giardia also caused decreased PAR2 expression in LS174T. Giardia NF and Giardia GSM are both able to cleave PAR1 and PAR2 at the N terminal domain. Cleavage by NF was more efficient than GSM, and PAR1 was cleaved more extensively than PAR2 by both strains. Giardia infection increased Muc2 and Muc5ac expression in the colon and increased Muc5ac expression in the jejunum of wild‐type mice compared to uninfected controls. In PAR2−/− mice, Giardia infection reduced expression of Muc5ac in the jejunum, and had no impact on either gene in the colon. Giardia infection caused thinning of the mucus layer in wild‐type mice. In contrast, infection induced thickening of the mucus layer in PAR2−/− mice.ConclusionsUsing a model of Giardia infection, the findings demonstrate that PAR2 plays a significant role in mucin gene regulation and function in mice and in a human colonic goblet cell line, and that Giardia is capable of cleaving both PAR1 and PAR2 receptors with strain‐specific efficiencies.Support or Funding InformationCrohn's Colitis Canada (CCC), NSERCThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

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.

Giardiasis: Serum antibodies and coproantigens in brown rats (Rattus norvegicus) from Grenada, West Indies.

Aim:Giardia is a serious zoonotic parasite, which causes diarrheal disease in humans and animals including rodents. The purpose of this study was to estimate the prevalence of Giardia spp. in brown rats (Rattus norvegicus) in Grenada.Materials and Methods:Intestinal contents from 99 and serum samples from 169 brown rats (R. norvegicus) from Grenada were collected. These samples were examined for the Giardia coproantigens using Cryptosporidium/Giardia Quik Chek assay (Tech lab® Inc., USA), and the serum was screened through an enzyme-linked immunosorbent assay (ELISA) test kit for Giardia antibody (anti-GD) ELISA kit (MyBioSource, San Diego, CA, USA).Result:Giardia coproantigens were positive in 17.17% (95% confidence interval [CI]; 10.33-26.06%) rats, whereas 55% (95% CI: 47.20-62.68) were positive with serum antibodies (anti-GD) to Giardia.Conclusion:The prevalence of Giardia spp. in brown rats in Grenada was moderate based on the presence of coproantigens in the intestinal contents and antibody in serum. The findings of Giardia infections and prevalence in brown rats will help veterinarians and physicians to better plan diagnostic and preventative strategies. This is the first report of prevalence of Giardia in brown rats in Grenada.

Spatial distribution of Giardia lamblia infection among general population in Mazandaran Province, north of Iran.

Giardia lamblia is the most prevalent intestinal parasites of humans in Iran and other in the world although information on geographical distribution of giardiasis plays significant role in identifying communities at high risk, little attention has been paid to study human giardiasis using geographical information system. Therefore, the aim of the current study was to determine temporal and spatial patterns of human giardiasis distribution to identify possible high risk areas and seasons in northern Iran. A total of 4788 people referred to health centers in the Mazandaran Province of northern Iran were surveyed January to December 2015. From each person stool sample and questionnaire with socio-demographic data were collected. Giardia infection was diagnosed using direct wet mount, formalin ether concentration and trichrome staining. The results were analyzed using Moran Local Indicators of spatial association and geographically weighted regression. The overall prevalence of Giardia infection was 4.6% (222/4788), and was significantly higher among those aged 5-9years compared to their older peers (P<0.0001). Our data showed a significant dependency between the prevalence of G. lamblia and age, job, residence, season and height from the sea (P<0.0001). The results of this study provided aprecise and specificspatial and temporal pattern of human giardiasis distribution in the Mazandaran Province, Iran. These evidences should be considered for proper control of disease decisions and strategies.

Occurrence of Giardia duodenalis assemblages in farmed long-tailed chinchillas Chinchilla lanigera (Rodentia) from Romania

BackgroundGiardia duodenalis is a parasitic protist that infects a large number of species, being localized in the small intestine. Two of the eight recognized assemblages have zoonotic potential, but studies regarding their distribution in less important pet or farm species are scarce. Of these species, the long-tailed chinchilla is a host for Giardia spp., although data on the spread of infection and assemblages involved are confined. The present work aimed to determine the prevalence of Giardia infection and assemblage identification in farmed chinchillas in Romania. A total of 341 fecal samples were collected from 5 farms and microscopically examined using flotation test based on saturated sodium chloride solution. DNA from all positive samples was extracted and identified by PCR targeting the gdh gene.ResultsThe overall prevalence of Giardia infection was 55.7% (190/341); there was no statistically significant difference (P = 0.25) in prevalence between young animals (58.8%) and adults (52.6%). Assemblages B (151/190), D (33/190) and E (6/190) were identified. Among assemblage B, sub-assemblages BIII (6/151) and BIV (145/151) were determined.ConclusionsThis study demonstrates that Giardia spp. infection is highly prevalent in farmed chinchillas from Romania, and the sub-assemblages identified are potentially zoonotic.

Island-Wide Surveillance of Gastrointestinal Protozoan Infection on Fiji by Expanding Lymphatic Filariasis Transmission Assessment Surveys as an Access Platform.

.As part of lymphatic filariasis (LF) transmission assessment surveys (TAS) on Fiji, an island-wide assessment of gastrointestinal protozoan infection was performed by inspection of a concomitant stool sample collection to investigate the distribution of parasitic protozoa. All grade 1 and 2 students of 69 schools on the two main islands were targeted in two phases (one in the Western Division and the other in the Central and Northern Divisions, except Taveuni sub-Division of Northern), where fecal samples of 1,800 students were available for coproscopy using formalin-ether-acetate concentration. The overall prevalence of Giardia infection was 1.6%, having 2.2% in Western and 0.8% in Central/Northern Divisions (P = 0.094). The school-level prevalence of giardiasis ranged from 0% to 15.4%, and hotspot analysis using the Getis-Ord Gi* method detected spatial heterogeneity of giardiasis prevalence in schools around Lautoka (Z-score = 3.36, P value < 0.05), an area affected by Cyclone Kofi in February 2014. Any protozoan infection prevalence was 4.9% in Western and 4.4% in Central/Northern Divisions (P = 0.825). Real-time polymerase chain reaction analysis to confirm the findings from a parasitological examination of a 10% stool archive in 95% ethanol from Western Division revealed an elevated prevalence of giardiasis up to 22.4%, the presence of Entamoeba histolytica, and the absence of Cryptosporidium parvum. Obtaining stool samples alongside LF TAS is a convenient access platform for cosurveillance of gastrointestinal protozoan infection and has pinpointed hitherto unknown hotspots of giardiasis in urban city centers of Fiji. This calls for greater attention to apply tailored water, sanitation and hygiene measures for the control of these parasites.

Presence and molecular characterization of Cryptosporidium and Giardia in recreational lake water in Tianjin, China: a preliminary study

Little is known about the occurrence of Cryptosporidium and Giardia in recreational water in China. A total of 52 samples were collected from recreational lakes in Tianjin during a high-occurrence season (June–October) for the waterborne cryptosporidiosis and giardiasis, and the occurrence and genotypes of Cryptosporidium and Giardia were investigated. The results showed that 82.7% (43) and 98.1% (51) of samples were positive for Cryptosporidium oocyst and Giardia cysts, respectively. The mean concentration of parasites was 3.65 oocysts/10 L and 12.58 cysts/10 L, respectively. Molecular characterization revealed that the presence of Cryptosporidium parvum, C. andersoni, C. hominis, C. meleagridis, C. fragile, C. ubiquitum, and Giardia lamblia assemblage A, B and D. The protozoan contamination in the studied lakes may originate from animal feces on ground, which was washed into the lake by stormwater runoff. Nevertheless, there is a potential risk of infection during recreational activities in the lake because the dominant detected protozoan genotypes are common human pathogens. Moreover, microbial indicators analysis does not adequately indicate the protozoan contamination in recreational water. The information from this study will be valuable for future protozoan source tracking, and any further control interventions against Cryptosporidium and/or Giardia infection associated with recreational water.

Detecting endomysial and tissue transglutaminase antibodies in patients with giardiasis

Celiac disease is a genetic disease diagnosed to be associated with chronic intestinal inflammation. Endomysial and tissue transglutaminase antibodies are the best serum markers for celiac disease (CD) diagnosis. This research aimed to determine the levels of endomysial and tissue transglutaminase antibodies in patients with giardiasis. Forty cases of giardiasis were selected among the referees to Milad Hospital in Tehran, as well as a children’s hospital and some health centers in Karaj. Euro-immune IgA immunofluorescence and ELISA were utilized to measure their titers of endomysial and tissue transglutaminase antibodies, respectively. Twenty random serum samples of negative Giardia and 16 serum samples of positive anti-(tissue transglutaminase) tTG antibodies were evaluated by using ELISA and endomysium antibody through immunofluorescence techniques. Among the 40 cases of giardiasis, 16 positive endomysial and transglutaminase antibodies (40%) were detected. Sixteen positive samples of endomysial antibody (EMA) were also positive for anti-tTG, and 20 random negative samples were negative for EMA and anti-tTG. The chi-square test revealed a significant association between antibodies and giardiasis (P = 0.001). Atrophy of the intestinal villi can arise after giardia infection by mimicking the behavioral patterns of anti-EMA and anti-tTG antibodies. Due to low specificity, anti-gliadin antibody test is not helpful in detecting CD in patients with giardiasis. In the present study on anti-EMA and anti-tTG in patients with giardiasis, these antibodies were positive in giardiasis. Thus, the best and most reliable way to diagnose CD and treat giardiasis is intestinal biopsy as the gold standard method.

Estimating Cryptosporidium and Giardia disease burdens for children drinking untreated groundwater in a rural population in India.

BackgroundIn many low-income settings, despite improvements in sanitation and hygiene, groundwater sources used for drinking may be contaminated with enteric pathogens such as Cryptosporidium and Giardia, which remain important causes of childhood morbidity. In this study, we examined the contribution of diarrhea caused by Cryptosporidium and Giardia found in groundwater sources used for drinking to the total burden of diarrheal disease among children < 5 in rural India.Methodology/Principal findingsWe studied a population of 3,385 children < 5 years of age in 100 communities of Puri District, Odisha, India. We developed a coupled quantitative microbial risk assessment (QMRA) and susceptible-infected-recovered (SIR) population model based on observed levels of Cryptosporidium and Giardia in improved groundwater sources used for drinking and compared the QMRA-SIR estimates with independently measured all-cause (i.e., all fecal-oral enteric pathogens and exposure pathways) child diarrhea prevalence rates observed in the study population during two monsoon seasons (2012 and 2013). We used site specific and regional studies to inform assumptions about the human pathogenicity of the Cryptosporidium and Giardia species present in local groundwater. In all three human pathogenicity scenarios evaluated, the mean daily risk of Cryptosporidium or Giardia infection (0.06–1.53%), far exceeded the tolerable daily risk of infection from drinking water in the US (< 0.0001%). Depending on which protozoa species were present, median estimates of daily child diarrhea prevalence due to either Cryptosporidium or Giardia infection from drinking water was as high as 6.5% or as low as < 1% and accounted for at least 2.9% and as much as 65.8% of the all-cause diarrhea disease burden measured in children < 5 during the study period. Cryptosporidium tended to account for a greater share of estimated waterborne protozoa infections causing diarrhea than did Giardia. Diarrhea prevalence estimates for waterborne Cryptosporidium infection appeared to be most sensitive to assumptions about the probability of infection from ingesting a single parasite (i.e. the rate parameter in dose-response model), while Giardia infection was most sensitive to assumptions about the viability of parasites detected in groundwater samples.Conclusions/SignificanceProtozoa in groundwater drinking sources in rural India, even at low concentrations, especially for Cryptosporidium, may account for a significant portion of child diarrhea morbidity in settings were tubewells are used for drinking water and should be more systematically monitored. Preventing diarrheal disease burdens in Puri District and similar settings will benefit from ensuring water is microbiologically safe for consumption and consistent and effective household water treatment is practiced.

Assessment of the diagnostic performance of four methods for the detection of Giardia duodenalis in fecal samples from human, canine and feline carriers

Enteric parasitic diseases including giardiasis are of public health concern. Different methods are available for the diagnosis of this parasitic infection in fecal samples such as the identification of protozoan cysts and trophozoites by light microscopy, detection of specific antigens by ELISA, and amplification of DNA fragments by PCR. The present study aimed at assessing the performance of four laboratory tests for the detection of Giardia duodenalis in fecal specimens from three different host species with a previous diagnosis of giardiasis; canine, feline and human patients provided new stool samples to be retested for Giardia before initiating treatment with antiprotozoal drugs. For this purpose, triplicate fecal specimens from 54 humans, 24 dogs and 18 cats living in the city of Niterói, RJ, southeast Brazil, were analysed by light microscopy, ELISA, immunochromatography, and nested PCR. The centrifugal-flotation method detected Giardia cysts in 89.6% (86/96) of the fecal samples. The protozoan parasite was detected via immunochromatography in 87.5% (84/96) of these samples. Giardia was detected by ELISA in 69.8% (67/96) of the stool specimens from carriers with a previous diagnosis of Giardia infection. Giardia was detected by PCR in only 39.6% (38/96) of the fecal specimens. Based on these findings, we suggest that, among the four assays that were used in this study, the zinc sulphate flotation technique (Faust et al., 1939) is the best diagnostic assay in terms of sensitivity and specificity to detect G. duodenalis on serially collected samples from dogs, cats and humans.

The Molecular Detection of Cryptosporidium and Giardia in Sika Deer (Cervus Nippon Centralis) in Japan.

Fecal specimens (271 samples) from wild deer, Cervus nippon centralis, were collected from nine different areas in Japan; these samples were subjected to a real-time reverse transcription PCR for Cryptosporidium-and Giardia-specific 18S ribosomal RNA to investigate the prevalence of Cryptosporidium and Giardia infection. The incidence of Cryptosporidium and Giardia in the nine areas ranged from 0% to 20.0% and 0% to 3.4%, respectively. The prevalence of Cryptosporidium among male and female deer was 8.1% and 3.9%, respectively, while that of Giardia was 0.7% and 0.8%. Sequence analysis identified the Cryptosporidium deer genotype, Cryptosporidium bovis, Cryptosporidium ryanae and Cryptosporidium meleagridis from the sequence of Cryptosporidium-specific partial 18S ribosomal RNA and Giardia intestinalis assemblage A from the partial sequence of Giardia-specific 18S rRNA. The variation in regional prevalence indicates that Cryptosporidium infection depends on environmental factors, and that bovine Cryptosporidium was detected more frequently than cervine Cryptosporidium. These data suggest that wild deer might be a healthy carrier of bovine Cryptosporidium.

Prevalence and Molecular Characterization of Giardia duodenalis in Calves in Turkey

Background: Giardia duodenalis (G. duodenalis) is an ubiquitous, flagellated intestinal protozoan with major public health significance worldwide. Limited data are available on the epidemiology of G. duodenalis in dairy cattle from Turkey. Determining the zoonotic potential of the Giardia infection requires molecular characterization. The aim of the present study was to investigate the prevalence and to molecularly characterize G. duodenalis in calves less than three months of age in Aydin, Aegean region of Turkey.Materials, Methods &amp; Results: The study was conducted on different dairy farms in the south-western part of the Turkey, Aegean Region, Aydin. A total of 198 Holstein Friesian calves less than three months of age, of both sexes were enrolled into the study. Faecal samples from each calf were collected manually from the rectum using a disposable latex glove. The consistency of collected samples was recorded as diarrhoeic or non-diarrhoeic. Diagnosis of G. duodenalis infection was made microscopically by detection of cysts in the faecal samples. One hundred and sixteen (58.5%) of the 198 faecal samples were diarrheic. Giardia cysts were found in 27 (23.28%) of the diarrheic samples and in 8 (9.76%) of nondiarrheic samples (P &lt; 0.05). The overall prevalence of giardiosis in calves was determined as 17.67%. The prevalence of Giardia genotypes was identified by DNA sequence analysis of the beta-giardin gene for every PCR positive sample. The beta-giardin nested PCR assay was revealed assemblage A and sub-genotype A3 was detected in all of 35 samples (100%).Discussion: The highest prevalence of Giardia infection in calves is reported at the age between 1 and 6 months, and the prevalence shows decreased rate from the age of 6 months. The present study was conducted in Aydin, a province of south-western Turkey in the Aegean Region, and the overall prevalence from a total of 198 dairy calves was 17.67%. The prevalence rate in calves with diarrhoea was higher and reached up to 23.28%, whereas it was 9.76% in non-diarrhoeic calves. A prevalence study with molecular characterization of G. duodenalis isolates in cattle has not yet been reported from Turkey. Molecular studies have shown that mostly assemblage E predominates in cattle, but recent studies denoted that assemblage A is increasingly being detected and might be more widespread than expected before. In the present study, Giardia positive samples identified with a beta-giardin nested PCR assay. The sub-genotype A3 was identified in all samples. The same sub-genotype was identified in human and dog samples from different countries. Furthermore, sub-genotype A3 was found in humans and dogs from Turkey. In this context, results of the present study suggested an important role of calves as potential reservoirs of human infections in Turkey. In conclusion, epidemiological data revealed that G. duodenalis infection is frequent in calves with diarrhoea in Aydin, Turkey. The presence of the potentially zoonotic sub-genotype A3 and high prevalence of Giardia infection in diarrheic calves indicated the importance of treatment and necessary preventative measures. Further studies in human and animal populations living in this region are warranted regarding the zoonotic epidemiology of Giardia duodenalis.

English

The aim of the study is to evaluate paediatric patients with protein losing enteropathy (PLE). Fourteen cases diagnosed as PLE were evaluated in terms ofaetiologies, diagnostic methods, laboratory findings, treatment procedures and long-term prognosis. Four of the cases had coeliac disease, three intestinal lymphangiectasia, three giardia infection, one H pylori infection and three cytomegalovirus (CMV) infection. Histopathological examinations of duodenum specimens revealed total villous atrophy in four cases, lymphatic dilatation in three cases, severe nodular appearance in four cases and no pathology in four cases. All of the cases except patients with intestinal lymphangiectasia were controlled by the appropriate treatment given for the underlying disease. The cases with CMV infection were treated with only supportive treatment and gancyclovir therapy was not needed. When proteinuria is not detected in well-appearing children admitted with oedema, PLE must be considered.

Predominance of Giardia intestinalis assemblage B in diarrhoeic children in Sharkia, Egypt

Background: Giardia intestinalis (G. intestinalis) is one of the most common human enteric protozoa that infect Egyptian children, causing most of the diarrhoeic outbreaks worldwide. Identification of G. intestinalis assemblage is important because of its role in determining sources of infection, in understanding the ecological and clinical impact of giardiasis, and hence its management and control.Objective: Study of this cross-sectional sample aimed to determine the genotypes of G. intestinalis isolated from the feces of diarrhoeic children attending outpatient clinic of Zagazig University hospital.Subjects and Methods: A single fecal sample was collected from each child (n=126). All samples were subjected to microscopic examination by direct wet mount before and after formal- ethyl acetate concentration. Positive samples were amplified by nested PCR (nPCR) and sequenced for intra and inter assemblage identification targeting tpi gene.Results: Microscopic examination revealed detection of G. intestinalis in 38 samples (30.2%). In 36 (28.6%) samples there was assemblage B predominance in 34 (94.4%) isolates, among which 24 (70.6%) were subgenotype BIV and 10 (29.4%) were sub-genotype BIII. Only 2 (5.6%) samples had assemblage A; all of them were AII subgenotype. All studied patient`s demographic and clinical data showed no significant association with Giardia infection or prevailing Giardia assemblages.Conclusion: G. intestinalis is the prevailing intestinal pathogen in diarrhoeic Egyptian children, with Giardia assemblage B predominance. These findings necessitate physicians’ attention and further genetic studies in Egypt and other endemic areas targeting different genetic loci, with the inclusion of larger population samples. This will lead to a better understanding of the ecological and clinical impact of giardiasis, its management and control.

Giardia duodenalis mouse model for the development of novel antigiardial agents

This study describes a neonatal mouse model of Giardia infection for development of novel antigiardials. Mice were infected with the axenically cultured Assemblage A BAH2c2 strain, with 105 trophozoites per animal recovered. This model proved to be robust and consistent for use in preliminary drug efficacy trials and drug development.

Prevalence, genotyping and risk factors of Giardia duodenalis from dogs in Vietnam.

This study was carried out to determine the prevalence, genotypes/assemblages and possible risk factors associated with Giardia duodenalis infection in dogs in central Vietnam. A total of 209 dog fecal samples, randomly collected from private owned dogs (n=105) and dogs from stores (n=104), were examined for Giardia cysts by microscopy. Positive samples were genotyped by PCR-sequence analysis of β-giardin and triosephosphate isomerase genes markers. Risk factors were studied using a structured questionnaire and collected data were analyzed by univariate and multivariate logistic regression analyses. Results indicated that the overall infection rate was 8.6% (18/209) with the detected parasites were belonging to the non-zoonotic assemblages C and D. Age, gender and origin of animals were the main risk factors associated with G. duodenalis infection in dogs under study. Occurrence of infection was more likely in young animals compared to old ones and in females compared to males. Dogs originated from stores were more prone to Giardia infection compared to private owned counterparts.

Giardia in a selected population of dogs and cats in Germany – diagnostics, coinfections and assemblages

Infections with the zoonotic endoparasite Giardia duodenalis are widely spread among dogs and cats worldwide. Since the question whether the infection might be transmitted from domestic animals to their owners is still an important topic, a reliable detection of patent Giardia infections and the determination of the associated Giardia assemblages is of major concern. The objectives of the present study were to determine the prevalence of Giardia infections in dogs and cats living in Germany using different diagnostic tests and to identify the Giardia assemblages of infected animals. Furthermore, a possible correlation of coinfections with other endoparasites was analysed. All samples were investigated by enzyme-linked immunosorbent assay (ELISA), merthiolate-iodine-formalin concentration technique (MIFC) and zinc chloride flotation. ELISA-positive samples were additionally screened with a direct immunofluorescence assay (IFA). Faecal DNA was extracted from all Giardia cyst-positive samples and used for multilocus sequence typing with nested PCRs targeting the following gene loci: SSU rRNA (SSU), glutamate dehydrogenase (gdh) and triosephosphate isomerase (tpi). Samples from dogs and cats tested positive for Giardia coproantigen (ELISA) in 30.6% and 17.9%, respectively. The MIFC technique revealed Giardia cysts in 33.9% of canine and in 34.6% of feline ELISA-positive samples, while using IFA, cysts were present in 90.4% of canine and in 76.9% of feline ELISA-positive samples. Coinfections with other endoparasites besides Giardia were found in both dogs and cats, yet a statistically significant correlation could solely be drawn for the canine samples. The success rate of the different PCR protocols varied between 23.1% (tpi) and 91.3% (SSU) for dogs and between 25.0% (gdh) and 90.0% (SSU) for cats. Dog-specific Giardia assemblages C and D were detected in 42 and 55 canine isolates, respectively. The cat-specific Giardia assemblage F was detected in 14 feline isolates. Two canine and two feline samples harboured the zoonotic assemblage A. According to the results of the study, Giardia is a common endoparasite in dogs and cats from Germany. The exclusive application of MIFC is insufficient for a reliable identification of patent Giardia infections since the IFA revealed a higher sensitivity for the detection of Giardia cysts in feline and canine faecal samples. Even though the majority of investigated animals harboured the species-specific Giardia assemblages C, D and F, a zoonotic potential arising from assemblage A could not be excluded.

Prevalence and associated risk factors for Giardia and Cryptosporidium infections among children of northwest Mexico: a cross-sectional study

BackgroundG. intestinalis and Cryptosporidium spp. are responsible for gastrointestinal infections worldwide. Contaminated food, feces, drinking water and predictors such as poverty, cultural and behavioral aspects have been involved in their transmission. Published studies about these infections are limited in Mexico. Cananea, Sonora is located in northwest Mexico and is one of the regions with the lowest marginalization index in the Sonora state. However, its rate of gastrointestinal infections increased from 48.7/1000 in 2003 to 77.9/1000 in 2010 in the general population. It was estimated that the prevalence of giardiasis can range from 20 to 30% in the Sonoran childhood population. However, the prevalence of giardiasis and cryptosporidiosis are unknown in Cananea, Sonora and they are likely contributing to its gastrointestinal infections rates.MethodsA total of 173 children (average age 8.8 ± 2.8 years) participated in this cross-sectional study. Anthropometric measurements and stool analysis were performed. Socioeconomic, cultural and symptomatology information were collected. The association between the risk factors and intestinal parasitic infections was analyzed by multivariate analysis using the STATA/SE package at a significance level of p ≤ 0.05.ResultsMore than half of the children (n = 103, 60%) had intestinal parasitic infections. Cryptosporidium spp. showed the highest prevalence (n = 47, 27%), which was followed by G. intestinalis (n = 40, 23%). Children with giardiasis and cryptosporidiosis had lower H/A and BMI/A Z scores than children who were free of these infections. Children with giardiasis were at higher risk (OR = 4.0; 95%CI = 1.11–13.02; p = 0.030) of reporting abdominal pain, and children who drank tap water were at higher risk (OR = 5.0; 95% CI = 1.41–17.20; p = 0.012) of cryptosporidiosis.ConclusionsThis was the first epidemiological study conducted in children in the region of Cananea, Sonora in northwest Mexico. The findings revealed a high prevalence of cryptosporidiosis and giardiasis, and their interactions with multiple risk factors were investigated. This study suggested that giardiasis and cryptosporidiosis may play an important role as causative factors of gastrointestinal diseases in the study region. Regional authorities must analyze water for human consumption to search for Cryptosporidium spp. and G. intestinalis.