Giardia Duodenalis Infection Research Articles

Intestinal parasitic infections: Current status and associated risk factors among school aged children in an archetypal African urban slum in Nigeria.

Intestinal parasitic infections (IPIs) among school aged children (SAC) in Nigeria remains endemic, hence the need for regular surveillance to attract the attention of policy makers. This cross-sectional study investigated the current prevalence and factors associated with intestinal parasitic infections among school aged children in an urban slum of Lagos City, Nigeria. Single stool samples from 384 school aged children (188 boys and 196 girls) wereexamined by employing Merthiolate-iodine-formaldehyde concentration (MIFC) and Kato-Katz methods. Demographic characteristics and risk factors were obtained by questionnaires investigation. The overall prevalence was 86.2% in school children, out of them 39.1% had polyparasitism. IPIs showed the highest to the lowest prevalence of 62% (238/384), 25% (97/384), 12.3% (47/384), 11.8% (45/384), 9.9% (38/384), 8.4% (32/384), 3.4% (13/384), and 0.5% (2/384) found in Ascaris lumbricoides, Entamoeba histolytica/dispar, Giardia duodenalis, Endolimax nana, Entamoeba coli, Trichuris trichiura, Blastocystis hominis, and hookworm infections, respectively. MIFC technique showed superiority to Kato-Katz technique in the detection of IPIs (p<0.0001). Drinking untreated water was a significant risk factor for these school aged children in acquiring protozoan infections after multivariate adjustment (OR=1.86, 95% CI=1.08-3.20, p=0.02). Intestinal parasitic infections are very severe among school aged children in the urban slums, thus regular mass de-worming programs, health education, and the provision of safe drinking water is recommended to combat IPIs among the school aged children.

Prevalence and Multilocus Genotyping Analysis of Cryptosporidium and Giardia Isolates from Dogs in Chiang Mai, Thailand.

The occurrence and zoonotic potential of Cryptosporidium spp. and Giardia duodenalis isolated from dogs in Chiang Mai, Thailand were determined. Fecal samples were collected from 109 dogs between July and August 2008. Cryptosporidium spp. infection was determined by immunofluorescent assay (IFA), PCR assays that amplify Cryptosporidium heat-shock protein 70 kDa (hsp70), and two PCR assays that amplify a small subunit-ribosomal RNA (SSU-rRNA). Giardia duodenalis infection was identified using zinc sulfate centrifugal flotation, IFA, and four PCR assays that amplify the Giardia glutamate dehydrogenase (gdh), beta-giardin (bg), and generic and dog-specific assays of triosephosphate isomerase (tpi) genes. Overall prevalence of Cryptosporidium spp. and G. duodenalis was 31.2% and 45.9%, respectively. Sequence analysis of 22 Cryptosporidium-positive samples and 21 Giardia-positive samples revealed the presence of C. canis in 15, and C. parvum in 7, G. duodenalis Assemblage C in 8, D in 11, and mixed of C and D in 2 dogs. Dogs in Chiang Mai were commonly exposed to Cryptosporidium spp. and G. duodenalis. Cryptosporidium parvum can be isolated from the feces of dogs, and all G. duodenalis assemblages were dog-specific. Dogs could be a reservoir for a zoonotic Cryptosporidium infection in humans, but further studies will be required to determine the clinical and zoonotic importance.

Chloroquine treatment against naturally occuring Giardia duodenalis infection in dogs

The aim of the present study was to evaluate the efficacy of chloroquine on lessening or eliminating cyst shedding in dogs naturally infected with Giardia duodenalis. A total of 26 dogs naturally infected with G. duodenalis, from various breeds, ages and of both sexes were selected and randomly assigned into two groups based on treatment (group I, n=20 dogs treated orally with 2.5 mg/kg chloroquine twice daily for 5 consecutive days) and control (group II, n=6 untreated control dogs). Diagnosis was based on microscopic faecal examination and rapid test kits. Cyst excretion was determined on days 0, 3, 7 and 10, before and after treatment. Evaluation of the percentage reduction in cyst excretion revealed 99.8% efficacy on day 3 and 99.9 % on days 7 and 10 in the treatment group. Geometric means of the number of excreted cysts did not change significantly in the control group. Chloroquine at the proposed dosage might be a practical in application, low priced and highly effective treatment option in dogs with giardiasis.

Water, sanitation and hygiene related risk factors for soil-transmitted helminth and Giardia duodenalis infections in rural communities in Timor-Leste

There is little evidence on prevalence or risk factors for soil transmitted helminth infections in Timor-Leste. This study describes the epidemiology, water, sanitation and hygiene, and socioeconomic risk factors of STH and intestinal protozoa amongst communities in Manufahi District, Timor-Leste. As part of a cluster randomised controlled trial, a baseline cross-sectional survey was conducted across 18 villages, with data from six additional villages. Stool samples were assessed for soil transmitted helminth and protozoal infections using quantitative PCR (qPCR) and questionnaires administered to collect water, sanitation and hygiene and socioeconomic data. Risk factors for infection were assessed using multivariable mixed-effects logistic regression, stratified by age group (preschool, school-aged and adult). Overall, soil transmitted helminth prevalence was 69% (95% Confidence Interval 67–71%), with Necator americanus being most common (60%; 95% Confidence Interval 58–62%) followed by Ascaris spp. (24%; 95% Confidence Interval 23–26%). Ascaris-N. americanus co-infection was common (17%; 95% Confidence Interval 15%-18%). Giardia duodenalis was the main protozoan identified (13%; 95% Confidence Interval 11–14%). Baseline water, sanitation and hygiene infrastructure and behaviours were poor. Although risk factors varied by age of participants and parasite species, risk factors for N. americanus infection included, generally, age in years, male sex, and socioeconomic quintile. Risk factors for Ascaris included age in years for children, and piped water to the yard for adults. In this first known assessment of community-based prevalence and associated risk factors in Timor-Leste, soil transmitted helminth infections were highly prevalent, indicating a need for soil transmitted helminth control. Few associations with water, sanitation and hygiene were evident, despite water, sanitation and hygiene being generally poor. In our water, sanitation and hygiene we will investigate implications of improving WASH on soil transmitted helminth infection in impoverished communities.

Performance of microscopy and ELISA for diagnosing Giardia duodenalis infection in different pediatric groups

Techniques for Giardia diagnosis based on microscopy are usually applied as routine laboratory testing; however, they typically exhibit low sensitivity. This study aimed to evaluate Giardia duodenalis and other intestinal parasitic infections in different pediatric groups, with an emphasis on the comparison of Giardia diagnostic techniques. Feces from 824 children from different groups (diarrheic, malnourished, with cancer and from day care) were examined by microscopy and ELISA for Giardia, Cryptosporidium sp. and Entamoeba histolytica coproantigen detection. Giardia-positive samples from day-care children, identified by either microscopy or ELISA, were further tested by PCR targeting of the β-giardin and Gdh genes. Statistically significant differences (P<0.05) were observed when comparing the frequency of each protozoan among the groups. Giardia duodenalis was more frequent in day-care children and Cryptosporidium sp. in diarrheic and malnourished groups; infections by Entamoeba histolytica were found only in children with diarrhea. Considering positivity for Giardia by at least one method, ELISA was found to be more sensitive than microscopy (97% versus 55%). To examine discrepancies among the diagnostic methods, 71 Giardia-positive stool samples from day-care children were tested by PCR; of these, DNA was amplified from 51 samples (77.4%). Concordance of positivity between microscopy and ELISA was found for 48 samples, with 43 confirmed by PCR. Parasite DNA was amplified from eleven of the 20 Giardia samples (55%) identified only by ELISA. This study shows the higher sensitivity of ELISA over microscopy for Giardia diagnosis when a single sample is analyzed and emphasizes the need for methods based on coproantigen detection to identify this parasite in diarrheic fecal samples.

Prevalence of Giardiaduodenalis among children from a central region of Cuba: molecular characterization and associated risk factors.

Giardia duodenalis is one of the most frequent intestinal parasitic infections in children worldwide. To date, eight main assemblages of G. duodenalis have been described, but only A and B genetic groups are known to infect humans. A cross-sectional study was conducted to determine the prevalence and risk factors of Giardia duodenalis infection in 417 preschool children from the Fomento municipality in the central region of Cuba between January and June 2013. The overall prevalence of Giardia infection was 10.79%. Assemblage identification was carried out by the amplification of a fragment of the triose phosphate isomerase (tpi) gene. DNA from 36 of 45 (80%) samples was successfully amplified by PCR-tpi. Assemblage B and mixed assemblages A+B represented 52.78 and 36.11% respectively, of genotyped samples. Assemblage A accounts for only 11.11%. Children who were cared for at home were associated with diarrhea caused by assemblage B. No associations were found between other clinical variables with infecting assemblage of Giardia. Univariate analysis identified the use of unsafe water resources (OR 2.9; CI 1.2-6.8) and-even more interestingly-keeping dogs indoor (OR 2.5; CI 1.2-5.4) were significant risk factors associated with Giardia infection among children. Multivariate analysis using introduction test logistic regression ratified the association of these two risk factors: kept dogs indoor (OR 2.8, CI 1.1-5.3), and untreated water (OR 1.4, CI 1.4-4.9) with Giardia infection. This information may be useful for an effective prevention and control programme of giardiasis in this population.

Adaptive immune response in symptomatic and asymptomatic enteric protozoal infection: evidence for a determining role of parasite genetic heterogeneity in host immunity to human giardiasis

The genetic basis of the ultimate clinical outcomes of human giardiasis has been the subject of numerous investigations. We previously demonstrated roles for both host and parasite factors in determining the outcome of enteric infection in a murine model of Giardia duodenalis infection. In the current study, fecal and serum specimens from healthy controls and human subjects infected with the intestinal parasite G. duodenalis were assessed. Using a semi-nested PCR method, clinical isolates were genetically characterized based on the gdh and tpi loci, and the phylogenetic trees were constructed. Using a sandwich ELISA method, the serum levels of representative TH1 and TH2 cytokines were measured in infected human subjects and healthy controls. Here we showed that symptomatic human giardiasis was characterized by significantly elevated serum levels of the TH1 cytokine IFN-γ compared to healthy controls, whereas asymptomatic human subjects and healthy controls had comparable levels of serum IFN-γ. Further analyses showed that human subjects infected with G. duodenalis genotype AI had significantly elevated levels of serum IFN-γ and IL-10, but not IL-5, whereas human subjects infected with AII had similar levels of those cytokines compared to healthy controls. These data demonstrate roles for both host and parasite factors in the determination of the outcome of enteric infections and may further broaden our understanding of host-parasite interaction during enteric protozoal infections.

The efficacy of chloroquine treatment against naturally occuring Giardia duodenalis infection in lambs

Objective. The aim of the present study was to determine the efficacy of Chloroquine (Cq), an antimalarial medicine, administered at a dose of 2.5 mg/kg, orally, during 5 consecutive days, in Sakiz and Merino lambs naturally infected with Giardia duodenalis. Materials and methods. To this extent weaned 10 weeks of aged lambs were enrolled and randomly assigned into two groups based on treatment (group C, n=18 lambs treated with Cq) and placebo (group P, n=8 untreated control animals). Diagnosis was based on detection of trophozoit and/or cysts on fecal flotation. Cyst count per gram feces (days 0, 3, 7 and 10) was analyzed among groups. Results. During the trial, regarding the efficacy of Cq on days 3., 7., and 10. There was significant (p&lt;0.01) reduction in cyst excretion; whereas evaluation of mean geometric cyst excretion revealed 100% reduction. Conclusions. There was a very high (100%) reduction in cyst excretion in the Cq treatment group compared to the positive untreated control group on days 3, 7 and 10, resulting in a significant (p&lt;0.001) reduction, making Cq, safety, and thus highly effective treatment option of lambs with naturally occuring giardiasis.Objetivo. El objetivo del presente estudio fue determinar la eficacia de la cloroquina, un medicamento contra la malaria, administrado a una dosis de 2.5 mg/kg, por vía oral, durante 5 días consecutivos, en Corderos Sakiz y Merino infectados naturalmente con Giardia duodenalis. Materiales y metodos. En esta medida destetados 10 semanas de edad fueron incluidos y asignados al azar en dos grupos sobre la base del tratamiento (grupo C, n = 18 corderos tratados con cloroquina) y placebo (grupo P, n = 8 animales de control no tratados). El diagnóstico se basa en la detección de trophozoit y/o quistes en la flotación fecal. Quiste recuento por gramo de heces (día 0, 3, 7 y 10) se analizó entre los grupos. Resultados. Respecto a la eficacia de la cloroquina en los días 3, 7 y 10 existió una reducción significativa (p&lt;0.01) en la excreción de quistes; mientras que la evaluación de la media de la excreción Rev.MVZ Córdoba 21(2):5328-5335, 2016. ISSN: 0122-0268 ORIGINAL 5329 de quistes reveló una reducción del 100%. Conclusiones. Durante el estudio hubo una reducción del 100% en la excreción de quistes en el grupo de tratamiento con cloroquina en comparación con el grupo control no tratado positivo en los días 3, 7 y 10, lo que resulta en una disminución significativa (p&lt;0.001) por lo que la cloroquina razonablemente es una opción de tratamiento por el costo, seguridad, y por lo tanto muy eficaz de corderos infectados naturalmente con giardiasis.

Giardia duodenalis Surface Cysteine Proteases Induce Cleavage of the Intestinal Epithelial Cytoskeletal Protein Villin via Myosin Light Chain Kinase.

Giardia duodenalis infections are among the most common causes of waterborne diarrhoeal disease worldwide. At the height of infection, G. duodenalis trophozoites induce multiple pathophysiological processes within intestinal epithelial cells that contribute to the development of diarrhoeal disease. To date, our understanding of pathophysiological processes in giardiasis remains incompletely understood. The present study reveals a previously unappreciated role for G. duodenalis cathepsin cysteine proteases in intestinal epithelial pathophysiological processes that occur during giardiasis. Experiments first established that Giardia trophozoites indeed produce cathepsin B and L in strain-dependent fashion. Co-incubation of G. duodenalis with human enterocytes enhanced cathepsin production by Assemblage A (NF and S2 isolates) trophozoites, but not when epithelial cells were exposed to Assemblage B (GSM isolate) trophozoites. Direct contact between G. duodenalis parasites and human intestinal epithelial monolayers resulted in the degradation and redistribution of the intestinal epithelial cytoskeletal protein villin; these effects were abolished when parasite cathepsin cysteine proteases were inhibited. Interestingly, inhibition of parasite proteases did not prevent degradation of the intestinal tight junction-associated protein zonula occludens 1 (ZO-1), suggesting that G. duodenalis induces multiple pathophysiological processes within intestinal epithelial cells. Finally, this study demonstrates that G. duodenalis-mediated disruption of villin is, at least, in part dependent on activation of myosin light chain kinase (MLCK). Taken together, this study indicates a novel role for parasite cathepsin cysteine proteases in the pathophysiology of G. duodenalis infections.

Albendazole induces oxidative stress and DNA damage in the parasitic protozoan Giardia duodenalis.

The control of Giardia duodenalis infections is carried out mainly by drugs, among these albendazole (ABZ) is commonly used. Although the cytotoxic effect of ABZ usually involves binding to β-tubulin, it has been suggested that oxidative stress may also play a role in its parasiticidal mechanism. In this work the effect of ABZ in Giardia clones that are susceptible or resistant to different concentrations (1.35, 8, and 250 μM) of this drug was analyzed. Reactive oxygen species (ROS) were induced by ABZ in susceptible clones and this was associated with a decrease in growth that was alleviated by cysteine supplementation. Remarkably, ABZ-resistant clones exhibited partial cross-resistance to H2O2, whereas a Giardia H2O2-resistant strain can grow in the presence of ABZ. Lipid oxidation and protein carbonylation in ABZ-treated parasites did not show significant differences as compared to untreated parasites; however, ABZ induced the formation of 8OHdG adducts and DNA degradation, indicating nucleic acid oxidative damage. This was supported by observations of histone H2AX phosphorylation in ABZ-susceptible trophozoites treated with 250 μM ABZ. Flow cytometry analysis showed that ABZ partially arrested cell cycle in drug-susceptible clones at G2/M phase at the expense of cells in G1 phase. Also, ABZ treatment resulted in phosphatidylserine exposure on the parasite surface, an event related to apoptosis. All together these data suggest that ROS induced by ABZ affect Giardia genetic material through oxidative stress mechanisms and subsequent induction of apoptotic-like events.

Differences in the faecal microbiome of non-diarrhoeic clinically healthy dogs and cats associated with Giardia duodenalis infection: impact of hookworms and coccidia

The protozoan parasite Giardia duodenalis causes a waterborne diarrhoeal disease in animals and humans, yet many Giardia-infected hosts remain asymptomatic. Mixed parasite infections are common in both animals and humans with unknown consequences for Giardia or other parasites. We compared the composition and diversity of bacterial communities from 40 dogs, including free-roaming dogs, and 21 surrendered cats from Australia. The dog cohort included 17 (42.5%) dogs positive for Giardia and 13 (32.5%) dogs positive for dog hookworm (Ancylostoma caninum). The cat samples included eight positive for Giardia and eight positive for Cystoisospora. The V4 region of 16S rRNA was sequenced at an average of 36,383 high quality sequences (>200bp) per sample using the Ion Torrent PGM™ platform. In dogs we found significant (P<0.05, AnoSim) difference between the Giardia-positive and -negative groups when evaluating bacterial genera. No such difference was demonstrated between Ancylostoma-positive and -negative dogs. However, there was a modest but not significant separation of the Giardia-negative and -positive dogs (P=0.09, UniFrac) using principal coordinate analysis. Removal of dogs with hookworms further separated Giardia-positive and -negative groupings (P=0.06, UniFrac). In cats, the presence of Giardia was not associated with a significant difference based on bacterial genera (P>0.05, AnoSim). Cystoisospora-positive cats, however, exhibited significantly different profiles from Cystoisospora-negative cats (P=0.02, AnoSim) and UniFrac showed significant separation of Cystoisospora-positive and -negative samples (P<0.01). The results suggest that in clinically heathy dogs and cats, helminths and protozoa are associated with different microbiomes and possibly variable gut microbiota functions. Understanding the association of parasites and microbiomes has important consequences for the administration of antiparasitic drugs in animals and humans.

Age-dependent decline and association with stunting of Giardia duodenalis infection among schoolchildren in rural Huye district, Rwanda

Giardia duodenalis infection is highly prevalent and a cause of underweight in pre-school children in rural Rwanda. The present study aimed at assessing the age-pattern of Giardia infection and its manifestation in older children, i.e., during school age.Stool samples were collected from 622 schoolchildren at two schools in the Huye district of southern Rwanda (rural, 301; urban, 321) and subjected to G. duodenalis specific PCR assays. Clinical and anthropometric data, socio-economic status and factors potentially associated with G. duodenalis infection were assessed.Of the 622 children (mean age, 10.4 years), 35.7% were infected with G. duodenalis (rural, 43.9%; urban, 28.0%; P<0.0001). Only few indicators of low socio-economic status were found to be associated with infection. In rural but not urban schoolchildren, infection prevalence declined significantly with age. G. duodenalis infection more than doubled the odds of stunting in both rural (adjusted OR, 2.35 (95%CI, 1.25–4.41)) and urban children (adjusted OR, 2.27 (95%CI, 1.01–5.09)).In the study area of rural southern Rwanda, G. duodenalis prevalence among children declined throughout school-age. The data suggest that while lacking overt clinical manifestation at high endemicity, G. duodenalis infection is a common cause of stunting in schoolchildren.

Giardia duodenalis and soil-transmitted helminths infections in children in São Tomé and Príncipe: do we think Giardia when addressing parasite control?

Giardia duodenalis prevalence is commonly as high as soil-transmitted helminths (STH), nevertheless is not considered for large-scale chemotherapy through mass drug administration (MDA) due to its short incubation period and frequent reinfections, its control being associated to improving access to water and sanitation. A study enrolling 444 children attending preschools was conducted in May 2011 during a deworming campaign. Faecal samples were obtained and analysed through microscopy of wet mounting and after Kato-Katz and formol-ether concentration techniques. The majority of children were infected with at least one pathogenic parasite (86.7%, 385 of 444). Ascaris lumbricoides and Trichuris trichiura (56.3%, 250 of 444 and 52.5%, 233 of 444, respectively) were the most frequent parasites followed by G. duodenalis infecting 41.7% (185 of 444) of the children. The present work aimed at obtaining updated information concerning intestinal parasite infections in children attending preschools in São Tomé and Príncipe and to contribute for the adequate management of the enteric infections.

Giardia duodenalis infection reduces granulocyte infiltration in an in vivo model of bacterial toxin-induced colitis and attenuates inflammation in human intestinal tissue.

Giardia duodenalis (syn. G. intestinalis, G. lamblia) is a predominant cause of waterborne diarrheal disease that may lead to post-infectious functional gastrointestinal disorders. Although Giardia-infected individuals could carry as much as 106 trophozoites per centimetre of gut, their intestinal mucosa is devoid of overt signs of inflammation. Recent studies have shown that in endemic countries where bacterial infectious diseases are common, Giardia infections can protect against the development of diarrheal disease and fever. Conversely, separate observations have indicated Giardia infections may enhance the severity of diarrheal disease from a co-infecting pathogen. Polymorphonuclear leukocytes or neutrophils (PMNs) are granulocytic, innate immune cells characteristic of acute intestinal inflammatory responses against bacterial pathogens that contribute to the development of diarrheal disease following recruitment into intestinal tissues. Giardia cathepsin B cysteine proteases have been shown to attenuate PMN chemotaxis towards IL-8/CXCL8, suggesting Giardia targets PMN accumulation. However, the ability of Giardia infections to attenuate PMN accumulation in vivo and how in turn this effect may alter the host inflammatory response in the intestine has yet to be demonstrated. Herein, we report that Giardia infection attenuates granulocyte tissue infiltration induced by intra-rectal instillation of Clostridium difficile toxin A and B in an isolate-dependent manner. This attenuation of granulocyte infiltration into colonic tissues paralled decreased expression of several cytokines associated with the recruitment of PMNs. Giardia trophozoite isolates that attenuated granulocyte infiltration in vivo also decreased protein expression of cytokines released from inflamed mucosal biopsy tissues collected from patients with active Crohn’s disease, including several cytokines associated with PMN recruitment. These results demonstrate for the first time that certain Giardia infections may attenuate PMN accumulation by decreasing the expression of the mediators responsible for their recruitment.

First molecular characterisation of Giardia duodenalis infection in dairy goats in Brazil

The aim of this study was to perform the first molecular genotyping of Giardia duodenalis from goats in Brazil, in order to assess the risk for zoonotic transmission. Samples were collected from two dairy goat farms (Saanen breed) located in the city of Niteroi in the state of Rio de Janeiro, Brazil. Goat faecal samples (n&amp;nbsp;=&amp;nbsp;58) were collected directly from the rectums of all animals up to one year of age and were subjected to centrifuge-flotation in sugar saturate solution. Nested-PCR and sequencing using &amp;beta; -giardin and tpi gene targets was performed on positive samples. Seventeen out of fifty-eight (29.31%) faecal samples were positive for Giardia duodenalis cysts, all belonging to the same farm. Only eight isolates were successfully sequenced (eight samples for &amp;beta;-giardin and four samples for tpi), all belonging to genotype E. Two types of sequences were identified for each locus within isolates from the current study, which exhibited sequence heterogeneity with variable numbers of single nucleotide polymorphisms. The present study contributes to a better understanding of the molecular epidemiology of this parasite. &amp;nbsp;

Reducing occurrence of Giardia duodenalis in children living in semiarid regions: impact of a large scale rainwater harvesting initiative.

BackgroundIn Brazil, about two million people living in rural semiarid regions were benefited with the construction of rainwater cement cisterns, as an initiative from the program “One Million Cisterns” (P1MC). Nevertheless, few epidemiological studies have been conducted to assess health risks or protection effects associated with consumption of this water source. The aim of this study was to evaluate whether access to rainwater harvesting cisterns is associated with the decrease in the occurrence of Giardia duodenalis infections in children, compared to other children living in households supplied by other water sources.Methodology/Principal FindingsA quasi-experimental study with two concurrent cohorts was developed in two rural municipalities of the semiarid region of Brazil. A sample of 664 children, aged between 4 months and 5 years old, was followed up, of which 332 had access to rainwater cisterns (cistern group) and 332 did not, having water supplied from alternative sources (comparison group). In a period of approximately one year (2010) intestinal parasites were investigated in feces three times. The prevalence of G. duodenalis in children from the cistern group ranged from 4.8 to 10.5%, while the prevalence in the comparison group ranged from 7.6 to 16.7%. Multivariate analysis (GEE) showed a higher risk of G. duodenalis infection in children who did not have access to rainwater cisterns, when compared to children who did (OR 1.72; 95% CI 1.14–2.59). The other variables associated with G. duodenalis infection were: number of rooms per house (OR 0.89; 95% CI 0.80–0.99); family income (OR0.48; 95% CI 0.26–0.88); birth order (OR 1.72; 95% CI 1.17–2.51); preterm children (OR 1.70; 95% CI 1.19–2.43); and improper hand hygiene prior to food preparation (OR 4.78; 95% CI 1.95–11.76).Conclusions/SignificanceOwnership of a rainwater cistern is associated with a lower prevalence of G. duodenalis infection in children after adjustment for environmental and family-related factors. Nevertheless, the study suggests the necessity to complement physical interventions with actions related to personal and domestic hygiene to enable further reductions in parasite infections affecting mainly the underprivileged populations.

Social determinants associated with Giardia duodenalis infection in southern Côte d'Ivoire.

The purpose of this investigation was to analyze the association between different social determinants of health at the local scale and Giardia duodenalis infection in diverse settlements in southern Côte d'Ivoire. Stool samples from 306 individuals aged 1-16years were collected from six rural villages and a small town. Five variables were categorized to classify the increasing risk levels of acquiring intestinal parasites. Giardia prevalences (%) and odds ratios (ORs) were evaluated. Correlation and regression analyses were conducted to determine the correlation coefficients and to propose predictive models based on social determinants to forecast the risk of giardiasis. The overall observed prevalence of Giardia was 21.6%. When the analysis was conducted at the local level, the percentage of infected people varied from a minimum of 12.7 up to 36.4%. A significant association (p < 0.001) was found between the selected social determinants and G. duodenalis prevalence in the different localities. Correlation and regression analyses allowed us to describe two predictive models to estimate the OR of Giardia transmission. This study helps to clarify the possible impact of different social determinants of health on the risk of giardiasis at the local scale. Both predictive models could be suitable in order to assess the likelihood of the transmission of intestinal parasitic infection in developing countries.

Prevalence and risk factors of Giardia doudenalis in dogs from China

The aim of this study was to carry out a survey for the presence of Giardia duodenalis infection in canine using ELISA and PCR and to identify risk factors for infection. Samples from 318 dogs’ feces living in nine cities in China were used in the present study. Each sample was tested for the presence of G. duodenalis-specific antigens using ELISA and 197 out of 318 samples were further examined for the presence of G. duodenalis using PCR. The overall rate of canines infected with giardiasis in the present study was 16.04 % and 15.22 % using ELISA and PCR, respectively. No significant difference was found between sex and Giardia positivity. Young dogs (up to one year) and living in communities were identified as risk factors for infection by multivariate logistic regression analysis. In conclusion, giardiasis in dogs was present in nine cities in China; as risk factors, young dogs (up to one year) and living in communities were of great significance. Giardia-infected canine should be treated for hygienic management to prevent transmission of the infection from dog to human.

Novel insights in post‐infectious irritable bowel syndrome in experimental giardiasis (650.15)

Giardia duodenalis infections can lead to post‐infectious irritable bowel syndrome (PI‐IBS), a disorder characterized by chronic visceral pain. Using a new model of post‐giardiasis IBS, this study aimed to reveal novel mechanisms responsible for PI‐IBS. Weaning rats were gavaged with live Giardia trophozoites (assemblages A or B). Visceral hypersensitivity was assessed 50 days post‐infection (DPI) by measuring blood pressure changes in response to jejunal/rectal balloon distension. Spinal cord expression of c‐fos was used as a marker of nociceptive signaling. Caco‐2 monolayers were used to assess non‐invasive E. Coli HB101 translocation, as well as the integrity of epithelial barrier structure and function at early time points. c‐fos activation was observed during the acute phase. While the infection was cleared by 21DPI, jejunal and rectal hypersensitivity was observed 50 DPI with either assemblage along with mast cell infiltration. In vitro challenge with Giardia also facilitated the paracellular translocation of E. coli, increased epithelial permeability, and disrupted the tight junctional (TJ) proteins occludin and claudin‐4. These data show that Giardia‐induced IBS is associated with TJ proteins disruption, translocation of a commensal E. coli and c‐fos activation during the acute phase of the infection, as well as mast cell infiltration and visceral hypersensitivity. Findings in this model will help identify the mechanisms of Giardia leading to post‐giardiasis‐IBS.Grant Funding Source: Supported by the French ministry of secondary education and research, NSERC‐CREATE

Evaluation of cellular and humoral systemic immune response against Giardia duodenalis infection in cattle

Giardia duodenalis causes diarrhoea in humans and a wide range of mammals, including cattle. In cattle, the infection often has a chronic character. Infected calves may excrete cysts for several months, suggesting that Giardia is able to suppress and evade the immune response.In this study six calves were infected with G. duodenalis assemblage A and E and housed in an environment that allowed reinfection. Cyst excretion was monitored twice a week and blood was collected every 2 weeks, until decreasing cyst counts indicated the development of protective immunity. The kinetics of the circulating memory cells and serum antibodies were followed up throughout this period. Cyst excretion started 1 week post-infection and remained high until week 14. Low cyst counts from week 15 p.i. onwards indicated that the calves had developed immunity.From week 5 p.i. significant proliferation of CD4+ αβ T-cells was observed after in vitro stimulation with G. duodenalis antigen. Characterisation of the proliferating CD4+ T-cells using real time qPCR showed that at the peak of antigen driven PBMC proliferation the majority of cells were CD4+ T-cells expressing IL-17 and to a lesser extent FoxP3. The cell proliferation was strongly reduced after plastic adhesion of the PBMC, suggesting a role for antigen-presenting cells. Failure to restore proliferation of depleted PBMC with Giardia-stimulated monocyte-derived dendritic cells (MoDC) and unchanged proliferation after depletion of CD21+ B-cells showed that other antigen-presenting cells than MoDC and B-cells were important for T-cell proliferation. Analysis of the antibody response indicated that serum IgG1 and IgA levels against G. duodenalis assemblage A and E increased from week 11 post-infection. From the start of the antibody response, all trophozoites stained positive in an immunofluorescence assay with serum antibodies, indicating that a broad repertoire of antibodies was produced against all variant-specific surface proteins.Further research is necessary to determine which effector T-cell subset produces IL-17 and which cells play a role in antigen presentation.