Giardia intestinalis and nutritional status in children participating in the complementary nutrition program, Antioquia, Colombia, May to October 2006

Systematic Review of Diagnostic Approaches for Human Giardiasis: Unveiling Optimal Strategies

Giardiasis, caused by the protozoan Giardia intestinalis, affects around 400 million people worldwide, emphasizing the critical need for accurate diagnosis to enhance human health, especially in children. Prolonged giardiasis in childhood can lead to intellectual deficits and other complications. A variety of diagnostic tools, including microscopic, immunological, and molecular methods, are available for detecting G. intestinalis infection. Choosing the most suitable method can be challenging due to the abundance of options. This systematic review assesses the reliability and applicability of these diagnostic modalities. Utilizing the Dimensions and Wordart platforms for data analysis, we focus on relevant literature addressing diagnostic methods for human giardiasis. Microscopic techniques, particularly Ritchie's method, emerge as the primary choice, followed by enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). PCR's limited use is attributed to its high cost and infrastructure challenges in developing nations. In conclusion, our analysis supports microscopic methods as the gold standard for giardiasis diagnosis. However, in cases where symptoms persist despite a negative diagnosis, employing more sensitive diagnostic approaches is advisable.

Malaria, gastrointestinal parasite infection and nutritional status among febrile children In Accra, Ghana

Introduction

Malaria and intestinal parasite infection are common in developing countries. These Parasites causes anaemia and malnutrition mostly in children. For this reason, it is important to study these infections and their effects in order to monitor interventions to control them. This study aims to determine prevalence of malaria and intestinal parasite infections and their association with nutritional status among febrile children in Accra, Ghana.

Methods

The study was conducted among febrile children aged 6 months to 5 years attending three health facilities in Accra from May to October, 2022. A total of 315 children were selected for the study. Anthropometric measurement was done for each participant. Blood and stool samples were collected for investigation. Thick and thin blood smears stained with 10% Giemsa were prepared and examined for Plasmodium parasite using microscopy. Stool samples were processed using direct wet mount and formalin-ether concentration method and examined for intestinal parasites using microscopy. Haemoglobin concentration was measured using automatic haematology analyzer.

Results

A total of 24% (76/315) were positive for malaria. Plasmodium falciparum accounted for 77.6% (59/76) of parasitaemia, whereas Plasmodium malariae was 22.4% (17/76). Prevalence of intestinal parasite infection was 10.7% (34/315). Giardia lamblia accounted for 17/315 (5.3%) of the entire children, followed by Ascaris lumbricoides 8/315 (2.5%), Hookworm 6/315 (1.9%) and Trichuris trichiura 3/315 (0.9%). A total of 15/315 (5%) of the participants had co-infection of malaria and intestinal parasite infection. Prevalence of anaemia, malnutrition, stunting, wasting and underweight were (72%), (30.7%), (16.2%), (24.4%) and (57.1%) respectively. Malaria was significantly associated with anaemia (p = 0.000) and underweight (p = 0.013). Ascaris lumbricoides was significantly associated with wasting (p = 0.010). Giardia lamblia was significantly association with malnutrition (p = 0.000) and Stunting (p = 0.000), whereas Hookworm was found to be significantly associated with anaemia (p = 0.021).

Conclusion

Prevalence of IPI in this study was less than previously reported, most likely due to regular deworming of most of the children. However, Malaria and intestinal parasitic infection were significantly associated with anaemia and malnutrition including wasting, stunting, and underweight.

Evaluation of School Children Nutritional Status in Ecuador Using Nutrimetry: A Proposal of an Education Protocol to Address the Determinants of Malnutrition

The education sector is a cornerstone in the battle against malnutrition in children. However, there are still no consolidated protocols that outline strategies for how nutrition programs in low- and middle-income countries can be delivered through the education sector. Establishing the correct community diagnosis is essential prior to the elaboration of an intervention plan for a school population that takes into account more than just traditional variables related to the nutritional status. A total of 574 boys and girls aged 3–11 years from three educational institutions in different municipalities in Ecuador participated in the study. Sociodemographic, anthropometric (weight and height) and coproparasitological data were obtained. Nutrimetry, which is a combination of two classical anthropometrics indicators, was used for the analysis of the nutritional status, and the indicators’ frequencies varied among the schools. In order to improve the nutritional status of children, we proposed a framework mainly focusing on establishing alliances with the education sector and taking into account gender equality; respect for the environment; and the customs, beliefs and traditions of each population. The results obtained from the analyses of other variables demonstrated the importance of an adequate diagnosis prior to any type of intervention at the nutritional level, since characteristics could vary by local area and have an impact on the successfulness of the intervention.

Systematic review to evaluate a potential association between helminth infection and physical stunting in children

Background

Despite considerable public health efforts over the past 20 years, childhood stunting (physical and/or cognitive) levels globally remain unacceptably high—at 22% amongst children under 5 years old in 2020. The aetiology of stunting is complex and still largely unknown. Helminths can cause significant mortality and morbidity and have often been cited as major causative agents for stunting, although their actual role in childhood stunting remains unclear. Our aim was to systematically review the current evidence to help support or refute the hypothesis that helminths cause physical stunting in children.

Methods

Inclusion criteria were as follows: infected with (and/or exposed to) helminths (soil-transmitted helminths, schistosomes or food-borne trematodes), children, pregnant or breastfeeding women as study participants (children included infants 0–1 year old, preschool-age children 1–5 years and school-age children > 5 years old), anthelmintic treatment intervention, stunting-related variables reported (e.g. height, height-for-age z-score, birth weight), helminth infection reported in relation to stunting, any geographic location, any date, peer-reviewed literature only. Exclusion criteria were: non-primary research, study protocols, studies with no new data, non-English language papers and animal (non-human) helminth studies. Seven databases were searched on 28 May 2021. Risk of bias was assessed for included studies and GRADE was used for studies included in RCT subgroup meta-analyses (in preschool-age children and pregnant women). This systematic review was registered with PROSPERO (CRD42021256201).

Results

Eighty studies were included in the analyses. No significant overall evidence was found in support of the hypothesis that helminths cause physical stunting in children, although there was some association with wasting.

Conclusions

Whilst analyses of the available literature to date failed to support a direct association between helminth infection and childhood stunting, there was significant heterogeneity between studies, and many had follow-up periods which may have been too short to detect impacts on growth. Most apparent was a lack of available data from key demographic groups wherein one may predict the greatest association of helminth infection with stunting—notably that of infants, preschool-age children, and pregnant or nursing women. Thus this review highlights the urgent need for further targeted empirical research amongst these potentially most vulnerable demographic groups.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05235-5.

Anthropometric Indices of Giardia-Infected Under-Five Children Presenting with Moderate-to-Severe Diarrhea and Their Healthy Community Controls: Data from the Global Enteric Multicenter Study

Among all intestinal parasitosis, giardiasis has been reported to be associated with delayed growth in malnourished children under 5 living in low- and middle-income countries. Relevant data on the nutritional status of children aged 0–59 months presenting with moderate-to-severe diarrhea (MSD) and giardia infection were collected from sentinel health facilities of the Global Enteric Multicenter Study’s (GEMS) seven field settings, placed in diverse countries of Sub-Saharan Africa and South Asia between, December 2007 and February 2011. Then, this study analyzed a robust dataset of study participants (n = 22,569). Children having giardiasis with MSD constituted as cases (n = 1786), and those without MSD constituted as controls (n = 3470). Among the seven field sites, symptomatic giardiasis was 15% and 22% in Asian and African sites, respectively, whereas asymptomatic giardia infection (healthy without MSD) in Asian and African sites was 21.7% and 30.7%, respectively. Wasting and underweight were more frequently associated and stunting less often associated with symptomatic giardiasis (for all, p < 0.001). Symptomatic giardiasis had a significant association with worsening of nutritional status in under-five children. Improved socio-economic profile along with proper sanitation and hygienic practices are imperative to enhance child nutritional status, particularly in resource limited settings.

Benefits and Risks of Smallholder Livestock Production on Child Nutrition in Low- and Middle-Income Countries

Livestock production may improve nutritional outcomes of pregnant women and children by increasing household income, availability of nutrient-dense foods, and women's empowerment. Nevertheless, the relationship is complex, and the nutritional status of children may be impaired by presence of or proximity to livestock and their pathogens. In this paper, we review the benefits and risks of livestock production on child nutrition. Evidence supports the nutritional benefits of livestock farming through income, production, and women's empowerment. Increasing animal source food consumption requires a combination of efforts, including improved animal management so that herd size is adequate to meet household income needs and consumption and addressing sociocultural and gendered norms. Evidence supports the inclusion of behavior change communication strategies into livestock production interventions to facilitate the sustainability of nutritional benefits over time, particularly interventions that engage women and foster dimensions of women's empowerment. In evaluating the risks of livestock production, evidence indicates that a broad range of enteric pathogens may chronically infect the intestines of children and, in combination with dietary deficits, may cause environmental enteric dysfunction (EED), a chronic inflammation of the gut. Some of the most important pathogens associated with EED are zoonotic in nature with livestock as their main reservoir. Very few studies have aimed to understand which livestock species contribute most to colonization with these pathogens, or how to reduce transmission. Control at the point of exposure has been investigated in a few studies, but much less effort has been spent on improving animal husbandry practices, which may have additional benefits. There is an urgent need for dedicated and long-term research to understand which livestock species contribute most to exposure of young children to zoonotic enteric pathogens, to test the potential of a wide range of intervention methods, to assess their effectiveness in randomized trials, and to assure their broad adaptation and sustainability. This review highlights the benefits and risks of livestock production on child nutrition. In addition to identifying research gaps, findings support inclusion of poor gut health as an immediate determinant of child undernutrition, expanding the established UNICEF framework which includes only inadequate diet and disease.

An image-based Pathogen Box screen identifies new compounds with anti-Giardia activity and highlights the importance of assay choice in phenotypic drug discovery

Giardia duodenalis, the most prevalent human intestinal parasite causes the disease, giardiasis. On an annual basis G. duodenalis infects ~1 billion people, of which ~280 million develop symptomatic disease. Giardiasis can be severe and chronic, causing malnutrition, stunted growth and poor cognitive development in children. Current treatment options rely on drugs with declining efficacy and side-effects. To improve the health and well-being of millions of people world-wide, new anti-Giardia drugs with different modes of action to currently used drugs are required. The Medicines for Malaria Venture's Pathogen Box, a collection of bio-active compounds specifically chosen to stimulate infectious disease drug discovery, represents an opportunity for the discovery of new anti-Giardia agents. While the anti-Giardia activity of Pathogen Box compounds has been reported, this work failed to identify known anti-Giardia controls within the compound set. It also reported the activity of compounds previously screened and shown to be inactive by others, suggesting data may be inaccurate. Given these concerns the anti-Giardia activity of Pathogen Box compounds was re-assessed in the current study. Data from this work identified thirteen compounds with anti-Giardia IC₅₀ values ≤2 μM. Five of these compounds were reference compounds (marketed drugs with known anti-microbial activity), or analogues of compounds with previously described anti-Giardia activity. However, eight, including MMV676358 and MMV028694, which demonstrated potent sub-μM IC₅₀s against assemblage A, B and metronidazole resistant parasites (0.3 μM and 0.9 μM respectively), may represent new leads for future drug development. Interestingly, only four of these compounds were identified in the previously reported Pathogen Box screen highlighting the importance of assay selection and design when assessing compounds for activity against infectious agents.

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13 compounds with anti-Giardia IC₅₀ values < 2 μM were identified.

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8 compounds represent new leads for drug development.

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MMV676358 and MMV028694 demonstrated the most promising acting.

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Data highlight the importance of assay selection and design in drug discovery.

Intestinal Parasites, Anemia and Nutritional Status in Young Children from Transitioning Western Amazon

Young children are particularly vulnerable to the chronic sequelae of anemia, including poor nutritional status. The aim of this study was to assess intestinal parasitic-infections and nutritional status (anemia and linear growth) in preschool children living in contemporary Amazonian communities. A cross-sectional study measured children’s intestinal parasites and hair-Hg (HHg)—biomarkers of fish consumption, hemoglobin levels, and growth (anthropometric Z-scores). Children came from traditional-living families (Itapuã), and tin-mining settlements (Bom Futuro) representing current transitioning populations. It covered 937 pre-school children (from 1 to 59 months of age) from traditional (247) and immigrant tin-mining families (688). There was a high prevalence of intestinal polyparasitic-infection in children from both communities, but mild anemia (hemoglobin concentrations) and moderate (chronic) malnutrition were more frequent in children from traditional families than in children from tin-mining settlers. Children from traditional families ate significantly more fish (HHg mean of 4.3 µg/g) than children from tin-mining families (HHg mean of 2.3 µg/g). Among traditional villagers, children showed a significant correlation (r = 0.2318; p = 0.0005) between hemoglobin concentrations and HHg concentrations. High rates of parasitic infection underlie the poverty and attendant health issues of young children in the Brazilian Amazon. The intestinal parasite burden affecting poor Amazonian children resulting from unsafe water, lack of sanitation and poor hygiene is the most urgent environmental health issue.

Occurrence and molecular characterization of Giardia duodenalis in child population from Colombia

Giardia duodenalis is one of the most prevalent human intestinal parasite, with children living in developing countries being particularly at risk of infection. The occurrence and molecular diversity of G. duodenalis was investigated in stools specimens from 307 individuals aged one to nineteen years in Colombia. Samples were collected in three educational establishments (n: 163) and two hospital laboratories (n: 144) from urban and rural areas. Feces were concentrated using a biphasic sedimentation method and wet mounts of the sediment were examined by light microscopy. G. duodenalis assemblages and sub-assemblages were determined on positive samples by PCR of the triose phosphate isomerase (tpi), β-giardin (bg) and small-subunit (ssu) rRNA genes. G. duodenalis infection was detected by microscopy in 23 individuals (7.5%). The protozoan was more prevalent among specimens collected in educational establishments (11.6%) than in those obtained from hospital laboratories (2.8%). Infection was most common in individuals from urban areas and children aged 1-5 years. No significant association between diarrhea and infection could be demonstrated. Twenty Giardia-positive samples were successfully allocated to assemblage B (n: 11), sub-assemblage AII (n: 7), and assemblage A (n: 2). Results indicate the potential for transmission of G. duodenalis infection in children attending educational establishments and individuals from urban areas, where transmission seems to be primarily anthroponotic.

Molecular characterization of Giardia lamblia in children less than 5 years of age with diarrhoea attending the Bengo General Hospital, Angola

Background

Giardia lamblia is a pathogenic intestinal protozoan with high prevalence in developing countries, especially among children. Molecular characterization has revealed the existence of eight assemblages, with A and B being more commonly described in human infections. Despite its importance, to our knowledge this is the first published molecular analysis of G. lamblia assemblages in Angola.

Methods

The present study aimed to identify the assemblages of G. lamblia in children with acute diarrhoea presenting at the Bengo General Hospital, Angola. A stool sample was collected and microscopy and immunochromatographic tests were used. DNA was extracted and assemblage determination was performed through amplification of the gene fragment ssu-rRNA (175 bp) and β-giardin (511 bp) through polymerase chain reaction and DNA sequencing.

Results

Of the 16 stool samples screened, 12 were successfully sequenced. Eleven isolates were assigned to assemblage B and one to assemblage A. Subassemblage determination was not possible for assemblage B, while the single isolate assigned to assemblage A was identified as belonging to subassemblage A3.

Conclusion

This study provides information about G. lamblia assemblages in Bengo Province, Angola and may contribute as a first step in understanding the molecular epidemiology of this protozoan in the country.

GenBank accession numbers for the ssur-RNA gene: MF479750, MF479751, MF479752, MF479753, MF479754, MF479755, MF479756, MF479757, MF479758, MF479759, MF479760, MF479761.

GenBank accession numbers for the β-giardin gene: MF565378, MF565379, MF565380, MF565381.

Occurrence and Multilocus Genotyping of Giardia duodenalis in Yunnan Black Goats in China

Giardia duodenalis is an important zoonotic parasite which can parasitize in the intestines of humans and various animals. However, the information about the prevalence and genetic diversity of G. duodenalis in goats in China is limited. It is yet to be known whether Yunnan black goats, a unique goat breed in subtropical Yunnan province, southwestern China, are infected with G. duodenalis. Thus, a total of 907 fecal samples were collected from Yunnan black goats in five regions in Yunnan province, to estimate the prevalence and genotypes of G. duodenalis using a PCR-based approach. The G. duodenalis prevalence is 4.2% (38/907) in Yunnan black goats by nested amplification of the β-giardin (bg) gene, and the genotypes are identified as assemblage E, with 5 novel subtypes (E₁₁-E₁₅). Multilocus sequence typing revealed that 11, 18, and 38 samples were amplifiable on tpi (triose phosphate isomerase), gdh (glutamate dehydrogenase), and bg locus, respectively, and identified three novel multilocus genotypes (MLGs): MLGE9-MLGE11. To our knowledge, this is the first report of G. duodenalis prevalence and genotypes in Yunnan black goats in China, which extended the host range of G. duodenalis and provided basic data for controlling G. duodenalis infection in Yunnan black goats.

Screening of the Pathogen Box for inhibitors with dual efficacy against Giardia lamblia and Cryptosporidium parvum

There is need for a more efficient cell-based assay amenable to high-throughput drug screening against Giardia lamblia. Here, we report the development of a screening method utilizing G. lamblia engineered to express red-shifted firefly luciferase. Parasite growth and replication were quantified using D-luciferin as a substrate in a bioluminescent read-out plateform. This assay was validated for reproducibility and reliability against the Medicines for Malaria Venture (MMV) Pathogen Box compounds. For G. lamblia, forty-three compounds showed ≥ 75% inhibition of parasite growth in the initial screen (16 μM), with fifteen showing ≥ 95% inhibition. The Pathogen Box was also screened against Nanoluciferase expressing (Nluc) C. parvum, yielding 85 compounds with ≥ 75% parasite growth inhibition at 10 μM, with six showing ≥ 95% inhibition. A representative set of seven compounds with activity against both parasites were further analyzed to determine the effective concentration that causes 50% growth inhibition (EC50) and cytotoxicity against mammalian HepG2 cells. Four of the seven compounds were previously known to be effective in treating either Giardia or Cryptosporidium. The remaining three shared no obvious chemical similarity with any previously characterized anti-parasite diarrheal drugs and offer new medicinal chemistry opportunities for therapeutic development. These results suggest that the bioluminescent assays are suitable for large-scale screening of chemical libraries against both C. parvum and G. lamblia.

[Hospitalization for infectious diseases, parasitism and nutritional evolution of children attended in public child day care centers]

The scope of this article is to analyze the influence of hospitalizations by infectious diseases (diarrhea and pneumonia) and parasitism in nutritional evolution, over the period of a year, among children enrolled in municipal public day care centers. Mothers of children in a cohort were asked about previous hospitalization due to diarrhea and pneumonia, as well as in relation to the elimination of worms, during the period of one year of attendance at day care centers. Anthropometrics were measured at each visit. An adjusted model to examine the relationship between infections experienced and growth outcomes (weight and height) was applied. In a subset analysis of 269 children followed up at every visit over the course of 12 months, hospitalization due to pneumonia and parasite infection were associated with decelerated growth in weight and height. Parasitic infection and pneumonia were associated with growth impairment in terms of weight and height.

Molecular identification of Giardia intestinalis in two cities of the Colombian Caribbean Coast

INTRODUCTION

Parasitoses are an important health problem and its post-infectious consequences can cause high morbidity and mortality, worldwide. Epidemiological data is scarce in our region. We aimed to obtain frequency and circulating genotypes of Giardia intestinalis in two cities of the Caribbean Coast.

METHODS

To identify parasites in samples, a fecal concentration and microscopical examination were performed. For further identification and genotyping of G. intestinalis, molecular analyses were performed using specific available primers.

RESULTS

Only 22.1% of participants had gastrointestinal symptoms (most frequently: abdominal pain and diarrhea). Microscopy examination was positive in 72.7% of the samples. The most frequent parasite was G. intestinalis (48.1%) and we found mixed parasitic infections in 46.7% of the participants. All the samples from Santa Marta were molecularly characterized as assemblage A of G. intestinalis, while in Cartagena we confirmed the presence of assemblages A and B.

CONCLUSIONS

Molecular tools are important in the diagnosis of parasites and to increase comprehension of their distribution. In this study, a higher frequency of parasites, mostly protozoa, was observed.

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.

Estimating and mapping the incidence of giardiasis in Colombia, 2009-2013

BACKGROUND

Giardiasis is one of the most common intestinal infections in the world. There have been no national studies on the morbidity of giardiasis in Colombia. In this study, incidence rates of giardiasis were estimated for the years 2009-2013.

METHODS

An observational, retrospective study of the giardiasis incidence in Colombia, 2009-2013, was performed using data extracted from the personal health records system (Registro Individual de Prestación de Servicios, RIPS). Official population estimates from the National Department of Statistics (DANE) were used for the estimation of crude and adjusted incidence rates (cases/100 000 population).

RESULTS

During the period studied, 15 851 cases were reported (median 3233/year; 5-year cumulated crude national rate of 33.97 cases/100 000 population). Of these, 50.3% were female; 58.4% were <10 years old and 14.8% were 10-19 years old. By region, 17.7% were from Bogotá (10.07 cases/100 000 population, 2009), 10.9% from Antioquia (9.42, 2009), 8.6% from Atlántico (15.67, 2009), and 6.5% from Risaralda (33.38, 2009). Cases were reported in all departments (even insular areas).

CONCLUSIONS

As giardiasis is neglected in many countries, surveillance is not regularly undertaken. Despite its limitations, this study is the first attempt to provide estimates of national giardiasis incidence with consistent findings regarding affected age groups and geographical distribution.

Presence of helminth eggs in domestic wastewater and its removal at low temperature UASB reactors in Peruvian highlands

This work studied the anaerobic sludge filtration capacity for pathogens reduction in a 29 L and 1.65 m height lab-scale UASB reactor treating domestic wastewater at low temperatures in the city of Puno (Peru). The anaerobic sludge filtration capacity was performed applying upflow velocities of 0.12, 0.14, 0.16, 0.20, 0.27 and 0.41 m/h. Results show that the HE removal varied between 89 and 95% and the most common specie was Ascaris lumbricoides. Faecal coliform and Escherichia coli removal varied in the range of 0.9-2.1 and 0.8-1.6 log10 respectively. Likely related to the low operational temperatures, the total COD removal varied between 37 and 62%. The best performance in terms of removal of HE, total COD and turbidity was obtained at the lowest upflow velocity of 0.12 m/h. In order to meet WHO standards for water reuse a post-treatment unit will be required to polish the effluent.

Detection by PCR of pathogenic protozoa in raw and drinkable water samples in Colombia

We evaluated the presence of DNA of Giardia, Toxoplasma, and Cryptosporidium by PCR, and of Giardia and Cryptosporidium genera by immunofluorescence antibody test (IFAT), in water samples, before, during, and after plant treatment for drinkable water. We applied this method in 38 samples of 10 l of water taken from each of the water treatment steps and in 8 samples taken at home (only for Toxoplasma PCR) in Quindio region in Colombia. There were 8 positive samples for Cryptosporidium parvum (21 %), 4 for Cryptosporidium hominis (10.5 %), 27 for Toxoplasma gondii (58.6 %), 2 for Giardia duodenalis assemblage A (5.2 %), and 5 for G. duodenalis assemblage B (13.1 %). By IFAT, 23 % were positive for Giardia and 21 % for Cryptosporidium. An almost perfect agreement was found between IFAT and combined results of PCR, by Kappa composite proportion analysis. PCR positive samples were significantly more frequent in untreated raw water for C. parvum (p = 0.02). High mean of fecal coliforms, high pH values, and low mean of chlorine residuals were strongly correlated with PCR positivity for G. duodenalis assemblage B. High pH value was correlated with PCR positivity for C. parvum. Phylogenetic analysis of DNA sequences was possible, showing water and human clinical sequences for Toxoplasma within the same phylogenetic group for B1 repeated sequence. PCR assay is complementary to IFAT assay for monitoring of protozoa in raw and drinkable water, enabling species identification and to look for phylogenetic analysis in protozoa from human and environmental sources.

Predominance of Giardia lamblia assemblage A among iron deficiency anaemic pre-school Egyptian children

Intestinal parasites and nutritional deficiency can coexist and influence each other. This study aimed to clarify the association between Giardia genotypes and presence of iron deficiency anaemia (IDA) among pre-school Egyptian children. Two groups (IDA and non-anaemic) of giardiasis children (44/group) were selected according to their recovery response after treatment of giardiasis. Each group included 24 and 20 gastrointestinal symptomatic and asymptomatic, respectively. Giardia human genotypes were performed by intergenic spacer (IGS) gene based polymerase chain reaction (PCR) with high-resolution melting curve (HRM). PCR/HRM proved that Tms of assemblage A and B ranged from 79.31 ± 0.29 to 84.77 ± 0.31. In IDA patients, assemblages A and B were found among 40/44 (90.9 %) and 4/44 (9.1 %), respectively, while in non-anaemic patients, assemblages A and B were found in 10/44 (22.7 %) and 32/44 (72.7 %), respectively, beside two (4.6 %) cases had mixed infection. The difference was statistically significant. No significant relation was found between symptomatic or asymptomatic assemblages and IDA as assemblage A was found in 21/24 (87.5 %) and 19/20 (95 %) of symptomatic and asymptomatic, respectively, while 3/24 (12.5 %) and 1/20 (5 %) of assemblage B were symptomatic was asymptomatic, respectively. A significant relation was found between assemblage A subtypes distribution among IDA patients as AI and AII were detected on 23 (52.3 %) and 16 (36.4 %) of patients, respectively, while one case (2.3 %) had mixed infection. In conclusion, assemblage A is predominant among IDA giardiasis children suggesting its role in enhancing the occurrence of IDA while B has a protective role.

Infection by Intestinal Parasites, Stunting and Anemia in School-Aged Children from Southern Angola

INTRODUCTION

Intestinal parasites are responsible for morbidity in children worldwide, especially in low income countries. In the present study we determine the prevalence of intestinal parasites and explore its association with anemia and stunting in school-aged children.

METHODS

A cross-sectional study was conducted from September to October 2010 enrolling 328 children attending the primary school in Lubango, the second largest city after the capital Luanda. Stool samples were collected for parasite detection through microscopy and molecular identification of Entamoeba histolytica and Entamoeba dispar. Stunting was assessed using the z-scores of height for age and hemoglobin concentration was determined using a portable hemoglobin analyzing system.

RESULTS

The global prevalence of pathogenic intestinal parasites was 44.2%, the most common being Ascaris lumbricoides (22.0%), Giardia lamblia (20.1%) and Hymenolepis nana (8.8%). Molecular detection revealed that 13.1% of the children carried E. dispar and 0.3% were infected with E. histolytica. The prevalence of stunting (mild to severe) was 41.5%. Stunting was more frequent in older children (p = 0.006, OR = 1.886), while anemia was more frequent in younger children (p = 0.005, OR = 2.210). The prevalence of anemia was 21.6%, and we found a significant association with infection by H. nana (p = 0.031, OR = 2.449).

CONCLUSIONS

This is one of the few published studies reporting intestinal parasites infection, nutritional status and anemia in children from Angola. Furthermore, the present work highlights the importance of regular intestinal parasites screening in children.

Prevalence of Giardia intestinalis and Hymenolepis nana in Afghan refugee population of Mianwali district, Pakistan

BACKGROUND

Present study aimed to investigate prevalence of Giardia intestinalis and Hymenolepis nana in Afghan refugees visiting Central Health Unit (CHU), Kot Chandana (Mianwali, Northern Punjab) during two years period (February 2007 to December 2009).

METHODS

A total of 687 stool samples were collected from different age groups of both genders. Samples were processed under sterile conditions after gross examination. Microscopic examination was done on same day along with eggs (H. nana), cyst and trophozoites (G. intestinalis) detection after staining.

RESULTS

The prevalence of G. intestinalis was significantly higher (x2=59.54, p<0.001) than that of H. nana. Females were found more likely to be infected as compared to males (OR: 1.40, 95% CI=1.03-1.92). Prevalence of both parasites decreased with age and highest prevalence was observed in young individuals belonging to 1-15 years of age group (41.8% and 48.7% respectively for H. nana and G. intestinalis, p<0.001). Abdominal distress (OR: 1.13, 95%CI=0.83-1.53), vomiting (OR: 1.13, 95%CI=1.13-1.81) and rectal prolapse (OR: 4.26, 95%CI=1.38-13.16) were the gastro-intestinal clinical symptoms observed in G. intestinalis. Whereas, bloody diarrhea (OR: 1.56, 95%CI=1.00-2.43) and rectal prolapse (OR: 5.79, 95%CI=1.87-17.91) were associated with H. nana infections.

CONCLUSIONS

Intestinal parasitic infections are common among Afghan refugees and serious preventive measures should be implemented to promote the safety and healthy lifestyle of these people.

Advances in understanding Giardia: determinants and mechanisms of chronic sequelae

Giardia lamblia is a flagellated protozoan that is the most common cause of intestinal parasitic infection in children living in resource-limited settings. The pathogenicity of Giardia has been debated since the parasite was first identified, and clinical outcomes vary across studies. Among recent perplexing findings are diametrically opposed associations between Giardia and acute versus persistent diarrhea and a poorly understood potential for long-term sequelae, including impaired child growth and cognitive development. The mechanisms driving these protean clinical outcomes remain elusive, but recent advances suggest that variability in Giardia strains, host nutritional status, the composition of microbiota, co-infecting enteropathogens, host genetically determined mucosal immune responses, and immune modulation by Giardia are all relevant factors influencing disease manifestations after Giardia infection.

Giardia duodenalis assemblages in Egyptian children with diarrhea

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

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.

Burden of Giardia duodenalis infection and its adverse effects on growth of schoolchildren in rural Malaysia

BACKGROUND

Giardia duodenalis infection and malnutrition are still considered as public health problems in many developing countries especially among children in rural communities. This study was carried out among Aboriginal (Orang Asli) primary schoolchildren in rural peninsular Malaysia to investigate the burden and the effects of Giardia infection on growth (weight and height) of the children.

METHODS/FINDINGS

Weight and height of 374 children aged 7-12 years were assessed before and after treatment of Giardia infection. The children were screened for Giardia parasite using trichrome staining technique. Demographic and socioeconomic data were collected via face-to-face interviews using a pre-tested questionnaire. Overall, 22.2% (83/374) of the children were found to be infected with Giardia. Nutritional status of children was assessed and the results showed that the mean weight and height were 23.9 kg (95% CI = 23.3, 24.5) and 126.6 cm (95% CI = 125.6, 127.5), respectively. Overall, the prevalence of severe underweight, stunting and wasting were 28.3%, 23.8% and 21.0%, respectively. Multiple linear regression analyses showed sex, Giardia infection and household monthly income as the significant determinants of weight while sex and level of mother's education were the significant determinants of height. Weight and height were assessed at 3 and 6 months after treatment of Giardia infection. It was found that Giardia infection has a significant association with the weight of children but not with height.

CONCLUSIONS/SIGNIFICANCE

This study reveals high prevalence of Giardia infection and malnutrition among Aboriginal children in rural Malaysia and clearly highlights an urgent need to identify integrated measures to control these health problems in the rural communities. Essentially, proper attention should be given to the control of Giardia infection in Aboriginal communities as this constitutes one of the strategies to improve the nutritional status of Aboriginal children.

High malnutrition rate in Venezuelan Yanomami compared to Warao Amerindians and Creoles: significant associations with intestinal parasites and anemia

BACKGROUND

Children in rural areas experience the interrelated problems of poor growth, anemia and parasitic infections. We investigated the prevalence of and associations between intestinal helminth and protozoan infections, malnutrition and anemia in school-age Venezuelan children.

METHODS

This cross-sectional study was conducted in 390 children aged 4-16 years from three rural areas of Venezuela: the Amazon Region, Orinoco Delta and Carabobo State. Stool samples were collected for direct parasitic examinations. Anthropometric indicators of chronic (height-for-age Z score) and acute (weight-for-height and Body Mass Index (BMI)-for-age Z score in respectively children under 5 years of age and children aged 5 years and above) malnutrition were calculated. Multivariate linear and logistic regression models were built to determine factors associated with nutritional status and polyparasitism.

RESULTS

Hookworm and Strongyloides stercoralis prevalences were highest in children from the Amazon rainforest (respectively 72% and 18%) while children from the Orinoco Delta and Carabobo State showed higher rates of Ascaris lumbricoides (respectively 28% and 37%) and Trichuris trichiura (40% in both regions). The prevalence of Giardia lamblia infection was not significantly different between regions (average: 18%). Anemia prevalence was highest in the Amazon Region (24%). Hemoglobin levels were significantly decreased in children with a hookworm infection. Malnutrition was present in respectively 84%, 30% and 13% of children from the Amazon Region, Orinoco Delta and Carabobo State. In multivariate analysis including all regions, G. lamblia and helminth infections were significantly and negatively associated with respectively height-for-age and weight-for-height/BMI-for-age Z scores. Furthermore, hemoglobin levels were positively associated with the height-for-age Z score (0.11, 95% CI 0.02 - 0.20).

CONCLUSIONS

In rural populations in Venezuela helminthiasis and giardiasis were associated with acute and chronic nutritional status respectively. These data highlight the need for an integrated approach to control transmission of parasites and improve the health status of rural Venezuelan children.

Molecular and Clinical Characterization of Giardia duodenalis Infection in Preschool Children from Lisbon, Portugal

Giardia duodenalis is the most prevalent intestinal protozoan infection especially in children. In Portugal scarce data are available relative to this infection in preschoolers. The present study was conducted from April to July 2009 in public preschools in Lisbon enrolling 316 children. Stool examination was performed through microscopy. Molecular analysis was conducted in all positive samples for G. duodenalis in order to determine the assemblage and subassemblage of this parasite. Eight of the preschoolers studied children (2.5%, 8/316) were infected with G. duodenalis. Additionally the brother of one of the infected children was also infected. Genotyping analysis targeting ssu-rRNA and β -giardin loci revealed six infections with assemblage A and 3 with assemblage B. Sub-assemblage determination was possible in four of the samples, with three A2 and one A3. The limited number of cases precluded an association of a determined symptom with an assemblage. The data presented here show the relevance of considering G. duodenalis analysis in children with intestinal complaints even in developed countries.

Persistent G. lamblia impairs growth in a murine malnutrition model

Giardia lamblia infections are nearly universal among children in low-income countries and are syndemic with the triumvirate of malnutrition, diarrhea, and developmental growth delays. Amidst the morass of early childhood enteropathogen exposures in these populations, G. lamblia–specific associations with persistent diarrhea, cognitive deficits, stunting, and nutrient deficiencies have demonstrated conflicting results, placing endemic pediatric giardiasis in a state of equipoise. Many infections in endemic settings appear to be asymptomatic/ subclinical, further contributing to uncertainty regarding a causal link between G. lamblia infection and developmental delay. We used G. lamblia H3 cyst infection in a weaned mouse model of malnutrition to demonstrate that persistent giardiasis leads to epithelial cell apoptosis and crypt hyperplasia. Infection was associated with a Th2-biased inflammatory response and impaired growth. Malnutrition accentuated the severity of these growth decrements. Faltering malnourished mice exhibited impaired compensatory responses following infection and demonstrated an absence of crypt hyperplasia and subsequently blunted villus architecture. Concomitantly, severe malnutrition prevented increases in B220+ cells in the lamina propria as well as mucosal Il4 and Il5 mRNA in response to infection. These findings add insight into the potential role of G. lamblia as a "stunting" pathogen and suggest that, similarly, malnourished children may be at increased risk of G. lamblia– potentiated growth decrements.

Prevalence and epidemiology of intestinal parasitism, as revealed by three distinct techniques in an endemic area in the Brazilian Amazon

This survey aims to estimate the prevalence of intestinal parasitic infections in Santa Isabel do Rio Negro, Amazonian Brazil, through three distinct techniques, correlating the prevalence rates with family income and age groups as well as assessing the household clustering of infections. Prevalence rates were assessed through Graham (n=113), Baermann-Moraes (n=232) and Ritchie (n=463) methods. The Graham method was adopted only for children under 5 years old, 15% of whom were positive for Enterobius vermicularis. By the Baermann-Moraes technique, 5·6% of the samples were positive for Strongyloides stercoralis larvae. The Ritchie technique disclosed the following results: Ascaris lumbricoides (26%), Trichuris trichiura (22·5%), hookworms (9·5%), Entamoeba histolytica/Entamoeba dispar (25·3%), Giardia lamblia (12·5%) and E. vermicularis (0·6%). Children aged 5-14 years presented the highest prevalence for pathogenic parasites. Giardiasis and hookworm infection rates were inversely related to family income. The presence of positive contacts in the same household substantially increased the risk of infection by enteric parasites: odds ratio (OR)=2·70, 95% confidence interval (CI)=1·69-4·29 for ascariasis; OR=2·17, 95% CI=1·34-3·51 for trichuriasis; OR=2·13, 95% CI=1·08-4·17 for hookworm disease; OR=3·42, 95% CI=1·86-6·30 for giardiasis; and OR=2·16, 95% CI=1·35-3·47 for amoebiasis, supporting infection clustering in the home. Intestinal parasitoses are extremely frequent in the studied area, and routine methods for diagnosis may underestimate the prevalence of enterobiasis and strongyloidiasis.

Intestinal protozoan infections in relation to nutritional status and gastrointestinal morbidity in Colombian school children

While Giardia duodenalis infection has been consistently associated with nutrient malabsorption and stunting in children, the effects of other protozoans on nutritional status or gastrointestinal morbidity are less clear. We sought to determine whether infection with common intestinal protozoans including Giardia duodenalis, Entamoeba coli and Blastocystis hominis was associated with anthropometric and micronutrient status, gastrointestinal symptoms, visits to the doctor or school absenteeism in children 5-12 years of age from Bogotá, Colombia. We obtained stool samples from 442 children enrolled in primary schools in 2006 and examined the presence of intestinal protozoans in relation to height, body mass index, plasma concentrations of vitamins A and B12, ferritin and zinc and erythrocyte folate. In addition, we examined the associations between protozoan infections and the incidence of common gastrointestinal symptoms, which were registered prospectively in morbidity diaries. The prevalence rates of G. duodenalis, E. coli and B. hominis infection were 6.3, 23.1 and 22.4%, respectively. Giardia infection was associated with lower height-for-age z-score (p = 0.04), whereas E. coli infection was associated with low erythrocyte folate (p = 0.04), and B. hominis infection was related to higher vitamin A levels (p = 0.05). Infection with E. coli was also associated with a significantly higher incidence of fever but fewer visits to the doctor, while B. hominis infection was associated with significantly less diarrhea, diarrhea with vomiting, doctor visits and school absenteeism. In conclusion, G. duodenalis and E. coli infections were associated with indicators of poor nutritional status in this population, while B. hominis was related to apparently decreased morbidity.

Giardiasis--why do the symptoms sometimes never stop?

Although giardiasis is considered by most medical practitioners to be an easily treated infection, prolonged symptoms due to, or following, Giardia duodenalis infection can have a significant impact on quality of life. Symptom recurrence, including abdominal symptoms and fatigue, can result from re-infection, treatment failure, disturbances in the gut mucosa or post-infection syndromes. In developed countries, these sequelae can have an enormous impact on quality of life; in developing countries, particularly in children, they add yet another burden to populations that are already disadvantaged. Here, we outline current knowledge, based on individual case sequelae from sporadic infections, observations of population effects following outbreaks and studies of phenotypic and genotypic diversity between morphologically identical isolates of parasites. We also raise further questions, looking for clues as to why giardiasis sometimes becomes an intrusive, long-term problem.