Giardiasis as a predictor of childhood malnutrition in Orang Asli children in Malaysia

Microscopy detection and molecular characterisation of Giardia duodenalis infection in outpatients seeking medical care in Egypt

Introduction

Giardiosis remains one of the most prevalent enteric parasitic infections globally. Earlier molecular-based studies conducted in Egypt have primarily focused on paediatric clinical populations and most were based on single genotyping markers. As a result, there is limited information on the frequency and genetic diversity of G. duodenalis infections in individuals of all age groups.

Methods

Individual stool samples (n = 460) from outpatients seeking medical care were collected during January-December 2021 in Kafr El-Sheikh governorate, northern Egypt. Initial screening for the presence of G. duodenalis was conducted by coprological examination. Microscopy-positive samples were further confirmed by real-time PCR. A multilocus sequence typing approach targeted amplification of the glutamate dehydrogenase (gdh), beta-giardin (bg), and triose phosphate isomerase (tpi) genes was used for genotyping purposes. A standardised epidemiological questionnaire was used to gather basic sociodemographic and clinical features of the recruited patients.

Results

Giardia duodenalis cysts were observed in 5.4% (25/460, 95% CI: 3.6-7.9) of the stool samples examined by conventional microscopy. The infection was more frequent in children under the age of 10 years and in individuals presenting with diarrhoea but without reaching statistical significance. Stool samples collected during the winter period were more likely to harbour G. duodenalis. All 25 microscopy-positive samples were confirmed by real-time PCR, but genotyping data was only available for 56.0% (14/25) of the isolates. Sequence analyses revealed the presence of assemblages A (78.6%, 11/14) and B (21.4%, 3/14). All assemblage A isolates were identified as sub-assemblage AII, whereas the three assemblage B sequences belonged to the sub-assemblage BIII. Patients with giardiosis presenting with diarrhoea were more frequently infected by the assemblage A of the parasite.

Conclusion

This is one of the largest epidemiological studies evaluating G. duodenalis infection in individuals of all age groups in Egypt. Our molecular data suggest that G. duodenalis infections in the surveyed population are primarily of anthropic origin. However, because assemblages A and B are zoonotic, some of the infections identified can have an animal origin. Additional investigations targeting animal (domestic and free-living) and environmental (water) samples are warranted to better understand the epidemiology of giardiosis in Egypt.

Giardiasis and diarrhea in dogs: Does the microbiome matter?

BACKGROUND

Giardia duodenalis (Gd) causes intestinal parasitosis. The involvement of the intestinal microbiome in determining the infection's clinical phenotype is unknown.

OBJECTIVE

Investigate the fecal microbiome features in dogs with giardiasis.

ANIMALS AND METHODS

Cross-sectional study, including fecal samples of kenneled dogs with Gd diagnosed by fecal Giardia antigen dot ELISA. The fecal microbial compositional characteristics and dysbiosis index (DI) were compared between diarrheic and nondiarrheic dogs.

RESULTS

Fecal samples of 38 Gd-infected dogs (diarrheic, 21; nondiarrheic, 17) were included. No differences were found in Faith's phylogenic diversity and beta diversity (weighted UniFrac distances) and in specific taxa abundances at the phylum, genus, and species levels, as well as in alpha and beta diversities between diarrheic and nondiarrheic dogs, and also when divided by sex or age. Among diarrheic dogs, alpha diversity was higher in males than in females (pairwise Kruskal-Wallis, q = 0.01). Among males, fecal abundances of the genus Clostridium (W = 19) and Clostridium spiroforme species (W = 33) were higher in diarrheic compared to nondiarrheic dogs. In diarrheic dog fecal samples, Proteobacteria were more prevalent (W = 1), whereas Verrucomicrobia were less prevalent in dogs <1 year of age than in older dogs. The fecal sample DI of 19 diarrheic and 19 nondiarrheic dogs was similar (median, -0.2; range, -4.3 to 4.5 and median, -1.0; range, -4.3 to 5.8, respectively).

CONCLUSIONS

The fecal microbial composition of symptomatic and asymptomatic dogs with giardiasis is similar. Based on fecal DI, giardiasis is not characterized by prominent dysbiosis. Other host and parasite characteristics might determine the severity of giardiasis in dogs.

Individual and Community-Level Risk Factors for Giardiasis in Children under Five Years of Age in Pakistan: A Prospective Multi-Regional Study

OBJECTIVES

This study aimed to estimate the prevalence of Giardia lamblia infection and identify associated risk factors at both individual and community levels in a pediatric population in different agroecological zones of Khyber Pakhtunkhwa, Pakistan.

METHODS

A community-based cross-sectional study was conducted from March to December 2022. Using stratified sampling, 1026 households were recruited from nine agroecological zones. Stool samples were collected from 1026 children up to the age of five years and processed for detection of Giardia using a commercial ELISA kit. Data on potential risk factors were collected using a pre-structured questionnaire. A multivariable logistic regression model was used to identify risk factors associated with giardiasis.

RESULTS

The study found that the prevalence of giardiasis in the study area was 3.31%. Children aged 13-24 months were found to be at higher risk for giardiasis. Illiterate mothers and fathers attending daycare institutions/kindergartens, mothers not practicing hand washing during critical times, households with companion animals, and homes where stray dogs/cats enter were identified as predictors of giardiasis at the individual level. Children living in sub-mountain valleys use un-piped water, inadequate domestic water storage vessels, drink un-boiled or unfiltered water, live near rubbish heaps or un-paved streets/pathways, and have unimproved latrine facilities were identified as risk factors of giardiasis at the community level.

CONCLUSIONS

The study highlights the need for integrated intervention approaches at both individual and community levels to reduce the incidence of giardiasis in Khyber Pakhtunkhwa, Pakistan. Interventions aimed at promoting behavioral change and providing safe and adequate water sources, combined with individual-level interventions such as hand washing and awareness of giardiasis prevention methods, would be critical to addressing this health concern. Inter-sectoral collaboration between the health sector and other sectors would also be necessary to achieve meaningful progress in reducing the incidence of giardiasis in resource-limited areas.

Assessment of the Health Status of Spanish Schoolchildren Based on Nutrimetry, Lifestyle and Intestinal Parasites

Malnutrition in Spanish schoolchildren, and its relationship with lifestyles, has been studied, but Nutrimetry (a nutritional status indicator), and data on intestinal parasitism and its risk factors, have never before been taken into account. A total of 206 children aged 3-11 years, from two schools in the Valencian Community, participated. Demographic characteristics, diet, lifestyles, behavioural habits and anthropometric (weight, height) and coproparasitological data were collected. Nutrimetry was used to analyse nutritional status. Statistical analyses were performed to ascertain associations between lifestyle, selected parasite species and nutritional status. Multivariate logistic regression analysis was used to assess the strength of the association of the suspected risk factors with the presence of intestinal parasitism. The prevalence of overweight was 32.6%. A total of 43.9% had a high adherence to the Mediterranean Diet, for which mean daily intake was 2428.7 kcal. Intestinal parasitism was identified in 49.5% of the children (Giardia duodenalis: 28.6%). The source of drinking water was found to be a risk factor for intestinal parasitism. No positive association between the variables analysed and nutritional status could be confirmed. Nutrimetry is a good indicator for a complete analysis of nutritional status. It highlights the prevalence of overweight. Intestinal parasitism was identified in almost half of the participants and is a variable that should not be underestimated.

Stem-Loop Structures in Iron-Regulated mRNAs of Giardia duodenalis

Giardia duodenalis is a significant cause of waterborne and foodborne infections, day-care center outbreaks, and traveler's diarrhea worldwide. In protozoa such as Trichomonas vaginalis and Entamoeba histolytica, iron affects the growth, pathogenicity mechanisms, and expression of virulence genes. One of the proposed iron regulatory mechanisms is at the post-transcriptional level through an IRE/IRP-like (iron responsive element/iron regulatory protein) system. Recently, the expression of many putative giardial virulence factors in the free-iron levels has been reported in subsequent RNAseq experiments; however, the iron regulatory mechanism remains unknown. Thus, this work aimed to determine the effects of iron on the growth, gene expression, and presence of IRE-like structures in G. duodenalis. First, the parasite's growth kinetics at different iron concentrations were studied, and the cell viability was determined. It was observed that the parasite can adapt to an iron range from 7.7 to 500 µM; however, in conditions without iron, it is unable to survive in the culture medium. Additionally, the iron modulation of three genes was determined by RT-PCR assays. The results suggested that Actin, glucosamine-6-phosphate deaminase, and cytochrome b5 mRNA were down-regulated by iron. To investigate the presence of IRE-like structures, in silico analyses were performed for different mRNAs from the Giardia genome database. The Zuker mfold v2.4 web server and theoretical analysis were used to predict the secondary structures of the 91 mRNAs analyzed. Interestingly, the iron-induced downregulation of the genes analyzed corresponds to the location of the stem-loop structures found in their UTR regions. In conclusion, iron modulates the growth and expression of specific genes, likely due to the presence of IRE-like structures in G. duodenalis mRNAs.

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.

Mucosal Defense Against Giardia at the Intestinal Epithelial Cell Interface

Human giardiasis, caused by the protozoan parasite Giardia duodenalis (syn. Giardia lamblia, Giardia intestinalis, Lamblia intestinalis), is one of the most commonly-identified parasitic diseases worldwide. Chronic G. duodenalis infections cause a malabsorption syndrome that may lead to failure to thrive and/or stunted growth, especially in children in developing countries. Understanding the parasite/epithelial cell crosstalk at the mucosal surfaces of the small intestine during human giardiasis may provide novel insights into the mechanisms underlying the parasite-induced immunopathology and epithelial tissue damage, leading to malnutrition. Efforts to identify new targets for intervening in the development of intestinal immunopathology and the progression to malnutrition are critical. Translating these findings into a clinical setting will require analysis of these pathways in cells and tissues from humans and clinical trials could be devised to determine whether interfering with unwanted mucosal immune responses developed during human giardiasis provide better therapeutic benefits and clinical outcomes for G. duodenalis infections in humans.

Current state of infection and prevalence of giardiasis in Malaysia: a review of 20 years of research

Background

Giardiasis is a neglected parasitic zoonotic disease caused by Giardia duodenalis that is often overlooked despite the damage inflicted upon humans and domestic/wild animals. Lack of surveillance studies, low sensitivity of diagnostic tools, and resistance to giardiasis treatment add to the challenge in managing giardiasis, leaving a gap that continues to render giardiasis a silent threat to public health worldwide. This situation is not much different in Malaysia, where giardiasis remains a public health problem, especially in the indigenous communities. Realizing the existence of gaps in the literature and information on giardiasis in Malaysia, this review aims to revisit and update the situation of giardiasis in Malaysia based on articles published in 20 years from 2000 to 2020, providing estimates on the incidence of giardiasis in humans, animals, and the environment, which may inform efforts to prevent and control the impact of giardiasis in the country.

Methodology

We searched PubMed, Science Direct, and Scopus using MeSH terms and text keywords "Giardia duodenalis OR Giardia intestinalis OR Giardia lamblia OR intestinal protozoa AND Malaysia". Information was collected from all giardiasis reports published between 2000 and 2020.

Results

Giardiasis in Malaysia is more prevalent among the poorest segments of the population, namely the indigenous communities and people living in densely populated areas such as slums and prisons, due to low standard of personal hygiene, unsafe water resources, and improper sanitation. While the prevalence data is hugely dependent on microscopic fecal examination in epidemiological studies of giardiasis, current studies mostly focused on species identification and genotype distribution by multilocus genotyping. Thus far, the outbreak of giardiasis has not been reported in the country, but the disease was found to be significantly associated with stunting, wasting, and malnutrition among children of the indigenous communities. Surveillance studies also discovered the simultaneous presence of Giardia in the animal-environments, including wild animals, ruminants, and treated and untreated water. The data collected here will be a useful addition to the literature body on giardiasis in Malaysia, which can be exploited in efforts to prevent and control the impact of giardiasis in the country.

Conclusions

The last 10 years have shown that the overall mean rate of giardiasis in Malaysia is quite encouraging at 13.7%. While this figure appears to be declining, there has been a slight increase in the prevalence of underweight, stunting, and wasting among rural children in 2019. The fact that giardiasis is linked to long-term childhood developmental problems, indicates that addressing and providing better disease control against giardiasis should be a priority in supporting the national agenda to achieve Malaysia Global Nutrition Targets by 2025.

Nutritional status, hemoglobin level and their associations with soil-transmitted helminth infections between Negritos (indigenous) from the inland jungle village and resettlement at town peripheries

This study compared the current nutritional status, hemoglobin levels and their associations with soil-transmitted helminth (STH) infections between two categories of Negritos (indigenous): (i) Inland Jungle Villages (IJV) (ii) and Resettlement Plan Scheme (RPS) near town peripheries, decades after redevelopment and demarginalization. A total of 416 Negritos (IJV: 149; RPS: 267) was included for nutritional profiling based on anthropometric analysis. However, only 196 (IJV: 64; RPS: 132) individuals consented to blood taking for the hemoglobin (Hb) measurements. Subsequently, the association of undernutrition and anemia with STH infections were determined based on univariate and multivariate logistic regression analyses. The overall prevalence of stunting, wasting, and underweight amongst children and adolescents (n = 343) were 45.8%, 42.3% and 59.1%, respectively. In adults (n = 73), the prevalence of underweight was low (6.8%) but overweight and obese was prominent (26.0%). For anemia (n = 196), an overall prevalence rate of 68.4% were observed with 80% and 70.4% of children aged 2–6 y/o and aged 7–12 y/o, respectively being anemic. Comparatively, the prevalence of underweight (WAZ) was significantly higher in the RPS versus the IJV (P = 0.03) In the IJV, children aged ≤ 6 y/o and having STH poly-parasitism were associated with underweight (P = 0.01) and moderate-severe T. trichiura infection was associated with anemia. Whilst in the RPS, underweight was highly associated with only T. trichiura infection (P = 0.04). Wasting was significantly associated with young children aged ≤10 in both IJV (P = 0.004) and RPS (P = 0.02). Despite efforts in improving provision of facilities and amenities among the indigenous, this study highlighted a high magnitude of nutritional issues among the Negritos especially those in the RPS and their likely association with STH infections and decades of demarginalization. Joint nutritional intervention strategies with mass anti-helminthic treatment are imperative and urgently needed to reduce the undernutrition problems especially among indigenous children.

Giardiasis notifications are associated with socioeconomic status in Sydney, Australia: a spatial analysis

OBJECTIVE

In developed countries prolonged symptoms due to, or following, Giardia intestinalis infection can have a significant impact on the quality of life. In this research, we investigate the presence of a socioeconomic status (SES) gradient in the reporting of giardiasis in South West Sydney Local Health District (SWSLHD), New South Wales (NSW), Australia, across geographic scales.

METHODS

We used a large database, spatial-cluster analysis and a linear model.

RESULTS

Firstly, we found one spatial cluster of giardiasis in one of the most advantaged neighbourhoods of SWSLHD. Secondly, rates of giardiasis notifications were significantly and consistently lower in SWSLHD compared to an unnamed advantaged Local Health District and NSW over multiple years. Finally, we found an overall significant positive dose-response relationship between counts of giardiasis and area-level SES.

CONCLUSIONS

Lower reporting in disadvantaged areas may represent true differences in incidence across SES groups or may result from differential use of health services and reporting. Implications for public health: If the disparities result from differential use of health services, research should be directed toward identifying barriers and facilitators of use. If disparities result from a true difference in incidence, then the behavioural mediators between SES and giardiasis should be identified and addressed.

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.

Giardia duodenalis infection in the context of a community-based deworming and water, sanitation and hygiene trial in Timor-Leste

Background

Giardiasis is a common diarrhoeal disease caused by the protozoan Giardia duodenalis. It is prevalent in low-income countries in the context of inadequate access to water, sanitation and hygiene (WASH), and is frequently co-endemic with neglected tropical diseases such as soil-transmitted helminth (STH) infections. Large-scale periodic deworming programmes are often implemented in these settings; however, there is limited evidence for the impact of regular anthelminthic treatment on G. duodenalis infection. Additionally, few studies have examined the impact of WASH interventions on G. duodenalis.

Methods

The WASH for WORMS cluster randomised controlled trial was conducted in remote communities in Manufahi municipality, Timor-Leste, between 2012 and 2016. All study communities received four rounds of deworming with albendazole at six-monthly intervals. Half were randomised to additionally receive a community-level WASH intervention following study baseline. We measured G. duodenalis infection in study participants every six months for two years, immediately prior to deworming, as a pre-specified secondary outcome of the trial. WASH access and behaviours were measured using questionnaires.

Results

There was no significant change in G. duodenalis prevalence in either study arm between baseline and the final study follow-up. We found no additional benefit of the community-level WASH intervention on G. duodenalis infection (relative risk: 1.05, 95% CI: 0.72–1.54). Risk factors for G. duodenalis infection included living in a household with a child under five years of age (adjusted odds ratio, aOR: 1.35, 95% CI: 1.04–1.75), living in a household with more than six people (aOR: 1.32, 95% CI: 1.02–1.72), and sampling during the rainy season (aOR: 1.23, 95% CI: 1.04–1.45). Individuals infected with the hookworm Necator americanus were less likely to have G. duodenalis infection (aOR: 0.71, 95% CI: 0.57–0.88).

Conclusions

Prevalence of G. duodenalis was not affected by a community WASH intervention or by two years of regular deworming with albendazole. Direct household contacts appear to play a dominant role in driving transmission. We found evidence of antagonistic effects between G. duodenalis and hookworm infection, which warrants further investigation in the context of global deworming efforts.

Trial registration Australian New Zealand Clinical Trials Registry, ACTRN12614000680662. Registered 27 June 2014, retrospectively registered. https://anzctr.org.au/Trial/Registration/TrialReview.aspx?id=366540.

A prevalence survey of enteral parasites in preschool children in the Mangochi District of Malawi

Background

Helminthic and protozoan infections are common, particularly in low- or middle-income countries. Although an association between parasite carriage and markers of poor growth have been shown in some studies, systematic reviews have suggested only a modest impact of clearing carriage. The prevalence of these pathogens and the effect that they have on growth in preschool children has never been investigated in Malawi.

Methods

One hundred ninety-three children aged 0–72 months were randomly recruited from rural villages in the Mangochi district of Malawi. Formol-ether concentration was performed on stool and the samples examined with a light microscope. Anthropometric data was taken for each child and the haemoglobin measured with a point of care test.

Results

The mean age of the children was 2 years 4 months. Overall prevalence of intestinal parasite infection was 37.3%. Protozoa were found in 28.5% of children, while helminths were found in 8.8%. The most commonly found organisms were Giardia lambia (12.4%), Entamoeba coli (10.4%) and Hookworm species (3.6%). Stunting was seen in 47.8% of children, 12.9% were underweight and 5.0% were wasted. No significant association was found between markers of poor growth and infection with any intestinal parasite.

Conclusions

We found that prevalence of helminth infection was low in preschool children living in the Mangochi district compared to international standards. However a significant proportion of the preschool population are infected with protozoa, particularly Giardia lambia. In this cohort, despite a significant prevalence of stunting, helminth infection was not significantly associated with any markers of poor growth. The significance of protozoal carriage and contribution to growth restriction in this context creates further avenues for future research.

Prophylactic Potential of Synbiotic (Lactobacillus casei and Inulin) in Malnourished Murine Giardiasis: an Immunological and Ultrastructural Study

Giardiasis is a re-emerging infectious disease with outbreaks reported globally specially in children and malnourished individuals leading to malabsorption, growth retardation, and severe diarrhea. Thus, in the present study, prophylactic administration of synbiotic as the functional food was used to assess its antigiardial potential in malnourished murine giardiasis. Interestingly, prior administration of synbiotic (Lactobacillus casei + inulin) even to malnourished-Giardia-infected mice led to increased body mass, small intestine mass, lactobacilli counts, and reduced severity of giardiasis as evident by decreased cyst and trophozoite counts. Synbiotic therapy further boosted the innate and acquired immune response resulting into increase in nitric oxide, antigiardial secretory IgA and IgG antibody levels along with IL-6 and IL-10 cytokines, and decreased levels of inflammatory TNF-α cytokine in both serum and intestinal fluid in malnourished-synbiotic-Giardia-infected mice compared with malnourished-Giardia-infected mice. More specifically, histopathological and scanning electron microscopy analysis of the small intestine also confirmed the modulatory potentials of synbiotic in malnourished-synbiotic-Giardia mice which had less cellular and mucosal damage compared with severely damaged, mummified, and blunted villi in malnourished-Giardia-infected mice. Taken together, this is the first experimental study to report that prior supplementation of synbiotic restored the gut morphology and improved the immune status of the malnourished-Giardia-infected mice, and could be considered as the prophylactic adjunct therapy for malnourished individuals.

An Epidemiological Review on Emerging and Re-Emerging Parasitic Infectious Diseases in Malaysia

Emerging infectious diseases are infections that have recently appeared in a population over a defined period of time whereas, re-emerging infectious diseases are those that were once a health problem in a particular region or a country and are now emerging again. Parasitic infectious diseases represent a serious health problem in many developing countries and recently have started spreading to developed nations via international traveling or immigration. Malaysia is facing many challenges caused by various parasitic pathogens. The lack of awareness among disadvantaged populations such as the Orang Asli community and the dependency on foreign workers has led to an influx of immigrants to Malaysia from countries endemic to various parasitic diseases. Understanding the social and economic dynamics of such diseases can help anticipate and subsequently control their emergence. Raising public awareness, developing robust public health infrastructure and implementing point-of-care diagnostics will help curb the spread of such diseases. This review provides epidemiological insights into the reported emerging and re-emerging parasitic infectious diseases in Malaysia over the past two decades.

Cross-sectional epidemiological investigations of Giardia lamblia in children in Pakistan

BACKGROUND

The prevalence of Giardia lamblia in Pakistani children is currently unknown. The aim here was to evaluate the prevalence and risk factors of Giardia lamblia in children exhibiting diarrhea.

DESIGN AND SETTING

Cross-sectional study at different district healthcare hospitals in Pakistan.

METHODS

A total of 800 samples were collected from children aged 0-10 years. Information regarding personal data, demographic data and supposed risk factors was collected through a structured questionnaire. Giardia lamblia was detected through direct microscopy and antigens through the enzyme-linked immunosorbent assay (ELISA).

RESULTS

The prevalence of Giardia lamblia was 2.75% through direct microscopy and inflated to 9.5% through ELISA. The demographic factors positively associated with occurrences of giardiasis were age (P = 0.035; odds ratio, OR = 1.96; 95% confidence interval, CI = 1.094-3.533), mother's educational level (P = 0.031; OR = 2.67; 95% CI = 1.186-6.045) and father's educational level (P = 0.004; OR = 3.56; 95% CI = 1.612-7.899). Similarly, among the supposed risk factors, rural residency (P = 0.032; OR = 1.76; 95% CI = 1.098- 2.851), absence of proper sewerage system (P = 0.000; OR = 6.60; 95% CI = 4.029-10.841) and unavailability of safe drinking water (P = 0.000; OR = 4.08; 95% CI = 2.207-7.547) were the factors strongly connected with giardiasis. Abdominal discomfort was a prominent clinical sign with 46% frequency.

CONCLUSION

Various risk factors were associated with occurrences of Giardia, thus emphasizing the importance of parents' education, safe drinking water and proper sewerage systems for Pakistani children's health.

Distribution of Giardia duodenalis (Assemblages A and B) and Cryptosporidium parvum amongst migrant workers in Peninsular Malaysia

The influx of low skilled workers from socioeconomically deprived neighbouring countries to Malaysia has raised concerns about the transmission of communicable gastrointestinal diseases such as giardiasis and cryptosporidiosis to the local population. Therefore, a cross sectional study was conducted to investigate the prevalence of both diseases and the genetic diversity of these pathogens in the migrant population. Microscopic examination of faecal samples from 388 migrant workers involved in five working sectors were screened and 10.8% (n = 42) were found to be positive with Giardia spp. and 3.1% (n = 12) with Cryptosporidium spp. infections. PCR amplicons at the triosephosphate isomerase (tpi) gene were successfully obtained for Giardia duodenalis from 30 (30/388; 7.73%) samples with assemblages AII and B in 13 (13/30; 43.3%) and 17 (17/30; 56.7%) positive samples, respectively. Nine samples (9/388; 2.3%) were identified as Cryptosporidium parvum using PCR-RFLP analysis. Country of origin, duration of residence in Malaysia and working sectors significantly influenced G. duodenalis assemblage AII infections amongst the targeted population. Meanwhile, C. parvum infection was significantly associated with those working in the food service sector. Despite the low presence of pathogenic G. duodenalis and C. parvum in the study population, the results highlight the risk of anthroponotic foodborne and waterborne transmission and therefore call for implementation of control strategies through improvements in personal hygiene and sanitation standards.

Understanding Giardia infections among rural communities using the one health approach

The epidemiology of giardiasis in rural villages in Peninsular Malaysia was examined in the context of the One Health triad that encompasses humans, animals and environment (i.e. river water). A cross-sectional study was carried out among five rural communities in Malaysia to determine the prevalence of Giardia duodenalis in humans, animals and river water. Fecal samples collected from humans and animals were examined by light microscopy. Water was sampled from the rivers adjacent to the target communities and investigated for the occurrence of Giardia cysts. The isolated cysts were further genotyped targeting the glutamate dehydrogenase and triosephosphate isomerase genes. The overall prevalence of G. duodenalis was 6.7% (18/269) and 4.7% (8/169) among humans and animals, respectively. Giardia cysts (mean concentration range: 0.10-5.97 cysts/L) were also found in adjacent rivers at four out of the five villages examined. At Kemensah and Kuala Pangsun, Giardia cysts were isolated from humans [rate: 3.7% each (of 54 each)], animals [rates: 6.3% (of 62) and 11.3% (of 16), respectively] and river water [average concentration of 9 samples each: 0.83±0.81 and 5.97±7.00, respectively]. For both villages at Pos Piah and Paya Lebar, 12.2% (of 98) and 6.1% (of 33) of collected human samples were infected, respectively whilst none of the collected animals samples in these villages were found to be positive. The river water samples of these two villages were also contaminated (average concentration: 0.20±0.35 (of 9) and 0.10±0.19 (of 3), respectively). In conclusion, Giardia cysts were simultaneously observed in the human-animal-environment (i.e., river water) interfaces in at least two of five studied communities highlighting a vital need to improve understanding on the interplay of transmission dynamics, the role of infected humans and animals in contaminating the water sources and the role of water as a vehicle of disease transmission in these communities. Indeed, this study illustrates the One Health approach which is to recognize that the optimal health of humans are interconnected with the well-being of animals and their environment.

A novel in vitro image-based assay identifies new drug leads for giardiasis

Giardia duodenalis is an intestinal parasite that causes giardiasis, a widespread human gastrointestinal disease. Treatment of giardiasis relies on a small arsenal of compounds that can suffer from limitations including side-effects, variable treatment efficacy and parasite drug resistance. Thus new anti-Giardia drug leads are required. The search for new compounds with anti-Giardia activity currently depends on assays that can be labour-intensive, expensive and restricted to measuring activity at a single time-point. Here we describe a new in vitro assay to assess anti-Giardia activity. This image-based assay utilizes the Perkin-Elmer Operetta^® and permits automated assessment of parasite growth at multiple time points without cell-staining. Using this new approach, we assessed the "Malaria Box" compound set for anti-Giardia activity. Three compounds with sub-μM activity (IC₅₀ 0.6-0.9 μM) were identified as potential starting points for giardiasis drug discovery.

Nested PCR targeting intergenic spacer (IGS) in genotyping of Giardia duodenalis isolated from symptomatic and asymptomatic infected Egyptian school children

Distinct sequences of Giardia duodenalis assemblages raised the hypothesis that certain assemblages may contribute to its clinical outcome. However, sequences analysis is time consuming, expensive, and needs many manual operations. Nested PCR targeting intergenic spacer (IGS) region was applied successfully to genotype G. duodenalis. This study aimed to identify the prevalence of G. duodenalis assemblages among giardiasis school children and its relation to the presence of symptoms using nested IGS/PCR. Of 65 microscopically confirmed Giardia-positive samples, 65 samples were genotyped proving high sensitivity (92.3%) of IGS/PCR. Negative IGS/PCR samples were also negative for β-giardin gene. Subassemblage AI was the commonest with 66.6% (20/30) among asymptomatic children compared to 53.3% (16/30) of symptomatic, while assemblage B was found in 40% (12/30) of symptomatic compared to 20% (6/30) of asymptomatic. The difference was significant. AII was only found in asymptomatic with 13.4% (4/30), while mixed infections (AI&B) were recorded only in 6.6% (2/30) of symptomatic group. A significant relation was found between younger children susceptibility for AI and B infections as presented in 77.7 (12/16) and 83.3% (10/12) of symptomatic, respectively, and 80 (16/80) and 33.4% (2/4) of asymptomatic, respectively. Significant relations were found between AI with intermittent diarrhea and B with chronic. A significant relation was found between assemblage distributions and heavy infection intensity. In conclusion, higher incidence of assemblage B among symptomatic children compared to asymptomatic could denote its possible pathogenic potential.

Prevalence of Cryptosporidium spp., Enterocytozoon bieneusi, Encephalitozoon spp. and Giardia intestinalis in Wild, Semi-Wild and Captive Orangutans (Pongo abelii and Pongo pygmaeus) on Sumatra and Borneo, Indonesia

Background

Orangutans are critically endangered primarily due to loss and fragmentation of their natural habitat. This could bring them into closer contact with humans and increase the risk of zoonotic pathogen transmission.

Aims

To describe the prevalence and diversity of Cryptosporidium spp., microsporidia and Giardia intestinalis in orangutans at seven sites on Sumatra and Kalimantan, and to evaluate the impact of orangutans’ habituation and location on the occurrence of these zoonotic protists.

Result

The overall prevalence of parasites in 298 examined animals was 11.1%. The most prevalent microsporidia was Encephalitozoon cuniculi genotype II, found in 21 animals (7.0%). Enterocytozoon bieneusi genotype D (n = 5) and novel genotype Pongo 2 were detected only in six individuals (2.0%). To the best of our knowledge, this is the first report of these parasites in orangutans. Eight animals were positive for Cryptosporidium spp. (2.7%), including C. parvum (n = 2) and C. muris (n = 6). Giardia intestinalis assemblage B, subtype MB6, was identified in a single individual. While no significant differences between the different human contact level groups (p = 0.479–0.670) or between the different islands (p = 0.992) were reported in case of E. bieneusi or E. cuniculi, Cryptosporidium spp. was significantly less frequently detected in wild individuals (p < 2×10⁻¹⁶) and was significantly more prevalent in orangutans on Kalimantan than on Sumatra (p < 2×10⁻¹⁶).

Conclusion

Our results revealed that wild orangutans are significantly less frequently infected by Cryptosporidium spp. than captive and semi-wild animals. In addition, this parasite was more frequently detected at localities on Kalimantan. In contrast, we did not detect any significant difference in the prevalence of microsporidia between the studied groups of animals. The sources and transmission modes of infections were not determined, as this would require repeated sampling of individuals, examination of water sources, and sampling of humans and animals sharing the habitat with orangutans.

Giardia duodenalis and Giardia enterica in children: first evidence of assemblages A and B in Eastern Slovakia

For an overview on the occurrence of Giardia assemblages in children in Eastern Slovakia, we examined 259 faecal samples of children from the segregated settlement in Medzev, 30 samples of children from the orphanage in Medzev and 40 samples of children with autism from the Special Elementary School in Košice. Thirty-eight samples (14.67 %) from the segregated settlement, 19 samples (63.33 %) from the orphanage and two samples (5.0 %) from the Special Elementary School were positive for Giardia by flotation. The initial microscopic diagnostics were completed by the genotyping of the triosephosphate isomerase-gene loci (tpi genes) which revealed the existence of two Giardia assemblages in Slovak population, namely Giardia duodenalis (assemblage A) and Giardia enterica (assemblage B). These results represent the first evidence of A and B assemblages in children in Slovakia. Epidemiological significance and the impact on the public health of Giardia infection are highlighted.

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.

A cluster-randomised controlled trial integrating a community-based water, sanitation and hygiene programme, with mass distribution of albendazole to reduce intestinal parasites in Timor-Leste: the WASH for WORMS research protocol

INTRODUCTION

There is limited evidence demonstrating the benefits of community-based water, sanitation and hygiene (WASH) programmes on infections with soil-transmitted helminths (STH) and intestinal protozoa. Our study aims to contribute to that evidence base by investigating the effectiveness of combining two complementary approaches for control of STH: periodic mass administration of albendazole, and delivery of a community-based WASH programme.

METHODS AND ANALYSIS

WASH for WORMS is a cluster-randomised controlled trial to test the hypothesis that a community-based WASH intervention integrated with periodic mass distribution of albendazole will be more effective in reducing infections with STH and protozoa than mass deworming alone. All 18 participating rural communities in Timor-Leste receive mass chemotherapy every 6 months. Half the communities also receive the community-based WASH programme. Primary outcomes are the cumulative incidence of infection with STH. Secondary outcomes include the prevalence of protozoa; intensity of infection with STH; as well as morbidity indicators (anaemia, stunting and wasting). Each of the trial outcomes will be compared between control and intervention communities. End points will be measured 2 years after the first albendazole distribution; and midpoints are measured at 6 months intervals (12 months for haemoglobin and anthropometric indexes). Mixed-methods research will also be conducted in order to identify barriers and enablers associated with the acceptability and uptake of the WASH programme.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the human ethics committees at the University of Queensland, Australian National University, Timorese Ministry of Health, and University of Melbourne. The results of the trial will be published in peer-reviewed journals presented at national and international conferences, and disseminated to relevant stakeholders in health and WASH programmes. This study is funded by a Partnership for Better Health--Project grant from the National Health and Research Council (NHMRC), Australia.

TRIAL REGISTRATION NUMBER

ACTRN12614000680662; Pre-results.

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.

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.

Undernutrition and associated risk factors among school age children in Addis Ababa, Ethiopia

Background

Causes of child undernutrition are diverse and change in space and time. Investigating current determinants of undernutrition remains vital to design an effective intervention strategy. The study assessed prevalence of undernutrition and its associated factors among children living in Addis Ababa, Ethiopia.

Methods

A community based cross-sectional study was conducted in 459 school age children and their parents or caregivers living in Lideta sub-city, Addis Ababa, Ethiopia. Participants were selected using a multi-stage simple random sampling technique. Height and weight of children was measured and their parents or care givers were interviewed for factors associated with undernutrition.

Results

About 31% (n = 141) of the children were undernourished (19.6% stunted, 15.9% underweight). Being male, higher birth order (>2), larger family size (6–8), low meal frequency (≤3 times) in a day prior to the survey and mud floor house were significantly associated with undernutrition. Similarly, the risk of underweight increased significantly with an increase in age, birth order, family size and also the absence of hand washing facilities. The odds of undernutrition was lower in children born to 20–30 years old mothers compared to those born to mothers younger than 20 years.

Conclusions

Undernutrition is prevalent among school age children living in Lideta sub city, Addis Ababa. Policy makers should consider school age children in their nutrition policy documents and implement screening program and intervention strategy.

Prevalence and associated risk factors of Giardia infection among indigenous communities in rural Malaysia

This study was carried out to investigate the prevalence and risk factors of Giardia infection among indigenous people in rural Malaysia. Faecal samples were collected from 1,330 participants from seven states of Malaysia and examined by wet mount and formalin-ether sedimentation methods while demographic, socioeconomic and environmental information was collected using a pre-tested questionnaire. The overall prevalence of Giardia infection was 11.6% and was significantly higher among those aged ≤ 12 years compared to their older counterparts. Multivariate logistic regression identified age of ≤12 years, lacking of toilet at household, not washing hands before eating, not washing hands after playing with animals, not boiling water before consumption, bathing in the river, and not wearing shoes when outside as the significant risk factors of Giardia infection among these communities. Based on a multilocus genotyping approach (including tpi, gdh and bg gene sequences), 69 isolates were identified as assemblage A, and 69 as assemblage B. No association between the assemblages and presence of symptoms was found. Providing proper sanitation, as well as provision of clean drinking water and proper health education regarding good personal hygiene practices will help significantly in reducing the prevalence and burden of Giardia infection in these communities.

Genome sequencing of Giardia lamblia genotypes A2 and B isolates (DH and GS) and comparative analysis with the genomes of genotypes A1 and E (WB and Pig)

Giardia lamblia (syn G. intestinalis, G. duodenalis) is the most common pathogenic intestinal parasite of humans worldwide and is a frequent cause of endemic and epidemic diarrhea. G. lamblia is divided into eight genotypes (A-H) which infect a wide range of mammals and humans, but human infections are caused by Genotypes A and B. To unambiguously determine the relationship among genotypes, we sequenced GS and DH (Genotypes B and A2) to high depth coverage and compared the assemblies with the nearly completed WB genome and draft sequencing surveys of Genotypes E (P15; pig isolate) and B (GS; human isolate). Our results identified DH as the smallest Giardia genome sequenced to date, while GS is the largest. Our open reading frame analyses and phylogenetic analyses showed that GS was more distant from the other three genomes than any of the other three were from each other. Whole-genome comparisons of DH_A2 and GS_B with the optically mapped WB_A1 demonstrated substantial synteny across all five chromosomes but also included a number of rearrangements, inversions, and chromosomal translocations that were more common toward the chromosome ends. However, the WB_A1/GS_B alignment demonstrated only about 70% sequence identity across the syntenic regions. Our findings add to information presented in previous reports suggesting that GS is a different species of Giardia as supported by the degree of genomic diversity, coding capacity, heterozygosity, phylogenetic distance, and known biological differences from WB_A1 and other G. lamblia genotypes.

Reduced prevalence of Giardia duodenalis in iron-deficient Rwandan children

OBJECTIVE

Acute symptomatic infection with Giardia duodenalis impairs iron absorption, but iron deficiency may protect against infections caused by various micro-organisms including parasites. We therefore examined the association of G. duodenalis infection and iron deficiency in 575 Rwandan children under 5 years of age.

METHODS

Giardia duodenalis infection was diagnosed by triplicate microscopy and PCR assays, and iron deficiency was defined as a ferritin concentration <12 ng/ml.

RESULTS

Largely asymptomatic G. duodenalis infection was seen in 65.3% of the children and iron deficiency in 17.4%. G. duodenalis infection was less common in iron-deficient children (51%) than in non-deficient children (68%, P = 0.002). In multivariate analysis, the odds of G. duodenalis infection were almost halved in iron-deficient children (adjusted odds ratio, 0.54; 95% confidence interval, 0.33-0.86).

CONCLUSION

In this highly endemic setting, there was no evidence that Giardia infection impairs iron status. Rather, iron deficiency appeared to protect against infection with this parasite.

Molecular epidemiology of giardiasis among Orang Asli in Malaysia: application of the triosephosphate isomerase gene

BACKGROUND

Giardia duodenalis is a flagellate parasite which has been considered the most common protozoa infecting human worldwide. Molecular characterization of G. duodenalis isolates have revealed the existence of eight groups (Assemblage A to H) which differ in their host distribution. Assemblages A and B are found in humans and in many other mammals.

METHODS

This cross-sectional study was conducted to identify assemblage's related risk factors of G. duodenalis among Orang Asli in Malaysia. Stool samples were collected from 611 individuals aged between 2 and 74 years old of whom 266 were males and 345 were females. Socioeconomic data were collected through a pre-tested questionnaire. All stool samples were processed with formalin-ether sedimentation and Wheatley's trichrome staining techniques for the primary identification of G. duodenalis. Molecular identification was carried out by the amplification of a triosephosphate isomerase gene using nested-PCR assay.

RESULTS

Sixty-two samples (10.2%) were identified as assemblage A and 36 (5.9%) were assemblage B. Risk analysis based on the detected assemblages using univariate and logistic regression analyses identified subjects who have close contact with household pets i.e. dogs and cats (OR = 2.60; 95% CI = 1.42, 4.78; P = 0.002) was found to be significant predictor for assemblage A. On the other hand, there were three significant risk factors caused by assemblage B: (i) children ≤15 years old (OR = 2.33; 95% CI = 1.11, 4.87; P = 0.025), (ii) consuming raw vegetables (OR = 2.82; 95% CI = 1.27, 6.26; P = 0.011) and (iii) the presence of other family members infected with giardiasis (OR = 6.31; 95% CI = 2.99, 13.31; P < 0.001).

CONCLUSIONS

The present study highlighted that G. duodenalis infection among Orang Asli was caused by both assemblages with significant high prevalence of assemblage A. Therefore, taking precaution after having contact with household pets and their stool, screening and treating infected individuals, awareness on the importance of good health practices and washing vegetables are the practical intervention ways in preventing giardiasis in Orang Asli community.

Parasitic Infections among Children under Five Years in Senegal: Prevalence and Effect on Anaemia and Nutritional Status

Although malaria is declining in many countries in Africa, malaria and anaemia remain frequent in children. This study was conducted to assess the relationship between malaria parasitaemia, intestinal worms, and anaemia, in children <5 years living in low transmission area in Senegal. A survey was carried out in 30 villages in the central part of Senegal. A two-level random cluster sampling technique was used to select study participant. Children <5 years were enrolled after informed consent. For each child, blood thick and smear tests were performed, haemoglobin concentration was measured with HemoCue, and stool samples were collected and examined using the Ritchie technique. A total of 736 children were recruited. Malaria parasite prevalence was 1.5% (0.7-2.6); anaemia was found in 53.4% (48.2-58.9), while intestinal parasites and stunting represented 26.2% (22.6-30.2) and 22% (18.6-25.5), respectively. In a logistic regression analysis, anaemia was significantly associated with malaria parasitaemia (aOR= 6.3 (1.5-53.5)) and stunting (aOR = 2 (1.2-3.1)); no association was found between intestinal parasites and anaemia. Malaria and anaemia remain closely associated even when malaria is declining. Scaling up antimalarial interventions may contribute to eliminate malaria and reduce the occurrence of anaemia among children.

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.

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.

Immune responses and protection in children in developing countries induced by oral vaccines

Oral mucosal vaccines have great promise for generating protective immunity against intestinal infections for the benefit of large numbers of people especially young children. There however appears to be a caveat since these vaccines have to overcome the inbuilt resistance of mucosal surfaces and secretions to inhibit antigen stimulation and responses. Unfortunately, these vaccines are not equally immunogenic nor protective in different populations. When compared to industrialized countries, children living in developing countries appear to have lower responses, but the reasons for these lowered responses are not clearly defined. The most likely explanations relate to undernutrition, micronutrient deficiencies, microbial overload on mucosal surfaces, alteration of microbiome and microbolom and irreversible changes on the mucosa as well as maternal antibodies in serum or breast milk may alter the mucosal pathology and lower immune responses to interventions using oral vaccines. The detrimental effect of adverse environment and malnutrition may bring about irreversible changes in the mucosa of children especially in the first 1000 days of life from conception to after birth and up to two years of age. This review aims to summarize the information available on lowered immune responses to mucosal vaccines and on interventions that may help address the constraints of these vaccines when they are used for children living under the greatest stress and under harmful adverse circumstances.

Molecular epidemiology of amoebiasis in Malaysia: highlighting the different risk factors of Entamoeba histolytica and Entamoeba dispar infections among Orang Asli communities

Currently, species-specific information on Entamoeba infections is unavailable in Malaysia and is restricted worldwide due to the re-description of pathogenic Entamoeba histolytica and non-pathogenic Entamoeba dispar and Entamoeba moshkovskii. Therefore, this cross-sectional study was conducted to provide the first known documented data on the true prevalence of these three species in western Malaysia using a molecular method. Another aim of this study was to determine the association of potential risk factors associated with each Entamoeba sp. A total of 500 stool samples from three Orang Asli tribes were randomly collected. The overall prevalence of E. histolytica, E. dispar and E. moshkovskii determined by microscopy was 18.6% (93/500). Molecular analysis revealed that while most Entamoeba-positive individuals were infected with E. dispar (13.4%), followed by E. histolytica (3.2%) and E. moshkovskii (1.0%), the present findings show low prevalence rates of mixed infections with E. histolytica and E. dispar (2%), E. dispar and E. moshkovskii (1.2%) and association infections of E. histolytica, E. dispar and E. moshkovskii (0.4%). Logistical regression analysis indicates that the dynamics of the transmission of the three Entamoeba spp. was different. Of six statistically significant variables observed in the univariate analysis, three were retained as significant risk factors for E. histolytica infection in the logistical regression model. These factors were (i) not washing hands after playing with soil or gardening (Odds ratio (OR)=4.7; 95% confidence level (CI)=1.38, 16.14; P=0.013), (ii) indiscriminate defecation in the river or bush (OR=5.7; 95% CI=1.46, 21.95; P=0.012) and (iii) close contact with domestic animals (OR=5.4; 95% CI=1.36, 2.51; P=0.017). However, subjects with family members who were infected with E. histolytica/E. dispar/E. moshkovskii (OR=3.8; 95 CI=2.11, 6.86; P<0.001) and those who consumed raw vegetables (OR=1.8; 95% CI=1.01, 3.23; P=0.047) were more likely to be infected with E. dispar. On the other hand, no associated factor was identified with E. moshkovskii infection. Nevertheless, diarrhoea (P=0.002) and other gastroenteritis symptoms (P<0.001) were only associated with E. histolytica infection. The present study provides new insight into the distribution and risk factors of E. histolytica, E. dispar and E. moshkovskii infections among Orang Asli communities in Malaysia. Identifying the different risk factors of E. histolytica and E. dispar infections will help in the planning specific strategies in the control and prevention of each infection in the communities. Moreover, it emphasises the need for molecular methods to determine the species-specific prevalence of Entamoeba spp.

The association between malaria parasitaemia, erythrocyte polymorphisms, malnutrition and anaemia in children less than 10 years in Senegal: a case control study

Background

Malaria and anaemia (Haemoglobin <11 g/dl) remain frequent in tropical regions and are closely associated. Although anaemia aetiologies are known to be multi-factorial, most studies in malaria endemic areas have been confined to analysis of possible associations between anaemia and individual factors such as malaria. A case control study involving children aged from 1 to 10 years was conducted to assess some assumed contributors to anaemia in the area of Bonconto Health post in Senegal.

Methods

Study participants were randomly selected from a list of children who participated in a survey in December 2010. Children aged from 1 to 10 years with haemoglobin level below 11 g/dl represented cases (anaemic children). Control participants were eligible if of same age group and their haemoglobin level was >= 11 g/dl. For each participant, a physical examination was done and anthropometric data collected prior to a biological assessment which included: malaria parasitaemia infection, intestinal worm carriage, G6PD deficiency, sickle cell disorders, and alpha-talassaemia.

Results

Three hundred and fifty two children < 10 years of age were enrolled (176 case and 176 controls). In a logistic regression analysis, anaemia was significantly associated with malaria parasitaemia (aOR=5.23, 95%CI[1.1-28.48]), sickle cell disorders (aOR=2.89, 95%CI[1,32-6.34]), alpha-thalassemia (aOR=1.82, 95%CI[1.2-3.35]), stunting (aOR=3.37, 95%CI[1.93-5.88], age ranged from 2 to 4 years (aOR=0.13, 95%CI[0.05-0.31]) and age > 5 years (aOR=0.03, 95%CI[0.01-0.08]). Stratified by age group, anaemia was significantly associated with stunting in children less than 5 years (aOR=3.1 95%CI[1.4 – 6.8]), with, sickle cell disorders (aOR=3.5 95%CI [1.4 – 9.0]), alpha-thalassemia (or=2.4 95%CI[1.1–5.3]) and stunting (aOR=3.6 95%CI [1.6–8.2]) for children above 5 years. No association was found between G6PD deficiency, intestinal worm carriage and children’s gender.

Conclusion

Malaria parasitaemia, stunting and haemoglobin genetic disorders represented the major causes of anaemia among study participants. Anaemia control in this area could be achieved by developing integrated interventions targeting both malaria and malnutrition.

Giardiasis among different tribes of Orang Asli in Malaysia: highlighting the presence of other family members infected with Giardia intestinalis as a main risk factor

The flagellate protozoan parasite, Giardia intestinalis, is widely distributed throughout the world with a high prevalence in developing countries in the tropics and subtropics, including Malaysia. Approximately 200 million people are infected with the parasite globally, with 500,000 new cases reported annually. This cross-sectional study was conducted among three tribes of Orang Asli communities in Selangor, Perak and Pahang states of Malaysia. The main objective was to determine the prevalence of and risk factors for giardiasis. Stool samples were collected from 500 individuals aged between 2 and 74 years (males=219, females=281). The samples were examined with formalin-ether sedimentation and trichrome staining techniques. Socioeconomic data were collected through a pre-tested questionnaire. The overall prevalence of giardiasis was 20.0% with the highest prevalence in the Proto-Malays (33.3%) followed by Negritos (20.1%) and Senois (10.4%). The positive cases showed a decrease with increasing age and most of the positive cases were observed in individuals less than 24 years old. Males had significantly higher prevalence than females (χ(2)=5.283, P=0.022). Logistic regression analysis of the overall population studied and the Senoi tribe confirmed that being a child aged less than 15 years, being male, the consumption of raw vegetables and the presence of other family members infected with G. intestinalis were the main risk factors for giardiasis. The presence of other family members infected with G. intestinalis was the only risk factor highlighted in the Proto-Malay and Negrito tribes. Diarrhoea was significantly associated with giardiasis. However, the cause and effect relationship has yet to be determined. Thus, screening family members and treating the infected individuals are the main strategies that should be adopted by the public health authority in combating this infection in Orang Asli communities as well as health education regarding good personal and food hygiene practises.

Giardia--from genome to proteome

In this review, the current status of genomic and proteomic research on Giardia is examined in terms of evolutionary biology, phylogenetic relationships and taxonomy. The review also describes how characterising genetic variation in Giardia from numerous hosts and endemic areas has provided a better understanding of life cycle patterns, transmission and the epidemiology of Giardia infections in humans, domestic animals and wildlife. Some progress has been made in relating genomic information to the phenotype of Giardia, and as a consequence, new information has been obtained on aspects of developmental biology and the host-parasite relationship. However, deficiencies remain in our understanding of pathogenesis and host specificity, highlighting the limitations of currently available genomic datasets.