Malnutrition as an enteric infectious disease with long-term effects on child development

Vitamin D₃supplementation and childhood diarrhea: a randomized controlled trial

OBJECTIVE

To investigate the effect of vitamin D3 supplementation on the incidence and risk for first and recurrent diarrheal illnesses among children in Kabul, Afghanistan.

METHODS

This double-blind placebo-controlled trial randomized 3046 high-risk 1- to 11-month-old infants to receive 6 quarterly doses of oral vitamin D3 (cholecalciferol 100000 IU) or placebo in inner city Kabul. Data on diarrheal episodes (≥ 3 loose/liquid stools in 24 hours) was gathered through active and passive surveillance over 18 months of follow-up. Time to first diarrheal illness was analyzed by using Kaplan-Meier plots. Incidence rates and hazard ratios (HRs) were calculated by using recurrent event Poisson regression models.

RESULTS

No significant difference existed in survival time to first diarrheal illness (log rank P = .55). The incidences of diarrheal episodes were 3.43 (95% confidence interval [CI], 3.28-3.59) and 3.59 per child-year (95% CI, 3.44-3.76) in the placebo and intervention arms, respectively. Vitamin D3 supplementation was found to have no effect on the risk for recurrent diarrheal disease in either intention-to-treat (HR, 1.05; 95% CI, 0.98-1.17; P = .15) or per protocol (HR, 1.05; 95% CI, 0.98-1.12; P = .14) analyses. The lack of preventive benefit remained when the randomized population was stratified by age groups, nutritional status, and seasons.

CONCLUSIONS

Quarterly supplementation with vitamin D3 conferred no reduction on time to first illness or on the risk for recurrent diarrheal disease in this study. Similar supplementation to comparable populations is not recommended. Additional research in alternative settings may be helpful in elucidating the role of vitamin D3 supplementation for prevention of diarrheal diseases.

Recent advances in understanding enteric pathogenic Escherichia coli

Although Escherichia coli can be an innocuous resident of the gastrointestinal tract, it also has the pathogenic capacity to cause significant diarrheal and extraintestinal diseases. Pathogenic variants of E. coli (pathovars or pathotypes) cause much morbidity and mortality worldwide. Consequently, pathogenic E. coli is widely studied in humans, animals, food, and the environment. While there are many common features that these pathotypes employ to colonize the intestinal mucosa and cause disease, the course, onset, and complications vary significantly. Outbreaks are common in developed and developing countries, and they sometimes have fatal consequences. Many of these pathotypes are a major public health concern as they have low infectious doses and are transmitted through ubiquitous mediums, including food and water. The seriousness of pathogenic E. coli is exemplified by dedicated national and international surveillance programs that monitor and track outbreaks; unfortunately, this surveillance is often lacking in developing countries. While not all pathotypes carry the same public health profile, they all carry an enormous potential to cause disease and continue to present challenges to human health. This comprehensive review highlights recent advances in our understanding of the intestinal pathotypes of E. coli.

Persistent diarrhea: still a serious public health problem in developing countries

Diarrhea is still responsible for high rates of morbidity and mortality in children under 5 years of age. The prolongation of the acute episode may cause digestive and absorptive malfunction and, consequently, malnutrition, raising the risk of death. The objective of this review is to supply the most recent knowledge in the field of persistent diarrhea and to contribute to the decrease of its incidence. Some possible etiologic agents may be involved, including viruses, bacteria, and parasites. Treatment must be addressed to avoid malabsorption of the nutrients of the diet, associated with replacement of the hydroelectrolytic losses, to prevent its prolongation. In the great majority of the episodes, antibiotics are not indicated. Breastfeeding, introduction of safe dietary strategies to prevent protein-energy malnutrition, and improvement of sanitary conditions and hygiene are measures to be promoted with the objective of decreasing the morbidity/mortality of the diarrheic disease in children less than 5 years of age.

New concepts in diagnostics for infectious diarrhea

Conventional approaches to the diagnosis of infectious diarrhea must include several modalities to detect an array of potential viruses, bacteria, and parasites. We will provide a general overview of the wide range of diagnostic modalities available for enteropathogens, briefly discuss some of the limitations of conventional methods, and then focus on new molecular methods, including real-time PCR and next-generation sequencing. In particular, we will discuss quantitation of pathogen load with these techniques. We will then describe examples whereby novel diagnostics may help illuminate the etiology of infectious diarrhea, where they may not, and how they may benefit studies of immunity to enteric infections.

Cluster-randomised controlled trials of individual and combined water, sanitation, hygiene and nutritional interventions in rural Bangladesh and Kenya: the WASH Benefits study design and rationale

INTRODUCTION

Enteric infections are common during the first years of life in low-income countries and contribute to growth faltering with long-term impairment of health and development. Water quality, sanitation, handwashing and nutritional interventions can independently reduce enteric infections and growth faltering. There is little evidence that directly compares the effects of these individual and combined interventions on diarrhoea and growth when delivered to infants and young children. The objective of the WASH Benefits study is to help fill this knowledge gap.

METHODS AND ANALYSIS

WASH Benefits includes two cluster-randomised trials to assess improvements in water quality, sanitation, handwashing and child nutrition-alone and in combination-to rural households with pregnant women in Kenya and Bangladesh. Geographically matched clusters (groups of household compounds in Bangladesh and villages in Kenya) will be randomised to one of six intervention arms or control. Intervention arms include water quality, sanitation, handwashing, nutrition, combined water+sanitation+handwashing (WSH) and WSH+nutrition. The studies will enrol newborn children (N=5760 in Bangladesh and N=8000 in Kenya) and measure outcomes at 12 and 24 months after intervention delivery. Primary outcomes include child length-for-age Z-scores and caregiver-reported diarrhoea. Secondary outcomes include stunting prevalence, markers of environmental enteropathy and child development scores (verbal, motor and personal/social). We will estimate unadjusted and adjusted intention-to-treat effects using semiparametric estimators and permutation tests.

ETHICS AND DISSEMINATION

Study protocols have been reviewed and approved by human subjects review boards at the University of California, Berkeley, Stanford University, the International Centre for Diarrheal Disease Research, Bangladesh, the Kenya Medical Research Institute, and Innovations for Poverty Action. Independent data safety monitoring boards in each country oversee the trials. This study is funded by a grant from the Bill & Melinda Gates Foundation to the University of California, Berkeley.

REGISTRATION

Trial registration identifiers (http://www.clinicaltrials.gov): NCT01590095 (Bangladesh), NCT01704105 (Kenya).

Does comorbidity increase the risk of mortality among children under 3 years of age?

OBJECTIVES

Diarrhoea and pneumonia remain leading causes of morbidity and mortality in children under 5 years of age. Little data is available to quantify the burden of comorbidity and the relationship between comorbid diarrhoea and pneumonia infections and mortality. We sought to quantify the relationship between comorbidity and risk of mortality among young children in two community-based studies conducted among South Asian children.

DESIGN

Secondary data analysis of two cohort studies.

PARTICIPANTS

We identified two cohort studies of children under 3 years of age with prospective morbidity at least once every 2 weeks and ongoing mortality surveillance.

OUTCOME MEASURES

We calculated the mortality risk for diarrhoea and acute lower respiratory infection (ALRI) episodes and further quantified the risk of mortality when both diseases occur at the same time using a semiparametric additive model.

RESULTS

Among Nepali children, the estimated additional risk of mortality for comorbid diarrhoea and ALRI was 0.0014 (-0.0033, 0.0060). Among South Indian children, the estimated additional risk of mortality for comorbid diarrhoea and ALRI was 0.0032 (-0.0098, 0.0162). This risk is in addition to the single infection risk of mortality observed among these children.

CONCLUSIONS

We observed an additional risk of mortality in children who experienced simultaneous diarrhoea and ALRI episodes though the CI was wide indicating low statistical support. Additional studies with adequate power to detect the increased risk of comorbidity on mortality are needed to improve confidence around the effect size estimate.

Interventions to improve water quality and supply, sanitation and hygiene practices, and their effects on the nutritional status of children

BACKGROUND

Water, sanitation and hygiene (WASH) interventions are frequently implemented to reduce infectious diseases, and may be linked to improved nutrition outcomes in children.

OBJECTIVES

To evaluate the effect of interventions to improve water quality and supply (adequate quantity to maintain hygiene practices), provide adequate sanitation and promote handwashing with soap, on the nutritional status of children under the age of 18 years and to identify current research gaps.

SEARCH METHODS

We searched 10 English-language (including MEDLINE and CENTRAL) and three Chinese-language databases for published studies in June 2012. We searched grey literature databases, conference proceedings and websites, reviewed reference lists and contacted experts and authors.

SELECTION CRITERIA

Randomised (including cluster-randomised), quasi-randomised and non-randomised controlled trials, controlled cohort or cross-sectional studies and historically controlled studies, comparing WASH interventions among children aged under 18 years.

DATA COLLECTION AND ANALYSIS

Two review authors independently sought and extracted data on childhood anthropometry, biochemical measures of micronutrient status, and adherence, attrition and costs either from published reports or through contact with study investigators. We calculated mean difference (MD) with 95% confidence intervals (CI). We conducted study-level and individual-level meta-analyses to estimate pooled measures of effect for randomised controlled trials only.

MAIN RESULTS

Fourteen studies (five cluster-randomised controlled trials and nine non-randomised studies with comparison groups) from 10 low- and middle-income countries including 22,241 children at baseline and nutrition outcome data for 9,469 children provided relevant information. Study duration ranged from 6 to 60 months and all studies included children under five years of age at the time of the intervention. Studies included WASH interventions either singly or in combination. Measures of child anthropometry were collected in all 14 studies, and nine studies reported at least one of the following anthropometric indices: weight-for-height, weight-for-age or height-for-age. None of the included studies were of high methodological quality as none of the studies masked the nature of the intervention from participants.Weight-for-age, weight-for-height and height-for-age z-scores were available for five cluster-randomised controlled trials with a duration of between 9 and 12 months. Meta-analysis including 4,627 children identified no evidence of an effect of WASH interventions on weight-for-age z-score (MD 0.05; 95% CI -0.01 to 0.12). Meta-analysis including 4,622 children identified no evidence of an effect of WASH interventions on weight-for-height z-score (MD 0.02; 95% CI -0.07 to 0.11). Meta-analysis including 4,627 children identified a borderline statistically significant effect of WASH interventions on height-for-age z-score (MD 0.08; 95% CI 0.00 to 0.16). These findings were supported by individual participant data analysis including information on 5,375 to 5,386 children from five cluster-randomised controlled trials.No study reported adverse events. Adherence to study interventions was reported in only two studies (both cluster-randomised controlled trials) and ranged from low (< 35%) to high (> 90%). Study attrition was reported in seven studies and ranged from 4% to 16.5%. Intervention cost was reported in one study in which the total cost of the WASH interventions was USD 15/inhabitant. None of the studies reported differential impacts relevant to equity issues such as gender, socioeconomic status and religion.

AUTHORS' CONCLUSIONS

The available evidence from meta-analysis of data from cluster-randomised controlled trials with an intervention period of 9-12 months is suggestive of a small benefit of WASH interventions (specifically solar disinfection of water, provision of soap, and improvement of water quality) on length growth in children under five years of age. The duration of the intervention studies was relatively short and none of the included studies is of high methodological quality. Very few studies provided information on intervention adherence, attrition and costs. There are several ongoing trials in low-income country settings that may provide robust evidence to inform these findings.

Diarrhea as a risk factor for acute lower respiratory tract infections among young children in low income settings

Background

Diarrhea and acute lower respiratory tract infections (ALRI) are leading causes of morbidity and mortality among children under 5 years of age. We sought to quantify the correlation of diarrhea and respiratory infections within an individual child and to determine if infection with one illness increases the risk of infection with the other during the same time period.

Methods

We quantified the likelihood of an ALRI and a diarrhea episode occurring during the same week compared to the likelihood of each occurring independently in two cohorts of children under 3 years of age using a bivariate probit regression model. We also quantified the likelihood of an ALRI episode conditioned on a child’s diarrhea history and the likelihood of a diarrhea episode conditioned on a child’s ALRI history using Cox Proportional Hazard models.

Results

In Indian and Nepali children, diarrhea and ALRI occurred simultaneously more than chance alone. Incidence of ALRI increased in both cohorts as the number of days with diarrhea in the prior 28 days increased; the greatest incident rate ratio was reported among children with 20 or more days of diarrhea (1.02, 95% confidence interval (CI) 1.01 – 1.03 in Nepal and 1.07, 95% CI 1.05 – 1.09 in South India). Incidence of diarrhea was affected differently by ALRI prevalence depending on season.

Conclusions

Diarrhea may be a direct risk factor for ALRI among children under 3 years of age. The risk of comorbidity increases as disease severity increases, providing additional rationale for prompt community case–management of both diarrhea and pneumonia.

Severity of diarrhea and malnutrition among under five-year-old children in rural Bangladesh

Enteric pathogens are commonly associated with diarrhea among malnourished children. This study aimed to determine the association between the severity of diarrheal illnesses and malnutrition among under 5-year-old children. During 2010 and 2011, we studied 2,324 under 5-year-old diarrheal children with mild disease (MD) and moderate-to-severe disease (MSD) attending a hospital in Bangladesh. Children with MSD were more likely to be malnourished compared with children with MD (35% versus 24%, P < 0.001). In multivariate analysis, malnutrition (odds ratio [95% confidence interval] = 1.53 [1.22, 1.92]), age of the child (24-59 months; 1.67 [1.28, 2.19]), fever (1.65 [1.28, 2.12]), abdominal pain (1.87 [1.48, 2.37]), straining (5.93 [4.80, 7.33]), and infection with Shigella (3.26 [2.38, 4.46]) and Vibrio cholerae (2.21 [1.07, 4.58]) were shown to be significantly associated with MSD. Factors significantly associated with malnutrition were disease severity (1.56 [1.24, 1.95]), age (24-59 months; 1.75 [1.38, 2.22]), mother's schooling (1.54 [1.16, 2.04]), and monthly household income (1.71 [1.42, 2.07]). Childhood malnutrition was associated with dysentery and dehydrating diarrhea.

Specially formulated foods for treating children with moderate acute malnutrition in low- and middle-income countries

BACKGROUND

Moderate acute malnutrition, also called moderate wasting, affects around 10% of children under five years of age in low- and middle-income countries. There are different approaches to addressing malnutrition with prepared foods in these settings; for example, providing lipid-based nutrient supplements or blended foods, either a full daily dose or in a low dose as a complement to the usual diet. There is no definitive consensus on the most effective way to treat children with moderate acute malnutrition.

OBJECTIVES

To evaluate the safety and effectiveness of different types of specially formulated foods for children with moderate acute malnutrition in low- and middle-income countries, and to assess whether foods complying or not complying with specific nutritional compositions, such as the WHO technical specifications, are safe and effective.

SEARCH METHODS

In October 2012, we searched CENTRAL, MEDLINE, LILACS, CINAHL, BIBLIOMAP, POPLINE, ZETOC, ICTRP, mRCT, and ClinicalTrials.gov. In August 2012, we searched Embase. We also searched the reference lists of relevant papers and contacted nutrition-related organisations and researchers in this field.    

SELECTION CRITERIA

We planned to included any relevant randomised controlled trials (RCTs), controlled clinical trials (CCTs), controlled before-and-after studies (CBAs), and interrupted time series (ITS) that evaluated specially formulated foods for the treatment of moderate acute malnutrition in children aged between six months and five years in low- and middle-income countries.

DATA COLLECTION AND ANALYSIS

Two authors assessed trial eligibility and risk of bias, and extracted and analysed the data. We summarised dichotomous outcomes using risk ratios (RR) and continuous outcomes using mean differences (MD) with 95% confidence intervals (CI). Where appropriate, we combined data in meta-analyses using the random-effects model and assessed heterogeneity. The quality of evidence was assessed using GRADE methods.

MAIN RESULTS

Eight randomised controlled trials, enrolling 10,037 children, met our inclusion criteria. Seven of the trials were conducted in Africa. In general, the included studies were at a low risk of bias. There may have been a risk of performance bias as trial participants were aware which intervention group they were in, but we did not consider this likely to have biased the outcome measurement. We were unable to assess the risk of reporting bias in half of the trials and two trials were at high risk of attrition bias. Any specially formulated food versus standard care - the provision of food increased the recovery rate by 29% (RR 1.29, 95% CI 1.20 to 1.38; 2152 children, two trials; moderate quality evidence), decreased the number dropping out by 70% (RR 0.30, 95% CI 0.22 to 0.39; 1974 children, one trial; moderate quality evidence), and improved weight-for-height (MD 0.20 z-score, 95% CI 0.03 to 0.37; 1546 children, two trials; moderate quality evidence). The reduction in mortality did not reach statistical significance (RR 0.44; 95% CI 0.14 to 1.36; 1974 children, one trial; low quality evidence). Lipid-based nutrient supplements versus any blended foods (dry food mixtures, without high lipid content), at full doses - there was no significant difference in mortality (RR 0.93, 95% CI 0.54 to 1.62; 6367 children, five trials; moderate quality evidence), progression to severe malnutrition (RR 0.88, 95% CI 0.72 to 1.07; 4537 children, three trials; high quality evidence), or the number of dropouts from the nutritional programme (RR 1.14, 95% CI 0.62 to 2.11; 5107 children, four trials; moderate quality evidence). However, lipid-based nutrient supplements significantly increased the number of children recovered (RR 1.10, 95% CI 1.04 to 1.16; 6367 children, five trials; moderate quality evidence), and decreased the number of non-recovering children (RR 0.53, 95% CI 0.40 to 0.69; 4537 children, three trials; high quality evidence). LNS also improved weight gain, weight-for-height, and mid-upper arm circumference, although for these outcomes, the improvement was modest (moderate quality evidence). One trial observed more children with vomiting in the lipid-based nutrient supplements group compared to those receiving blended food (RR 1.43, 95% CI 1.11 to 1.85; 2712 children, one trial; low quality evidence). Foods at complementary doses - no firm conclusion could be drawn on the comparisons between LNS at complementary dose and blended foods at complementary or full dose (low quality evidence). Lipid-based nutrient supplements versus specific types of blended foods - a recently developed enriched blended food (CSB++) resulted in similar outcomes to LNS (4758 children, three trials; moderate to high quality evidence). Different types of blended foods - in one trial, CSB++ did not show any significant benefit over locally made blended food, for example, Misola, in number who recovered, number who died, or weight gain (moderate to high quality evidence). Improved adequacy of home diet - no study evaluated the impact of improving adequacy of local diet, such as local foods prepared at home according to a given recipe or of home processing of local foods (soaking, germination, malting, fermentation) in order to increase their nutritional content.

AUTHORS' CONCLUSIONS

In conclusion, there is moderate to high quality evidence that both lipid-based nutrient supplements and blended foods are effective in treating children with MAM. Although lipid-based nutrient supplements (LNS) led to a clinically significant benefit in the number of children recovered in comparison with blended foods, LNS did not reduce mortality, the risk of default or progression to SAM. It also induced more vomiting. Blended foods such as CSB++ may be equally effective and cheaper than LNS. Most of the research so far has focused on industrialised foods, and on short-term outcomes of MAM. There are no studies evaluating interventions to improve the quality of the home diet, an approach that should be evaluated in settings where food is available, and nutritional education and habits are the main determinants of malnutrition. There are no studies from Asia, where moderate acute malnutrition is most prevalent.

Diarrhea among children in developing countries

Diarrhea continues to stand among the most important causes of global morbidity and mortality in children under 5 years of age. Although the introduction of oral rehydration and other case-management strategies have reduced acute diarrhea fatalities, many of the survivors develop persistent diarrhea and/or deficiencies of growth and cognition. Thus understanding the true global burden of diarrhea requires attention to acute diarrhea as well is its sequelae. To understand the etiology of moderate to severe diarrhea among children in high mortality areas of sub-Saharan Africa and south Asia we performed a comprehensive case-control study of children under 5 years of age at seven sites. Each site employed an identical case-control study design and each utilized a uniform comprehensive set of microbiological assays to identify the likely bacterial, viral and protozoal etiologies. Results of the studies will inform diarrhea prevention and management efforts worldwide.

Crystal structure of a macrophage migration inhibitory factor from Giardia lamblia

Macrophage migration inhibitory factor (MIF) is a eukaryotic cytokine that affects a broad spectrum of immune responses and its activation/inactivation is associated with numerous diseases. During protozoan infections MIF is not only expressed by the host, but, has also been observed to be expressed by some parasites and released into the host. To better understand the biological role of parasitic MIF proteins, the crystal structure of the MIF protein from Giardia lamblia (Gl-MIF), the etiological agent responsible for giardiasis, has been determined at 2.30 Å resolution. The 114-residue protein adopts an α/β fold consisting of a four-stranded β-sheet with two anti-parallel α-helices packed against a face of the β-sheet. An additional short β-strand aligns anti-parallel to β4 of the β-sheet in the adjacent protein unit to help stabilize a trimer, the biologically relevant unit observed in all solved MIF crystal structures to date, and form a discontinuous β-barrel. The structure of Gl-MIF is compared to the MIF structures from humans (Hs-MIF) and three Plasmodium species (falciparum, berghei, and yoelii). The structure of all five MIF proteins are generally similar with the exception of a channel that runs through the center of each trimer complex. Relative to Hs-MIF, there are differences in solvent accessibility and electrostatic potential distribution in the channel of Gl-MIF and the Plasmodium-MIFs due primarily to two "gate-keeper" residues in the parasitic MIFs. For the Plasmodium MIFs the gate-keeper residues are at positions 44 (Y --> R) and 100 (V --> D) and for Gl-MIF it is at position 100 (V --> R). If these gate-keeper residues have a biological function and contribute to the progression of parasitemia they may also form the basis for structure-based drug design targeting parasitic MIF proteins.

Natural contamination of human hands with enteric parasites in Indian Subcontinent

AIM: To investigate the prevalence of enteric parasite contamination on hands and the potential role naturally contaminated hands may have in their transmission.

METHODS: Prior to initiating the survey, the protocol was reviewed and approved by respective Institutional Review Boards of each survey site (Dhaka, Bangladesh and Kolkata, India). Both stool and corresponding hand wash samples collected, were analyzed for the presence of enteric parasitic ova/(oo)cysts employing conventional microscopy coupled with permanent staining techniques. Additionally molecular approaches such as polymerase chain reaction (PCR) of enteric parasites recovered from both stool and corresponding hand wash samples, were also used to further confirm their identity.

RESULTS: A total of 972 stool samples were collected from both sites surveyed (300 volunteers from Kolkata, India and 672 from Dhaka, Bangladesh). Parasitic analysis revealed, 113 (38%) from Kolkata, India and 267 (40%) of stool samples from Dhaka, Bangladesh were positive for parasitic ova/(oo)cysts. When the corresponding hand wash samples were analyzed, 43 (14%) stool-positive volunteers in Kolkata, India and 47 (7%) in Dhaka, Bangladesh were positive for enteric parasitic ova/(oo)cysts. Ascaris lumbricoides (A. lumbricoides) ova and Giardia lamblia (G. lamblia) cysts predominated in hands wash samples from both sites surveyed (from India, A. lumbricoides ova, 53%; G. lamblia cysts 31% and from Bangladesh, A. lumbricoides ova, 47%; G. lamblia cysts 19%). Genotypic analysis of enteric parasitic ova/(oo)cysts obtained from both stool and corresponding hand wash samples taken from the same person were found to be identical.

CONCLUSION: These results suggest a possible role of hands contaminated with enteric parasites’ ova/(oo)cysts in the transmission of these parasites highlighting another role of hand hygiene/proper hand washing in reducing the disease burden in low socioeconomic communities.

Optimization of benzoxazole-based inhibitors of Cryptosporidium parvum inosine 5'-monophosphate dehydrogenase

Cryptosporidium parvum is an enteric protozoan parasite that has emerged as a major cause of diarrhea, malnutrition, and gastroenteritis and poses a potential bioterrorism threat. C. parvum synthesizes guanine nucleotides from host adenosine in a streamlined pathway that relies on inosine 5'-monophosphate dehydrogenase (IMPDH). We have previously identified several parasite-selective C. parvum IMPDH (CpIMPDH) inhibitors by high-throughput screening. In this paper, we report the structure-activity relationship (SAR) for a series of benzoxazole derivatives with many compounds demonstrating CpIMPDH IC50 values in the nanomolar range and >500-fold selectivity over human IMPDH (hIMPDH). Unlike previously reported CpIMPDH inhibitors, these compounds are competitive inhibitors versus NAD(+). The SAR study reveals that pyridine and other small heteroaromatic substituents are required at the 2-position of the benzoxazole for potent inhibitory activity. In addition, several other SAR conclusions are highlighted with regard to the benzoxazole and the amide portion of the inhibitor, including preferred stereochemistry. An X-ray crystal structure of a representative E·IMP·inhibitor complex is also presented. Overall, the secondary amine derivative 15a demonstrated excellent CpIMPDH inhibitory activity (IC50 = 0.5 ± 0.1 nM) and moderate stability (t1/2 = 44 min) in mouse liver microsomes. Compound 73, the racemic version of 15a, also displayed superb antiparasitic activity in a Toxoplasma gondii strain that relies on CpIMPDH (EC50 = 20 ± 20 nM), and selectivity versus a wild-type T. gondii strain (200-fold). No toxicity was observed (LD50 > 50 μM) against a panel of four mammalian cells lines.

Food insufficiency is associated with psychiatric morbidity in a nationally representative study of mental illness among food insecure Canadians

PURPOSE

Studies suggest that people who are food insecure are more likely to experience mental illness. However, little is known about which aspects of food insecurity place individuals most at risk of mental illness. The purpose of this study was to establish the prevalence of mental illness among food insecure Canadians, and examine whether mental illness differs between those who are consuming insufficient amounts of food versus poor quality foods.

METHODS

This analysis utilized the publically available dataset from the Canadian Community Health Survey cycle 4.1. Bivariable and multivariable logistic regression were used to examine the associations between food insecurity and mental health disorder diagnosis, while adjusting for potential confounders. Stratified analyses were used to identify vulnerable sub-groups.

RESULTS

Among 5,588 Canadian adults (18-64 years) reporting food insecurity, 58 % reported poor food quality and 42 % reported food insufficiency. The prevalence of mental health diagnosis was 24 % among participants with poor food quality, and 35 % among individuals who were food insufficient (hunger). After adjusting for confounders, adults experiencing food insufficiency had 1.69 adjusted-odds [95 % confidence interval (CI): 1.49-1.91] of having a mental health diagnosis. Stratified analyses revealed increased odds among women (a-OR 1.89, 95 % CI 1.62-2.20), single parent households (a-OR 2.05, 95 % CI 1.51-2.78), and non-immigrants (a-OR 1.88, 95 % CI 1.64-2.16).

CONCLUSION

The prevalence of mental illness is alarmingly high in this population-based sample of food insecure Canadians. These findings suggest that government and community-based programming aimed at strengthening food security should integrate supports for mental illness in this population.

An update on the use and investigation of probiotics in health and disease

Probiotics are derived from traditional fermented foods, from beneficial commensals or from the environment. They act through diverse mechanisms affecting the composition or function of the commensal microbiota and by altering host epithelial and immunological responses. Certain probiotic interventions have shown promise in selected clinical conditions where aberrant microbiota have been reported, such as atopic dermatitis, necrotising enterocolitis, pouchitis and possibly irritable bowel syndrome. However, no studies have been conducted that can causally link clinical improvements to probiotic-induced microbiota changes. Whether a disease-prone microbiota pattern can be remodelled to a more robust, resilient and disease-free state by probiotic administration remains a key unanswered question. Progress in this area will be facilitated by: optimising strain, dose and product formulations, including protective commensal species; matching these formulations with selectively responsive subpopulations; and identifying ways to manipulate diet to modify bacterial profiles and metabolism.

Early childhood diarrhea and cardiometabolic risk factors in adulthood: the Institute of Nutrition of Central America and Panama Nutritional Supplementation Longitudinal Study

BACKGROUND

Nutritional deficits in early life have been associated with a higher prevalence of the metabolic syndrome (MetS) in adulthood. Early childhood diarrhea contributes to undernutrition and may potentially increase the risk for adult noncommunicable diseases. Our objective was to examine associations between early childhood diarrhea burden and later development of MetS.

METHODS

We studied individuals who participated in the Institute of Nutrition of Central America and Panama Nutritional Supplementation Longitudinal Study (1969-1977) and were followed up in 2002-2004. We used logistic regression to determine associations of diarrhea burden at ages 0 to 6, 6 to 12, and 12 to 24 months with odds of MetS and elevations in its components as adults.

RESULTS

Among 389 adults age 25 to 42 years at follow-up, the prevalence of MetS was 29%. Adjusting for several confounders including adult body mass index (BMI), each absolute 1% increase in diarrhea burden at age 0 to 6 months (but not at other time periods) was associated with increased odds of MetS (odds ratio [OR], 1.03; 95% confidence interval [CI], 1.01-1.06). This was attributable primarily to associations with elevated blood pressure (OR, 1.03; 95% CI, 1.00-1.06) and waist circumference (OR, 1.03; 95% CI, 1.00-1.06).

CONCLUSIONS

Childhood diarrhea burden at 0 to 6 months is associated with MetS in adulthood after controlling for childhood growth parameters and adult BMI.

The impoverished gut--a triple burden of diarrhoea, stunting and chronic disease

More than one-fifth of the world's population live in extreme poverty, where a lack of safe water and adequate sanitation enables high rates of enteric infections and diarrhoea to continue unabated. Although oral rehydration therapy has greatly reduced diarrhoea-associated mortality, enteric infections still persist, disrupting intestinal absorptive and barrier functions and resulting in up to 43% of stunted growth, affecting one-fifth of children worldwide and one-third of children in developing countries. Diarrhoea in children from impoverished areas during their first 2 years might cause, on average, an 8 cm growth shortfall and 10 IQ point decrement by the time they are 7-9 years old. A child's height at their second birthday is therefore the best predictor of cognitive development or 'human capital'. To this 'double burden' of diarrhoea and malnutrition, data now suggest that children with stunted growth and repeated gut infections are also at increased risk of developing obesity and its associated comorbidities, resulting in a 'triple burden' of the impoverished gut. Here, we Review the growing evidence for this triple burden and potential mechanisms and interventions that must be understood and applied to prevent the loss of human potential and unaffordable societal costs caused by these vicious cycles of poverty.

Enteroaggregative Escherichia coli strain in a novel weaned mouse model: exacerbation by malnutrition, biofilm as a virulence factor and treatment by nitazoxanide

Enteroaggregative Escherichia coli (EAEC) is increasingly recognized as a common cause of diarrhoea in healthy, malnourished and immune-deficient adults and children. There is no reproducible non-neonatal animal model for longitudinal studies of disease mechanism or therapy. Using two strains of human-derived EAEC to challenge weaned C57BL/6 mice, we explored an in vivo model of EAEC infection in mice, in which disease was monitored quantitatively as the growth rate, stool shedding and tissue burden of organisms; nutritional status was varied, and a new class of therapeutics was assessed. A single oral challenge of EAEC strain 042 resulted in significant growth shortfalls (5-8 % of body weight in 12 days), persistent shedding of micro-organisms in stools [>10(3.2) c.f.u. (10 mg stool)(-1) for at least 14 days] and intestinal tissue burden [~10(3) c.f.u. (10 mg tissue)(-1) detectable up to 14 days post-challenge]. Moderate malnourishment of mice using a 'regional basic diet' containing 7 % protein and reduced fat and micronutrients heightened all parameters of infection. Nitazoxanide in subMIC doses, administered for 3 days at the time of EAEC challenge, lessened growth shortfalls (by >10 % of body weight), stool shedding [by 2-3 logs (10 mg stool)(-1)] and tissue burden of organisms (by >75 % in the jejunum and colon). Thus, weaned C57BL/6 mice challenged with EAEC is a convenient, readily inducible model of EAEC infection with three highly quantifiable outcomes in which disease severity is dependent on the nutritional status of the host, and which is modifiable in the presence of inhibitors of pyruvate ferredoxin oxidoreductase such as nitazoxanide.

Risk Factors Associated With Rotavirus Gastroenteritis During a Community Outbreak in Chiapas, Mexico During the Postvaccination Era

BACKGROUND

In January 2010, surveillance detected a rotavirus gastroenteritis outbreak in Chiapas, Mexico. We aimed to identify risk and protective factors for developing rotavirus gastroenteritis of any severity among children in the epidemic setting.

METHODS

A case-control study was conducted, comparing case patients (defined as children <36 months of age with acute gastroenteritis of any severity whose stool tested positive for rotavirus by enzyme immunoassay) with age- and municipality-matched controls. Information was obtained through face-to-face interviews on clinical outcome, demographics, breastfeeding history, rotavirus immunization status, and indicators of socioeconomic status.

RESULTS

Eighty-five case patients and 170 controls were enrolled. Factors associated with lower risk of rotavirus gastroenteritis included current breastfeeding, owning a refrigerator, and being immunized with 1 or 2 doses of a live-attenuated monovalent rotavirus vaccine. History of previous diarrheal episodes and living with 7 or more people in the same household were associated with higher risk of developing rotavirus gastroenteritis.

CONCLUSION

During this outbreak, dietary, socioeconomic, and environmental factors were independently associated with risk of developing rotavirus disease. Rotavirus vaccine also offered significant protection against rotavirus disease of any severity, emphasizing the value of vaccination as a simple and highly effective public health strategy for prevention of rotavirus illness.

The role of peroxisome proliferator-activated receptor γ in immune responses to enteroaggregative Escherichia coli infection

Background

Enteroaggregative Escherichia coli (EAEC) is recognized as an emerging cause of persistent diarrhea and enteric disease worldwide. Mucosal immunity towards EAEC infections is incompletely understood due in part to the lack of appropriate animal models. This study presents a new mouse model and investigates the role of peroxisome proliferator-activated receptor gamma (PPARγ) in the modulation of host responses to EAEC in nourished and malnourished mice.

Methods/Principal Findings

Wild-type and T cell-specific PPARγ null C57BL/6 mice were fed protein-deficient diets at weaning and challenged with 5×10⁹cfu EAEC strain JM221 to measure colonic gene expression and immune responses to EAEC. Antigen-specific responses to E. coli antigens were measured in nourished and malnourished mice following infection and demonstrated the immunosuppressive effects of malnutrition at the cellular level. At the molecular level, both pharmacological blockade and deletion of PPARγ in T cells resulted in upregulation of TGF-β, IL-6, IL-17 and anti-microbial peptides, enhanced Th17 responses, fewer colonic lesions, faster clearance of EAEC, and improved recovery. The beneficial effects of PPARγ blockade on weight loss and EAEC clearance were abrogated by neutralizing IL-17 in vivo.

Conclusions

Our studies provide in vivo evidence supporting the beneficial role of mucosal innate and effector T cell responses on EAEC burden and suggest pharmacological blockade of PPARγ as a novel therapeutic intervention for EAEC infection.

Randomized double-blind controlled trial of bovine lactoferrin for prevention of diarrhea in children

OBJECTIVE

To determine the effect of bovine lactoferrin (bLF) on prevention of diarrhea in children.

STUDY DESIGN

We conducted a community-based randomized double-blind placebo controlled trial comparing supplementation with bLF vs placebo. Previously weaned children were enrolled at 12-18 months and followed for 6 months with daily home visits for data collection and supplement administration. Anthropometric measures were done monthly.

RESULTS

Five hundred fifty-five children were randomized: 277 to bLF and 278 to placebo; 65 dropped out; 147 894 doses were administered (92% compliance). Overall there were 91 446 child-days of observation and 1235 diarrhea episodes lasting 6219 days. The main pathogens isolated during diarrheal episodes were norovirus (35.0%), enteropathogenic E coli (11.4%), Campylobacter (10.6%), enteroaggregative E coli (8.4%), enterotoxigenic E coli (6.9%), and Shigella (6.6%). The diarrhea incidence was not different between groups: 5.4 vs 5.2 episodes/child/year for bLF and placebo, respectively (P = .375). However, the diarrhea longitudinal prevalence was lower in the bLF group vs placebo (6.6% vs 7.0%, P = .017), as well as the median duration of episodes (4.8 vs 5.3 days, P = .046), proportion of episodes with moderate or severe dehydration (1.0% vs 2.6%, P = .045), and liquid stools load (95.0 vs 98.6) liquid stools/child/year, P < .001). There were no adverse events related to the intervention.

CONCLUSIONS

Although there was no decrease in diarrhea incidence, longitudinal prevalence and severity were decreased with LF.

Apparent and content validation of maternal self-efficiency scale for prevention of childhood diarrhea

AIM: The aim of this paper is to describe the apparent and content validation for the Maternal Self-Efficiency Scale for the Prevention of Childhood Diarrhoea. METHOD: Methodological study with the execution of apparent and content validation by seven judges; semantic analysis, by 30 mothers of children under 5 years old and also a pre-test involving 31 mothers who have been selected through convenience. It has been considered necessary to have the agreement of at least 70% of the judges for apparent validation and a minimum of 80% for pertinence and Index of Content Validation. RESULTS: This paper shows that most items have been considered clear, comprehensive and relevant by the judges. The final Content Validity Index of the scale was 0.96. The suggestions of the mothers were accepted. CONCLUSION: The scale ended up having 25 items and two domains (family hygiene and general/eating practices) which assess the maternal self-efficiency for the prevention of diarrhea in their children, thereby contributing to the planning of nursing interventions.

Effect of recent diarrhoeal episodes on risk of pneumonia in children under the age of 5 years in Karachi, Pakistan

BACKGROUND

We assessed the association between the duration of diarrhoea and the risk ofpneumonia incidence among children <5 years of age.

METHODS

We analysed data from a cluster randomized controlled trial in Karachi, Pakistan, which assessed the effect of promoting hand washing with soap (antibacterial and plain) on child health. Field workers visited households with children <5 years of age weekly and asked primary caregivers if their child had diarrhoea, cough or difficulty breathing in the preceding week. We used the WHO clinical case definitions for diarrhoea and pneumonia.We used adjusted time-to-event analyses with cumulative diarrhoea prevalence over the previous 2 and 4 weeks as exposure and pneumonia as outcome. We calculated the attributable risk of pneumonia due to recent diarrhoea across the intervention groups.

RESULTS

873 households with children <5 years were visited. Children had an increased risk of pneumonia for every additional day of diarrhoea in the 2 weeks (1.06, 95% CI: 1.03-1.09) and 4 weeks (1.04, 95% CI: 1.03-1.06) prior to the week of pneumonia onset. The attributable risk of pneumonia cases due to recent exposure to diarrhoea was 6%. A lower associated pneumonia risk following diarrhoea was found in the control group: (3%) compared with soap groups (6% in antibacterial soap, 9% in plain soap).

CONCLUSION

Children <5 years of age are at an increased risk of pneumonia following recent diarrhoeal illness. Public health programmes that prevent diarrhoea may also reduce the burden of respiratory illnesses.

Global burden of maternal and child undernutrition and micronutrient deficiencies

Maternal and child undernutrition and micronutrient deficiencies affect approximately half of the world's population. These conditions include intrauterine growth restriction (IUGR), low birth weight, protein-energy malnutrition, chronic energy deficit of women, and micronutrient deficiencies. Although the rates of stunting or chronic protein-energy malnutrition are increasing in Africa, the absolute numbers of stunted children are much higher in Asia. The four common micronutrient deficiencies include those of iron, iodine, vitamin A, and zinc. All these conditions are responsible directly or indirectly for more than 50% of all under-5 deaths globally. According to more recent estimates, IUGR, stunting and severe wasting are responsible for one third of under-5 mortality. About 12% of deaths among under-5 children are attributed to the deficiency of the four common micronutrients. Despite tremendous progress in different disciplines and unprecedented improvement with many health indicators, persistently high undernutrition rates are a shame to the society. Human development is not possible without taking care to control undernutrition and micronutrient deficiencies. Poverty, food insecurity, ignorance, lack of appropriate infant and young child feeding practices, heavy burden of infectious illnesses, and poor hygiene and sanitation are factors responsible for the high levels of maternal and child undernutrition in developing countries. These factors can be controlled or removed by scaling up direct nutrition interventions and eliminating the root conditions including female illiteracy, lack of livelihoods, lack of women's empowerment, and poor hygiene and sanitation.

Zinc, vitamin A, and glutamine supplementation in Brazilian shantytown children at risk for diarrhea results in sex-specific improvements in verbal learning

OBJECTIVE

To identify the impact of supplemental zinc, vitamin A, and glutamine, alone or in combination, on long-term cognitive outcomes among Brazilian shantytown children with low median height-for-age z-scores.

METHODS

A randomized, double-blind, placebo-controlled trial was conducted in children aged three months to nine years old from the urban shanty compound community of Fortaleza, Brazil. Demographic and anthropometric information was assessed. The random treatment groups available for cognitive testing (total of 167 children) were: (1) placebo, n = 25; (2) glutamine, n = 23; (3) zinc, n = 18; (4) vitamin A, n = 19; (5) glutamine+zinc, n = 20; (6) glutamine+vitamin A, n = 21; (7) zinc+vitamin A, n = 23; and (8) glutamine+zinc+vitamin A, n = 18. Neuropsychological tests were administered for the cognitive domains of non-verbal intelligence and abstraction, psychomotor speed, verbal memory and recall ability, and semantic and phonetic verbal fluency. Statistical analyses were performed using SPSS, version 16.0. ClinicalTrials.gov: NCT00133406.

RESULTS

Girls receiving a combination of glutamine, zinc, and vitamin A had higher mean age-adjusted verbal learning scores than girls receiving only placebo (9.5 versus 6.4, p = 0.007) and girls receiving zinc+vitamin A (9.5 versus 6.5, p = 0.006). Similar group differences were not found between male study children.

CONCLUSIONS

The findings suggest that combination therapy offers a sex-specific advantage on tests of verbal learning, similar to that seen among female patients following traumatic brain injury.

Early childhood growth failure and the developmental origins of adult disease: do enteric infections and malnutrition increase risk for the metabolic syndrome?

Hypotheses regarding the developmental origins of health and disease postulate that developing fetuses - and potentially young children - undergo adaptive epigenetic changes that have longstanding effects on metabolism and other processes. Ongoing research explores whether these adaptations occur during early life following early childhood malnutrition. In the developing world, there remains a high degree of nutritional stunting, defined as linear growth failure caused by inadequate caloric intake, which may be exacerbated by inflammation from ongoing infections. In areas with poor sanitation, children experience vicious cycles of enteric infections and malnutrition, resulting in poor nutrient absorption as a result of changes in the intestinal mucosa, now termed "environmental enteropathy." Emerging evidence links early childhood diarrhea and/or growth failure with an increased occurrence of risk factors for cardiovascular disease in later life, including dyslipidemia, hypertension, and glucose intolerance. The mechanisms for these associations remain poorly understood and may relate to epigenetic responses to poor nutrition, increased inflammation, or both. Given the increased incidence of cardiovascular disease in developing areas of the world, associations between childhood malnutrition, early-life infections, and the increased occurrence of risk factors for cardiovascular disease underscore further reasons to improve nutrition and infection-related outcomes for young children worldwide.

Intranasal vaccination in mice with an attenuated Salmonella enterica Serovar 908htr A expressing Cp15 of Cryptosporidium: impact of malnutrition with preservation of cytokine secretion

Cryptosporidium is a protozoan parasite associated with acute and persistent diarrhea that, even in asymptomatic persons, can impair normal growth and potentially cognitive and physical development in young children. The recent availability of the complete gene sequence for Cryptosporidium hominis antigen Cp15 allows examination of innovative vaccine regimens involving intra-nasal antigen priming with live bacterial vectors applicable to human populations. We used a recently described weaned mouse model of cryptosporidiosis, where nourished and malnourished vaccinated mice receive the Cp15 antigen recombinant with cytolysinA on a Salmonella serovar Typhi CVD 908-htr A vector, followed by parenteral exposure to antigen with adjuvant. After challenge with Cryptosporidium oocysts via gavage, parameters of infection and disease (stool shedding of parasites, growth rates) were quantified, and serum/lymphoid tissue harvested to elucidate the Cp15-specific adaptive immune response. In vaccinated nourished mice, the regimen was highly immunogenic, with strong antigen-specific IL-6 and IFN-γ secretion and robust Cp15-specific immunoglobulin titers. In vaccinated malnourished mice, secretion of cytokines, particularly IFN-γ, and antigen-specific humoral immunity were generally undiminished despite protein deprivation and stunted growth. In contrast, after natural (oral) challenge with an identical inoculum of Cryptosporidium oocysts, cytokine and humoral responses to Cp15 were less than one-fourth those in vaccinated mice. Nevertheless, vaccination resulted in only transient reduction in stool shedding of parasites and was not otherwise protective against disease. Overall, immunogenicity for a C. hominis antigen was documented in mice, even in the setting of prolonged malnutrition, using an innovative vaccine regimen involving intra-nasal antigen priming with a live enteric bacterial vector, that has potential applicability to vulnerable human populations irrespective of nutritional status.

How to do in persistent diarrhea of children?: concepts and treatments of chronic diarrhea

Chronic diarrhea is defined as passing watery stools that lasts for more than 2 weeks. Persistent diarrhea belongs to chronic diarrhea and is a chronic episode of diarrhea of infectious etiology. The etiology of chronic diarrhea is varied. It is important to consider the child's age and clinical manifestations with alarm signals for an application of proper treatments to children with chronic diarrhea. Vicious cycle is present in chronic diarrhea and nutritional rehabilitation can break the vicious cycle of chronic diarrhea and is one of the main one thing among treatments. We should know the exact concept of chronic diarrhea and provide appropriate treatments according to etiologies of chronic diarrhea.

The dynamic interdependence of amebiasis, innate immunity, and undernutrition

Entamoeba histolytica, the protozoan parasite that causes amebic dysentery, greatly contributes to disease burden in the developing world. Efforts to exhaustively characterize the pathogenesis of amebiasis have increased our understanding of the dynamic host-parasite interaction and the process by which E. histolytica trophozoites transition from gut commensals to invaders of the intestinal epithelium. Mouse models of disease continue to be instrumental in this area. At the same time, large-scale studies in human populations have identified genetic and environmental factors that influence susceptibility to amebiasis. Nutritional status has long been known to globally influence immune function. So it is not surprising that undernutrition has emerged as a critical risk factor. A better understanding of how nutritional status affects immunity to E. histolytica will have dramatic implications in the development of novel treatments. Future work should continue to characterize the fascinating host-parasite arms race that occurs at each stage of infection.

Does childhood diarrhea influence cognition beyond the diarrhea-stunting pathway?

Background

Diarrhea is a leading cause of morbidity among children under 5 years of age in low- and middle-income countries yet the additional effects and sequelae, such as cognitive impairment associated with diarrhea, have not been quantified.

Methods

We quantified the association between diarrhea prevalence and cognitive outcomes while controlling for linear growth in 4 study populations. Cognition was assessed using different methods across sites and was expressed in standardized units. We built linear regression models for each study with standardized cognitive score as the outcome and diarrhea prevalence as the main predictor variable. We then conducted meta-analyses of the regression coefficients to generate pooled estimates of the association between diarrhea prevalence and cognition whilst controlling for anthropometric status and other covariates.

Results

Diarrhea was not a significant predictor of cognitive score in any site in the regression models or in the meta-analyses (Coefficient = 0.07; 95% CI: −0.1, 0.2). The length for age Z- score was negatively related to cognition in all sites (0.18; 95% CI: 0.14, 0.21), with coefficients remarkably similar across sites (Coefficient Range: 0.168–0.186).

Conclusions

We did not demonstrate an association between diarrhea and cognition with stunting included in the model. The links between diarrhea, stunting, and cognition provide additional rationale for accelerating interventions to reduce diarrhea.

Off the map: the health and social implications of being a non-notified slum in India

Approximately half of all slums in India are not recognized by the government. Lack of government recognition, also referred to as "non-notified status" in the Indian context, may create entrenched barriers to legal rights and basic services such as water, sanitation, and security of tenure. In this paper, we explore the relationship between non-notified status and health outcomes in Kaula Bandar (KB), a slum in Mumbai, India. We illuminate this relationship using the findings of a four-year series of studies in the community. By comparing KB's statistics to those from other Mumbai slums captured by India's National Family Health Survey-3, we show that KB has relative deficiencies in several health and social outcomes, including those for educational status, child health, and adult nutrition. We then provide an explanatory framework for the role that KB's non-notified status may play in generating poor health outcomes by discussing the health consequences of the absence of basic services and the criminalization of activities required to fulfill fundamental needs such as water access, toileting, and shelter. We argue that the policy vacuum surrounding non-notified slums like KB results in governance failures that lead to poor health outcomes. Our findings highlight the need for cities in India and other developing countries to establish and fulfill minimum humanitarian standards in non-notified slums for the provision of basic services such as water, sanitation, solid waste removal, electricity, and education.

Selective and potent urea inhibitors of cryptosporidium parvum inosine 5'-monophosphate dehydrogenase

Cryptosporidium parvum and related species are zoonotic intracellular parasites of the intestine. Cryptosporidium is a leading cause of diarrhea in small children around the world. Infection can cause severe pathology in children and immunocompromised patients. This waterborne parasite is resistant to common methods of water treatment and therefore a prominent threat to drinking and recreation water even in countries with strong water safety systems. The drugs currently used to combat these organisms are ineffective. Genomic analysis revealed that the parasite relies solely on inosine-5'-monophosphate dehydrogenase (IMPDH) for the biosynthesis of guanine nucleotides. Herein, we report a selective urea-based inhibitor of C. parvum IMPDH (CpIMPDH) identified by high-throughput screening. We performed a SAR study of these inhibitors with some analogues exhibiting high potency (IC(50) < 2 nM) against CpIMPDH, excellent selectivity >1000-fold versus human IMPDH type 2 and good stability in mouse liver microsomes. A subset of inhibitors also displayed potent antiparasitic activity in a Toxoplasma gondii model.

Host response to probiotics determined by nutritional status of rotavirus-infected neonatal mice

OBJECTIVES

Beneficial microbes and probiotics are promising agents for the prevention and treatment of enteric and diarrheal diseases in children; however, little is known about their in vivo mechanisms of action. We used a neonatal mouse model of rotavirus diarrhea to gain insight into how probiotics ameliorate acute gastroenteritis.

METHODS

Rotavirus-infected mice were treated with 1 of 2 strains of human-derived Lactobacillus reuteri. We assessed intestinal microbiome composition with 16S metagenomic sequencing, enterocyte migration and proliferation with 5-bromo-2'-deoxyuridine, and antibody and cytokine concentrations with multiplex analyses of intestinal explant cultures.

RESULTS

Probiotics reduced diarrhea duration, improved intestinal histopathology, and enhanced intestinal microbiome richness and phylogenetic diversity. The magnitude of reduction of diarrhea by probiotics was strain specific and influenced by nutritional status. L reuteri DSM 17938 reduced diarrhea duration by 0, 1, and 2 days in underweight, normal weight, and overweight pups, respectively. The magnitude of reduction of diarrhea duration correlated with increased enterocyte proliferation and migration. Strain ATCC PTA 6475 reduced diarrhea duration by 1 day in all of the mice without increasing enterocyte proliferation. Both probiotic strains decreased concentrations of proinflammatory cytokines, including macrophage inflammatory protein-1α and interleukin-1β, in all of the animals, and increased rotavirus-specific antibodies in all but the underweight animals. Body weight also influenced the host response to rotavirus, in terms of diarrhea duration, enterocyte turnover, and antibody production.

CONCLUSIONS

These data suggest that probiotic enhancement of enterocyte proliferation, villus repopulation, and virus-specific antibodies may contribute to diarrhea resolution, and that nutritional status influences the host response to both beneficial microbes and pathogens.

Adaptation of Ritchie's Method for Parasites Diagnosing with Minimization of Chemical Products

Latin America, Africa, and Asia present wide dissemination and high prevalence rates of waterborne parasitic diseases, which is a strong indicative of the fragility of public sanitation systems. In this context, parasitological analyses represent extremely relevant instruments. Several parasite diagnosis methods exist, among which Ritchie's method (1948) stands out. This method uses formaldehyde and ether, two reagents of toxicological importance that can cause damages to environmental and occupational health. The present study aimed to compare Ritchie's method modified by Régis Anécimo, without use of solvents, with the traditional Ritchie's method, routinely used for helminth and protozoa diagnosing in Brazil. Some changes were introduced in the modified method, such as controlled increase of water temperature used after stool dilution and substitution of formaldehyde and ether by a neutral detergent before material centrifugation for observation of parasites. In examined samples by both methods, multiple infections were commonly observed; the modified method presented a similar sensitivity to identify the parasites. The development of analytic diagnosis methods that minimize the use of chemical products like ether and formaldehyde represents an important tool to prevent occupational diseases among exposed professionals, as well as to preserve environmental quality through the use of clean techniques.

Enteric pathogens through life stages

Enteric infections and diarrheal diseases constitute pervasive health burdens throughout the world, with rates being highest at the two ends of life. During the first 2–3 years of life, much of the disease burden may be attributed to infection with enteric pathogens including Salmonella, rotavirus, and many other bacterial, viral, and protozoan organisms; however, infections due to Clostridium difficile exhibit steady increases with age. Still others, like Campylobacter infections in industrialized settings are high in early life (<2 years old) and increase again in early adulthood (called the “second weaning” by some). The reasons for these differences undoubtedly reside in part in pathogen differences; however, host factors including the commensal intestinal microbial communities, immune responses (innate and acquired), and age-dependant shifts likely play important roles. Interplay of these factors is illustrated by studies examining changes in human gut microbiota with inflammatory bowel disease and irritable bowel syndrome. Recent gut microbial surveys have indicated dramatic shifts in gut microbial population structure from infants to young adults to the elders. An understanding of the evolution of these factors and their interactions (e.g., how does gut microbiota modulate the “inflamm-aging” process or vice versa) through the human life “cycle” will be important in better addressing and controlling these enteric infections and their consequences for both quality and quantity of life (often assessed as disability adjusted life-years or “DALYs”).

Goat milk with and without increased concentrations of lysozyme improves repair of intestinal cell damage induced by enteroaggregative Escherichia coli

BACKGROUND

Enteroaggregative Escherichia coli (EAEC) causes diarrhea, malnutrition and poor growth in children. Human breast milk decreases disease-causing bacteria by supplying nutrients and antimicrobial factors such as lysozyme. Goat milk with and without human lysozyme (HLZ) may improve the repair of intestinal barrier function damage induced by EAEC. This work investigates the effect of the milks on intestinal barrier function repair, bacterial adherence in Caco-2 and HEp-2 cells, intestinal cell proliferation, migration, viability and apoptosis in IEC-6 cells in the absence or presence of EAEC.

METHODS

Rat intestinal epithelial cells (IEC-6, ATCC, Rockville, MD) were used for proliferation, migration and viability assays and human colon adenocarcinoma (Caco-2, ATCC, Rockville, MD) and human larynx carcinoma (HEp-2, ATCC, Rockville, MD) cells were used for bacterial adhesion assays. Goats expressing HLZ in their milk were generated and express HLZ in milk at concentration of 270 μg/ml. Cells were incubated with pasteurized milk from either transgenic goats expressing HLZ or non-transgenic control goats in the presence and absence of EAEC strain 042 (O44:H18).

RESULTS

Cellular proliferation was significantly greater in the presence of both HLZ transgenic and control goat milk compared to cells with no milk. Cellular migration was significantly decreased in the presence of EAEC alone but was restored in the presence of milk. Milk from HLZ transgenic goats had significantly more migration compared to control milk. Both milks significantly reduced EAEC adhesion to Caco-2 cells and transgenic milk resulted in less colonization than control milk using a HEp-2 assay. Both milks had significantly increased cellular viability as well as less apoptosis in both the absence and presence of EAEC.

CONCLUSIONS

These data demonstrated that goat milk is able to repair intestinal barrier function damage induced by EAEC and that goat milk with a higher concentration of lysozyme offers additional protection.

Immune responses to cholera in children

Cholera is a severe acute dehydrating diarrheal disease caused by Vibrio cholerae O1 or O139 infection, and is associated with significant mortality and morbidity globally. Although young children bear a high burden of the disease, currently available oral vaccines give a lower efficacy and shorter duration of protection in this group than in adults. According to the studies of natural infection, young children achieve comparable systemic anti-V. cholerae antigen-specific antibody, gut-homing antibody-secreting cell and memory B-cell responses as adults. Studies on innate and cell-mediated immune responses are lacking in children, and may offer important insights into differences in vaccine efficacy. The impact of host factors such as malnutrition, genetics and coinfection with other pathogens also remains to be fully defined.

Dietary folic acid promotes survival of Foxp3+ regulatory T cells in the colon

Dietary compounds as well as commensal microbiota contribute to the generation of a unique gut environment. In this study, we report that dietary folic acid (FA) is required for the maintenance of Foxp3+ regulatory T cells (Tregs) in the colon. Deficiency of FA in the diet resulted in marked reduction of Foxp3+ Tregs selectively in the colon. Blockade of folate receptor 4 and treatment with methotrexate, which inhibits folate metabolic pathways, decreased colonic Foxp3+ Tregs. Compared with splenic Tregs, colonic Tregs were more activated to proliferate vigorously and were highly sensitive to apoptosis. In colonic Tregs derived from mice fed with a FA-deficient diet, expression of anti-apoptotic molecules Bcl-2 and Bcl-xL was severely decreased. A general reduction of peripheral Tregs was induced by a neutralizing Ab against IL-2, but a further decrease by additional FA deficiency was observed exclusively in the colon. Mice fed with an FA-deficient diet exhibited higher susceptibility to intestinal inflammation. These findings reveal the previously unappreciated role of dietary FA in promotion of survival of Foxp3+ Tregs that are in a highly activated state in the colon.

Enteroaggregative Escherichia coli pathotype: a genetically heterogeneous emerging foodborne enteropathogen

Until now, a common feature that defines the enteroaggregative Escherichia coli (EAEC) strains is the ability to produce a 'stacked-brick' appearance on epithelial cells, but it does not distinguish between pathogenic and nonpathogenic strains. Numerous adhesins, toxins, and proteins associated with virulence have been described, as well as multiple factors contributing to EAEC-induced inflammation. None of these factors are found in all EAEC isolates, and no single factor has ever been implicated in EAEC virulence. The European outbreak of Shiga-toxin-producing EAEC raises its pathogenic potential and interest on finding the true pathogenic factors that may define this pathotype. EAEC were first associated with persistent diarrhea in infants from developing countries, since then they have increasingly been linked as a cause of acute and persistent diarrhea in young infants and children in developing and industrialized countries, individuals infected with human immunodeficiency virus, as a cause of acute diarrhea in travelers from industrialized regions, and with foodborne outbreaks. A major effect of EAEC infection is on the malnourished children in developing countries. Here, we will discuss the EAEC public health relevance and their complexity because of the strain heterogeneity regarding their pathogenesis, identification, diagnosis, lineage, epidemiology, and clinical manifestations.

A systems science perspective and transdisciplinary models for food and nutrition security

We argue that food and nutrition security is driven by complex underlying systems and that both research and policy in this area would benefit from a systems approach. We present a framework for such an approach, examine key underlying systems, and identify transdisciplinary modeling tools that may prove especially useful.

Enteropathies in the developing world: neglected effects on global health

A spectrum of enteropathies, characterized by small intestinal inflammation, reduced absorptive capacity, and increased intestinal permeability, commonly affect people in developing countries. This subclinical intestinal pathology facilitates microbial translocation across the compromised intestinal barrier, leading to chronic systemic inflammation that may adversely impact health. Environmental enteropathy (EE), ubiquitous among people living in unhygienic conditions, likely mediates two interlinked public health problems of childhood, stunting and anemia, and underlies poor oral vaccine efficacy in developing countries. Human immunodeficiency virus (HIV) enteropathy, which frequently overlaps with EE, may contribute to immune activation and modulate HIV disease progression. The interacting effects of infection and enteropathy drive a vicious cycle that can propagate severe acute malnutrition, which underlies almost half of under-5-y deaths. Enteropathies are therefore highly prevalent, interacting causes of morbidity and mortality in developing countries. Interventions to prevent or ameliorate enteropathies have potential to improve the health of millions of people in developing countries.

Novel in vitro and in vivo models and potential new therapeutics to break the vicious cycle of Cryptosporidium infection and malnutrition

BACKGROUND

Although several animal models of cryptosporidiosis have been reported, most involve genetically or pharmacologically immune-suppressed hosts.

METHODS

We report challenge with excysted (in vitro and in vivo) and unexcysted (in vivo) Cryptosporidium parvum oocysts in human colonic adenocarcinoma (HCT-8) cells and weaned nourished and malnourished C57BL/6 mice, following outcomes of growth rate, stool shedding, and tissue burden. We tested treatment with an oligodeoxynucleotide containing unmethylated CpG motif (CpG-ODN) and alanyl-glutamine in vivo and in vitro.

RESULTS

C. parvum-challenged mice showed prolonged weight loss (>10% over 4 days), robust stool shedding (>3 logs/d over 7 days), and epithelial infection in the ileum, cecum, and colon. Of 2 potential therapeutic compounds evaluated in the model, CpG-ODN reduced body weight loss (to <6% on days 3-7 after challenge), reduced shedding of organisms (by 25% on days 1 and 3 after challenge), and decreased the burden of parasites in the ileum. Alanyl-glutamine showed similar benefits. In vitro findings suggested that effects on the epithelial component of the mucosa probably likely responsible for beneficial effects seen in vivo.

CONCLUSIONS

Weaned mice provide a convenient and reproducible model of cryptosporidial disease, including its vicious cycle with body weight loss and heavier infection with malnutrition, and this model may be useful in exploring innovative therapeutic solutions for this challenging infectious disease.

Arginine decreases Cryptosporidium parvum infection in undernourished suckling mice involving nitric oxide synthase and arginase

OBJECTIVE

This study investigated the role of L-arginine supplementation to undernourished and Cryptosporidium parvum-infected suckling mice.

METHODS

The following regimens were initiated on the fourth day of life and injected subcutaneously daily. The C. parvum-infected controls received L-arginine (200 mmol/L) or phosphate buffered saline. The L-arginine-treated mice were grouped to receive NG-nitro-arginine methyl ester (L-NAME) (20 mmol/L) or phosphate buffered saline. The infected mice received orally 10(6) excysted C. parvum oocysts on day 6 and were euthanized on day 14 at the infection peak.

RESULTS

L-arginine improved weight gain compared with the untreated infected controls. L-NAME profoundly impaired body weight gain compared with all other groups. Cryptosporidiosis was associated with ileal crypt hyperplasia, villus blunting, and inflammation. L-arginine improved mucosal histology after the infection. L-NAME abrogated these arginine-induced improvements. The infected control mice showed an intense arginase expression, which was even greater with L-NAME. L-arginine decreased the parasite burden, an effect that was reversed by L-NAME. Cryptosporidium parvum infection increased urine NO(3)(-)/NO(2)(-) concentrations compared with the uninfected controls, which was increased by L-arginine supplementation, an effect that was also reversed by L-NAME.

CONCLUSION

These findings show a protective role of L-arginine during C. parvum infection in undernourished mice, with involvement of arginase I and nitric oxide synthase enzymatic actions.

Climate variability and child height in rural Mexico

We examine the impacts of weather shocks, defined as rainfall or growing degree days, a cumulative measure of temperature, more than a standard deviation from their respective long run mean, on the stature of children between 12 and 47 months of age in Mexico. We find that after a positive rainfall shock children are shorter regardless of their region or altitude. Negative temperature shocks have a negative impact on height in the central and southern parts of the country as well as in higher altitudes. Although on average there are no statistically significant impacts from positive temperature shocks, certain sub-populations - namely boys, children between 12 and 23 months at the time of measurement, and children of less educated mothers - in some of the regions are negatively impacted. The results also suggest that potentially both agricultural income and communicable disease prevalence contribute to the effects.