Childhood Helicobacter pylori infection and growth impairment in developing countries: a vicious cycle?

Determinants of coexistence of undernutrition and anemia among under-five children in Rwanda; evidence from 2019/20 demographic health survey: Application of bivariate binary logistic regression model

BACKGROUND

Undernutrition and anemia are significant public health issues among under-5 children, with potential long-term consequences for growth, development, and overall health. Thus, this study aims to conduct a bivariate binary logistic regression model by accounting for the possible dependency of childhood undernutrition and anemia.

METHODS

The data came from the DHS program's measurement. A total of 3,206 under-five children were involved in this study. A single composite index measure was calculated for stunting, wasting, and underweight using principal component analysis. A bivariate binary logistic regression model is used to assess the association between undernutrition and anemia given the effect of other predictors.

RESULTS

Among 3,206 under-five children considered in this study, 1482 (46.2%) and 658 (20.5%) children were agonized by anemia and undernutrition, respectively. In bivariate binary logistic regression model; Urban children [AOR = 0.751, 96% CI: 0.573-0.984; AOR = 0.663, 95% CI: 0.456-0.995] and anemic mothers [AOR = 1.160, 95% CI: 1.104-1.218; AOR = 1.663, 95% CI: 1.242-2.225] were significantly associated with both childhood anemia and undernutrition, respectively. Improved water sources [AOR = 0.681, 95% CI: 0.446-0.996], average-sized children [AOR = 0.567, 95% CI: 0.462-0.696], and diarrhea [AOR = 1.134, 95% CI: 1.120-2.792] were significantly associated with childhood anemia. Large-sized children [AOR = 0.882, 95% CI: 0.791-0.853] and those with fever [AOR = 1.152, 95% CI: 1.312-2.981] were significantly associated with under-five children's undernutrition.

CONCLUSION

The prevalence of both undernutrition and anemia among under-five-year-old children was high in Rwanda. The following determinants are statistically associated with both childhood undernutrition and anemia: place of residence; source of drinking water; maternal anemia; being a twin; birth size of children; diarrhea; fever; and child age. Anemia and nutritional deficiencies must be treated concurrently under one program, with evidence-based policies aimed at vulnerable populations.

Helicobacter pylori-Associated Iron Deficiency Anemia in Childhood and Adolescence-Pathogenesis and Clinical Management Strategy

Many epidemiological studies and meta-analyses show that persistent Helicobacter pylori infection in the gastric mucosa can lead to iron deficiency or iron deficiency anemia (IDA), particularly in certain populations of children and adolescents. Moreover, it has been demonstrated that H. pylori infection can lead to and be closely associated with recurrent and/or refractory iron deficiency and IDA. However, the pathogenesis and specific risk factors leading to this clinical outcome in H. pylori-infected children remain poorly understood. In general, most of pediatric patients with H. pylori-associated IDA do not show evidence of overt blood loss due to gastrointestinal hemorrhagic lesions. In adult populations, H. pylori atrophic gastritis is reported to cause impaired iron absorption due to impaired gastric acid secretion, which, subsequently, results in IDA. However, significant gastric atrophy, and the resultant substantial reduction in gastric acid secretion, has not been shown in H. pylori-infected children. Recently, it has been hypothesized that competition between H. pylori and humans for iron availability in the upper gastrointestinal tract could lead to IDA. Many genes, including those encoding major outer membrane proteins (OMPs), are known to be involved in iron-uptake mechanisms in H. pylori. Recent studies have been published that describe H. pylori virulence factors, including specific OMP genes that may be associated with the pathogenesis of IDA. Daily iron demand substantively increases in children as they begin pubertal development starting with the associated growth spurt, and this important physiological mechanism may play a synergistic role for the microorganisms as a host pathogenetic factor of IDA. Like in the most recent pediatric guidelines, a test-and-treat strategy in H. pylori infection should be considered, especially for children and adolescents in whom IDA is recurrent or refractory to iron supplementation and other definitive causes have not been identified. This review will focus on providing the evidence that supports a clear biological plausibility for H. pylori infection and iron deficiency, as well as IDA.

Helicobacter pylori Pathogenicity Islands and Giardia lamblia Cysteine Proteases in Role of Coinfection and Pathogenesis

Helicobacter pylori is a well-known human-specific stomach pathogen that infects more than half of the world’s population. The infection with this bacterium can cause a variety of gastrointestinal problems, including chronic gastritis, peptic ulcers, and even cancer. H. pylori is a highly infectious bacterium. H. pylori causes an increase in gastric mucosa pH or gastric mucosa intestinal metaplasia. These modifications in the stomach environment are necessary for G. lamblia colonization to occur. Giardia lamblia is a flagellate protozoan parasite that can cause giardiasis in humans and other mammals. It dwells in the duodenum and upper jejunum. Globally, over 280 million cases of human giardiasis are predicted to occur each year. Simultaneous human colonization by G. lamblia and H. pylori is a typical occurrence since the viruses’ predisposing factors are similar in both groups. Giardiasis is a parasitic infection that affects both children and adults worldwide. Infection with Giardia is more common in underdeveloped countries. Globally, more than 200 million cases of giardiasis are detected each year. In contrast, the presence of G. lamblia in the host body triggers an immunological response comparable to that of H. pylori, with lymphocytes strongly polarized towards Th1. As a result, their combined presence exacerbates host tissue damage. The major goal of this seminar is to describe the pathophysiology, immunology, and clinical aspects of G. lamblia and H. pylori coinfection using a comprehensive search of PubMed, Lancet, and Google Scholar sources. Upper gastrointestinal problems such as upper abdominal pain, abdominal bloating, nausea, vomiting, epigastric pain/burning, and belching are all caused by both organisms. Differentiation by physical examination is impossible in people infected with both bacteria. For this coinfection distinction, a laboratory diagnosis is required. G. lamblia and H. pylori, when present together, have a synergistic effect on the host and can cause serious damage. As a result, researchers should delve deeper into the mechanics underlying this potential microbial interaction.

Everolimus-induced effector mechanism in macrophages and survivability of Erdman, CDC1551 and HN878 strains of Mycobacterium tuberculosis infection

With a disease as widespread and destructive as tuberculosis, more effective drugs and healthcare strategies, in addition to the current antibiotics regimen, are crucial for the enhanced well-being of millions of people suffering from the disease. Host-directed therapy is a new and emerging concept in treating chronic infectious diseases, such as tuberculosis. Repurposing of anti-cancer drugs, such as everolimus, may be an effective way to supplement the standard antibiotic treatment. Individuals with type 2 diabetes are increasingly susceptible to co-morbidities and co-infections including Mycobacterium tuberculosis, the causative agent of tuberculosis. We demonstrated in this study that in vitro everolimus treatment of granulomas from individuals with type 2 diabetes caused significant reduction in the viability of Mycobacterium tuberculosis.Further investigations revealed the effects of everolimus in targeting foamy macrophages, a macrophage phenotype that forms around granulomas, and is characterized by a higher lipid accumulation inside the cells. These foamy macrophages are thought to harbor dormant bacilli, which are potential sources of disease reactivation. Therefore, blocking foamy macrophage formation would help better killing of intracellular bacteria. Here, we report the potential of everolimus treatment to downregulate lipid content within the foamy macrophages of in vitro granulomas, thus leading to a potential decrease in the number of foamy macrophages and a more robust response to Mycobacterium tuberculosis.

Helicobacter pylori infection is associated with anemia, weight loss or both conditions among Bulgarian children

Some studies suggested an association between Helicobacter pylori infection and iron-deficiency anemia, however, the link between weight loss and the infection in childhood remains non-established. In a retrospective cohort study, we compared H. pylori positivity rates of Bulgarian children without or with anemia (47 children in each group) or weight loss (45 children in each group) and both conditions (17 children in each group). H. pylori infection was associated with the presence of anemia (in 76.6% of the anemic vs. 21.3% of the non-anemic patients, P < 0.0001) and weight loss (in 82.2% of the patients vs. 17.8% of the control children, P < 0.0001). All 17 patients with both conditions were H. pylori positive. Relative risk of anemia, weight loss and both conditions was 3.6 (95% CI, 2.0-6.4), 4.6 (95% CI, 2.4-8.8) and 5.7 (95% CI, 2.0-15.8), respectively, in the children with H. pylori infection. In conclusion, H. pylori infection was significantly associated with iron-deficiency anemia or/and weight loss in Bulgarian pediatric patients. Therefore, diagnostics and treatment of the infection as well as a proper control of the eradication success can be beneficial and thus, can be recommended for children with those conditions.

Helicobacter pylori Infection in Malnourished Children in Lagos

Background/Aim:

Helicobacter pylori infection is acquired in childhood, but there are conflicting reports on malnutrition and the infection. This study aimed to determine the prevalence of H. pylori infection among malnourished children and highlight the socioeconomic (SE) and clinical factors associated with the infection.

Methodology:

This was a descriptive cross-sectional study of 122 malnourished children and 120 healthy controls. Anthropometry was done for all the study participants, and the H. pylori status was determined with the use of monoclonal stool antigen test in all the participants. Logistic regression analysis was used to determine the factors that could predict the occurrence of the infection in the children.

Results:

Seventy percent (70.8%) of the malnourished children had moderate malnutrition, whereas 29.2% were severely malnourished. The prevalence of H. pylori in the malnourished children was 22.8% compared to 32.5% in the controls (P = 0.09). The infection was most prevalent in toddlers (60.7%). The SE class was significantly related to the infection (P = 0.01) and about a fifth (21.3%) of the malnourished children who belonged to the low SE class were H. pylori positive compared to 9.2% of the controls. About 64.3% of the malnourished children with H. pylori infection had fever and 25.8% had diarrhea. Multivariate analysis showed that stunting was significantly related to the infection (P = 0.02).

Conclusion:

H. pylori infection was prevalent among the toddlers and was significantly associated with stunting in this cohort of malnourished children. Screening of children for the infection is still advocated, and infected children should be referred for appropriate treatment and follow-up. The relationship between SE class and the infection still requires further research.

Sex effect on growth faltering in an indigenous ethnic minority population of infants in Israel

OBJECTIVE

We examined sex effects on growth faltering in an indigenous population of Bedouin Arab infants born in Israel, an economically developed country.

DESIGN

Retrospective cohort study. Height-for-age Z-score (HAZ) at age 6, 12, 18 and 24 months was calculated for full-term, normal-birth-weight Bedouin infants born during years 2000-2009 and attending maternal and child health (MCH) clinics. Multivariate linear regression analysis (MLRA) was used to calculate the association between sex and HAZ, controlling for year of birth, birth weight (BW) and residence by type of settlement (established settlement (ES); non-established settlement (NES)).

SETTING

Bedouin are an indigenous poor community of semi-nomadic Arabs, with the highest infant mortality rate in Israel. Fifty per cent of Bedouin infants live in NES with inadequate access to running water, electricity, and rubbish and sewage disposal. All Bedouin receive free well-baby care in community-based MCH clinics.

PARTICIPANTS

Full-term, normal Bedouin infants (n 5426) born during 2000-2009 and attending computerized MCH clinics who had growth measurements at age 6, 12, 18 and 24 months.

RESULTS

At all ages, girls had significantly higher mean HAZ than boys (P < 0·05). Increasing birth year, residence in ES and increasing BW were positively associated with HAZ (P < 0·05) at all ages. In MLRA controlling for birth year, BW and type of settlement, sex still had a significant effect, with lower HAZ among boys at 6, 12, 18 and 24 months of age (P < 0·001 at all ages).

CONCLUSIONS

Our results indicated that sex effects on growth faltering can occur in an indigenous population with low socio-economic status within an economically developed country.

The association of Helicobacter pylori with choroidal and retinal nerve fiber layer thickness

PURPOSE

To investigate the effect of Helicobacter pylori (H. pylori) infection on choroidal thickness (CT) and retinal nerve fiber layer thickness (RNFLT).

METHODS

The study included 25 patients with H. pylori infection and 25 healthy individuals as the control group. Helicobacter pylori patients were classified as the pre-treatment (Group 1; n: 25) and the post-treatment (Group 2; n: 25). RNFLT and CT were measured before and after treatment of H. pylori infection, using enhanced depth imaging (EDI) spectral-domain optical coherence tomography (Spectralis, Heidelberg Engineering, Heidelberg, Germany). The axial length and intraocular pressure were also measured.

RESULTS

The mean subfoveal CT was 320.96 ± 29.15 μm in Group 1 and 287.48 ± 49.17 in the control group (p = 0.007), while the mean subfoveal CT did not show any difference between Group 2 and the control group (p > 0.05). No statistically significant difference was determined between the H. pylori patients and the control group in respect of RNFLT values (p > 0.05).

CONCLUSIONS

CT increases during H. pylori infection and returns to the normal range within 6 weeks of treatment. RNFLT does not show any change during H. pylori infection. The data related to the subfoveal CT may be useful in understanding the pathogenesis of central serous chorioretinopathy developing in H. pylori patients.

Effect of Helicobacter pylori infection on growth trajectories in young Ethiopian children: a longitudinal study

BACKGROUND

Helicobacter pylori infection has been associated with early childhood growth impairment in high- and middle-income countries; however, few studies have examined this relationship within low-income countries or have used a longitudinal design. The possible effects of H. pylori infection on growth trajectories were examined in a cohort of young Ethiopian children.

METHODS

In 2011/12, 856 children (85.1% of the 1006 original singletons in a population-based birth cohort) were followed up at age 6.5 years. An interviewer-led questionnaire administered to mothers provided information on demographic and lifestyle variables. Height and weight were measured twice, and the average of the two measurements was used. Exposure to H. pylori infection was assessed using a rapid H. pylori stool antigen test. The independent associations of positive H. pylori infection status (measured at ages 3 and 6.5 years) with baseline height and weight (age 3 years) and height and weight growth trajectory (from age 3 to 6.5 years) were modelled using hierarchical linear models.

RESULTS

At baseline (age 3 years), the children's mean height was 85.7cm and their mean weight was 11.9kg. They gained height at a mean rate of 8.7cm/year, and weight at a mean rate of 1.76kg/year. H. pylori infection was associated with lower baseline measurements and linear height trajectory (β=-0.74cm and -0.79cm/year, respectively), after controlling for demographics and markers of socio-economic status. However, the positive coefficient was associated with quadratic growth in height among H. pylori-infected children (β=0.28, 95% confidence interval 0.07 to 0.49, p<0.01), and indicated an increase in height trajectory as the child increased in age. A non-significant difference in baseline and trajectory of weight was observed between H. pylori-infected and non-infected children.

CONCLUSIONS

These findings add to the growing body of evidence supporting that H. pylori infection is inversely associated with childhood growth trajectory, after controlling for a range of factors associated with reduced growth and H. pylori status. Further follow-up will be important to confirm possible catch-up in height trajectory among H. pylori-infected children as they grow older.

Helicobacter pylori Infection in Children: Nutritional Status and Associations with Serum Leptin, Ghrelin, and IGF-1 Levels

BACKGROUND

Helicobacter pylori is associated with gastrointestinal diseases such as gastritis, peptic ulcers, malignancy and lymphoma, and extra-gastrointestinal conditions. H. pylori infection is negatively associated with children's growth. Chronic inflammation of the stomach that results in the loss of appetite and, dysregulation of neuroendocrine hormones such as leptin, and ghrelin are the probable reasons of this negative association. The objective of this study is to determine the serum levels of leptin, ghrelin, and IGF-1 in H. pylori-infected children and their relations with growth.

MATERIALS AND METHODS

A hundred and sixty-one school children aged between 6 and 14 years were selected randomly from five primary schools representing a cross section of population. Demographic and sociocultural characteristics, and anthropometric measurements were recorded. Serum H. pylori IgG, insulin-like growth factor-1, leptin, and ghrelin levels were measured in all children. The children were grouped according to the nutritional status and Helicobacter pylori seropositivity. Nutritional indices were compared among groups in association with serum leptin, ghrelin, and insulin-like growth factor-1 levels.

RESULTS

H. pylori IgG positivity was found in 34.2%, and 14.9% of children were malnourished. H. pylori seropositivity was significantly higher in older ages (10.32 ± 2.26 vs 9.53 ± 2.36 years, p = .036), and body weight and height Z scores were significantly lower in H. pylori-seropositive children (-0.33 ± 1.08 vs 0.04 ± 1.26, p = .044 and 0.13 ± 0.92 vs 0.23 ± 0.91, p = .018 respectively). H. pylori seropositivity was found to be an independent risk factor for shorter body height (p = .01). Serum leptin, ghrelin, and IGF-1 levels were not associated with H. pylori IgG seropositivity (0.35 vs 0.55 ng/mL, p = .3; 3267.4 ± 753.0 vs 2808.3 ± 911.4 pg/mL, p = .06; 470 ± 176 vs 521 ± 179 ng/mL, p = .32, respectively).

CONCLUSIONS

Children infected with H. pylori are prone to short stature. This effect seems to be independent of neuroendocrine hormones.

Helicobacter pylori Infection and Children's Growth: An Overview

OBJECTIVES

Helicobacter pylori infection is acquired in early childhood, yet its role in children's health is still not fully clear. In this narrative review, we focused on the association between H pylori infection and children's growth.

METHODS

A literature search of the Ovid MEDLINE (till June 2015) and EMBASE (till August 2015) databases was performed using the terms "Helicobacter pylori, growth, body height, growth disorders and child development." Original studies that addressed the association between H pylori infection or eradication and children's growth were reviewed and the risk of bias of each study was assessed.

RESULTS

The existing evidence is based on observational studies (N = 48) and suggests that H pylori infection may adversely influence children's growth; findings were more consistent across studies with low risk of bias. Regarding linear growth, observational studies have repeatedly linked between H pylori infection and slower or diminished linear growth; yet, it is not known whether this association is causal. The association between H pylori infection and ponderal growth has been less consistent. Scarce evidence exists on the effect of H pylori eradication on children's skeletal growth and weight gain, but there is an indication that H pylori eradication may benefit nutritional status.

CONCLUSIONS

H pylori infection may impair children's growth. Additional studies, especially clinical trials, are needed to elucidate the role of H pylori eradication in children's growth, and the mechanisms that may be involved in such.

Helicobacter pylori Infection in Early Childhood and Growth at School Age

BACKGROUND

There are conflicting results regarding the role of H. pylori in children's growth. We examined differences in growth indices at school age according to H. pylori infection acquisition in preschool age.

MATERIALS AND METHODS

A prospective study was undertaken between 2004 and 2009, in which of healthy children (N = 139, ages 3-5 years at baseline) were tested for the presence of H. pylori antigen in their stool using enzyme-linked immunoassay and followed-up till age 6-9 years (median follow-up time 45 months). Height, weight, and hemoglobin levels were measured, and socioeconomic data were obtained. Z scores of height for age, weight for age, and body mass index for age at baseline and follow-up were calculated using the 2000 Center for Disease Control and Prevention growth reference curves. Growth velocity (cm/month) between preschool and school age was compared between H. pylori-infected and uninfected children using mixed models.

RESULTS

Fifty-three percent of the children were H. pylori positive at baseline, and all except one child tested positive at follow-up. The adjusted mean Z score of height for age at follow-up was significantly lower among H. pylori-infected children than uninfected ones: 0.15 (95% confidence intervals (CIs) 0.02, 0.29) and 0.45 (95% CI 0.29, 0.60), respectively (p = .002). Growth velocity was slower in the former group -0.0264 cm/month (95% CI -0.047, -0.005) (p = .014), after adjusting for baseline height and age. H. pylori infection was not associated with body weight.

CONCLUSIONS

Helicobacter pylori infection acquired in early childhood may have long-term adverse influence on linear growth at school age.

Environmental enteric dysfunction: an overview

BACKGROUND

Environmental enteric dysfunction (EED) refers to an incompletely defined syndrome of inflammation, reduced absorptive capacity, and reduced barrier function in the small intestine. It is widespread among children and adults in low- and middle-income countries. Understanding of EED and its possible consequences for health is currently limited.

OBJECTIVE

A narrative review of the current understanding of EED: epidemiology, pathogenesis, therapies, and relevance to child health.

METHODS

Searches for key papers and ongoing trials were conducted using PUBMED 1966-June 2014; ClinicalTrials.gov; the WHO Clinical Trials Registry; the Cochrane Library; hand searches of the references of retrieved literature; discussions with experts; and personal experience from the field.

RESULTS

EED is established during infancy and is associated with poor sanitation, certain gut infections, and micronutrient deficiencies. Helicobacter pylori infection, small intestinal bacterial overgrowth (SIBO), abnormal gut microbiota, undernutrition, and toxins may all play a role. EED is usually asymptomatic, but it is important due to its association with stunting. Diagnosis is frequently by the dual sugar absorption test, although other biomarkers are emerging. EED may partly explain the reduced efficacy of oral vaccines in low- and middle-income countries and the increased risk of serious infection seen in children with undernutrition.

CONCLUSIONS

Despite its potentially significant impacts, it is currently unclear exactly what causes EED and how it can be treated or prevented. Ongoing trials involve nutritional supplements, water and sanitation interventions, and immunomodulators. Further research is needed to better understand this condition, which is of likely crucial importance for child health and development in low- and middle-income settings.

Microbiologic methods utilized in the MAL-ED cohort study

A central hypothesis of The Etiology, Risk Factors and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development (MAL-ED) study is that enteropathogens contribute to growth faltering. To examine this question, the MAL-ED network of investigators set out to achieve 3 goals: (1) develop harmonized protocols to test for a diverse range of enteropathogens, (2) provide quality-assured and comparable results from 8 global sites, and (3) achieve maximum laboratory throughput and minimum cost. This paper describes the rationale for the microbiologic assays chosen and methodologies used to accomplish the 3 goals.

Infection and inflammation in somatic maintenance, growth and longevity

All organisms must display a certain degree of environmental adaptability to survive and reproduce. Growth and reproduction are metabolically expensive and carry other costs that contribute to aging. Therefore, animals have developed physiologic strategies to assess the harshness of the environment before devoting resources to reproduction. Presumably, these strategies maximize the possibility for offspring survival. Current views of aging reflect a trade-off between reproductive fitness and somatic maintenance whereby environmental stress induces an adaptive metabolic response aimed at preserving cellular integrity while inhibiting growth, whereas favorable environmental conditions (abundance of food and water, and optimal temperature, etc.) promote growth and reproductive maturity but simultaneously increase cellular damage and aging. Here we propose that the prevalence of infectious pathogens in a given niche represents an additional environmental factor that, via innate immune pathways, actively shifts this balance in favor of somatic maintenance at the expense of reproduction and growth. We additionally propose the construction of a genetic model system with which to test this hypothesis.

Role of Helicobacter pylori infection on nutrition and metabolism

Helicobacter pylori (H. pylori) is a gram-negative pathogen that is widespread all over the world, infecting more than 50% of the world’s population. It is etiologically associated with non-atrophic and atrophic gastritis, peptic ulcer and shows a deep association with primary gastric B-cell lymphoma and gastric adenocarcinoma. Recently, the medical research focused on the modification of the gastric environment induced by H. pylori infection, possibly affecting the absorption of nutrients and drugs as well as the production of hormones strongly implicated in the regulation of appetite and growth. Interestingly, the absorption of iron and vitamin B12 is impaired by H. pylori infection, while infected subjects have lower basal and fasting serum levels of ghrelin and higher concentration of leptin compared to controls. Since leptin is an anorexigenic hormone, and ghrelin stimulates powerfully the release of growth hormone in humans, H. pylori infection may finally induce growth retardation if acquired very early in the childhood and in malnourished children. This review is focused on the nutritional effects of H. pylori infection, such as the reduced bioavailability or the malabsorbption of essential nutrients, and of gastrointestinal hormones, as well as on the relationship between H. pylori and the metabolic syndrome.

First detected Helicobacter pylori infection in infancy modifies the association between diarrheal disease and childhood growth in Peru

BACKGROUND

In endemic settings, Helicobacter pylori infection can occur shortly after birth and may be associated with a reduction in childhood growth.

MATERIALS AND METHODS

This study investigated what factors promote earlier age of first H. pylori infection and evaluated the role of H. pylori infection in infancy (6-11 months) versus early childhood (12-23 months) on height. We included 183 children near birth from a peri-urban shanty town outside of Lima, Peru. Field-workers collected data on socioeconomic status (SES), daily diarrheal and breast-feeding history, antibiotic use, anthropometrics, and H. pylori status via carbon 13-labeled urea breath test up to 24 months after birth. We used a proportional hazards model to assess risk factors for earlier age at first detected infection and linear mixed-effects models to evaluate the association of first detected H. pylori infection during infancy on attained height.

RESULTS

One hundred and forty (77%) were infected before 12 months of age. Lower SES was associated with earlier age at first detected H. pylori infection (low vs middle-to-high SES Hazard ratio (HR) 1.59, 95% CI 1.16, 2.19; p = .004), and greater exclusive breast-feeding was associated with reduced likelihood (HR 0.63, 95% CI 0.40, 0.98, p = .04). H. pylori infection in infancy was not independently associated with growth deficits (p = .58). However, children who had their first detected H. pylori infection in infancy (6-11 months) versus early childhood (12-23 months) and who had an average number of diarrhea episodes per year (3.4) were significantly shorter at 24 months (-0.37 cm, 95% CI, -0.60, -0.15 cm; p = .001).

DISCUSSION

Lower SES was associated with a higher risk of first detected H. pylori infection during infancy, which in turn augmented the adverse association of diarrheal disease on linear growth.

Immune responses to Helicobacter pylori infection

Helicobacter pylori (H. pylori) infection is one of the most common infections in human beings worldwide. H. pylori express lipopolysaccharides and flagellin that do not activate efficiently Toll-like receptors and express dedicated effectors, such as γ-glutamyl transpeptidase, vacuolating cytotoxin (vacA), arginase, that actively induce tolerogenic signals. In this perspective, H. pylori can be considered as a commensal bacteria belonging to the stomach microbiota. However, when present in the stomach, H. pylori reduce the overall diversity of the gastric microbiota and promote gastric inflammation by inducing Nod1-dependent pro-inflammatory program and by activating neutrophils through the production of a neutrophil activating protein. The maintenance of a chronic inflammation in the gastric mucosa and the direct action of virulence factors (vacA and cytotoxin-associated gene A) confer pro-carcinogenic activities to H. pylori. Hence, H. pylori cannot be considered as symbiotic bacteria but rather as part of the pathobiont. The development of a H. pylori vaccine will bring health benefits for individuals infected with antibiotic resistant H. pylori strains and population of underdeveloped countries.

Dietary factors modulate Helicobacter-associated gastric cancer in rodent models

Since its discovery in 1982, the global importance of Helicobacter pylori-induced disease, particularly in developing countries, remains high. The use of rodent models, particularly mice, and the unanticipated usefulness of the gerbil to study H. pylori pathogenesis have been used extensively to study the interactions of the host, the pathogen, and the environmental conditions influencing the outcome of persistent H. pylori infection. Dietary factors in humans are increasingly recognized as being important factors in modulating progression and severity of H. pylori-induced gastric cancer. Studies using rodent models to verify and help explain mechanisms whereby various dietary ingredients impact disease outcome should continue to be extremely productive.

Unintended consequences of Helicobacter pylori infection in children in developing countries: iron deficiency, diarrhea, and growth retardation

Helicobacter pylori infection is predominantly acquired early in life. The prevalence of the infection in childhood is low in developed countries, whereas in developing countries most children are infected by 10 y of age. In poor resource settings, where malnutrition, parasitic/enteropathogen and H. pylori infection co-exist in young children, H. pylori might have potentially more diverse clinical outcomes. This paper reviews the impact of childhood H. pylori infection in developing countries that should now be the urgent focus of future research. The extra-gastric manifestations in early H. pylori infection in infants in poor resource settings might be a consequence of the infection associated initial hypochlorhydria. The potential role of H. pylori infection on iron deficiency, growth impairment, diarrheal disease, malabsorption and cognitive function is discussed in this review.

Helicobacter pylori infection in infants and toddlers in South America: concordance between [13C]urea breath test and monoclonal H. pylori stool antigen test

Accurate noninvasive tests for diagnosing Helicobacter pylori infection in very young children are strongly required. We investigated the agreement between the [(13)C]urea breath test ([(13)C]UBT) and a monoclonal ELISA (HpSA) for detection of H. pylori antigen in stool. From October 2007 to July 2011, we enrolled 414 infants (123 from Brazil and 291 from Peru) of ages 6 to 30 months. Breath and stool samples were obtained at intervals of at least 3 months from Brazilian (n = 415) and Peruvian (n = 908) infants. [(13)C]UBT and stool test results concurred with each other in 1,255 (94.86%) cases (kappa coefficient = 0.90; 95% confidence interval [CI] = 0.87 to 0.92). In the H. pylori-positive group, delta-over-baseline (DOB) and optical density (OD) values were positively correlated (r = 0.62; P < 0.001). The positivity of the tests was higher (P < 0.001; odds ratio [OR] = 6.01; 95% CI = 4.50 to 8.04) in Peru (546/878; 62.2%) than in Brazil (81/377; 21.5%) and increased with increasing age in Brazil (P = 0.02), whereas in Peru it decreased with increasing age (P < 0.001). The disagreement between the test results was associated with birth in Brazil and female gender but not with age and diarrhea. Our results suggest that both [(13)C]UBT and the stool monoclonal test are reliable for diagnosing H. pylori infection in very young children, which will facilitate robust epidemiological studies in infants and toddlers.

Iron status and Helicobacter pylori infection in symptomatic children: an international multi-centered study

Objective

Iron deficiency (ID) and iron deficiency anaemia (IDA) are global major public health problems, particularly in developing countries. Whilst an association between H. pylori infection and ID/IDA has been proposed in the literature, currently there is no consensus. We studied the effects of H. pylori infection on ID/IDA in a cohort of children undergoing upper gastrointestinal endoscopy for upper abdominal pain in two developing and one developed country.

Methods

In total 311 children (mean age 10.7±3.2 years) from Latin America - Belo Horizonte/Brazil (n = 125), Santiago/Chile (n = 105) - and London/UK (n = 81), were studied. Gastric and duodenal biopsies were obtained for evaluation of histology and H. pylori status and blood samples for parameters of ID/IDA.

Results

The prevalence of H. pylori infection was 27.7% being significantly higher (p<0.001) in Latin America (35%) than in UK (7%). Multiple linear regression models revealed H. pylori infection as a significant predictor of low ferritin and haemoglobin concentrations in children from Latin-America. A negative correlation was observed between MCV (r = −0.26; p = 0.01) and MCH (r = −0.27; p = 0.01) values and the degree of antral chronic inflammation, and between MCH and the degree of corpus chronic (r = −0.29, p = 0.008) and active (r = −0.27, p = 0.002) inflammation.

Conclusions

This study demonstrates that H. pylori infection in children influences the serum ferritin and haemoglobin concentrations, markers of early depletion of iron stores and anaemia respectively.

Increased gastric IL-1β concentration and iron deficiency parameters in H. pylori infected children

Association between H. pylori infection, iron deficiency and iron deficiency anaemia has been described, but the mechanisms involved have not been established. We hypothesized that in H. pylori infected children increased gastric concentrations of IL-1β and/or TNF-α, both potent inhibitors of gastric acid secretion that is essential for iron absorption, are predictors for low blood concentrations of ferritin and haemoglobin, markers of early depletion of iron stores and anaemia, respectively. We evaluated 125 children undergoing endoscopy to clarify the origin of gastrointestinal symptoms. Gastric specimens were obtained for H. pylori status and cytokine evaluation and blood samples for determination of iron deficiency/iron deficiency anaemia parameters and IL1 cluster and TNFA polymorphisms that are associated with increased cytokine secretions. Higher IL-1β and TNF-α gastric concentrations were observed in H. pylori-positive (n = 47) than in -negative (n = 78) children. Multiple linear regression models revealed gastric IL-1β, but not TNF-α, as a significant predictor of low ferritin and haemoglobin concentrations; results were reproduced in young children in whom IL1RN polymorphic genotypes associated with higher gastric IL-1β expression and lower blood ferritin and haemoglobin concentrations. In conclusion, high gastric levels of IL-1β can be the link between H. pylori infection and iron deficiency/iron deficiency anaemia in childhood.

Antimicrobial susceptibility and resistance patterns among Helicobacter pylori strains from The Gambia, West Africa

Helicobacter pylori is a globally important and genetically diverse gastric pathogen that infects most people in developing countries. Eradication efforts are complicated by antibiotic resistance, which varies in frequency geographically. There are very few data on resistance in African strains. Sixty-four Gambian H. pylori strains were tested for antibiotic susceptibility. The role of rdxA in metronidazole (Mtz) susceptibility was tested by DNA transformation and sequencing; RdxA protein variants were interpreted in terms of RdxA structure. Forty-four strains (69%) were resistant to at least 8 μg of Mtz/ml. All six strains from infants, but only 24% of strains from adults, were sensitive (P = 0.0031). Representative Mtz-resistant (Mtz(r)) strains were rendered Mtz susceptible (Mtz(s)) by transformation with a functional rdxA gene; conversely, Mtz(s) strains were rendered Mtz(r) by rdxA inactivation. Many mutations were found by Gambian H. pylori rdxA sequencing; mutations that probably inactivated rdxA in Mtz(r) strains were identified and explained using RdxA protein's structure. All of the strains were sensitive to clarithromycin and erythromycin. Amoxicillin and tetracycline resistance was rare. Sequence analysis indicated that most tetracycline resistance, when found, was not due to 16S rRNA gene mutations. These data suggest caution in the use of Mtz-based therapies in The Gambia. The increasing use of macrolides against respiratory infections in The Gambia calls for continued antibiotic susceptibility monitoring. The rich variety of rdxA mutations that we found will be useful in further structure-function studies of RdxA, the enzyme responsible for Mtz susceptibility in this important pathogen.

Gastric Helicobacter infection induces iron deficiency in the INS-GAS mouse

There is increasing evidence from clinical and population studies for a role of H. pylori infection in the aetiology of iron deficiency. Rodent models of Helicobacter infection are helpful for investigating any causal links and mechanisms of iron deficiency in the host. The aim of this study was to investigate the effects of gastric Helicobacter infection on iron deficiency and host iron metabolism/transport gene expression in hypergastrinemic INS-GAS mice. INS-GAS mice were infected with Helicobacter felis for 3, 6 and 9 months. At post mortem, blood was taken for assessment of iron status and gastric mucosa for pathology, immunohistology and analysis of gene expression. Chronic Helicobacter infection of INS- GAS mice resulted in decreased serum iron, transferrin saturation and hypoferritinemia and increased Total iron binding capacity (TIBC). Decreased serum iron concentrations were associated with a concomitant reduction in the number of parietal cells, strengthening the association between hypochlorhydria and gastric Helicobacter-induced iron deficiency. Infection with H. felis for nine months was associated with decreased gastric expression of iron metabolism regulators hepcidin, Bmp4 and Bmp6 but increased expression of Ferroportin 1, the iron efflux protein, iron absorption genes such as Divalent metal transporter 1, Transferrin receptor 1 and also Lcn2 a siderophore-binding protein. The INS-GAS mouse is therefore a useful model for studying Helicobacter-induced iron deficiency. Furthermore, the marked changes in expression of gastric iron transporters following Helicobacter infection may be relevant to the more rapid development of carcinogenesis in the Helicobacter infected INS-GAS model.

Advances in gastric cancer prevention

Gastric cancer is a multifactorial neoplastic pathology numbering among its causes both environmental and genetic predisposing factors. It is mainly diffused in South America and South-East Asia, where it shows the highest morbility percentages and it is relatively scarcely diffused in Western countries and North America. Although molecular mechanisms leading to gastric cancer development are only partially known, three main causes are well characterized: Helicobacter pylori (H. pylori) infection, diet rich in salted and/or smoked food and red meat, and epithelial cadherin (E-cadherin) mutations. Unhealthy diet and H. pylori infection are able to induce in stomach cancer cells genotypic and phenotypic transformation, but their effects may be crossed by a diet rich in vegetables and fresh fruits. Various authors have recently focused their attention on the importance of a well balanced diet, suggesting a necessary dietary education starting from childhood. A constant surveillance will be necessary in people carrying E-cadherin mutations, since they are highly prone in developing gastric cancer, also within the inner stomach layers. Above all in the United States, several carriers decided to undergo a gastrectomy, preferring changing their lifestyle than living with the awareness of the development of a possible gastric cancer. This kind of choice is strictly personal, hence a decision cannot be suggested within the clinical management. Here we summarize the key points of gastric cancer prevention analyzing possible strategies referred to the different predisposing factors. We will discuss about the effects of diet, H. pylori infection and E-cadherin mutations and how each of them can be handled.

Common coinfections of Giardia intestinalis and Helicobacter pylori in non-symptomatic Ugandan children

BACKGROUND

The protozoan parasite Giardia intestinalis and the pathogenic bacterium Helicobacter pylori are well known for their high prevalences in human hosts worldwide. The prevalence of both organisms is known to peak in densely populated, low resource settings and children are infected early in life. Different Giardia genotypes/assemblages have been associated with different symptoms and H. pylori with induction of cancer. Despite this, not much data are available from sub-Saharan Africa with regards to the prevalence of different G. intestinalis assemblages and their potential association with H. pylori infections.

METHODOLOGY/PRINCIPAL FINDINGS

Fecal samples from 427 apparently healthy children, 0-12 years of age, living in urban Kampala, Uganda were analyzed for the presence of H. pylori and G. intestinalis. G. intestinalis was found in 86 (20.1%) out of the children and children age 1<5 years had the highest rates of colonization. H. pylori was found in 189 (44.3%) out of the 427 children and there was a 3-fold higher risk of concomitant G. intestinalis and H. pylori infections compared to non-concomitant G. intestinalis infection, OR = 2.9 (1.7-4.8). No significant association was found in the studied population with regard to the presence of Giardia and gender, type of toilet, source of drinking water or type of housing. A panel of 45 G. intestinalis positive samples was further analyzed using multi-locus genotyping (MLG) on three loci, combined with assemblage-specific analyses. Giardia MLG analysis yielded a total of five assemblage AII, 25 assemblage B, and four mixed assemblage infections. The assemblage B isolates were highly genetically variable but no significant association was found between Giardia assemblage type and H. pylori infection.

CONCLUSIONS/SIGNIFICANCE

This study shows that Giardia assemblage B dominates in children in Kampala, Uganda and that the presence of H. pylori is an associated risk factor for G. intestinalis infection.

Alkyl hydroperoxide reductase: a candidate Helicobacter pylori vaccine

Helicobacter pylori (H. pylori) is the most important etiological agent of chronic active gastritis, peptic ulcer disease and gastric cancer. The aim of this study was to evaluate the efficacy of alkyl hydroperoxide reductase (AhpC) and mannosylated AhpC (mAhpC) as candidate vaccines in the C57BL/6J mouse model of H. pylori infection. Recombinant AhpC was cloned, over-expressed and purified in an unmodified form and was also engineered to incorporate N and C-terminal mannose residues when expressed in the yeast Pichia pastoris. Mice were immunized systemically and mucosally with AhpC and systemically with mAhpC prior to challenge with H. pylori. Serum IgG responses to AhpC were determined and quantitative culture was used to determine the efficacy of vaccination strategies. Systemic prophylactic immunization with AhpC/alum and mAhpC/alum conferred protection against infection in 55% and 77.3% of mice, respectively. Mucosal immunization with AhpC/cholera toxin did not protect against infection and elicited low levels of serum IgG in comparison with systemic immunization. These data support the use of AhpC as a potential vaccine candidate against H. pylori infection.

An association between Helicobacter pylori infection and cognitive function in children at early school age: a community-based study

Background

H. pylori infection has been linked to iron deficiency anemia, a risk factor of diminished cognitive development. The hypothesis on an association between H. pylori infection and cognitive function was examined in healthy children, independently of socioeconomic and nutritional factors.

Methods

A community-based study was conducted among 200 children aged 6-9 years, from different socioeconomic background. H. pylori infection was examined by an ELISA kit for detection of H. pylori antigen in stool samples. Cognitive function of the children was blindly assessed using Stanford-Benit test 5^th edition, yielding IQ scores. Data on socioeconomic factors and nutritional covariates were collected through maternal interviews and from medical records. Multivariate linear regression analysis was performed to obtain adjusted beta coefficients.

Results

H. pylori infection was associated with lower IQ scores only in children from a relatively higher socioeconomic community; adjusted beta coefficient -6.1 (95% CI -11.4, -0.8) (P = 0.02) for full-scale IQ score, -6.0 (95% CI -11.1, -0.2) (P = 0.04) for non-verbal IQ score and -5.7 (95% CI -10.8, -0.6) (P = 0.02) for verbal IQ score, after controlling for potential confounders.

Conclusions

H. pylori infection might be negatively involved in cognitive development at early school age. Further studies in other populations with larger samples are needed to confirm this novel finding.

Iron deficiency anemia: focus on infectious diseases in lesser developed countries

Iron deficiency anemia is thought to affect the health of more than one billion people worldwide, with the greatest burden of disease experienced in lesser developed countries, particularly women of reproductive age and children. This greater disease burden is due to both nutritional and infectious etiologies. Individuals in lesser developed countries have diets that are much lower in iron, less access to multivitamins for young children and pregnant women, and increased rates of fertility which increase demands for iron through the life course. Infectious diseases, particularly parasitic diseases, also lead to both extracorporeal iron loss and anemia of inflammation, which decreases bioavailability of iron to host tissues. This paper will address the unique etiologies and consequences of both iron deficiency anemia and the alterations in iron absorption and distribution seen in the context of anemia of inflammation. Implications for diagnosis and treatment in this unique context will also be discussed.

Malnutrition and gastrointestinal and respiratory infections in children: a public health problem

Infectious disease is the major cause of morbidity and mortality in developing countries, particularly in children. Increasing evidence suggests that protein-calorie malnutrition is the underlying reason for the increased susceptibility to infections observed in these areas. Moreover, certain infectious diseases also cause malnutrition, which can result in a vicious cycle. Malnutrition and bacterial gastrointestinal and respiratory infections represent a serious public health problem. The increased incidence and severity of infections in malnourished children is largely due to the deterioration of immune function; limited production and/or diminished functional capacity of all cellular components of the immune system have been reported in malnutrition. In this review, we analyze the cyclical relationship between malnutrition, immune response dysfunction, increased susceptibility to infectious disease, and metabolic responses that further alter nutritional status. The consequences of malnutrition are diverse and included: increased susceptibility to infection, impaired child development, increased mortality rate and individuals who come to function in suboptimal ways.

Endocrine impact of Helicobacter pylori: Focus on ghrelin and ghrelin o-acyltransferase

Ghrelin is predominantly produced by the gastric enteroendocrine cell compartment and is octanoylated by the recently discovered ghrelin o-acyltransferase (GOAT) before secretion into the bloodstream. This octanoylation is essential for many of the biological properties of ghrelin including appetite stimulation and anti-inflammatory properties as only the acylated form of ghrelin binds to the ghrelin receptor, the growth hormone secretagogue receptor (GHS-R). Given the gastric location of ghrelin production, it is perhaps not surprising that insult to the gastric mucosa affects circulating ghrelin levels in humans. Helicobacter pylori (H. pylori) infects more than fifty percent of the world’s population and once established within the gastric mucosa, can persist for life. Infection is associated with chronic gastritis, gastric atrophy and ulceration, reduced appetite and a lower body mass index (BMI). The large majority of studies investigating levels of circulating ghrelin and ghrelin expression in the stomach in patients with H. pylori infection indicate that the bacterium has a negative impact on ghrelin production and/or secretion. Eradication of infection restores ghrelin, improves appetite and increases BMI in some studies, however, a causative relationship between H. pylori-associated serum ghrelin decline and food intake and obesity has not been established. Most studies measure total ghrelin in the circulation although the measurement of the ratio of acyl/total ghrelin gives a clearer indication that the ghrelin acylation process is altered during infection and atrophy. GOAT is essential for the production of biologically-active, acyl ghrelin and the impact of H. pylori on GOAT expression and activity will be highly informative in the future.

The effect of Helicobacter pylori and economic status on growth parameters and leptin, ghrelin, and insulin-like growth factor (IGF)-I concentrations in children

BACKGROUND

It was suggested that gastric colonization with Helicobacter pylori (H. pylori) was associated with suboptimal nutrition and growth in childhood. Furthermore, several studies indicated a relationship between H. pylori colonization and alterations in the circulating levels of growth-related molecules (GRM). Accordingly, in this study, we investigate the effect of H. pylori infection on GRMs and on the growth of healthy school children, taking into consideration the effect of their economic status (ES) and anthropometric indices of their parents.

METHODS

To acquire sociodemographic and anthropometric nutritional parameters and to detect H. pylori-specific serum IgG antibodies and growth-related molecules, we evaluated a total of 473 children attending four different primary and secondary schools in Istanbul. Subsequently, we assessed the effect of H. pylori on growth-related parameters (weight for age SDS, height for age SDS, BMI SDS, TSF, and waist-to-hip ratio) and on GRMs (leptin, ghrelin, and insulin-like growth factor-1 (IGF-1)), controlling for age, gender, family income, household crowding (HC), breastfeeding, maternal and paternal BMI SDS, and midparental height SDS with complex statistical models.

RESULTS

Of the 473 children (275 F/198 M, age 6-15 years; mean: 10.3 ± 0.1 years), 161 (34%) were H. pylori-positive. The prevalence of H. pylori was significantly higher in lower economic status (ES) groups, in children living in crowded houses, and in older age groups. Using simple statistical models, we did not find any significant associations between H. pylori infection and the growth parameters. However, in complex models for height for age SDS and for weight for age SDS, there was a significant interaction between H. pylori infection status and ES. Whereas in H. pylori-positive subjects, mid-income family children were both taller and heavier than the low-income group, there was no such an association in H. pylori-negative subjects. Among biochemical parameters, only ghrelin levels were associated with H. pylori infection in all models. Leptin levels were associated with HC in girls, whereas none of the parameters was significantly associated with leptin levels in boys. For IGF-1 levels, for boys, age and maternal BMI, and for girls, age and HC were significantly associated with IGF-1 levels.

CONCLUSION

We suggest that H. pylori may impair growth significantly only in susceptible children where unfavorable socioeconomic conditions facilitate its action, probably through mechanisms, at least in part, involving growth-related molecules.

Anaemia among clinically well under-fives attending a community health centre in Venda, Limpopo Province

BACKGROUND

Anaemia has been reported to affect 20 - 75% of children in South Africa. The range suggests the effects that geography, health, and socio-economic status can have on the observed prevalence of anaemia within a specific community. Our objective was to investigate the prevalence of anaemia in children aged under 5 presenting for well-child examinations at a community health centre in Thohoyandou, Limpopo Province.

DESIGN

A cross-sectional observational study was carried out in June and July 2007. Caregivers participated in a brief interview where demographic, health, and nutritional information was collected. A blood sample was collected from each child, and haemoglobin levels were assessed with a point-of-care haemoglobin testing system. Anaemia was defined as having a haemoglobin value <2 standard deviations below age-altitude adjusted normal values.

RESULTS

Three-quarters (39/52 - 75%) of children were anaemic. Girls were significantly more likely to be anaemic than boys (20/20 v. 19/32 respectively; p=0.001). Anaemic children were significantly less likely to be underweight compared with their peers (32/38 v. 5/12 respectively; p=0.007). There was no significant association between anaemia and infection with Helicobacter pylori (p=0.729), intestinal helminths (p=1.000) or food insecurity (p=0.515).

CONCLUSION

We found a striking prevalence of anaemia among clinically well children <5 years old in Thohoyandou, Limpopo Province. The rates of anaemia were higher than those found in previous studies conducted in similar settings in South Africa. Future work should focus on aetiologies and interventions.

Seroprevalence of Helicobacter pylori infection among children of low socioeconomic level in São Paulo

CONTEXT AND OBJECTIVE

Helicobacter pylori infection is mainly acquired during childhood, and is associated with significant morbidity in adults. The aim here was to evaluate the seroprevalence and risk factors of H. pylori infection among children of low socioeconomic level attended at a public hospital in São Paulo, Brazil.

DESIGN AND SETTING

Cross-sectional study, among patients attended at an outpatient clinic.

METHODS

326 children were evaluated (150 boys and 176 girls; mean age 6.82 ± 4.07 years) in a cross-sectional study. Patients with chronic diseases or previous H. pylori treatment, and those whose participation was not permitted by the adult responsible for the child, were excluded. The adults answered a demographic questionnaire and blood samples were collected. The serological test used was Cobas Core II, a second-generation test. Titers > 5 U/ml were considered positive.

RESULTS

H. pylori infection was diagnosed in 116 children (35.6%). Infected children were older than uninfected children (7.77 ± 4.08 years versus 5.59 ± 3.86 years; p < 0.0001). The seroprevalence increased from 20.8% among children aged two to four years, to 58.3% among those older than 12 years. There were no significant relationships between seropositivity and gender, color, breastfeeding, number of people in the home, number of rooms, bed sharing, living in a shantytown, maternal educational level, family income or nutritional status. In multivariate analysis, the only variable significantly associated with H. pylori seropositivity was age.

CONCLUSION

Infection had intermediate prevalence in the study population, and age was associated with higher prevalence.

Comparison of two types of epidemiological surveys aimed at collecting daily clinical symptoms in community-based longitudinal studies

BACKGROUND

Investigators use prospective community-based studies to collect longitudinal information on childhood diarrhea. The interval in which data are collected may affect the accuracy and interpretation of results. Our objective was to compare data of reported daily clinical symptoms from surveys conducted daily versus twice-weekly surveys.

METHODS

We conducted our study in Lima, Peru, between October and December 2007. We asked 134 mothers to report daily symptoms by using a twice-weekly survey. We conducted daily surveys for the same data on 25% of participants randomly selected each day. We analyzed intersurvey variability by using Cohen's kappa and Signal Detection Theory (SDT).

RESULTS

We collected 6157 and 1181 child-days of data through the twice-weekly and daily surveys, respectively. The prevalence of diarrhea, fever, vomiting, and cough were 6.4%, 1.6%, 2.1%, and 22.7% from the twice-weekly survey and, 6.4%, 2.0%, 2.4%, and 26% from the daily survey, respectively. Despite similar prevalence, 20% of days with reported diarrhea were discrepant between the two surveys, and agreement in the report of diarrhea decreased as time between the interviews increased (p = .03).

CONCLUSIONS

Although twice-weekly surveys provide an adequate estimate of diarrheal prevalence compared with daily surveys, the prevalence of other symptoms based on dichotomous questions was lower under the former. Additionally, the agreement between the two surveys in the report of diarrhea decreased as the recall period increased, suggesting that data from daily interviews were of greater quality. Our analysis is a novel application of SDT to measure respondent certainty and bias, from which better inference about the quality of collected data may be drawn.

Advances in vaccination against Helicobacter pylori

A vaccination against Helicobacter pylori may represent both prophylactic and therapeutic approaches to the control of H. pylori infection. Different protective H. pylori-derived antigens, such as urease, vacuolating cytotoxin A, cytotoxin-associated antigen, neutrophil-activating protein and others can be produced at low cost in prokaryote expression systems and most of these antigens have already been administered to humans and shown to be safe. The recent development by Graham et al. of the model of H. pylori challenge in humans, the recent published clinical trials and the last insight generated in animal models of H. pylori infection regarding the immune mechanisms leading to vaccine-induced Helicobacter clearance will facilitate the evaluation of immunogenicity and efficacy of H. pylori vaccine candidates in Phase II and III clinical trials.

Development of vaccines against Helicobacter pylori

Helicobacter pylori is a Gram-negative, microaerophilic bacterium adapted to survive in the stomach of humans where it can cause peptide ulcers and gastric cancer. Although effective antibiotic treatment exists, there is a consensus that vaccines are necessary to limit the severity of this infection. Great progress has been made since its discovery 25 years ago in understanding the virulence factors and several aspects of the pathogenesis of the H. pylori gastric diseases. Several key bacterial factors have been identified: urease, vacuolating cytotoxin, cytotoxin-associated antigen, the pathogenicity island, neutrophil-activating protein, and among others. These proteins, in their native or recombinant forms, have been shown to confer protection against infectious challenge with H. pylori in experimental animal models. It is not known, however, through which effector mechanisms this protection is achieved. Nevertheless, a number of clinical trials in healthy volunteers have been conducted using urease given orally as a soluble protein or expressed in bacterial vectors with limited results. Recently, a mixture of H. pylori antigens was reported to be highly immunogenic in H. pylori-negative volunteers following intramuscular administration of the vaccine with aluminium hydroxide as an adjuvant. These data show that vaccination against this pathogen is feasible. More research is required to understand the immunological mechanisms underlying immune-mediate protection.

Gastroenterology in developing countries: issues and advances

Developing countries shoulder a considerable burden of gastroenterological disease. Infectious diseases in particular cause enormous morbidity and mortality. Diseases which afflict both western and developing countries are often seen in more florid forms in poorer countries. Innovative techniques continuously improve and update gastroenterological practice. However, advances in diagnosis and treatment which are commonplace in the West, have yet to reach many developing countries. Clinical guidelines, based on these advances and collated in resource-rich environments, lose their relevance outside these settings. In this two-part review, we first highlight the global burden of gastroenterological disease in three major areas: diarrhoeal diseases, hepatitis B, and Helicobacter pylori. Recent progress in their management is explored, with consideration of future solutions. The second part of the review focuses on the delivery of clinical services in developing countries. Inadequate numbers of healthcare workers hamper efforts to combat gastroenterological disease. Reasons for this shortage are examined, along with possibilities for increased specialist training. Endoscopy services, the mainstay of gastroenterology in the West, are in their infancy in many developing countries. The challenges faced by those setting up a service are illustrated by the example of a Nigerian endoscopy unit. Finally, we highlight the limited scope of many clinical guidelines produced in western countries. Guidelines which take account of resource limitations in the form of "cascades" are advocated in order to make these guidelines truly global. Recognition of the different working conditions facing practitioners worldwide is an important step towards narrowing the gap between gastroenterology in rich and poor countries.

Helicobacter pylori, helminth infections and growth: a cross-sectional study in a high prevalence population

AIM

Helicobacter pylori (H. pylori) infection is usually acquired in childhood and may adversely affect growth, although data are inconsistent. This study investigated growth parameters in a paediatric cohort with a high prevalence of H. pylori and helminth infection.

METHODS

A cross-sectional study of African refugee children (<16 years) recruited at their initial health assessment following resettlement in Australia. Detailed demographic, infection and anthropometric data were obtained. H. pylori infection was diagnosed by monoclonal faecal antigen enzyme immunoassay testing (MFAT). Growth restriction was defined as children with any anthropometric measures below the fifth centile for age and gender.

RESULTS

H. pylori infection was detected in 149/182 (81.9%). Children with H. pylori infection were older (mean 8.5 years, standard deviation (SD) 4.2 years vs. 5.8 years, SD 4.5 years, p < 0.001). No gender differences were observed. After adjustment for age, H. pylori did not adversely affect body mass index or other anthropometric measurements. Helminth infections were common (41.8%) but not associated with reduced growth or with H. pylori infection.

CONCLUSION

H. pylori and helminth infections are prevalent in African refugee children but neither is associated with growth restriction. Longitudinal growth velocity studies are necessary to identify any long-term consequences of H. pylori on childhood growth.