Global burden of childhood pneumonia and diarrhoea

Probiotics for the prevention of pediatric upper respiratory tract infections: a systematic review

BACKGROUND

Acute upper respiratory tract infections (URTIs) contribute substantially to pediatric morbidity and mortality worldwide. Prevention of these infections in childhood is a very important public health challenge. Previous systematic reviews, including both adult and childhood populations, have reported that probiotics seem promising, but with modest evidence. This study aimed to focus on prophylactic probiotic use in the prevention of URTIs in childhood.

METHODS

Relevant trials on two databases were identified in a systematic review, from inception to June 2014. Study selection, data extraction and quality assessment were carried out by two reviewers. In this review, the effects of probiotics, particularly the Lactobacillus and Bifidobacterium strains, on the incidence and symptom scores of URTI in otherwise healthy children were evaluated for the first time. This review comprises 14 randomized controlled trials (RCTs) applied to a pediatric population with high-quality methodology.

RESULTS

This systematic review suggests that probiotics in immunocompetent children have a modest effect both in diminishing the incidence of URTIs and the severity of the infection symptoms.

CONCLUSIONS

At least one beneficial effect of prophylactic probiotic was observed in the majority of RCTs. Even a minimal reduction of 5 - 10% in the incidence of URTIs would have an important clinical and economic mpact on societies. Furthermore, the long-term administration of probiotics appeared to have a good safety profile in childhood and none of the studies reported any serious adverse events related to the probiotic strain.

Aetiology, epidemiology and clinical characteristics of acute moderate-to-severe diarrhoea in children under 5 years of age hospitalized in a referral paediatric hospital in Rabat, Morocco

The objective of the study was to describe the aetiology, epidemiology and clinical characteristics of the principal causes of acute infectious diarrhoea requiring hospitalization among children under 5 years of age in Rabat, Morocco. A prospective study was conducted from March 2011 to March 2012, designed to describe the main pathogens causing diarrhoea in hospitalized children >2 months and less than 5 years of age. Among the 122 children included in the study, enteroaggregative Escherichia coli (EAEC) and rotavirus were the main aetiological causes of diarrhoea detected. Twelve (9.8 %) children were referred to an intensive care unit, while two, presenting infection by EAEC, and EAEC plus Shigella sonnei, developed a haemolytic uraemic syndrome. Additionally, six (4.9 %) deaths occurred, with EAEC being isolated in four of these cases. Diarrhoeagenic E. coli and rotavirus play a significant role as the two main causes of severe diarrhoea, while other pathogens, such as norovirus and parasites, seem to have a minimal contribution. Surveillance and prevention programmes to facilitate early recognition and improved management of potentially life-threatening diarrhoea episodes are needed.

Metagenomes of microbial communities in arsenic- and pathogen-contaminated well and surface water from bangladesh

The contamination of drinking water from both arsenic and microbial pathogens occurs in Bangladesh. A general metagenomic survey of well water and surface water provided information on the types of pathogens present and may help elucidate arsenic metabolic pathways and potential assay targets for monitoring surface-to-ground water pathogen transport.

Protocol for the economic evaluation of the diarrhea alleviation through zinc and oral rehydration salt therapy at scale through private and public providers in rural Gujarat and Uttar Pradesh, India

BACKGROUND

Child diarrhea persists as a leading public health problem in India despite evidence supporting zinc and low osmolarity oral rehydration salts as effective treatments. Across 2 years in 2010-2013, the Diarrhea Alleviation using Zinc and Oral Rehydration Salts Therapy (DAZT) program was implemented to operationalize delivery of these interventions at scale through private and public sector providers in rural Gujarat and Uttar Pradesh, India.

METHODS/DESIGN

This study evaluates the cost-effectiveness of DAZT program activities relative to status quo conditions existing before the study, comparing a Monte Carlo simulation method with net-benefit regression, discussing the strengths and weaknesses of each approach. A control group was not included in the 'before and after' study design as zinc has proven effectiveness for diarrhea treatment. Costs will be calculated using a societal perspective including program implementation and household out-of-pocket payments for care seeking, as well as estimates of wages lost. Outcomes will be measured in terms of episodes averted in net-benefit regression and in terms of the years of life lost component of disability-adjusted life years in the method based on Monte Carlo simulation. The Lives Saved Tool will be used to model anticipated changes in mortality over time and deaths averted based on incremental changes in coverage of oral rehydration salts and zinc. Data will derive from cross-sectional surveys at the start, midpoint, and endpoint of the program. In addition, Lives Saved Tool (LiST) projections will be used to define the reference case value for the ceiling ratio in terms of natural units.

DISCUSSION

This study will be useful both in its application to an economic evaluation of a public health program in its implementation phase but also in its comparison of two methodological approaches to cost-effectiveness analysis. Both policy recommendations and methodological lessons learned will be discussed, recognizing the limitations in drawing strong policy conclusions due to the uncontrolled study design. It is expected that this protocol will be useful to researchers planning what method to use for the evaluation of similar before and after studies.

The Burden of Diarrheal Diseases among Children under Five Years of Age in Arba Minch District, Southern Ethiopia, and Associated Risk Factors: A Cross-Sectional Study

Introduction. In Ethiopia diarrhea is the second cause for clinical presentation among under five-year child population next to pneumonia and it is also more common in rural than in urban areas. Methods. A community based cross-sectional study was conducted in Arba Minch District. Data were collected using structured questionnaire by trained data collectors. To identify predictors of diarrhea the negative binomial regression model was used to predict and control the effect of confounders. Results. The prevalence of diarrhea among under-five children was 30.5%. This study showed children whose mothers did not attend any formal education were 89% more likely to develop diarrhea (APR = 1.89, [95% CI: 1.35, 2.53]) compared to their counterparts. Similarly, children's being in age category 6-23 months (APR = 2.78 [95% CI: 1.72, 4.55]) and mothers' poor hand washing practice (APR = 2.33 [95% CI: 1.80, 4.15]) were found predictors of diarrhea. The study also showed that, out of 180 mothers whose child had got diarrhea, about 31% of mothers could not give anything to manage the diarrhea. Conclusions. In this study the prevalence of diarrhea was high which was significantly associated with maternal education level, age of the child, and personal hygiene practices. Therefore, women's education level of at least primary school and enhancing community based behavioral change communications using multiple channels (radio) and community health workers are recommended to reduce the occurrence and consequences of childhood diarrhea in the study area.

The role of macrophages in the innate immune response to Streptococcus pneumoniae and Staphylococcus aureus: mechanisms and contrasts

Macrophages are critical mediators of innate immune responses against bacteria. The Gram-positive bacteria Streptococcus pneumoniae and Staphylococcus aureus express a range of virulence factors, which challenge macrophages' immune competence. We review how macrophages respond to this challenge. Macrophages employ a range of strategies to phagocytose and kill each pathogen. When the macrophages capacity to clear bacteria is overwhelmed macrophages play important roles in orchestrating the inflammatory response through pattern recognition receptor-mediated responses. Macrophages also ensure the inflammatory response is tightly constrained, to avoid tissue damage, and play an important role in downregulating the inflammatory response once initial bacterial replication is controlled.

Early childhood diarrhoeal diseases and cognition: are we missing the rest of the iceberg?

Risk factors which interfere with cognitive function are especially important during the first 2 years of life - a period referred to as early child development and a time during which rapid growth and essential development occur. Malnutrition, a condition whose effect on cognitive function is well known, has been shown to be part of a vicious cycle with diarrhoeal diseases, and the two pathologies together continue to be the leading cause of illness and death in young children in developing countries. This paper reviews the burden of early childhood diarrhoeal diseases globally and the emerging evidence of their relationship with global disparities in neurocognitive development. The strength of evidence which indicates that the severe childhood diarrhoeal burden may be implicated in cognitive impairment of children from low- and middle-income counties is discussed. Findings suggest that greater investment in multi-site, longitudinal enteric infection studies that assess long-term repercussions are warranted. Furthermore, economic analyses using the concept of human capital should play a key role in advancing our understanding of the breadth and complexities of the health, social and economic ramifications of early childhood diarrhoeal diseases and enteric infections. This broadened awareness can serve to help advocate for more effective interventions, particularly in developing economies.

Changes in pneumococcal serotypes and antimicrobial resistance after introduction of the 13-valent conjugate vaccine in the United States

Ongoing surveillance for Streptococcus pneumoniae is needed to assess the impact of the pneumococcal conjugate vaccine introduced in 2010 (PCV13). Forty-two U.S. centers submitted S. pneumoniae isolates between 1 October 2012 and 31 March 2013. Susceptibility testing was performed by use of a broth dilution method as recommended by the Clinical and Laboratory Standards Institute. Serotyping was performed by multiplex PCR and the Quellung reaction. Multidrug resistance (MDR) was defined as nonsusceptibility to penicillin (PNSP; MIC ≥ 0.12 μg/ml) combined with resistance to ≥2 non-β-lactam antimicrobials. Penicillin-resistant S. pneumoniae (PRSP) was defined as a penicillin MIC of ≥2 μg/ml. For the 1,498 isolates collected during 2012-13, the PRSP and MDR rates were 14.2 and 21.0%, respectively. These percentages were lower than rates obtained in a surveillance study conducted 4 years earlier in 2008-09 (17.0 and 26.6%, respectively). The most common serotypes identified in 2012-13 were 3, 35B, and 19A, each representing 9 to 10% of all isolates. The largest percentage of PNSP in 2012-13 were found in serotypes 35B (24.8%), 19A (23.5%), and 15A (10.3%). Predominant PRSP serotypes were 19A (54.5%), 35B (28.2%), and 19F (7.0%). Major MDR serotypes were 19A (38.5%), 15A (16.9%), 6C (8.3%), and 35B (6.4%). The change in prevalence of PCV13 serotypes (43.4 to 27.1%) was primarily due to a decrease in serotype 19A strains, i.e., 22% of all strains in 2008-09 to 10% of all strains in 2012-13. Among the PNSP subset, serotypes showing a proportional increase were 35B, 15B, and 23B. Among MDR strains, the largest proportional increases were observed in serotypes 35B, 15B, and 23A.

Who died of what in rural KwaZulu-Natal, South Africa: a cause of death analysis using InterVA-4

Background

For public health purposes, it is important to see whether men and women in different age groups die of the same causes in South Africa.

Objective

We explored sex- and age-specific patterns of causes of deaths in a rural demographic surveillance site in northern KwaZulu-Natal in South Africa over the period 2000–2011.

Design

Deaths reported through the demographic surveillance were followed up by a verbal autopsy (VA) interview using a standardised questionnaire. Causes of death were assigned likelihoods using the publicly available tool InterVA-4. Cause-specific mortality fractions were determined by age and sex.

Results

Over the study period, a total of 5,416 (47%) and 6,081 (53%) deaths were recorded in men and women, respectively. Major causes of death proportionally affecting more women than men were (all p<0.0001): human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) (20.1% vs. 13.6%), other and unspecified cardiac disease (5.9% vs. 3.2%), stroke (4.5% vs. 2.7%), reproductive neoplasms (1.7% vs. 0.4%), diabetes (2.4% vs. 1.2%), and breast neoplasms (0.4% vs. 0%). Major causes of deaths proportionally affecting more men than women were (all p<0.0001) assault (6.1% vs. 1.7%), pulmonary tuberculosis (34.5% vs. 30.2%), road traffic accidents (3.0% vs. 1.0%), intentional self-harm (1.3% vs. 0.3%), and respiratory neoplasms (2.5% vs. 1.5%). Causes of death due to communicable diseases predominated in all age groups except in older persons.

Conclusions

While mortality during the 2000s was dominated by tuberculosis and HIV/AIDS, we found substantial sex-specific differences both for communicable and non-communicable causes of death, some which can be explained by a differing sex-specific age structure. InterVA-4 is likely to be a valuable tool for investigating causes of death patterns in other similar Southern African settings.

The relationship between zinc intake and growth in children aged 1-8 years: a systematic review and meta-analysis

BACKGROUND/OBJECTIVES

It is estimated that zinc deficiency affects 17% of the world's population, and because of periods of rapid growth children are at an increased risk of deficiency, which may lead to stunting. This paper presents a systematic review and meta-analysis of the randomised controlled trials (RCTs) that assess zinc intake and growth in children aged 1-8 years. This review is part of a larger systematic review by the European Micronutrient Recommendations Aligned Network of Excellence that aims to harmonise the approach to setting micronutrient requirements for optimal health in European populations (www.eurreca.org).

SUBJECT/METHODS

Searches were performed of literature published up to and including December 2013 using MEDLINE, Embase and the Cochrane Library databases. Included studies were RCTs in apparently healthy child populations aged from 1 to 8 years that supplied zinc supplements either as capsules or as part of a fortified meal. Pooled meta-analyses were performed when appropriate.

RESULTS

Nine studies met the inclusion criteria. We found no significant effect of zinc supplementation of between 2 weeks and 12 months duration on weight gain, height for age, weight for age, length for age, weight for height (WHZ) or WHZ scores in children aged 1-8 years.

CONCLUSIONS

Many of the children in the included studies were already stunted and may have been suffering from multiple micronutrient deficiencies, and therefore zinc supplementation alone may have only a limited effect on growth.

How well does physician selection of microbiologic tests identify Clostridium difficile and other pathogens in paediatric diarrhoea? Insights using multiplex PCR-based detection

The objective of this study was to compare the aetiologic yield of standard-of-care microbiologic testing ordered by physicians with that of a multiplex PCR platform. Stool specimens obtained from children and young adults with gastrointestinal illness were evaluated by standard laboratory methods and a developmental version of the FilmArray Gastrointestinal (GI) Diagnostic System (FilmArray GI Panel), a rapid multiplex PCR platform that detects 23 bacterial, viral and protozoal agents. Results were classified according to the microbiologic tests requested by the treating physician. A median of three (range 1-10) microbiologic tests were performed by the clinical laboratory during 378 unique diarrhoeal episodes. A potential aetiologic agent was identified in 46% of stool specimens by standard laboratory methods and in 65% of specimens tested using the FilmArray GI Panel (p < 0.001). For those patients who only had Clostridium difficile testing requested, an alternative pathogen was identified in 29% of cases with the FilmArray GI Panel. Notably, 11 (12%) cases of norovirus were identified among children who only had testing for Clostridium difficile ordered. Among those who had C. difficile testing ordered in combination with other tests, an additional pathogen was identified in 57% of stool specimens with the FilmArray GI Panel. For patients who had no C. difficile testing performed, the FilmArray GI Panel identified a pathogen in 63% of cases, including C. difficile in 8%. Physician-specified laboratory testing may miss important diarrhoeal pathogens. Additionally, standard laboratory testing is likely to underestimate co-infections with multiple infectious diarrhoeagenic agents.

Sentinel hospital-based surveillance for assessment of burden of rotavirus gastroenteritis in children in Pakistan

Objectives

To determine the burden and molecular epidemiology of rotavirus gastroenteritis in children hospitalized with severe acute watery diarrhea in Pakistan prior to introduction of rotavirus vaccine.

Methods

A cross-sectional study was carried out over a period of two years from 2006 – 2008 at five sentinel hospitals in the cities of Karachi, Lahore, Rawalpindi, and Peshawar. Stool samples collected from children under five years of age hospitalized with severe acute watery diarrhea were tested for rotavirus antigen via enzyme immunoassay (EIA) (IDEA REF K6020 Oxoid Ltd (Ely), Cambridge, United Kingdom). A subset of EIA positive stool samples were further processed for genotyping.

Results

6679 children were enrolled and stool specimens of 2039 (30.5%) were positive for rotavirus. Rotavirus positivity ranged from 16.3% to 39.4% in the 5 hospitals with highest positivity in Lahore. 1241 (61%) of all rotavirus cases were in infants under one year of age. Among the strains examined for G-serotypes, the occurrence of G1, G2, G9 and G4 strains was found to be 28%, 24%, 14% and 13%, respectively. Among P-types, the most commonly occurring strains were P6 (31.5%) followed by P8 (20%) and P4 (12%). Prevalent rotavirus genotype in hospitalized children of severe diarrhea were G1P[8] 11.6% (69/593), followed by G2P[4] 10.4% (62/593), and G4P[6] 10.1% (60/593).

Conclusions

Approximately one third of children hospitalized with severe gastroenteritis in urban centers in Pakistan have rotavirus. Introduction of rotavirus vaccine in Pakistan's national immunization program could prevent many severe episodes and diarrheal deaths.

Simultaneous exposure to Escherichia coli heat-labile and heat-stable enterotoxins increases fluid secretion and alters cyclic nucleotide and cytokine production by intestinal epithelial cells

Enterotoxigenic Escherichia coli (ETEC) is a significant cause of diarrheal disease and death, especially in children in developing countries. ETEC causes disease by colonizing the small intestine and producing heat-labile toxin (LT), heat-stable toxin (ST), or both LT and ST (LT+ST). The majority of ETEC strains produce both ST and LT. Despite the prevalence of LT+ST-producing organisms, few studies have examined the physiologic or immunologic consequences of simultaneous exposure to these two potent enterotoxins. In the current report, we demonstrate that when LT and ST are both present, they increase water movement into the intestinal lumen over and above the levels observed with either toxin alone. As expected, cultured intestinal epithelial cells increased their expression of intracellular cyclic GMP (cGMP) when treated with ST and their expression of intracellular cyclic AMP (cAMP) when treated with LT. When both toxins were present, cGMP levels but not cAMP levels were synergistically elevated compared with the levels of expression caused by the corresponding single-toxin treatment. Our data also demonstrate that the levels of inflammatory cytokines produced by intestinal epithelial cells in response to LT are significantly reduced in animals exposed to both enterotoxins. These findings suggest that there may be complex differences between the epithelial cell intoxication and, potentially, secretory outcomes induced by ETEC strains expressing LT+ST compared with strains that express LT or ST only. Our results also reveal a novel mechanism wherein ST production may reduce the hosts' ability to mount an effective innate or adaptive immune response to infecting organisms.

Epidemiology of nasopharyngeal colonization by S. pneumoniae in Indian infants in the first 2 years of life

BACKGROUND

Streptococcus pneumoniae is a leading cause of invasive disease in developing countries like India. Although the 13 valent pneumococcal vaccine has already been introduced in the country, there is very little epidemiological data regarding S. pneumoniae colonization and antibiotic susceptibility in Indian infants.

METHODS

We studied serogroup/serotype (SGT) distribution and antibiotic susceptibility pattern of S. pneumoniae in unvaccinated Indian infants by performing monthly nasopharyngeal swabbing of a birth cohort for 2 years.

RESULTS

Colonization began soon after birth and was complete in the first year of life in the majority of those colonized. Carriage rates increased during winter (p<0.01) and in those with upper respiratory infection (URI) (p<0.01). The most frequently (76.1%) isolated SGT were 19, 6, 15, 23, 9, 35 and 10. Vaccine SGT accounted for 60.5% of all colonizers. Antibiotic resistance was maximum for cotrimoxazole (94.3%) and least for erythromycin (11.2%) with no penicillin resistance. Ten of the commonest SGT which cause invasive disease among Indian infants comprised 46.9% of the colonizers. Serogroups 1, 5, 45 and 12 which cause invasive disease in under-fives were not seen in this birth cohort in the first year.

CONCLUSIONS

S. pneumoniae colonization in Indian infants commences soon after birth and chiefly occurs in the first year of life. The 13 valent vaccine may protect against a little less than half the commonly seen invasive SGT of S. pneumoniae.

Prevalence, one week incidence and knowledge on causes of diarrhea: household survey of under-fives and adults in Mkuranga district, Tanzania

Background

Diarrhea is known to be the major cause of mortality in children aged less than five years old. Although mortality from diarrheal disease is decreasing globally, morbidity is not. The objectives of this study were to determine the prevalence of diarrhea among under-fives and assess knowledge on causes of diarrhea among adults in Mkuranga district Tanzania.

Methods

Interviews with heads of households and observations were the methods of data collection employed by this study.

Results

The prevalence of diarrhea in children below the age of five years as reported by heads of households was 6.1% and most affected were children in age groups 12 – 17 and 18 – 23 months (11.6% and 15.8% respectively; p – value 0.001). The rate of diarrhea incidence was 1 episode per 10 children per week. The mean duration of diarrhea illness was 1.7 days. Most under-fives had diarrhea for one (38.1%) or two (24%) days. Respondents in the 4th least poor quintile were more likely to have comprehensive knowledge on causes of diarrhea compared to respondents in the 1st poorest quintile. Male respondents were two times more likely to have comprehensive knowledge than female respondents. Respondents with comprehensive knowledge on causes of diarrhea were less likely to have poor hand-washing practice and more likely to have received water, hygiene and sanitation education. Under-fives in age group 12 – 17 months and those from households with reported poor hand washing practice were more likely to experience diarrhea episodes.

Conclusion

Although prevalence of diarrhea reported in this study is low, the one week incidence is moderately high but less severe. Majority of household respondents had inadequate knowledge on causes of diarrhea and poor hand-washing practice. There is a need to provide WASH education to improve their knowledge on causes of diarrhea and hand washing practice.

Post-discharge mortality in children with severe malnutrition and pneumonia in Bangladesh

BACKGROUND

Post-discharge mortality among children with severe illness in resource-limited settings is under-recognized and there are limited data. We evaluated post-discharge mortality in a recently reported cohort of children with severe malnutrition and pneumonia, and identified characteristics associated with an increased risk of death.

METHODS

Young children (<5 years of age) with severe malnutrition (WHO criteria) and radiographic pneumonia on admission to Dhaka Hospital of icddr,b over a 15-month period were managed according to standard protocols. Those discharged were followed-up and survival status at 12 weeks post-discharge was determined. Verbal autopsy was requested from families of those that died.

RESULTS

Of 405 children hospitalized with severe malnutrition and pneumonia, 369 (median age, 10 months) were discharged alive with a follow-up plan. Of these, 32 (8.7%) died in the community within 3 months of discharge: median 22 (IQR 9-35) days from discharge to death. Most deaths were reportedly associated with acute onset of new respiratory or gastrointestinal symptoms. Those that died following discharge were significantly younger (median 6 [IQR 3,12] months) and more severely malnourished, on admission and on discharge, than those that survived. Bivariate analysis found that severe wasting on admission (OR 3.64, 95% CI 1.66-7.97) and age <12 months (OR 2.54, 95% CI 1.1-8.8) were significantly associated with post-discharge death. Of those that died in the community, none had attended a scheduled follow-up and care-seeking from a traditional healer was more common (p<0.001) compared to those who survived.

CONCLUSION AND SIGNIFICANCE

Post-discharge mortality was common in Bangladeshi children following inpatient care for severe malnutrition and pneumonia. The underlying contributing factors require a better understanding to inform the potential of interventions that could improve survival.

Respiratory risks from household air pollution in low and middle income countries

A third of the world's population uses solid fuel derived from plant material (biomass) or coal for cooking, heating, or lighting. These fuels are smoky, often used in an open fire or simple stove with incomplete combustion, and result in a large amount of household air pollution when smoke is poorly vented. Air pollution is the biggest environmental cause of death worldwide, with household air pollution accounting for about 3·5-4 million deaths every year. Women and children living in severe poverty have the greatest exposures to household air pollution. In this Commission, we review evidence for the association between household air pollution and respiratory infections, respiratory tract cancers, and chronic lung diseases. Respiratory infections (comprising both upper and lower respiratory tract infections with viruses, bacteria, and mycobacteria) have all been associated with exposure to household air pollution. Respiratory tract cancers, including both nasopharyngeal cancer and lung cancer, are strongly associated with pollution from coal burning and further data are needed about other solid fuels. Chronic lung diseases, including chronic obstructive pulmonary disease and bronchiectasis in women, are associated with solid fuel use for cooking, and the damaging effects of exposure to household air pollution in early life on lung development are yet to be fully described. We also review appropriate ways to measure exposure to household air pollution, as well as study design issues and potential effective interventions to prevent these disease burdens. Measurement of household air pollution needs individual, rather than fixed in place, monitoring because exposure varies by age, gender, location, and household role. Women and children are particularly susceptible to the toxic effects of pollution and are exposed to the highest concentrations. Interventions should target these high-risk groups and be of sufficient quality to make the air clean. To make clean energy available to all people is the long-term goal, with an intermediate solution being to make available energy that is clean enough to have a health impact.

Killed oral cholera vaccines: history, development and implementation challenges

Cholera is still a major global health problem, affecting mainly people living in unsanitary conditions and who are at risk for outbreaks of cholera. During the past decade, outbreaks are increasingly reported from more countries. From the early killed oral cholera vaccine, rapid improvements in vaccine development occurred as a result of a better understanding of the epidemiology of the disease, pathogenesis of cholera infection and immunity. The newer-generation oral killed cholera vaccines have been shown to be safe and effective in field trials conducted in cholera endemic areas. Likewise, they have been shown to be protective when used during outbreak settings. Aside from providing direct protection to vaccinated individuals, recent studies have demonstrated that these killed oral vaccines also confer indirect protection through herd immunity. Although new-generation oral cholera vaccines should not be considered in isolation from other preventive approaches in countries where they are most needed, especially improved water quality and sanitation, these vaccines serve as immediately available public health tools for preventing further morbidity and mortality from cholera. However, despite its availability for more than two decades, use of these vaccines has not been optimized. Although there are limitations of the currently available oral cholera vaccines, recent data show that the vaccines are safe, feasible to use even in difficult circumstances and able to provide protection in various settings. Clear identification of the areas and target population groups who will benefit from the use of the cholera vaccines will be required and strategies to facilitate accessibility and usage of these vaccines in these areas and population groups will need to be developed.

Dynamic changes in the Streptococcus pneumoniae transcriptome during transition from biofilm formation to invasive disease upon influenza A virus infection

Streptococcus pneumoniae is a leading cause of infectious disease globally. Nasopharyngeal colonization occurs in biofilms and precedes infection. Prior studies have indicated that biofilm-derived pneumococci are avirulent. However, influenza A virus (IAV) infection releases virulent pneumococci from biofilms in vitro and in vivo. Triggers of dispersal include IAV-induced changes in the nasopharynx, such as increased temperature (fever) and extracellular ATP (tissue damage). We used whole-transcriptome shotgun sequencing (RNA-seq) to compare the S. pneumoniae transcriptome in biofilms, bacteria dispersed from biofilms after exposure to IAV, febrile-range temperature, or ATP, and planktonic cells grown at 37°C. Compared with biofilm bacteria, actively dispersed S. pneumoniae, which were more virulent in invasive disease, upregulated genes involved in carbohydrate metabolism. Enzymatic assays for ATP and lactate production confirmed that dispersed pneumococci exhibited increased metabolism compared to those in biofilms. Dispersed pneumococci also upregulated genes associated with production of bacteriocins and downregulated colonization-associated genes related to competence, fratricide, and the transparent colony phenotype. IAV had the largest impact on the pneumococcal transcriptome. Similar transcriptional differences were also observed when actively dispersed bacteria were compared with avirulent planktonic bacteria. Our data demonstrate complex changes in the pneumococcal transcriptome in response to IAV-induced changes in the environment. Our data suggest that disease is caused by pneumococci that are primed to move to tissue sites with altered nutrient availability and to protect themselves from the nasopharyngeal microflora and host immune response. These data help explain pneumococcal virulence after IAV infection and have important implications for studies of S. pneumoniae pathogenesis.

The role of influenza in the severity and transmission of respiratory bacterial disease

Infections with influenza viruses and respiratory bacteria each contribute substantially to the global burden of morbidity and mortality. Simultaneous or sequential infection with these pathogens manifests in complex and difficult-to-treat disease processes that need extensive antimicrobial therapy and cause substantial excess mortality, particularly during annual influenza seasons and pandemics. At the host level, influenza viruses prime respiratory mucosal surfaces for excess bacterial acquisition and this supports increased carriage density and dissemination to the lower respiratory tract, while greatly constraining innate and adaptive antibacterial defences. Driven by virus-mediated structural modifications, aberrant immunological responses to sequential infection, and excessive immunopathological responses, co-infections are noted by short-term and long-term departures from immune homoeostasis, inhibition of appropriate pathogen recognition, loss of tolerance to tissue damage, and general increases in susceptibility to severe bacterial disease. At the population level, these effects translate into increased horizontal bacterial transmission and excess use of antimicrobial therapies. With increasing concerns about future possible influenza pandemics, the past decade has seen rapid advances in our understanding of these interactions. In this Review, we discuss the epidemiological and clinical importance of influenza and respiratory bacterial co-infections, including the foundational efforts that laid the groundwork for today's investigations, and detail the most important and current advances in our understanding of the structural and immunological mechanisms underlying the pathogenesis of co-infection. We describe and interpret what is known in sequence, from transmission and phenotypic shifts in bacterial dynamics to the immunological, cellular, and molecular modifications that underlie these processes, and propose avenues of further research that might be most valuable for prevention and treatment strategies to best mitigate excess disease during future influenza pandemics.

Tropical influenza and weather variability among children in an urban low-income population in Bangladesh

Background

Influenza seasonality in the tropics is poorly understood and not as well documented as in temperate regions. In addition, low-income populations are considered highly vulnerable to such acute respiratory disease, owing to limited resources and overcrowding. Nonetheless, little is known about their actual disease burden for lack of data. We therefore investigated associations between tropical influenza incidence and weather variability among children under five in a poor urban area of Dhaka, Bangladesh.

Design

Acute respiratory illness data were obtained from a population-based respiratory and febrile illness surveillance dataset of Kamalapur, a low-income urban area in southeast Dhaka. Analyzed data were from January 2005 through December 2008. Nasopharyngeal wash specimens were collected from every fifth eligible surveillance participant during clinic visits to identify influenza virus infection with viral culture and reverse transcriptase–polymerase chain reaction. Time series analysis was conducted to determine associations between the number of influenza cases per week and weather factors. Zero-inflated Poisson and generalized linear Poisson models were used in the analysis for influenza A and B, respectively.

Results

Influenza A had associations with minimum temperature, relative humidity (RH), sunlight duration, and rainfall, whereas only RH was associated with influenza B. Although associations of the other weather factors varied between the two subtypes, RH shared a similar positive association when humidity was approximately 50–70%.

Conclusions

Our findings of a positive RH association is consistent with prior studies, and may suggest the viral response in the tropics. The characteristics of settlement areas, population demographics, and typical overcrowding of urban poverty may also contribute to different impacts of rainfall from higher economic population. Further investigations of associations between tropical influenza and weather variability for urban low-income populations are required for better understanding.

Cryptosporidiumspecies in humans and animals: current understanding and research needs

Cryptosporidiumis increasingly recognized as one of the major causes of moderate to severe diarrhoea in developing countries. With treatment options limited, control relies on knowledge of the biology and transmission of the members of the genus responsible for disease. Currently, 26 species are recognized as valid on the basis of morphological, biological and molecular data. Of the nearly 20Cryptosporidiumspecies and genotypes that have been reported in humans,Cryptosporidium hominisandCryptosporidium parvumare responsible for the majority of infections. Livestock, particularly cattle, are one of the most important reservoirs of zoonotic infections. Domesticated and wild animals can each be infected with severalCryptosporidiumspecies or genotypes that have only a narrow host range and therefore have no major public health significance. Recent advances in next-generation sequencing techniques will significantly improve our understanding of the taxonomy and transmission ofCryptosporidiumspecies, and the investigation of outbreaks and monitoring of emerging and virulent subtypes. Important research gaps remain including a lack of subtyping tools for manyCryptosporidiumspecies of public and veterinary health importance, and poor understanding of the genetic determinants of host specificity ofCryptosporidiumspecies and impact of climate change on the transmission ofCryptosporidium.

Decline in severe diarrhea hospitalizations after the introduction of rotavirus vaccination in Ghana: a prevalence study

BACKGROUND

Almost all diarrhea deaths in young children occur in developing countries. Immunization against rotavirus, the leading cause of childhood severe dehydrating acute diarrhea may reduce the burden of severe diarrhea in developing countries. Ghana introduced rotavirus and pneumococcal vaccination in the national expanded program on immunization in May 2012.

METHODS

Review of all-cause diarrheal hospitalization data for children aged 59 months and younger at 2 pediatric referral hospitals in southern Ghana from 2008 to 2014. The proportion of acute diarrhea (defined as 3 or more watery, non-bloody stools within 24 hours that has lasted for less than 7 days) cases caused by rotavirus was determined. Temporal trend and age group distribution of all-cause diarrhea and rotavirus gastroenteritis before and after introduction of the new vaccines were compared.

RESULTS

Of the 5847 children hospitalized with all-cause diarrhea during the 74 months (January 2008 - February 2014), 3963 (67.8%) children were recruited for rotavirus surveillance and stool specimens were tested for rotavirus in 3160/3963 (79.7%). Median monthly hospitalization for all-cause diarrhea reduced from 84 [interquartile range (IQR) 62 - 105] during the 52 months pre-vaccination introduction to 46 (IQR 42 - 57) in the 22 months after implementation of vaccination. Significant decline in all-cause diarrhea hospitalization occurred in children aged 0 - 11 months: 56.3% (2711/4817) vs. 47.2% 486/1030 [p = 0.0001, 95% confidence interval (CI) 0.77 - 0.88] and there was significant reduction of rotavirus gastroenteritis hospitalization: 49.7% (1246/2505) vs. 27.8% (182/655) [p = 0.0001, 95% CI 0.32 - 0.47] before and after vaccine introduction respectively.

CONCLUSIONS

Implementation of rotavirus vaccination program may have resulted in significant reduction of severe diarrhea hospitalization even though this observational study could not exclude the effect of other confounding factors. Continued surveillance is recommended to monitor the progress of this program.

Spatiotemporal pattern of bacillary dysentery in China from 1990 to 2009: what is the driver behind?

Background

Little is known about the spatiotemporal pattern of bacillary dysentery (BD) in China. This study assessed the geographic distribution and seasonality of BD in China over the past two decades.

Methods

Data on monthly BD cases in 31 provinces of China from January 1990 to December 2009 obtained from Chinese Center for Disease Control and Prevention, and data on demographic and geographic factors, as well as climatic factors, were compiled. The spatial distributions of BD in the four periods across different provinces were mapped, and heat maps were created to present the seasonality of BD by geography. A cosinor function combined with Poisson regression was used to quantify the seasonal parameters of BD, and a regression analysis was conducted to identify the potential drivers of morbidity and seasonality of BD.

Results

Although most regions of China have experienced considerable declines in BD morbidity over the past two decades, Beijing and Ningxia still had high BD morbidity in 2009. BD morbidity decreased more slowly in North-west China than other regions. BD in China mainly peaked from July to September, with heterogeneity in peak time between regions. Relative humidity was associated with BD morbidity and peak time, and latitude was the major predictor of BD amplitude.

Conclusions

The transmission of BD was heterogeneous in China. Improved sanitation and hygiene in North-west China, and better access to clean water and food in the big floating population in some metropolises could be the focus of future preventive interventions against BD. BD control efforts should put more emphasis on those dry areas in summer.

Overlapping functionality of the Pht proteins in zinc homeostasis of Streptococcus pneumoniae

Streptococcus pneumoniae is a globally significant pathogen that causes a range of diseases, including pneumonia, sepsis, meningitis, and otitis media. Its ability to cause disease depends upon the acquisition of nutrients from its environment, including transition metal ions such as zinc. The pneumococcus employs a number of surface proteins to achieve this, among which are four highly similar polyhistidine triad (Pht) proteins. It has previously been established that these proteins collectively aid in the delivery of zinc to the ABC transporter substrate-binding protein AdcAII. Here we have investigated the contribution of each individual Pht protein to pneumococcal zinc homeostasis by analyzing mutant strains expressing only one of the four pht genes. Under conditions of low zinc availability, each of these mutants showed superior growth and zinc accumulation profiles relative to a mutant strain lacking all four genes, indicating that any of the four Pht proteins are able to facilitate delivery of zinc to AdcAII. However, optimal growth and zinc accumulation in vitro and pneumococcal survival and proliferation in vivo required production of all four Pht proteins, indicating that, despite their overlapping functionality, the proteins are not dispensable without incurring a fitness cost. We also show that surface-attached forms of the Pht proteins are required for zinc recruitment and that they do not contribute to defense against extracellular zinc stress.

The geographical co-distribution and socio-ecological drivers of childhood pneumonia and diarrhoea in Queensland, Australia

SUMMARY This study aimed to explore the spatio-temporal patterns, geographical co-distribution, and socio-ecological drivers of childhood pneumonia and diarrhoea in Queensland. A Bayesian conditional autoregressive model was used to quantify the impacts of socio-ecological factors on both childhood pneumonia and diarrhoea at a postal area level. A distinct seasonality of childhood pneumonia and diarrhoea was found. Childhood pneumonia and diarrhoea were mainly distributed in the northwest of Queensland. Mount Isa city was the high-risk cluster where childhood pneumonia and diarrhoea co-distributed. Emergency department visits (EDVs) for pneumonia increased by 3% per 10-mm increase in monthly average rainfall in wet seasons. By comparison, a 10-mm increase in monthly average rainfall may cause an increase of 4% in EDVs for diarrhoea. Monthly average temperature was negatively associated with EDVs for childhood diarrhoea in wet seasons. Low socioeconomic index for areas (SEIFA) was associated with high EDVs for childhood pneumonia. Future pneumonia and diarrhoea prevention and control measures in Queensland should focus more on Mount Isa.

The syndemics of childhood diarrhoea: a biosocial perspective on efforts to combat global inequities in diarrhoea-related morbidity and mortality

Diarrhoea remains the second leading cause of death in children under 5 years. Moreover, morbidity as a result of diarrhoea is high particularly in marginalised communities. Frequent bouts of diarrhoea have deleterious and irreversible effects on physical and cognitive development. Children are especially vulnerable given their inability to mount an active immune response to pathogen exposure. Biological limitations are exacerbated by the long-term effects of poverty, including reduced nutrition, poor hygiene and deprived home environments. Drawing from available literature, this paper uses syndemic theory to explore the role of adverse biosocial interactions in increasing the total disease burden of enteric infections in low-resources populations and assesses the limitations of recent global calls to action. The syndemic perspective describes situations in which adverse social conditions, including inequality, poverty and other forms of political and economic oppression, play a critical role in facilitating disease-disease interactions. Given the complex micro- and macro-nature of childhood diarrhoea, including interactions between pathogens, disease conditions and social environments, the syndemic perspective offers a way forward. While rarely the focus of health interventions, technologically advanced biomedical strategies are likely to be more effective if coupled with interventions that address the social conditions of disparity.

Randomised controlled trials in child health in developing countries: trends and lessons over 11 years

Using a uniform systematic approach annually, we reviewed 1553 publications from randomised controlled trials in child health in developing countries published between July 2002 and June 2013. There were annual increases in such publications, from 38 in the 12 months to July 2003 to over 200 in each of 2012 and 2013. These trials involved children in 76 developing countries. Studies of nutrition (366 publications, 23.6%) and malaria (336 publications, 21%) predominated. 79% of nutrition trials have been of micronutrients (288 publications), with comparatively few publications related to macronutrient interventions or complimentary feeding (48 publications) or measures to improve breast feeding (20 publications). Trials of malaria have involved a comprehensive range of treatment and preventive strategies and have heralded the implementation of new interventions as routine health strategies, and reductions in malaria in each affected country in the world in the last decade. There have been a relatively small number of trials of interventions for treatment or prevention of acute respiratory infection (98 publications, 6.3%), neonatal health (64 publications, 4.1%) and tuberculosis in children (26 publications, 1.7%). In the last 5 years there has been increasing focus on non-communicable diseases such as asthma and allergy, obesity, diabetes and cardiac disease, and behavioural-developmental disorders. Mental health conditions have received little attention (21 publications, 1.4% of publications). There is increasing research activity and capacity in child health in developing countries. Some areas have been the subject of a large amount of research, and have led to the design and implementation of effective public health interventions and reduced disease burdens, while in other areas comprehensive approaches and the systematic application of research findings have been lacking.

Systematic review on antibiotic therapy for pneumonia in children between 2 and 59 months of age

Community-acquired pneumonia (CAP) remains a force to reckon with, as it accounts for 1.1 million of all deaths in children less than 5 years of age globally, with disproportionately higher mortality occurring in the low and middle income-countries (LMICs) of Southeast Asia and Africa. Existing strategies to curb pneumonia-related morbidity and mortality have not effectively translated into meaningful control of pneumonia-related burden. In the present systematic review, we conducted a meta-analysis of trials conducted in LMICs to determine the most suitable antibiotic therapy for treating pneumonia (very severe, severe and non-severe). While previous reviews, including the most recent review by Lodha et al, have focused either on single modality of antibiotic therapy (such as choice of antibiotic) or children under the age of 16 years, the current review updates evidence on the choice of drug, duration, route and combination of antibiotics in children specifically between 2 and 59 months of age. We included randomised controlled trials (RCTs) and quasi-RCTs that assessed the route, dose, combination and duration of antibiotics in the management of WHO-defined very severe/severe/non-severe CAP. Study participants included children between 2 and 59 months of age with CAP. All available titles and abstracts were screened for inclusion by two review authors independently. All data was entered and analysed using Review Manager 5 software. The review identified 8122 studies on initial search, of which 22 studies which enrolled 20,593 children were included in meta-analyses. Evidence from these trials showed a combination of penicillin/ampicillin and gentamicin to be effective for managing very severe pneumonia in children between 2 and 59 months of age, and oral amoxicillin to be equally efficacious, as other parenteral antibiotics for managing severe pneumonia in children of this particular age group. Oral amoxicillin was also found to be effective in non-severe pneumonia as well. The review further found a short 3 day course of antibiotics to be equally beneficial as 5 day course for managing non-severe pneumonia in children between 2 and 59 months of age. This review updates evidence on the general spectrum of antibiotic recommendation for CAP in children between 2 and 59 months of age, which is an age group that warrants special focus owing to its high disease and mortality burden. Evidence derived from the review found oral amoxicillin to be equally effective as parenteral antibiotics for severe pneumonia in the 2-59 month age group, which holds important implications for LMICs where parenteral drug administration is an issue. Also, the review's finding that 3 day course of antibiotic is equally effective as 5 day course for non-severe pneumonia for 2-59 months of age is again beneficial for LMICs, as a shorter therapy will be associated with a lower cost. The review addresses some research gaps in antibiotic treatment for CAP as well, and this crucial information is presented with the aim of providing a targeted cure for the middle and low income setting.

Lactobacillus reuteri DSM 17938 effectively reduces the duration of acute diarrhoea in hospitalised children

AIM

Guidelines consider certain probiotics useful in the management of acute gastroenteritis. This study evaluated the use of Lactobacillus (L) reuteri DSM 17938.

METHODS

A multicentre, randomised, single-blind clinical trial was performed in hospitalised children with acute gastroenteritis lasting 12-72 h. Children received conventional therapy with, or without, 1 × 10(8) CFU of L. reuteri DSM 17938 for 5 days. The primary endpoint was the duration of diarrhoea and secondary outcomes were days of hospitalisation and the percentage of children with diarrhoea after each day of treatment.

RESULTS

We compared 64 children receiving L. reuteri with 63 controls. Lactobacillus reuteri reduced the duration of diarrhoea after 24 h (p < 0.001) and more diarrhoea-free children were seen in the L. reuteri than control group after 24 and 48 h (50% versus 5%, p < 0.001) and 72 h (69% versus 11%, p < 0.001). Lactobacillus reuteri reduced mean hospital stays (4.31 ± 1.3 days versus 5.46 ± 1.77 days, p < 0.001). Prolonged diarrhoea occurred in 17% of the controls, but none of the L. reuteri group. No adverse effects were reported.

CONCLUSION

Lactobacillus reuteri effectively reduced the duration of acute diarrhoea and hospital stays in children hospitalised with acute gastroenteritis. Outpatient data are now required.

Impact of temperature on childhood pneumonia estimated from satellite remote sensing

The effect of temperature on childhood pneumonia in subtropical regions is largely unknown so far. This study examined the impact of temperature on childhood pneumonia in Brisbane, Australia. A quasi-Poisson generalized linear model combined with a distributed lag non-linear model was used to quantify the main effect of temperature on emergency department visits (EDVs) for childhood pneumonia in Brisbane from 2001 to 2010. The model residuals were checked to identify added effects due to heat waves or cold spells. Both high and low temperatures were associated with an increase in EDVs for childhood pneumonia. Children aged 2-5 years, and female children were particularly vulnerable to the impacts of heat and cold, and Indigenous children were sensitive to heat. Heat waves and cold spells had significant added effects on childhood pneumonia, and the magnitude of these effects increased with intensity and duration. There were changes over time in both the main and added effects of temperature on childhood pneumonia. Children, especially those female and Indigenous, should be particularly protected from extreme temperatures. Future development of early warning systems should take the change over time in the impact of temperature on children's health into account.

Quantifying and exploiting the age dependence in the effect of supplementary food for child undernutrition

Motivated by the lack of randomized controlled trials with an intervention-free control arm in the area of child undernutrition, we fit a trivariate model of weight-for-age z score (WAZ), height-for-age z score (HAZ) and diarrhea status to data from an observational study of supplementary feeding (100 kCal/day for children with WAZ ) in 17 Guatemalan communities. Incorporating time lags, intention to treat (i.e., to give supplementary food), seasonality and age interactions, we estimate how the effect of supplementary food on WAZ, HAZ and diarrhea status varies with a child’s age. We find that the effect of supplementary food on all 3 metrics decreases linearly with age from 6 to 20 mo and has little effect after 20 mo. We derive 2 food allocation policies that myopically (i.e., looking ahead 2 mo) minimize either the underweight or stunting severity – i.e., the sum of squared WAZ or HAZ scores for all children with WAZ or HAZ . A simulation study based on the statistical model predicts that the 2 derived policies reduce the underweight severity (averaged over all ages) by 13.6–14.1% and reduce the stunting severity at age 60 mo by 7.1–8.0% relative to the policy currently in use, where all policies have a budget that feeds % of children. While these findings need to be confirmed on additional data sets, it appears that in a low-dose (100 kCal/day) supplementary feeding setting in Guatemala, allocating food primarily to 6–12 mo infants can reduce the severity of underweight and stunting.

Viral etiologies of hospitalized acute lower respiratory infection patients in China, 2009-2013

BACKGROUND

Acute lower respiratory infections (ALRIs) are an important cause of acute illnesses and mortality worldwide and in China. However, a large-scale study on the prevalence of viral infections across multiple provinces and seasons has not been previously reported from China. Here, we aimed to identify the viral etiologies associated with ALRIs from 22 Chinese provinces.

METHODS AND FINDINGS

Active surveillance for hospitalized ALRI patients in 108 sentinel hospitals in 24 provinces of China was conducted from January 2009-September 2013. We enrolled hospitalized all-age patients with ALRI, and collected respiratory specimens, blood or serum collected for diagnostic testing for respiratory syncytial virus (RSV), human influenza virus, adenoviruses (ADV), human parainfluenza virus (PIV), human metapneumovirus (hMPV), human coronavirus (hCoV) and human bocavirus (hBoV). We included 28,369 ALRI patients from 81 (of the 108) sentinel hospitals in 22 (of the 24) provinces, and 10,387 (36.6%) were positive for at least one etiology. The most frequently detected virus was RSV (9.9%), followed by influenza (6.6%), PIV (4.8%), ADV (3.4%), hBoV (1.9), hMPV (1.5%) and hCoV (1.4%). Co-detections were found in 7.2% of patients. RSV was the most common etiology (17.0%) in young children aged <2 years. Influenza viruses were the main cause of the ALRIs in adults and elderly. PIV, hBoV, hMPV and ADV infections were more frequent in children, while hCoV infection was distributed evenly in all-age. There were clear seasonal peaks for RSV, influenza, PIV, hBoV and hMPV infections.

CONCLUSIONS

Our findings could serve as robust evidence for public health authorities in drawing up further plans to prevent and control ALRIs associated with viral pathogens. RSV is common in young children and prevention measures could have large public health impact. Influenza was most common in adults and influenza vaccination should be implemented on a wider scale in China.

Influenza and other respiratory viruses involved in severe acute respiratory disease in northern Italy during the pandemic and postpandemic period (2009-2011)

Since 2009 pandemic, international health authorities recommended monitoring severe and complicated cases of respiratory disease, that is, severe acute respiratory infection (SARI) and acute respiratory distress syndrome (ARDS). We evaluated the proportion of SARI/ARDS cases and deaths due to influenza A(H1N1)pdm09 infection and the impact of other respiratory viruses during pandemic and postpandemic period (2009-2011) in northern Italy; additionally we searched for unknown viruses in those cases for which diagnosis remained negative. 206 respiratory samples were collected from SARI/ARDS cases and analyzed by real-time RT-PCR/PCR to investigate influenza viruses and other common respiratory pathogens; also, a virus discovery technique (VIDISCA-454) was applied on those samples tested negative to all pathogens. Influenza A(H1N1)pdm09 virus was detected in 58.3% of specimens, with a case fatality rate of 11.3%. The impact of other respiratory viruses was 19.4%, and the most commonly detected viruses were human rhinovirus/enterovirus and influenza A(H3N2). VIDISCA-454 enabled the identification of one previously undiagnosed measles infection. Nearly 22% of SARI/ARDS cases did not obtain a definite diagnosis. In clinical practice, great efforts should be dedicated to improving the diagnosis of severe respiratory disease; the introduction of innovative molecular technologies, as VIDISCA-454, will certainly help in reducing such "diagnostic gap."

Temperature variability and childhood pneumonia: an ecological study

BACKGROUND

Few data on the relationship between temperature variability and childhood pneumonia are available. This study attempted to fill this knowledge gap.

METHODS

A quasi-Poisson generalized linear regression model combined with a distributed lag non-linear model was used to quantify the impacts of diurnal temperature range (DTR) and temperature change between two neighbouring days (TCN) on emergency department visits (EDVs) for childhood pneumonia in Brisbane, from 2001 to 2010, after controlling for possible confounders.

RESULTS

An adverse impact of TCN on EDVs for childhood pneumonia was observed, and the magnitude of this impact increased from the first five years (2001-2005) to the second five years (2006-2010). Children aged 5-14 years, female children and Indigenous children were particularly vulnerable to TCN impact. However, there was no significant association between DTR and EDVs for childhood pneumonia.

CONCLUSIONS

As climate change progresses, the days with unstable weather pattern are likely to increase. Parents and caregivers of children should be aware of the high risk of pneumonia posed by big TCN and take precautionary measures to protect children, especially those with a history of respiratory diseases, from climate impacts.

Impact of experimental human pneumococcal carriage on nasopharyngeal bacterial densities in healthy adults

Colonization of the nasopharynx by Streptococcus pneumoniae is a necessary precursor to pneumococcal diseases that result in morbidity and mortality worldwide. The nasopharynx is also host to other bacterial species, including the common pathogens Staphylococcus aureus, Haemophilus influenzae, and Moraxella catarrhalis. To better understand how these bacteria change in relation to pneumococcal colonization, we used species-specific quantitative PCR to examine bacterial densities in 52 subjects 7 days before, and 2, 7, and 14 days after controlled inoculation of healthy human adults with S. pneumoniae serotype 6B. Overall, 33 (63%) of subjects carried S. pneumoniae post-inoculation. The baseline presence and density of S. aureus, H. influenzae, and M. catarrhalis were not statistically associated with likelihood of successful pneumococcal colonization at this study’s sample size, although a lower rate of pneumococcal colonization in the presence of S. aureus (7/14) was seen compared to that in the presence of H. influenzae (12/16). Among subjects colonized with pneumococci, the number also carrying either H. influenzae or S. aureus fell during the study and at 14 days post-inoculation, the proportion carrying S. aureus was significantly lower among those who were colonized with S. pneumoniae (p = 0.008) compared to non-colonized subjects. These data on bacterial associations are the first to be reported surrounding experimental human pneumococcal colonization and show that co-colonizing effects are likely subtle rather than absolute.

Respiratory syncytial virus transplacental antibody transfer and kinetics in mother-infant pairs in Bangladesh

BACKGROUND

Pneumonia is the leading cause of childhood mortality globally. Respiratory syncytial virus (RSV) is the most important viral cause of pneumonia. Maternal serum antibody protects infants from RSV disease. The objective of our study was to characterize RSV antibody levels in mother-infant pairs.

METHODS

Serial serum samples were collected from mother-infant pairs in Bangladesh from the third trimester of pregnancy to 72 weeks postpartum and tested using an RSV antibody microneutralization assay. Serologic infection was defined as a 4-fold increase in antibody titer. Maternal antibody half-life was calculated using infant antibody titers from birth to 20 weeks.

RESULTS

The ratio of infant cord blood to maternal serum RSV antibody titers in 149 mother-infant pairs was 1.01 (95% confidence interval [CI], .99-1.03). Maternal RSV antibody titers in the third trimester and at birth were strongly correlated (R = 0.68). Antibody half-life was 38 days (95% CI, 36-42 days). Higher cord blood RSV antibody titers were associated with a lower risk of serologic infection (P = .01) and maintenance of antibody titer above a potentially protective threshold (P < .001).

CONCLUSIONS

Efficient transplacental transfer of RSV-specific antibody from mother to the fetus was documented in mother-infant pairs in Asia. Higher cord blood antibody titers were associated with protection from serologic infection.

Prebiotics in healthy infants and children for prevention of acute infectious diseases: a systematic review and meta-analysis

Prebiotics, defined as nondigestible dietary ingredients resistant to gastric acidity and fermented by the intestinal flora, are used to positively influence the composition of intestinal flora, thereby promoting health benefits. The objective of this systematic review was to assess the efficacy of prebiotics in the prevention of acute infectious diseases in children. A systematic literature search was conducted using the Ovid Medline, Scopus, Web of Science, and Cochrane Library's Central databases. Finally, five randomized controlled trials, all of them investigating infants and children 0-24 months of age, were included in the review. Pooled estimates from three studies revealed a statistically significant decrease in the number of infectious episodes requiring antibiotic therapy in the prebiotic group as compared with the placebo group (rate ratio 0.68; 95% confidence interval 0.61-0.77). Studies available indicate that prebiotics may also be effective in decreasing the rate of overall infections in infants and children 0-24 months of age. Further studies in the age group 3-18 years are required to determine whether prebiotics can be considered for the prevention of acute infectious diseases in the older pediatric population.

Effect of non-stationary climate on infectious gastroenteritis transmission in Japan

Local weather factors are widely considered to influence the transmission of infectious gastroenteritis. Few studies, however, have examined the non-stationary relationships between global climatic factors and transmission of infectious gastroenteritis. We analyzed monthly data for cases of infectious gastroenteritis in Fukuoka, Japan from 2000 to 2012 using cross-wavelet coherency analysis to assess the pattern of associations between indices for the Indian Ocean Dipole (IOD) and El Niño Southern Oscillation (ENSO). Infectious gastroenteritis cases were non-stationary and significantly associated with the IOD and ENSO (Multivariate ENSO Index [MEI], Niño 1 + 2, Niño 3, Niño 4, and Niño 3.4) for a period of approximately 1 to 2 years. This association was non-stationary and appeared to have a major influence on the synchrony of infectious gastroenteritis transmission. Our results suggest that non-stationary patterns of association between global climate factors and incidence of infectious gastroenteritis should be considered when developing early warning systems for epidemics of infectious gastroenteritis.

Systematic review of the economic value of diarrheal vaccines

Diarrheal disease is a leading cause of child mortality in low-income settings and morbidity across a range of settings. A growing number of studies have addressed the economic value of new and emerging vaccines to reduce this threat. We conducted a systematic review to assess the economic value of diarrheal vaccines targeting a range of pathogens in different settings. The majority of studies focused on the economic value of rotavirus vaccines in different settings, with most of these concluding that vaccination would provide significant economic benefits across a range of vaccine prices. There is also evidence of the economic benefits of cholera vaccines in specific contexts. For other potential diarrheal vaccines data are limited and often hypothetical. Across all target pathogens and contexts, the evidence of economic value focuses the short-term health and economic gains. Additional information is needed on the broader social and long-term economic value of diarrhea vaccines.

Antibiotic therapy versus no antibiotic therapy for children aged two to 59 months with WHO-defined non-severe pneumonia and wheeze

BACKGROUND

Worldwide, pneumonia is the leading cause of death among children under five years of age and accounts for approximately two million deaths annually. The World Health Organization (WHO) has developed case management guidelines based on simple clinical signs to help clinicians decide on the appropriate pneumonia treatment. Children and infants who exhibit fast breathing (50 breaths per minute or more in infants two months to 12 months of age and 40 or more in children 12 months to five years of age) and cough are presumed to have non-severe pneumonia and the WHO recommends antibiotics. Implementation of these guidelines to identify and manage pneumonia at the community level has been shown to reduce acute respiratory infection (ARI)-related mortality by 36%, although apprehension exists regarding these results due to the questionable quality of evidence. As WHO guidelines do not make a distinction between viral and bacterial pneumonia, these children continue to receive antibiotics because of the concern that it may not be safe to do otherwise. Therefore, it is essential to explore the role of antibiotics in children with WHO-defined non-severe pneumonia and wheeze and to develop effective guidelines for initial antibiotic treatment.

OBJECTIVES

To evaluate the efficacy of antibiotic therapy versus no antibiotic therapy for children aged two to 59 months with WHO-defined non-severe pneumonia and wheeze.

SEARCH METHODS

We searched CENTRAL (2014, Issue 1), MEDLINE (1946 to March week 3, 2014), EMBASE (January 2010 to March 2014), CINAHL (1981 to March 2014), LILACS (1982 to March 2014), Networked Digital Library of Theses and Dissertations (23 July 2013) and Web of Science (1985 to March 2014).

SELECTION CRITERIA

Randomised controlled trials (RCTs) evaluating the efficacy of antibiotic therapy versus no antibiotic therapy for children aged two to 59 months with non-severe pneumonia and wheeze. We considered studies that defined non-severe pneumonia as cough or difficulty in breathing with a respiratory rate above the WHO-defined age-specific values (respiratory rate of 50 breaths per minute or more for children aged two to 12 months, or a respiratory rate of 40 breaths per minute or more for children aged 12 to 59 months) and wheeze for inclusion. We have excluded non-RCTs (quasi-RCTs).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the search results and extracted data.

MAIN RESULTS

We did not identify any study that completely fulfilled our inclusion criteria.

AUTHORS' CONCLUSIONS

There is a clear need for RCTs to address this question in representative populations. We do not currently have evidence to support or challenge the continued use of antibiotics for the treatment of non-severe pneumonia, as suggested by WHO guidelines.

Village-randomized clinical trial of home distribution of zinc for treatment of childhood diarrhea in rural Western kenya

Background

Zinc treatment shortens diarrhea episodes and can prevent future episodes. In rural Africa, most children with diarrhea are not brought to health facilities. In a village-randomized trial in rural Kenya, we assessed if zinc treatment might have a community-level preventive effect on diarrhea incidence if available at home versus only at health facilities.

Methods

We randomized 16 Kenyan villages (1,903 eligible children) to receive a 10-day course of zinc and two oral rehydration solution (ORS) sachets every two months at home and 17 villages (2,241 eligible children) to receive ORS at home, but zinc at the health–facility only. Children’s caretakers were educated in zinc/ORS use by village workers, both unblinded to intervention arm. We evaluated whether incidence of diarrhea and acute lower respiratory illness (ALRI) reported at biweekly home visits and presenting to clinic were lower in zinc villages, using poisson regression adjusting for baseline disease rates, distance to clinic, and children’s age.

Results

There were no differences between village groups in diarrhea incidence either reported at the home or presenting to clinic. In zinc villages (1,440 children analyzed), 61.2% of diarrheal episodes were treated with zinc, compared to 5.4% in comparison villages (1,584 children analyzed, p<0.0001). There were no differences in ORS use between zinc (59.6%) and comparison villages (58.8%). Among children with fever or cough without diarrhea, zinc use was low (<0.5%). There was a lower incidence of reported ALRI in zinc villages (adjusted RR 0.68, 95% CI 0.46–0.99), but not presenting at clinic.

Conclusions

In this study, home zinc use to treat diarrhea did not decrease disease rates in the community. However, with proper training, availability of zinc at home could lead to more episodes of pediatric diarrhea being treated with zinc in parts of rural Africa where healthcare utilization is low.

Trial Registration

ClinicalTrials.gov NCT00530829

Recent advances in understanding the long-term sequelae of childhood infectious diarrhea

Worldwide, early childhood infectious diarrhea continues to be a significant concern. Diarrheal illness affects the world's youngest and most vulnerable citizens disproportionately. Estimates are that over 70 % of deaths from diarrhea occur in people younger than 24 months of age. Diarrhea and environmental enteropathy have been associated with growth failure and stunting. In addition, the burden of enteric disease also leads to cognitive and academic losses, thus resulting in loss of human capital and economic productivity. While considerable progress has been made on preventing and treating childhood diarrheal illness, the mortality and morbidity still remain unacceptably high. This paper reviews recent (mainly from 2013) publications surrounding the global burden of childhood diarrhea and the implications for long-term sequelae.

Household effectiveness vs. laboratory efficacy of point-of-use chlorination

Treatment of water at the household level offers a promising approach to combat the global burden of diarrheal diseases. In particular, chlorination of drinking water has been a widely promoted strategy due to persistence of residual chlorine after initial treatment. However, the degree to which chlorination can reduce microbial levels in a controlled setting (efficacy) or in a household setting (effectiveness) can vary as a function of chlorine characteristics, source water characteristics, and household conditions. To gain more understanding of these factors, we carried out an observational study within households in rural communities of northern coastal Ecuador. We found that the efficacy of chlorine treatment under controlled conditions was significantly better than its household effectiveness when evaluated both by ability to meet microbiological safety standards and by log reductions. Water treated with chlorine achieved levels of microbial contamination considered safe for human consumption after 24 h of storage in the household only 39-51% of the time, depending on chlorine treatment regimen. Chlorine treatment would not be considered protective against diarrheal disease according to WHO log reduction standards. Factors that explain the observed compromised effectiveness include: source water turbidity, source water baseline contamination levels, and in-home contamination. Water in 38% of the households that had low turbidity source water (<10 NTU) met the safe water standard as compared with only 17% of the households that had high turbidity source water (>10 NTU). A 10 MPN/100 mL increase in baseline Escherichia coli levels was associated with a 2.2% increase in failure to meet the E. coli standard. Higher mean microbial contamination levels were seen in 54% of household samples in comparison to their matched controls, which is likely the result of in-home contamination during storage. Container characteristics (size of the container mouth) did not influence chlorine effectiveness. We found no significant differences between chlorine treatment regimens in ability to meet the safe water standards or in overall log reductions, although chlorine dosage did modify the effect of source conditions. These results underscore the importance of measuring both source water and household conditions to determine appropriate chlorine levels, as well as to evaluate the appropriateness of chlorine treatment and other point-of-use water quality improvement interventions.