Early-life rotavirus and norovirus infections in relation to development of atopic manifestation in infants

Burden and Subtypes of Early Life Infections Increase the Risk of Asthma

BACKGROUND

Early life respiratory tract infections have been linked to the development of asthma, but studies on the burden and subtypes of common infections in asthma development are sparse.

OBJECTIVE

To examine the association between burden of early life infections, including subtypes, with the risk of asthma from age 3 to 10 years and lung function at age 10 years.

METHODS

We included 662 children from the Copenhagen Prospective Studies on Asthma in Childhood 2010 birth cohort, for whom infections such as colds, acute tonsillitis, acute otitis media, pneumonia, gastroenteritis, and fever were registered prospectively in daily diaries at age 0 to 3 years and asthma was diagnosed longitudinally from age 3 to 10 years. The association between the burden of infection and subtypes and risk of asthma was analyzed by generalized estimating equations.

RESULTS

The children experienced a median of 16 infections (interquartile range, 12-23 infections) at age 0 to 3 years. Children with a high burden of infections (above the median) had an increased risk of asthma at age 3 to 10 years (adjusted odds ratio = 3.61; 95% CI, 2.39-5.45; P < .001), which was driven by colds, pneumonia, gastroenteritis, and fever episodes (P < .05) but not by acute otitis media and tonsillitis. Lower lung function measures at age 10 years were associated with the burden of pneumonia but not the overall infection burden. The association between colds and the risk of asthma was significantly higher in children with allergic rhinitis at age 6 years (P interaction = .032).

CONCLUSION

A high burden of early life infections in terms of colds, pneumonia, gastroenteritis, and fever is associated with an increased risk of developing asthma, particularly in children with respiratory allergy. Strategies to diminish these early life infections may offer a path for the primary prevention of childhood asthma.

Risk Factors Affecting Development and Persistence of Preschool Wheezing: Consensus Document of the Emilia-Romagna Asthma (ERA) Study Group

Wheezing at preschool age (i.e., before the age of six) is common, occurring in about 30% of children before the age of three. In terms of health care burden, preschool children with wheeze show double the rate of access to the emergency department and five times the rate of hospital admissions compared with school-age asthmatics. The consensus document aims to analyse the underlying mechanisms involved in the pathogenesis of preschool wheezing and define the risk factors (i.e., allergy, atopy, infection, bronchiolitis, genetics, indoor and outdoor pollution, tobacco smoke exposure, obesity, prematurity) and the protective factors (i.e., probiotics, breastfeeding, vitamin D, influenza vaccination, non-specific immunomodulators) associated with the development of the disease in the young child. A multidisciplinary panel of experts from the Emilia-Romagna Region, Italy, addressed twelve key questions regarding managing preschool wheezing. Clinical questions have been formulated by the expert panel using the PICO format (Patients, Intervention, Comparison, Outcomes). Systematic reviews have been conducted on PubMed to answer these specific questions and formulate recommendations. The GRADE approach has been used for each selected paper to assess the quality of the evidence and the degree of recommendations. Based on a panel of experts and extensive updated literature, this consensus document provides insight into the pathogenesis, risk and protective factors associated with the development and persistence of preschool wheezing. Undoubtedly, more research is needed to improve our understanding of the disease and confirm the associations between certain factors and the risk of wheezing in early life. In addition, preventive strategies must be promoted to avoid children's exposure to risk factors that may permanently affect respiratory health.

The role of TLR-3 in the course and outcomes of rotavirus infection in infants

It was found that the clinical picture of rotavirus infection in infants with an initially low number of immunocompetent cells expressing TLR-3 does not differ significantly from that of patients with an initially large number of cells expressing TLR-3. When analyzing the treatment, it turned out that antibacterial therapy due to the activation of bacterial microflora was used only in children with an initially low number of immunocompetent cells expressing TLR-3. In the same group of patients, the development of atopic dermatitis and food allergies was noted during catamnestic observation for 6—12 months after rotavirus infection.

Effect of Rotavirus Infection on Serum Micronutrients and Atopy in Children

Objective Rotavirus is a highly infectious and prevalent ribonucleic acid (RNA) virus that causes fatal gastroenteritis in children. Despite vitamin D deficiency is associated with susceptibility to infections, the relationship between ferritin and vitamin B12 levels is not known. This study aimed to investigate and compare the effect of rotavirus on micronutrient levels, atopy, and the frequency of allergic diseases in children with rotavirus.

Methods There were rotavirus gastroenteritis (RVG) (N = 92) and non-rotavirus (control) groups (N = 95). Serum micronutrient levels (B12, ferritin, and 25-hydroxyvitamin D [25-OH-D3]) were checked during the first control after gastroenteritis healed. Patients were also examined for allergic diseases on an average of 17 (14–32) months following rotavirus infection. Serum immunoglobulin E (IgE), eosinophil count, and percentage were analyzed. Skin tests and respiratory function tests were also performed on patients with allergic disease and asthma symptoms.

Results Mean ferritin, B12, and 25-OH-D3 levels were lower in the RVG group compared with the control group. Allergic diseases in the RVG group were more frequent than in the control group. The prevalence of the allergic disease in the RVG group was 16.3%, as opposed to 5.2% in the control group (p = 0.014). The IgE level was significantly higher in the RVG group.

Conclusion Children with rotavirus infection should be followed closely in terms of allergic diseases and micronutrient deficiency. Furthermore, rotavirus infection should be prevented in the society and early treatment should be made available via tests detecting micronutrient deficiency.

Association of different enteroviruses with atopy and allergic diseases in early childhood

BACKGROUND

Enterovirus (EV) infections, being among the most prevalent viruses worldwide, have been associated with reduced risk of allergic diseases. We sought to determine the association between EVs and allergic sensitization and disease in early childhood.

METHODS

The study was carried out in a nested case-control setting within a prospective birth cohort in Finland. We included 138 case children who had specific IgE (s-IgE) sensitization at the age of 5 years and 138 control children without s-IgE sensitization. Allergic disease was recorded at study visits and identified with the ISAAC questionnaire. We screened for the presence of serotype-specific antibodies against 41 EVs at 1-5 years of age and assessed their association with allergic sensitization and disease.

RESULTS

The overall number of EV infections did not differ between s-IgE-sensitized children and non-sensitized control children. However, there was a tendency of case children with an allergic disease having less EV infections than their controls. This observation was statistically significant for species A EVs in case children with atopic dermatitis vs. control children: OR 0.6 (95% CI 0.36-0.99), p = .048.

CONCLUSION

This study supports the evidence that EV exposure and development of allergic disease are inversely associated. Interestingly, the inverse association was not observed for bare atopic IgE sensitization, but for IgE sensitization coupled with clinical atopic disease. This suggests that environmental factors influencing IgE sensitization may differ from those influencing progression to clinical allergic disease.

The Role of the Environmental Risk Factors in the Pathogenesis and Clinical Outcome of Atopic Dermatitis

Atopic dermatitis (AD) prevalence is rising worldwide. Literature data suggest the incidence of AD in developing countries is gradually getting close to that of developed ones, in which AD affects 20% of the paediatric population. Such an increment, associated with significant variations in prevalence among the various countries, underlines the importance of environmental factors in the disease onset. Among these, great importance is given to hygiene, intestinal microbiota, exposure to bacterial endotoxins, outdoor living with contact to animals, atmospheric pollution, weather, and diet. Genetic (alteration of the skin barrier function) as well as immunologic factors concur with the environmental ones. Only the systematical study of all these elements can best elucidate AD epidemiology.

A multifactorial regression analysis of the features of community-acquired rotavirus requiring hospitalization in Spain as represented in the Minimum Basic Data Set

Over 10% of acute rotavirus gastroenteritis (ARGE) requires hospitalization because of complications. The aggravating factors have been widely analysed, but in an isolated way. We aimed to explore the interrelationship between the clinical and epidemiological factors that characterize rotavirus hospitalizations in Spain using information from the Minimum Basic Data Set (MBDS). Using ICD-9-CM codes, we classified acute gastroenteritis (AGE) cases by principal diagnosis fields and then categorized their comorbidities, complications, and epidemiological features by secondary fields. A multivariable, logistic, step-wise regression model was then constructed. We identified 1657 ARGE cases from 17 415 cases of AGE. Rotavirus hospitalizations were associated with place of residence, age, and season (P < 0·0001), as well as with dehydration [odds ratio (OR) 12·44, 95% confidence interval (CI) 1·52-40·38], intravenous rehydration (OR 1·74, 95% CI 1·29-2·35), metabolic acidosis (OR 1·51, 95% CI 1·24-1·83), respiratory tract infections (RTIs) (OR 1·60, 95% CI 1·09-1·98), and concomitant AGE (OR 1·52, 95% CI 1·03-2·25). Dehydration was four times more likely in patients aged <5 years (OR 4·36, 95% CI 1·20-12·96) and was associated with acidosis when ARGE and RTI were present simultaneously (P < 0·0001). Specific co-infecting viruses may play a role in acute respiratory symptoms and aggravation of gastrointestinal manifestations of rotaviruses, thus leading to complications requiring hospitalization.

The relationship between the season of birth and early-onset food allergies in children

BACKGROUND

This study examined the relationship between the season of birth (SoB) and other factors with the development of FA.

METHODS

A multicenter, cross-sectional pilot study recruited 1197 patients with FA. The main study recruited 440 incident cases (FA group) definitively diagnosed as FA at 0-1 year of age. In both studies, the frequency of autumn-winter births (AWBs) in FA patients was compared to the regional control population. In the main study, we analyzed the differences in the SoB and other factors between patients in the FA group and those in the non-FA group (n = 332) in allergy clinics.

RESULTS

The pilot study showed that the frequency of AWB (57.6%) in the FA patients was significantly higher than that of the regional control population (50.4%, OR, 1.34; p < 0.001). The main study also showed the dominance of AWB (62.7%) in the FA group in comparison with that in the regional control population (50.2%, OR, 1.70; p < 0.001). Preterm birth (OR, 0.43; p = 0.027) and the presence of two or more elder siblings (OR, 0.27; p = 0.012) were significantly associated with a lower frequency of FA than those of non-FA. AWB (RR, 1.21; p = 0.020) and preterm birth (RR, 0.55; p = 0.017) were significantly associated with a number of trigger foods. The SoB effect was observed in FA patients irrespective of the presence of infantile eczema.

CONCLUSIONS

AWB was predominant in the patients with newly diagnosed food allergies.

Immune-mediated diseases and microbial exposure in early life

The non-communicable disease pandemic includes immune-mediated diseases such as asthma and allergy, which are likely originating in early life where the immature immune system is prone to alterations caused by the exposome. The timing of exposure seems critical for the developing immune system, and certain exposures may have detrimental effects in the earliest life, but no or even beneficial effects later. The human microbiome and infections are candidates as intermediary in the interaction between the host and the environment. The evidence seems inconsistent as infections as well as particular colonization patterns in neonates drive both short-term and long-term asthma symptoms, while, on the other hand, the composition of the microbiome in early life may protect against asthma and allergy in later life. This apparent contradiction may be explained by a deeper disease heterogeneity than we are currently able to discriminate, and in particular, the indiscriminate lumping together of different diseases into one atopic disease category. Also, the microbiome needs a differentiated understanding, considering balance between microbial groups, diversity and microbial genetic capability. Furthermore, the effects of the microbial exposure may only affect individuals with certain susceptibility genes. Few of the observations have been replicated, and publication bias is likely. Therefore, we are still far from understanding, or having proved, causal effects of the human microbiome. Still, the microbiome-gene interaction is a fascinating paradigm that fosters exiting research and promises a breakthrough in the understanding of the mechanisms driving asthma, allergy and eczema, and potentially also other immune-mediated non-communicable diseases.

New insights into the epidemiology of childhood atopic dermatitis

There is a growing desire to explain the worldwide rise in the prevalence of atopic dermatitis (AD). Trend data on the burden of AD suggest that the picture in the developing world may soon resemble that of wealthier nations, where AD affects over 20% of children. This, combined with significant variations in prevalence within countries, emphasizes the importance of environmental factors. Many hypotheses have been explored, from the modulation of immune priming by hygiene, gut microbiota diversity, and exposure to endotoxins through farm animals to the effects of pollution, climate, and diet. The discovery of the filaggrin skin barrier gene and its importance in AD development and severity has brought the focus on gene-environment interactions and the identification of environmental factors that impact on skin barrier function. This article reviews our current understanding of the epidemiology of AD, with an emphasis on the findings reported in the international literature over the last 5 years.

Virus infections among young children--the first year of the INDIS study

The frequencies of early childhood infections were studied in healthy children with increased genetic risk for type 1 diabetes participating in the ongoing prospective high intensive infection follow-up Study, INDIS, started in 2009 in Turku, Finland. Here the results obtained from 160 stool to 160 nasal swab specimens collected in parallel at times of infectious symptoms in 2009-2010 from 45 children at the age of 24 months or younger are reported. The specimens were analyzed for enteric (human enterovirus, norovirus, rotavirus, sapovirus, astrovirus) and respiratory RNA viruses (human enterovirus and rhinovirus) common in early childhood, respectively, using highly validated virus-specific real-time PCR methods. According to the results 96% of the children had at least one virus infection during the study period and one or several viral agents were detected in 76% of sample sets. The most prevalent viral agents were human rhinovirus, enterovirus, parechovirus, and norovirus (genotype GII) with positive specimens 57.5%, 28.8%, 19.4%, and 6.9%, respectively. Other intestinal viruses were found in less than 2% of stool specimens. Single infections covered 40.0% of the specimens while multiple infections with two or more infectious agents were detected in 36.3% of specimens and altogether 11 combinations of viruses were included in the mixed infections. Although human enterovirus is known to be a frequent finding in stool specimens, especially during early childhood, it was found in this study more frequently in nasal swab specimens. Whether this is true, more general, in countries with the high hygiene level remains to be shown.

The burden of infectious intestinal disease (IID) in the community: a survey of self-reported IID in The Netherlands

In 2009, a 1-year retrospective survey was performed in The Netherlands to estimate the incidence and the disease burden of infectious intestinal disease (IID) in the community, to study the selection of patients consulting a general practitioner and to identify potential risk factors for IID in the community. A questionnaire was sent to 6000 persons selected at random from the population registries of 28 municipalities, with 500 persons being approached per month. A total of 1975 (33%) persons participated. The incidence rate of IID was 964/1000 person-years. Potential risk factors associated with IID in the community were young age (0-4 years) [odds ratio (OR) 3.9, 95% confidence interval (CI) 1.5-10.5], having asthma as a child (OR 3.4, 95% CI 1.1-10.3) and use of gastric acid suppressive medication by persons aged ≥ 45 years (OR 2.8, 95% CI 1.4-5.6). Of the 146 cases with IID, 11 (8%) consulted a physician. Cases with a long duration of symptoms, blood in the stool, children with IID and cases with a low level of education were more likely to consult a physician. Two cases had a stool sample taken and one was admitted to hospital. In conclusion, IID is common and has a significant burden of illness in The Netherlands. Our data indicate that about 15.9 million episodes of IID occur in The Netherlands per year. The incidence rate is substantially higher than the rate of 283/1000 person-years as estimated in 1999 in The Netherlands. This is probably largely due to the retrospective nature of the present study and, to a lesser extent, to differences in case definitions.

Variants of the FADS1 FADS2 gene cluster, blood levels of polyunsaturated fatty acids and eczema in children within the first 2 years of life

Background

Association of genetic-variants in the FADS1-FADS2-gene-cluster with fatty-acid-composition in blood of adult-populations is well established. We analyze this genetic-association in two children-cohort-studies. In addition, the association between variants in the FADS-gene-cluster and blood-fatty-acid-composition with eczema was studied.

Methods and Principal Findings

Data of two population-based-birth-cohorts in the Netherlands and Germany (KOALA, LISA) were pooled (n = 879) and analyzed by (logistic) regression regarding the mutual influence of single-nucleotide-polymorphisms (SNPs) in the FADS-gene-cluster (rs174545, rs174546, rs174556, rs174561, rs3834458), on polyunsaturated fatty acids (PUFA) in blood and parent-reported eczema until the age of 2 years. All SNPs were highly significantly associated with all PUFAs except for alpha-linolenic-acid and eicosapentaenoic-acid, also after correction for multiple-testing. All tested SNPs showed associations with eczema in the LISA-study, but not in the KOALA-study. None of the PUFAs was significantly associated with eczema neither in the pooled nor in the analyses stratified by study-cohort.

Conclusions and Significance

PUFA-composition in young children's blood is under strong control of the FADS-gene-cluster. Inconsistent results were found for a link between these genetic-variants with eczema. PUFA in blood was not associated with eczema. Thus the hypothesis of an inflammatory-link between PUFA and eczema by the metabolic-pathway of LC-PUFAs as precursors for inflammatory prostaglandins and leukotrienes could not be confirmed by these data.

Timing of infection and development of wheeze, eczema, and atopic sensitization during the first 2 yr of life: the KOALA Birth Cohort Study

To investigate if infections in pregnancy and very early in life present a risk for wheezing, eczema, or atopic sensitization in later infancy. A total of 2319 children enrolled before birth in the KOALA Birth Cohort Study were followed during their first 2 yr of life using repeated questionnaires. Information was obtained on common colds, fever, and diarrhea with fever as well as on wheeze and eczema at ages 3 and 7 months and 1 and 2 yr, respectively. Blood samples were collected from 786 children at age 2 yr for specific immunoglobulin E analyses. Children with a common cold [adjusted odds ratio (aOR) 2.03 95% CI 1.21-3.41] or fever episode (aOR 1.81 95% CI 1.10-2.96) in the first 3 months of life had a higher risk of new onset wheeze in the second year of life compared to children who had not. For children with diarrhea with fever in the first 3 months of life, the aOR for new onset wheeze in the second year of life was 3.94 (95% CI 1.36-11.40) compared to children without diarrhea. Infections becoming clinically manifest during the first 3 months of life may be a general marker for a wheezy phenotype.

Clinical aspects of pediatric food allergy and failed oral immune tolerance

Food allergy seems to represent a new spectrum of disease that has elicited significant community concern and extended waiting lists for allergists and gastroenterologists alike. The apparent rise in prevalence of IgE-mediated food allergy (and associated risk of anaphylaxis) has been postulated to result from effects of a "modern lifestyle" but as yet clear environmental risk factors have not yet emerged. Family history seems to contribute to risk suggesting that gene-environment interactions will be important for identifying a subpopulation with increased susceptibility to any identified lifestyle effects. Non-IgE-mediated food allergy (including food-induced enteropathies and colitides, eosinophilic esophagitis, and Crohn's disease) with potentially similar environmental triggers resulting in diverse immune dysregulatory mechanisms. The evidence underpinning the putative rise in food allergy is discussed and potential mechanisms of disease explored. Clinical aspects of various food allergic conditions including non-IgE-mediated food allergy are outlined.

Poverty-associated risk factors for wheezing in the first year of life in Honduras and El Salvador

BACKGROUND

Risk factors for wheezing specifically during the first year of life have been studied in well-developed countries, but the information from developing countries is very scarce. There are no such studies focusing on factors derived from poverty. The aim of the present study was to determine if risk factors related to poverty are associated to wheezing during the first year of life in infants from Honduras and El Salvador.

METHODS

A survey, using a validated questionnaire, was carried out in the metropolitan area of San Pedro Sula (Honduras) and in La Libertad (El Salvador) in centres where infants attended for a scheduled vaccination shot or a healthy child visit at 12 months of age. Fieldworkers offered questionnaires to parents and helped the illiterate when necessary. The main outcome variable was wheezing during the first year of life, as reported by parents.

RESULTS

A total of 1047 infants in El Salvador and 780 in Honduras were included in the analysis. The prevalence of wheeze in the first year was higher in El Salvador (41.2%) than in Honduras (27.7%), as was recurrent wheezing defined as three or more episodes (18.4% vs. 11.7%). Wheezing and recurrent wheezing was associated to unpaved floor in the household (summary odds ratios for both countries 1.55, p=0.036 and 1.72, p=0.054 for any wheeze and recurrent wheezing, respectively); dust entering from streets (1.30, p=0.052 and 1.67, p=0.008); living in a heavily polluted area (1.33, p=0.037 and 1.52, p=0.033); and having mould stains on the household walls (1.36, p=0.072 and 1.76, p=0.007). Furthermore, marginal associations were found for additional person at home and use of kerosene as cooking fuel. University studies in the mother (0.34, p=0.046 and 0.32, p=0.022) and a professional occupation in the father (0.34, p=0.046 and 0.26, p=0.047) were associated to a lower risk.

CONCLUSIONS

The prevalence of wheezing and recurrent wheezing is notoriously high in El Salvador and Honduras. In those populations factors related to poverty are associated to a higher prevalence of wheezing and recurrent wheezing, whereas higher maternal education and paternal professional occupation behave as protective factors.

Enteric reovirus infection stimulates peanut-specific IgG2a responses in a mouse food allergy model

IgE-mediated food allergies are an important cause of life-threatening hypersensitivity reactions. Orally administered peanut antigens mixed with the mucosal adjuvant cholera toxin (CT) induce a strong peanut extract (PE)-specific serum IgE response that is correlated with T-helper type 1 (Th1) and type 2 (Th2)-like T-cell responses. This study was conducted to determine if respiratory enteric orphan virus (reovirus), a non-pathogenic virus that induces robust Th1-mediated mucosal and systemic responses could modulate induction of PE-specific allergic responses when co-administered with PE. Young mice were orally exposed to PE mixed with CT, reovirus, or both CT and reovirus. As expected, CT promoted PE-specific serum IgE, IgG1, and IgG2a and intestinal IgA production as well as splenic Th1- and Th2-associated cytokine recall responses. Reovirus did not alter PE-specific serum IgE and IgG1 levels, but substantially increased the PE-specific IgG2a response when co-administered with PE with or without CT. Additionally, reovirus significantly decreased the percentage of the Peyer's patch CD8+ T-cells and Foxp3+CD4+ T-regulatory cells when co-administered with PE. These results demonstrate that an acute mucosal reovirus infection and subsequent Th1 immune response is capable of modulating the Th1/Th2 controlled humoral response to PE. The reovirus-mediated increase in the PE-specific IgG2a antibody response may have therapeutic implications as increased levels of non-allergenic PE-specific IgG2a could block PE antigens from binding to IgE-sensitized mast cells.