Life-course of atopy and allergy-related disease events in tropical sub-Saharan Africa: A birth cohort study

High frequencies of nonviral colds and respiratory bacteria colonization among children in rural Western Uganda

Introduction

Respiratory illness is the most common childhood disease globally, especially in developing countries. Previous studies have detected viruses in approximately 70-80% of respiratory illnesses.

Methods

In a prospective cohort study of 234 young children (ages 3-11 years) and 30 adults (ages 22-51 years) in rural Western Uganda sampled monthly from May 2019 to August 2021, only 24.2% of nasopharyngeal swabs collected during symptomatic disease had viruses detectable by multiplex PCR diagnostics and metagenomic sequencing. In the remaining 75.8% of swabs from symptomatic participants, we measured detection rates of respiratory bacteria Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae by quantitative PCR.

Results

100% of children tested positive for at least one bacterial species. Detection rates were 87.2%, 96.8%, and 77.6% in children and 10.0%, 36.7%, and 13.3% for adults for H. influenzae, M. catarrhalis, and S. pneumoniae, respectively. In children, 20.8% and 70.4% were coinfected with two and three pathogens, respectively, and in adults 6.7% were coinfected with three pathogens but none were coinfected with two. Detection of any of the three pathogens was not associated with season or respiratory symptoms severity, although parsing detection status by symptoms was challenged by children experiencing symptoms in 80.3% of monthly samplings, whereas adults only reported symptoms 26.6% of the time. Pathobiont colonization in children in Western Uganda was significantly more frequent than in children living in high-income countries, including in a study of age-matched US children that utilized identical diagnostic methods. Detection rates were, however, comparable to rates in children living in other Sub-Saharan African countries.

Discussion

Overall, our results demonstrate that nonviral colds contribute significantly to respiratory disease burden among children in rural Uganda and that high rates of respiratory pathobiont colonization may play a role. These conclusions have implications for respiratory health interventions in the area, such as increasing childhood immunization rates and decreasing air pollutant exposure.

Respiratory disease patterns in rural Western Uganda, 2019-2022

Introduction

Respiratory disease is a major cause of morbidity and mortality in the developing world, but prospective studies of temporal patterns and risk factors are rare.

Methods

We studied people in rural Western Uganda, where respiratory disease is pervasive. We followed 30 adults (ages 22-51 years; 534 observations) and 234 children (ages 3-11 years; 1,513 observations) between May 2019 and July 2022 and collected monthly data on their respiratory symptoms, for a total of 2,047 case records. We examined associations between demographic and temporal factors and respiratory symptoms severity.

Results

The timing of our study (before, during, and after the emergence of COVID-19) allowed us to document the effects of public health measures instituted in the region. Incidence rates of respiratory symptoms before COVID-19 lockdown were 568.4 cases per 1,000 person-months in children and 254.2 cases per 1,000 person-months in adults. These rates were 2.6 times higher than the 2019 global average for children but comparable for adults. Younger children (ages 3-6 years) had the highest frequencies and severities of respiratory symptoms. Study participants were most likely to experience symptoms in February, which is a seasonal pattern not previously documented. Incidence and severity of symptoms in children decreased markedly during COVID-19 lockdown, illustrating the broad effects of public health measures on the incidence of respiratory disease.

Discussion

Our results demonstrate that patterns of respiratory disease in settings such as Western Uganda resemble patterns in developed economies in some ways (age-related factors) but not in others (increased incidence in children and seasonal pattern). Factors such as indoor air quality, health care access, timing of school trimesters, and seasonal effects (rainy/dry seasons) likely contribute to the differences observed.

Burden of and Trends in Urticaria Globally, Regionally, and Nationally from 1990 to 2019: Systematic Analysis

BACKGROUND

Urticaria presents a significant global health challenge due to its sudden onset and potential for severe allergic reactions. Past data on worldwide prevalence and incidence is inconsistent due to differing study methodologies, regional differences, and evolving diagnostic criteria. Past studies have often provided broad ranges instead of specific figures, underscoring the necessity for a cohesive global perspective to inform public health strategies.

OBJECTIVE

We aimed to assess the global burden of urticaria using the 2019 Global Burden of Disease (GBD) study data and systematically analyze urticaria prevalence, incidence, and disability-adjusted life years (DALYs) at global, regional, and national levels, thereby informing more effective prevention and treatment strategies.

METHODS

We analyzed the global, regional, and national burden of urticaria from 1990 to 2019 using the 2019 GBD study coordinated by the Institute for Health Metrics and Evaluation. Estimations of urticaria prevalence, incidence, and DALYs were derived using DisMod-MR 2.1, a Bayesian meta-regression tool. The Socio-demographic Index (SDI) was used to correlate development status with health outcomes. The GBD's division of the world into 21 regions and 204 countries and territories facilitated a comprehensive assessment. Age-standardized estimated annual percentage changes were generated for urticaria metrics to quantify temporal trends, with age standardization adjusting for potential confounding from age structure.

RESULTS

From 1990 to 2019, the global age-standardized prevalence, incidence, and DALY rates of urticaria showed marginal changes. In 2019, 65.14 million individuals were affected, with a prevalence rate of 841.88 per 100,000 population. The DALY rate was 50.39 per 100,000 population. Compared to 1990, the global age-standardized prevalence, incidence, and DALY rates saw increases of 2.92, 4.84, and 0.31 per 100,000 population, respectively. Women persistently had higher rates than men. At a regional level in 2019, low-middle SDI regions exhibited the highest age-standardized metrics, whereas high SDI regions reported the lowest. Central Europe showed the highest rates, contrasting with Western Europe's lowest rates. Nationally, urticaria prevalence in 2019 varied dramatically, from a low of 27.1 per 100,000 population in Portugal to a high of 92.0 per 100,000 population in Nepal. India reported the most DALYs at 749,495.9, followed by China, Pakistan, and the United States. Agewise data showed higher rates in younger age groups, which diminished with age and then experienced a slight resurgence in the oldest populations. This pattern was pronounced in women and younger populations, with the largest rises seen in those aged less than 40 years and the smallest in those aged more than 70 years.

CONCLUSIONS

Urticaria remains a significant global health issue, with considerable variation across regions, countries, and territories. The increased burden among women, the rising burden in younger populations, and the regional differences in disease burden call for tailored interventions and policies to tackle this emerging public health issue.

Frequent IgE recognition of Blomia tropicalis allergen molecules in asthmatic children and young adults in equatorial Africa

Background

Asthma is not well investigated in equatorial Africa and little is known about the disease-associated allergen molecules recognized by IgE from patients in this area. The aim was to study the molecular IgE sensitization profile of asthmatic children and young adults in a semi-rural area (Lambaréné) of an equatorial African country (Gabon), to identify the most important allergen molecules associated with allergic asthma in equatorial Africa.

Methods

Fifty-nine asthmatic patients, mainly children and few young adults, were studied by skin prick testing to Dermatophagoides pteronyssinus (Der p), D. farinae (Der f), cat, dog, cockroach, grass, Alternaria and peanut. Sera were obtained from a subset of 35 patients, 32 with positive and 3 with negative skin reaction to Der p and tested for IgE reactivity to 176 allergen molecules from different allergen sources by ImmunoCAP ISAC microarray technology and to seven recombinant Blomia tropicalis (Blo t) allergens by IgE dot blot assay.

Results

Thirty-three of the 59 patients (56%) were sensitized to Der p and 23 of them (39%) were also sensitized to other allergen sources, whereas 9 patients (15%) were only sensitized to allergen sources other than Der p. IgE serology analyses (n=35) showed high IgE-binding frequencies to the Blo t allergens Blo t 5 (43%), Blo t 21 (43%) and Blo t 2 (40%), whereas the Der p allergens rDer p 2, rDer p 21 and rDer p 5 (34%, 29% and 26%) were less frequently recognized. Only few patients showed IgE reactivity to allergens from other allergen sources, except to allergens containing carbohydrate determinants (CCDs) or to wasp venom allergens (i.e., antigen 5).

Conclusion

Our results thus demonstrate that IgE sensitization to mite allergens is very prevalent in asthmatics in Equatorial Africa with B. tropicalis allergen molecules representing the most important ones associated with allergic asthma.

Multimorbidity of Allergic Conditions in Urban Citizens of Southern China: A Real-World Cross-Sectional Study

Background: Extensive knowledge of allergic multimorbidities is required to improve the management of allergic diseases with the industrialization of China. However, the demography and allergen distribution patterns of allergic multimorbidities in China remain unclear, despite the increasing prevalence of allergies. Methods: This was a real-world, cross-sectional study of 1273 outpatients diagnosed with one or more allergic diseases in Guangzhou, the most populated city of southern China, with leading industrial and commercial centers, between April 2021 and March 2022. Seven allergic diseases (allergic rhinitis (AR), asthma (AS)/cough variant asthma (CVA), atopic dermatitis (AD)/eczema, food allergy (FA), allergic conjunctivitis (AC), drug allergy (DA), and anaphylaxis) were assessed. Positive rates of sensitization to different allergens were measured using an allergen detection system of the UniCAP (Pharmacia Diagnostics, Sweden) instrument platform to compare the groups of allergic multimorbidities against a single entity. Results: There were 659 (51.8%) males and 614 (48.2%) females aged from 4 months to 74 years included in the analysis. The study participants who were diagnosed with allergic diseases had an average of 1.6 diagnoses. Overall, 46.5% (592 of 1273) of the patients had more than one allergic condition, and allergic rhinitis was the most common type of multimorbidity. Women were more likely to suffer from an allergic disease alone, whereas allergic multimorbidities were more likely to be diagnosed in men (p = 0.005). In addition, allergic multimorbidities were common in all age groups, with an incidence ranging from 37.1% to 57.4%, in which children and adolescents were more frequently diagnosed with allergic multimorbidities than adults (18–60 years old) (all p < 0.05). Allergic multimorbidity was observed throughout the year. A difference in the positive rate of allergens sensitization and total immunoglobulin E (tIgE) levels between different allergic multimorbidities was observed. Conclusions: Allergic multimorbidities were very commonly found in nearly half of all patients with allergies. The proportion of allergic multimorbidities varied with the type of disease, sex, age, and allergen distribution pattern. These findings may help clinicians to develop “One health” strategies for the clinical management of allergic diseases.

Association of rhinitis with asthma prevalence and severity

Asthma and rhinitis often co-exist in the same patient. Although some authors observed a higher prevalence and/or greater severity of asthma in patients with rhinitis, this view is not homogeneous and the debate continues. The aim of our study is to describe the prevalence of rhinitis in children and adolescents and to analyse their relationship with the prevalence of asthma. A multicentre study was conducted using the methodology of the International Study of Asthma and Allergies in Childhood (ISAAC). The target population of the study was all those school children aged 6–7 and 13–14 years from 6 of the main health catchment areas of Galicia (1.9 million inhabitants). The schools required were randomly selected, and all children in the targeted age ranges were included. Multiple logistic regression was used to obtain adjusted prevalence odds ratios (OR) between asthma symptoms of the schoolchildren and rhinitis prevalence. The results were adjusted for parental smoking habits, maternal education level, cat and dog exposure, and obesity. A total of 21,420 valid questionnaires were finally obtained. Rhinitis was associated with a significant increase in the prevalence of asthma in both age groups. The highest OR were 11.375 for exercise induced asthma (EIA) for children with recent rhinoconjunctivitis and 9.807 for children with recent rhinitis in 6–7 years old group. The prevalence OR’s are higher in EIA and severe asthmatics. Rhinitis in children and adolescents is associated with a higher prevalence and severity of asthma.

Infection-exposure in infancy is associated with reduced allergy-related disease in later childhood in a Ugandan cohort

Background

Lack of early infection-exposure has been associated with increased allergy-related disease (ARD) susceptibility. In tropical Africa, little is known about which infections contribute to development of ARDs, and at which time.

Methods

We used latent class analysis to characterise the early infection-exposure of participants in a Ugandan birth cohort and assessed ARDs in later childhood.

Results

Of 2345 live births, 2115 children (90%) had data on infections within the first year of life while 1179 (50%) had outcome data at 9 years. We identified two latent classes of children based on first-year infection-exposure. Class 1 (32% membership), characterised by higher probabilities for malaria (80%), diarrhoea (76%), and lower respiratory tract infections (LRTI) (22%), was associated with lower prevalence of wheeze, eczema, rhinitis, and Dermatophagoides skin prick test (SPT) positivity at 9 years. Based on 5-year cumulative infection experience, class 1 (31% membership), characterised by higher probabilities for helminths (92%), malaria (79%), and LRTI (45%), was associated with lower probabilities of SPT positivity at 9 years.

Conclusions

In this Ugandan birth cohort, early childhood infection-exposure, notably to malaria, helminths, LRTI, and diarrhoea, is associated with lower prevalence of atopy and ARDs in later childhood.

Funding

This work was supported by several funding sources. The Entebbe Mother and Baby Study (EMaBS) was supported by the Wellcome Trust, UK, senior fellowships for AME (grant numbers 064693, 079110, 95778) with additional support from the UK Medical Research Council. LL is supported by a PhD fellowship through the DELTAS Africa Initiative SSACAB (grant number 107754). ELW received funding from MRC Grant Reference MR/K012126/1. SAL was supported by the PANDORA-ID-NET Consortium (EDCTP Reg/Grant RIA2016E-1609). HM was supported by the Wellcome's Institutional Strategic Support Fund (grant number 204928/Z/16/Z).

Patterns of allergic sensitization and factors associated with emergence of sensitization in the rural tropics early in the life course: findings of an Ecuadorian birth cohort

Introduction

There are limited data on emergence of allergic sensitization (or atopy) during childhood in tropical regions.

Methods

We followed a birth cohort of 2404 newborns to 8 years in tropical Ecuador and collected: risk factor data by maternal questionnaires periodically from birth; atopy was measured by skin prick test reactivity (SPT) to aeroallergens in parents, and aeroallergens and food allergens in children at 2, 3, 5, and 8 years; and stool samples for soil-transmitted helminths (STH) from children periodically to 8 years and from parents and household members at the time of recruitment of cohort children. Data on risk factors were measured either at birth or repeatedly (time-varying) from birth to 8 years. Longitudinal repeated-measures analyses were done using generalized estimating equations to estimate an the age-dependent risk of positive SPT (SPT+) to any allergen or mite during early childhood to school age.

Results

SPT+ to any allergen was present in 29.0% of fathers and 24.8% of mothers, and in cohort children increased with age, initially to mite but later to cockroach, reaching 14.8% to any allergen (10.7% mite and 5.3% cockroach) at 8 years. Maternal SPT+, particularly presence of polysensitization (OR 2.04, 95% CI 1.49-2.77) significantly increased the risk of SPT+ during childhood, while household overcrowding at birth decreased the risk (OR 0.84, 95% CI 0.72-0.98). For mite sensitization, maternal polysensitization increased (OR 2.14, 95% CI 1.40-3.27) but rural residence (OR 0.69, 95% CI 0.50-0.94) and birth order (3^rd -4^th vs. 1^st - 2^nd: OR 0.71, 95% CI 0.52-0.98) decreased the risk. Time-varying exposures to agricultural activities (OR 0.77, 95% CI 0.60-0.98) and STH parasites (OR 0.70, 95% CI 0.64-0.91) during childhood decreased while anthelmintics increased the childhood risk (OR 1.47, 95% CI 1.05-2.05) of mite sensitization.

Conclusion

Our data showed the emergence of allergic sensitization, primarily to mite and cockroach allergens, during childhood in tropical Ecuador. A role for both antenatal and postnatal factors acting as potential determinants of SPT+ emergence was observed.

Lack of Consistent Association between Asthma, Allergic Diseases, and Intestinal Helminth Infection in School-Aged Children in the Province of Bengo, Angola

Epidemiological studies have shown conflicting findings on the relationship between asthma, atopy, and intestinal helminth infections. There are no such studies from Angola; therefore, we aimed to evaluate the relationship between asthma, allergic diseases, atopy, and intestinal helminth infection in Angolan schoolchildren. We performed a cross-sectional study of schoolchildren between September and November 2017. Five schools (three urban, two rural) were randomly selected. Asthma, rhinoconjunctivitis, and eczema were defined by appropriate symptoms in the previous 12 months: atopy was defined by positive skin prick tests (SPT) or aeroallergen-specific IgE; intestinal helminths were detected by faecal sample microscopy. In total, 1023 children were evaluated (48.4% female; 57.6% aged 10–14 years; 60.5% urban). Asthma, rhinoconjunctivitis, or eczema were present in 9%, 6%, and 16% of the studies children, respectively. Only 8% of children had positive SPT, but 64% had positive sIgE. Additionally, 40% were infected with any intestinal helminth (A. lumbricoides 25.9%, T. trichiura 7.6%, and H. nana 6.3%). There were no consistent associations between intestinal helminth infections and asthma, allergic diseases, or atopy, except for A. lumbricoides, which was inversely associated with rhinoconjuctivitis and directly associated with aeroallergen-specific IgE. We concluded that, overall, intestinal helminth infections were not consistently associated with allergic symptoms or atopy. Future, preferably longitudinal, studies should collect more detailed information on helminth infections as part of clusters of environmental determinants of allergies.

Prevalence and psychosocial impact of atopic dermatitis in Bangladeshi children and families

BACKGROUND

Skin conditions are the fourth leading cause of nonfatal disease globally, with atopic dermatitis (AD) a major and rising contributor. Though atopic dermatitis (AD) is rising in prevalence, little is known about its psychosocial effects on children and families in low- and middle-income countries (LMICs).

METHODS

We conducted a community-based, cross-sectional survey of 2242 under-5 children in rural Bangladesh using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire to measure AD prevalence and severity, the Patient-Oriented Eczema Measure (POEM) to measure severity, and the Infants' Dermatitis Quality of Life index (IDQoL) and Dermatitis Family Index (DFI) to measure quality of life.

FINDINGS

Overall AD prevalence in under-five children was 11.9% [95% confidence interval (CI) 10.6-13.3%]. Prevalence was highest in children age 30-35 months [16.2% (95% CI 11.4-21.0)]. IDQoL was significantly higher in males (2.67) vs. females (1.95, p = 0.015), the lowest (3.06) vs. highest (1.63) wealth quintile (p<0.001), and among mothers with < primary (2.41) vs. > secondary (1.43) education (p = 0.039). POEM severity was correlated with IDQoL (r = 0.77, p<0.001) and DFI (r = 0.56, p<0.001). Severe disease as rated by caretakers was correlated with POEM (r = 0.73, p<0.001), IDQoL (r = 0.82, p<0.001) and DFI (r = 0.57, p<0.001).

CONCLUSIONS

Severe AD significantly affects quality of life for children and families in Bangladesh. As access to healthcare expands in LMICs, identification and treatment of both the medical and psychosocial morbidities associated with the disease are needed.

A feasibility study to assess Imbrasia belina (mopane worm) sensitisation and related respiratory health outcomes in a rural community in Gwanda district, Zimbabwe

Background

Allergic diseases are considered to be some of the fastest growing chronic conditions in Africa. Of concern is the paucity of knowledge about the local environment and its role in allergic disease development. In response to this, we explored whether Imbrasia belina, a popular indigenous edible insect commonly known as mopane worm, is a potential allergen of clinical and public health significance in Zimbabwe. This study was intended to assess the plausibility and feasibility of this hypothesis with a view to evaluate the insect’s health impact in a larger study.

Methods

The study participants included male and female villagers aged 10 years and above in Gwanda district, Zimbabwe. Eligible participants who completed the household questionnaire were referred to the local clinic for skin prick tests and to measure lung function and allergic airway inflammation. Allergen sensitisation patterns were evaluated using 10 different inhalant allergen extracts including an in-house preparation of mopane worm. Lung function was measured with a Koko Legend spirometer, and fractional exhaled nitric oxide levels (FeNO) (NIOX VERO) were measured in participants with at least one abnormal spirometric parameter. Data was analysed using Stata version 13 software.

Results

Of the 46 eligible participants that completed the household questionnaire, 17 went to the clinic giving a response rate of 37%. The majority who completed the questionnaire were adults (91%) and the children (9%) were all female. The prevalence of sensitisation to Imbrasia belina was 50%, and the prevalence ranged from 22 to 72% for the other allergens including cockroach, mosquito and house dust mites. The data collection tools were safe and well tolerated by participants with no adverse events reported. Self-reported respiratory symptoms, abnormal lung function and elevated FeNO were recorded amongst participants sensitised to mopane worm.

Conclusion

Pre-defined feasibility criteria were met with the exception of a lower than expected response rate for clinic data collection in this pilot study. For the main study, modifying the sampling strategy and applying more consistent community engagement will improve the response rates.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-021-00780-9.

Prevalence of atopic dermatitis, asthma and rhinitis from infancy through adulthood in rural Bangladesh: a population-based, cross-sectional survey

OBJECTIVE

Describe the pattern of atopic disease prevalence from infancy to adulthood.

DESIGN

Cross-sectional household survey.

SETTING

Community-based demographic surveillance site, Mirzapur, Bangladesh.

PARTICIPANTS

7275 individuals in randomly selected clusters within 156 villages.

PRIMARY AND SECONDARY OUTCOME MEASURES

The 12-month prevalence of atopic dermatitis (by UK Working Party Criteria (UK criteria) and International Study of Asthma and Allergies in Childhood (ISAAC)), asthma and rhinitis (by ISAAC); disease severity (by ISAAC); history of ever receiving a medical diagnosis.

RESULTS

Children aged 2 years had the highest prevalence of atopic dermatitis-18.8% (95% CI 15.2% to 22.4%) by UK criteria and 14.9% (95% CI 11.6% to 18.1%) by ISAAC- and asthma (20.1%, 95% CI 16.4% to 23.8%). Prevalence of rhinitis was highest among 25-29 year olds (6.0%, (95% CI% 4.5 to 7.4%). History of a medical diagnosis was lowest for atopic dermatitis (4.0%) and highest for rhinitis (27.3%) and was significantly associated with severe disease compared with those without severe disease for all three conditions (atopic dermatitis: 30.0% vs 11.7%, p=0.015; asthma; 85.0% vs 60.4%, p<0.001; rhinitis: 34.2% vs 7.3%, p<0.001) and having a higher asset-based wealth score for asthma (29.7% (highest quintile) vs 7.5% (lowest quintile), p<0.001) and rhinitis (39.8% vs 12.5%, p=0.003). Prevalence of having >1 condition was highest (36.2%) at 2 years and decreased with age. Having atopic dermatitis (ISAAC) was associated with significantly increased odds ratios (OR) for comorbid asthma (OR 5.56 (95% CI 4.26 to 7.26)] and rhinitis (3.68 (95% CI 2.73 to 4.96)). Asthma and rhinitis were also strongly associated with each other (OR 8.39 (95% CI 6.48 to 10.86)).

CONCLUSIONS

Atopic disease burden was high in this rural Bangladeshi population. Having one atopic condition was significantly associated with the presence of another. Low incidence of ever obtaining a medical diagnosis highlights an important opportunity to increase availability of affordable diagnosis and treatment options for all age groups.

Sensitisation to aeroallergens in relation to asthma and other allergic diseases in Angolan children: a cross-sectional study

INTRODUCTION AND OBJECTIVES

In Africa, few studies of sensitisation profiles have been performed in children or adolescents and, in Angola, there are none. The objectives of the present study were to assess the sensitisation profile of Angolan schoolchildren and to determine the relationship between that pattern, sociodemographic factors, asthma and other allergic diseases.

MATERIALS AND METHODS

Cross-sectional, observational study in 5-14-year-old children, performed between September and November 2017, in the Province of Bengo, Angola. Five schools (15%) were randomly selected in the geographical area of the study: three from an urban area, and two from a rural area. Data were collected using the Portuguese versions of the ISAAC questionnaires for children and adolescents, regarding asthma, rhinitis and eczema. Skin prick tests (SPT) were performed with a battery of 12 aeroallergens. Stools were assessed for the presence of helminths. Descriptive statistics were used, as well as univariate calculation of odds ratios.

RESULTS

Sensitisation to aeroallergens was low (8%) and most sensitised children were asymptomatic. Most frequent sensitisations involved house dust mites, cockroach or fungi, and a high proportion of children (78.1%) were monosensitised. No relationship was detected between sensitisations and asthma, rhinitis or eczema. Place of residence, gender, age or helminthic infection did not affect the probability of having positive SPTs.

CONCLUSIONS

The most frequent sensitisations in children from Bengo Province in Angola involve house dust mites, followed by cockroach and fungi. No relationship was found between atopic sensitisation and asthma or other allergic diseases.

Personal and early life factors associated with new-onset asthma, remission, and persistence of asthma in a 2-year follow-up of schoolchildren

OBJECTIVE

The natural course of childhood asthma, after its onset, is characterized by periods of persistence, relapse and remission. To investigate personal and early life factors associated with new-onset asthma, persistence and remission among children.

METHODS

The study was conducted in the province of Saskatchewan, Canada. Children in grades Kindergarten to Grade 8 (ages 5-14 years) participated in a cross-sectional study in 2013. In 2015, we approached those who gave consent in 2013 to be re-contacted, creating a prospective cohort. Data were collected using questionnaires in both years. Participants in 2013 who also had data in 2015 (25%: n = 324/1,348) had their asthma status reclassified and longitudinal descriptors were applied: "no asthma", "new-onset asthma", "persistent" or "remission". Personal and early life factors associations with asthma outcomes in 2015 were evaluated.

RESULTS

Among those without asthma in 2013 (n = 245), the incidence of new-onset asthma in 2015 was 7.2%. Among those with asthma in 2013 (n = 79), 47.1% had remission and 52.9% had persistent asthma in 2015. Parental history of asthma (adjusted odds ratio (aOR): 4.99; 95% confidence interval (CI): 1.88-28.27), early life respiratory infection (aOR: 1.92; 95%CI: 1.47-7.88), early life allergy [aOR: 6.39; 95%CI: 1.34-30.58) and early life infection (aOR: 4.99; 95%CI: 1.19-20.93) were associated with new onset asthma. Similarly, while parental history of asthma (aOR: 1.13; 95%CI: 0.29-4.34), early life respiratory infection (aOR: 2.71; 95%CI: 0.70-10.45), and early life ear infection (aOR: 1.34; 95%CI: 0.36-5.05) were also positively association with persistent asthma, the associations were not statistically significant.

CONCLUSION

Parental history of asthma, early life respiratory infection and allergy might not only influence the onset of childhood asthma but also be associated with asthma persistence.

Associations between fungal and bacterial microbiota of airways and asthma endotypes

BACKGROUND

The relationship between asthma, atopy, and underlying type 2 (T2) airway inflammation is complex. Although the bacterial airway microbiota is known to differ in asthmatic patients, the fungal and bacterial markers that discriminate T2-high (eosinophilic) and T2-low (neutrophilic/mixed-inflammation) asthma and atopy are still incompletely identified.

OBJECTIVES

The aim of this study was to demonstrate the fungal microbiota structure of airways in asthmatic patients associated with T2 inflammation, atopy, and key clinical parameters.

METHODS

We collected endobronchial brush (EB) and bronchoalveolar lavage (BAL) samples from 39 asthmatic patients and 19 healthy subjects followed by 16S gene and internal transcribed spacer-based microbiota sequencing. The microbial sequences were classified into exact sequence variants. The T2 phenotype was defined by using a blood eosinophil count with a threshold of 300 cells/μL.

RESULTS

Fungal diversity was significantly lower in EB samples from patients with T2-high compared with T2-low inflammation; key fungal genera enriched in patients with T2-high inflammation included Trichoderma species, whereas Penicillium species was enriched in patients with atopy. In BAL fluid samples the dominant genera were Cladosporium, Fusarium, Aspergillus, and Alternaria. Using generalized linear models, we identified significant associations between specific fungal exact sequence variants and FEV1, fraction of exhaled nitric oxide values, BAL fluid cell counts, and corticosteroid use. Investigation of interkingdom (bacterial-fungal) co-occurrence patterns revealed different topologies between asthmatic patients and healthy control subjects. Random forest models with fungal classifiers predicted asthma status with 75% accuracy for BAL fluid samples and 80% accuracy for EB samples.

CONCLUSIONS

We demonstrate clear differences in bacterial and fungal microbiota in asthma-associated phenotypes. Our study provides additional support for considering microbial signatures in delineating asthma phenotypes.

Highlights and recent developments in airway diseases in EAACI journals (2017)

The European Academy of Allergy and Clinical Immunology (EAACI) owns three journals: Allergy, Pediatric Allergy and Immunology and Clinical and Translational Allergy. One of the major goals of EAACI is to support health promotion in which prevention of allergy and asthma plays a critical role and to disseminate the knowledge of allergy to all stakeholders including the EAACI junior members. There was substantial progress in 2017 in the identification of basic mechanisms of allergic and respiratory disease and the translation of these mechanisms into clinics. Better understanding of molecular and cellular mechanisms, efforts for the development of biomarkers for disease prediction, novel prevention and intervention studies, elucidation of mechanisms of multimorbidies, entrance of new drugs in the clinics as well as recently completed phase three clinical studies and publication of a large number of allergen immunotherapy studies and metaanalyses have been the highlights of the last year.

Allergy-related disorders (ARDs) among Ethiopian primary school-aged children: Prevalence and associated risk factors

Background

There has been a noticeable increase in the prevalence of allergy-related disorders (ARDs) in the modern era. Urbanization is believed to be a major environmental risk factor for the onset of ARDs but data from low- to middle-income countries is limited.

Objective

Our purpose was to assess the prevalence of ARDs and atopy among a population of rural Ethiopian school children and identify environmental and lifestyle factors associated with such disorders.

Methods

We performed a cross-sectional study on 541 school-children. An interviewer-led questionnaire administered to the mothers of each participant provided information on demographic and lifestyle variables. Questions on allergic disease symptoms were based on the International Study of Asthma and Allergies in Children (ISAAC) core allergy and environmental questionnaire. Skin prick test for common allergens German cockroach (Blattella germanica) and dust mite (Dermatophagoides) was performed to define atopy. Multiple logistic regression analyses were performed to determine the odds ratio between ARDs and atopy with specific environmental and lifestyle habits.

Results

541 children responded to the survey questions: the majority of participants were female (60.3%) and aged 10–15 years-old. The prevalence of any ARD was 27%, while the rates of ever-having eczema, rhinitis, and wheeze was found to be 16.8%, 9.6%, and 8.6% respectively. Only 3.6% (19 school-children) tested positive for any skin sensitization. Analysis of associated factors for ARDs found that a family history of allergic disorders (AOR: 2.80; p-value<0.01), use of insecticides (AOR: 2.05; p-value<0.01), and wearing open-toed shoes (AOR: 2.19; p-value = 0.02) were all significantly associated factors. Insecticide use, river-bathing, and infection with intestinal parasites were found to be significantly associated factors for atopy. Other potential risk factors such as frequent use of soap, bacterial infection, and household crowding had no statistical significance.

Conclusion

Our study suggests that the prevalence of skin sensitization and ARDs in rural populations of developing countries is still relatively low. We identified several possible risk factors for further investigation. Overall, the significance of identified risk factors appears to indicate that genetic predisposition and exposure to environmental pollution are more important to the etiology of ARDs and atopy than specific lifestyle behaviors.

Epithelial barrier dysfunctions in atopic dermatitis: a skin-gut-lung model linking microbiome alteration and immune dysregulation

BACKGROUND

Atopic dermatitis is a systemic disorder characterized by abnormal barrier function across multiple organ sites. Causes of epidermal barrier breakdown are complex and driven by a combination of structural, genetic, environmental and immunological factors. In addition, alteration in microflora diversity can influence disease severity, duration, and response to treatment. Clinically, atopic dermatitis can progress from skin disease to food allergy, allergic rhinitis, and later asthma, a phenomenon commonly known as the atopic march. The mechanism by which atopic dermatitis progresses towards gastrointestinal or airway disease remains to be elucidated.

OBJECTIVES

This review addresses how epithelial dysfunction linking microbiome alteration and immune dysregulation can predispose to the development of the atopic march.

METHODS

A literature search was conducted using the PubMed database for relevant articles with the keywords 'atopic dermatitis', 'epithelial barrier', 'skin', 'gut', 'lung', 'microbiome' and 'immune dysregulation'.

RESULTS

Initial disruption in the skin epidermal barrier permits allergen sensitization and colonization by pathogens. This induces a T helper 2 inflammatory response and a thymic stromal lymphopoietin-mediated pathway that further promotes barrier breakdown at distant sites, including the intestinal and respiratory tract.

CONCLUSIONS

As there are no immediate cures for food allergy or asthma, early intervention aimed at protecting the skin barrier and effective control of local and systemic inflammation may improve long-term outcomes and reduce allergen sensitization in the airway and gut.

Effects of treating helminths during pregnancy and early childhood on risk of allergy-related outcomes: Follow-up of a randomized controlled trial

BACKGROUND

Helminth infections, common in low-income countries, may protect against allergy-related disease. Early exposure may be a key. In the Entebbe Mother and Baby Study, treating helminths during pregnancy resulted in increased eczema rates in early childhood. We followed the cohort to determine whether this translated to increased asthma rates at school age.

METHODS

This randomized, double-blind, placebo-controlled trial, conducted in Entebbe, Uganda, had three interventions. During pregnancy, women were randomized, simultaneously, to albendazole vs placebo and to praziquantel vs placebo. Their children were independently randomized to quarterly albendazole vs placebo from age 15 months to 5 years. We here report follow-up to age 9 years. Primary outcomes at 9 years were recent reported wheeze, skin prick test positivity (SPT) to common allergens and allergen-specific IgE positivity to dust mite or cockroach. Secondary outcomes were doctor-diagnosed asthma and eczema rates between 5 and 9 years, recent eczema, rhinitis and urticaria at 9 years, and SPT and IgE responses to individual allergens.

RESULTS

2507 pregnant women were enrolled; 1215 children were seen at age nine, of whom 1188 are included in this analysis. Reported wheeze was rare at 9 years (3.7%) while SPT positivity (25.0%) and IgE positivity (44.1%) were common. There was no evidence of a treatment effect for any of the three interventions on any of the primary outcomes.

CONCLUSIONS

Prenatal and early-life treatment of helminths, in the absence of change in other exposures, is unlikely to increase the risk of atopic diseases later in childhood in this tropical, low-income setting.

Praziquantel for the treatment of schistosomiasis during human pregnancy

In 2014, an estimated 40 million women of reproductive age were infected with Schistosoma haematobium, S. japonicum and/or S. mansoni. In both 2003 and 2006, the World Health Organization (WHO) recommended that all schistosome-infected pregnant and breastfeeding women be offered treatment, with praziquantel, either individually or during treatment campaigns. In 2006, WHO also stated the need for randomized controlled trials to assess the safety and efficacy of such treatment. Some countries have yet to follow the recommendation on treatment and many programme managers and pregnant women in other countries remain reluctant to follow the recommended approach. Since 2006, two randomized controlled trials on the use of praziquantel during pregnancy have been conducted: one against S. mansoni in Uganda and the other against S. japonicum in the Philippines. In these trials, praziquantel treatment of pregnant women had no significant effect on birth weight, appeared safe and caused minimal side-effects that were similar to those seen in treated non-pregnant subjects. Having summarized the encouraging data, on efficacy, pharmacokinetics and safety, from these two trials and reviewed the safety data from non-interventional human studies, we recommend that all countries include pregnant women in praziquantel treatment campaigns. We identify the barriers to the treatment of pregnant women, in countries that already include such women in individual treatments and mass drug administration campaigns, and discuss ways to address these barriers.

Life-course of atopy and allergy-related disease events in tropical sub-Saharan Africa: A birth cohort study

BACKGROUND

In high-income countries, allergy-related diseases (ARDs) follow a typical sequence, the 'Atopic March'. Little is known about the life-course of ARDs in the markedly different, low-income, tropical environment. We describe ARDs in a tropical, African birth cohort.

METHODS

Ugandan children were followed from birth to 9 years. ISAAC questionnaires were completed at intervals; doctor-diagnosed ARDs were recorded throughout follow-up. Skin prick tests (SPTs) were performed at 3 and 9 years. Atopy was defined as ≥1 positive SPT.

RESULTS

Of the 2345 live-born children, 1214 (52%) were seen at 9 years. Wheeze and eczema were common in infancy, but by 9 years, only 4% reported recent wheeze, 5% eczema and 5% rhinitis. Between 3 and 9 years, atopy prevalence increased from 19% to 25%. Atopy at 3 or 9 years was associated with reported ARD events at 9 years, for example OR = 5.2 (95% CI 2.9-10.7) for atopy and recent wheeze at 9 years. Reported or doctor-diagnosed ARD events in early childhood were associated with the same events in later childhood, for example OR = 4.4 (2.3-8.4) for the association between reported wheeze before 3 years with reported recent wheeze at 9 years, but progression from early eczema to later rhinitis or asthma was not observed.

CONCLUSION

Allergen sensitization started early in childhood and increased with age. Eczema and wheeze were common in infancy and declined with age. Atopy was strongly associated with ARD among the few affected children. The typical Atopic March did not occur. Environmental exposures during childhood may dissociate atopy and ARD.