There are limited longitudinal data from non-industrialized settings on patterns and determinants of gut bacterial microbiota development in early childhood. We analysed epidemiological data and stool samples collected from 60 children followed from early infancy to 5 years of age in a rural tropical district in coastal Ecuador. Data were collected longitudinally on a wide variety of individual, maternal, and household exposures. Extracted DNA from stool samples were analysed for bacterial microbiota using 16S rRNA gene sequencing. Both alpha and beta diversity indices suggested stable profiles towards 5 years of age. Greater alpha diversity and lower beta diversity were associated with factors typical of rural poverty including low household incomes, overcrowding, and greater agricultural and animal exposures. Consumption of unpasteurized milk was consistently associated with greater alpha diversity indices. Delivery method and antibiotic exposures during pregnancy and early childhood appeared to have limited effects on developmental trajectories of gut microbiota. Infants living in a non-industrialized setting in conditions of greater poverty and typically rural exposures appeared to acquire more rapidly a stable and diverse gut bacterial microbiome during childhood.

Daily adherence to WHO recommended physical activity guidelines has multiple health benefits in children and adolescents. Limited data from low and middle-income countries are available regarding adherence to WHO physical activity recommendations. This study aims to objectively measure physical activity intensities and explore associations with sociodemographic and anthropometric factors related to nonadherence to the WHO minimum physical activity recommendations. Two cross-sectional studies were conducted between 2014 and 2019 in two distinct populations of Ecuador in terms of poverty and residency (Cuenca: 66% live in urban areas, and 38.2% have unsatisfied basic needs; Quininde, 76.4% live in rural areas and 91% have unsatisfied basic needs). Waist-worn accelerometers were used to measure daily physical activity, standardized questionnaires were used to assess sociodemographic variables (age, sex, ethnicity, and socioeconomic status), and anthropometric (weight, height, waist circumference) measurements were taken. Multivariable regression was used to assess the relationship between sociodemographic and anthropometric factors with physical activity in each study population. The study involved 650 participants in Cuenca, with a mean age of 9.1 years (SD 2.9), and 985 children and adolescents in Quinindé, with a mean age of 8.3 years (SD 0.4). In both settings, boys were more likely than girls (Cuenca: adj. OR 3.09, 95% CI 2.17-4.39; Quinindé adj. OR 5.63, 95% CI 4.03-7.85) to achieve the WHO physical activity guidelines. More affluent participants were much less likely to meet this recommendation than their poorer counterparts in both settings. In Cuenca, a higher waist circumference was inversely associated with meeting WHO daily physical activity recommendation (adj. OR 0.96, 95% CI 0.94-0.98), whereas in Quinindé, adherence to WHO guidelines was more likely in non-Mestizo than Mestizo children (adj. OR 1.45, 95% CI 1.02-2.07). The findings suggest that anthropometric differences and sociodemographic disparities influence the attainment of WHO physical activity recommendations in Ecuadorian children.

AbstractBackgroundThere are limited data from non‐industrialized settings on the effects of early life viral respiratory disease on childhood respiratory illness. We followed a birth cohort in tropical Ecuador to understand how early viral respiratory disease, in the context of exposures affecting airway inflammation including ascariasis, affect wheezing illness, asthma, and rhinoconjunctivitis in later childhood.MethodsA surveillance cohort nested within a birth cohort was monitored for respiratory infections during the first 2 years in rural Ecuador and followed for 8 years for the development of wheeze and rhinoconjunctivitis. Nasal swabs were examined for viruses by polymerase chain reaction and respiratory symptom data on recent wheeze and rhinoconjunctivitis were collected by periodic questionnaires at 3, 5, and 8 years. Stools from pregnant mothers and periodically from children aged 2 years were examined microscopically for soil‐transmitted helminths. Atopy was measured by allergen skin prick testing at 2 years. Spirometry, fractional exhaled nitric oxide measurement, and nasal washes were performed at 8 years. Associations between clinically significant respiratory disease (CSRD) and wheezing or rhinoconjunctivitis at 3, 5, and 8 years were estimated using multivariable logistic regression.ResultsFour hundred and twenty six children were followed of which 67.7% had at least one CSRD episode; 12% had respiratory syncytial virus (RSV)+CSRD and 36% had rhinovirus (RHV)+CSRD. All‐cause CSRD was associated with increased wheeze at 3 (OR 2.33 [95% confidence intervals (CI) 1.23–4.40]) and 5 (OR: 2.12 [95% CI 1.12–4.01]) years. RHV+CSRD was more strongly associated with wheeze at 3 years in STH‐infected (STH‐infected [OR 13.41, 95% CI 1.56–115.64] vs. uninfected [OR 1.68, 95% CI 0.73–3.84]) and SPT+ (SPT+ [OR 9.42, 95% CI 1.88–47.15] versus SPT‐ [OR 1.92, 95% CI 0.84–4.38]) children. No associations were observed between CSRD and rhinoconjunctivitis.DiscussionCSRD was significantly associated with childhood wheeze with stronger associations observed for RHV+CSRD in SPT+ and STH‐infected children.

Abstract Asthma is an important health concern in Latin America (LA) where it is associated with variable prevalence and disease burden between countries. High prevalence and morbidity have been observed in some regions, particularly marginalized urban populations. Research over the past 10 years from LA has shown that childhood disease is primarily non‐atopic. The attenuation of atopy may be explained by enhanced immune regulation induced by intense exposures to environmental factors such as childhood infections and poor environmental conditions of the urban poor. Non‐atopic symptoms are associated with environmental and lifestyle factors including poor living conditions, respiratory infections, psychosocial stress, obesity, and a diet of highly processed foods. Ancestry (particularly African) and genetic factors increase asthma risk, and some of these factors may be specific to LA settings. Asthma in LA tends to be poorly controlled and depends on access to health care and medications. There is a need to improve management and access to medication through primary health care. Future research should consider the heterogeneity of asthma to identify relevant endotypes and underlying causes. The outcome of such research will need to focus on implementable strategies relevant to populations living in resource‐poor settings where the disease burden is greatest.

Introduction: There are limited data on emergence of allergic sensitization (or atopy) during childhood in tropical regions. Methods: We followed a birth cohort of 2,404 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 the age-dependent risk of positive SPT (SPT+) to any allergen or mite during early childhood. 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 (3rd−4th vs. 1st−2nd: 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 show the emergence of allergic sensitization, primarily to mite and cockroach allergens, during childhood in tropical Ecuador. A role for both antenatal and post-natal factors acting as potential determinants of SPT+ emergence was observed.

Study effect of maternal geohelminths and infections in children during the first 5 years on atopy, wheeze/asthma, and airways reactivity/inflammation at 8 years. Birth cohort of 2,404 neonates followed to 8 years in rural Ecuador. Data on wheeze/asthma were collected by questionnaire and atopy by skin prick test (SPT) reactivity to 9 allergens. We measured airways reactivity to bronchodilator, fractional exhaled nitric oxide (FeNO), and nasal eosinophilia. Stool samples were examined for geohelminths by microscopy. 1,933 FeNO eosinophilia geohelminth exposures on childhood atopy but highlight the complex nature of the relationship between geohelminths and the airways. Registered as an observational study (ISRCTN41239086).

Background: Early-life exposures to geohelminths may protect against the development of wheeze/asthma and atopy. Objective: Study effect of maternal geohelminths and infections in children during the first 5 years of life on atopy, wheeze/asthma, and airways reactivity/inflammation at 8 years. Methods: Birth cohort of 2,404 neonates followed to 8 years in rural Ecuador. Data on wheeze/asthma were collected by questionnaire and atopy by skin prick test (SPT) reactivity to 9 allergens. We measured airways reactivity to bronchodilator, fractional exhaled nitric oxide (FeNO), and nasal eosinophilia. Stool samples were examined for geohelminths by microscopy. Results: 1,933 (80.4%) children were evaluated at 8 years. Geohelminths were detected in 45.8% of mothers and in 45.5% of children to 5 years. Frequencies of outcomes at 8 years were: wheeze (6.6%), asthma between 5 and 8 years (7.9%), SPT (14.7%), airways reactivity (10%), and elevated FeNO (10.3%) and nasal eosinophilia (9.2%). Any maternal geohelminth was associated with reduced prevalence of SPT (OR 0.72). Childhood T. trichiura infections were associated with reduced wheeze (OR 0.57) but greater parasite burdens with A. lumbricoides were associated with increased wheeze (OR 2.83) and asthma (OR 2.60). Associations between maternal geohelminths and wheeze/asthma were modified by atopy. Parasite-specific effects on wheeze/asthma and airways reactivity and inflammation were observed in non-atopic children. Conclusions: Our data provide novel evidence for persistent effects of in utero geohelminth exposures on childhood atopy but highlight the complex nature of the relationship between geohelminths and the airways. Registered as an observational study (ISRCTN41239086).

Background There are few prospective longitudinal studies of soil-transmitted helminth (STH) infections during early childhood. We studied the epidemiology of and risk factors for soil-transmitted helminth infections from birth to 8 years of age in tropical Ecuador. Methods 2,404 newborns were followed to 8 years of age with periodic stool sample collections. Stool samples were collected also from household members at the time of the child's birth and examined by microscopy. Data on social, environmental, and demographic characteristics were collected by maternal questionnaire. Associations between potential risk factors and STH infections were estimated using generalized estimated equations applied to longitudinal binary outcomes for presence or absence of infections at collection times. Results Of 2,404 children, 1,120 (46.6%) were infected with at least one STH infection during the first 8 years of life. The risk of A. lumbricoides (16.2%) was greatest at 3 years, while risks of any STH (25.1%) and T. trichiura (16.5%) peaked at 5 years. Factors significantly associated with any STH infection in multivariable analyses included age, day-care (OR 1.34, 95% CI 1.03-1.73), maternal Afro-Ecuadorian ethnicity (non-Afro vs. Afro, OR 0.55, 95% CI 0.43-0.70) and lower educational level (secondary vs. illiterate, OR 0.31, 95% CI 0.22-0.45)), household overcrowding (OR 1.53, 95% CI 1.21-1.94)), having a latrine rather than a water closet (WC vs. latrine, OR 0.77, 95% CI 0.62-0.95)), and STH infections among household members (OR 2.03, 95% CI 1.59-2.58)). T. trichiura was more associated with poverty (high vs. low socioeconomic status, OR, 0.63, 95% CI 0.40-0.99)] and presence of infected siblings in the household (OR 3.42, 95% CI 2.24-5.22). Conclusion STH infections, principally with A. lumbricoides and T. trichiura, peaked between 3 and 5 years in this cohort of children in tropical Ecuador. STH infections among household members were an important determinant of infection risk and could be targeted for control and elimination strategies.

BackgroundThe urbanisation process has been associated with increases in asthma prevalence, an observation supported largely by studies comparing urban with rural populations. The nature of this association remains poorly understood, likely because of the limitations of the urban–rural approach to understand what a multidimensional process is.ObjectiveThis study explored the relationship between the urbanisation process and asthma prevalence using a multidimensional and quantitative measure of urbanicity.MethodsA cross-sectional analysis was conducted in 1843 children living in areas with diverse levels of urbanisation in the district of Quinindé, Ecuador in 2013–2015. Categorical principal components analysis was used to generate an urbanicity score derived from 18 indicators measured at census ward level based on data from the national census in 2010. Indicators represent demographic, socioeconomic, built environment and geographical dimensions of the urbanisation process. Geographical information system analysis was used to allocate observations and urban characteristics to census wards. Logistic random effects regression models were used to identify associations between urbanicity score, urban indicators and three widely used definitions for asthma.ResultsThe prevalence of wheeze ever, current wheeze and doctor diagnosis of asthma was 33.3%, 13% and 6.9%, respectively. The urbanicity score ranged 0–10. Positive significant associations were observed between the urbanicity score and wheeze ever (adjusted OR=1.033, 95% CI 1.01 to 1.07, p=0.05) and doctor diagnosis (adjusted OR=1.06, 95% CI 1.02 to 1.1, p=0.001). For each point of increase in urbanicity score, the prevalence of wheeze ever and doctor diagnosis of asthma increased by 3.3% and 6%, respectively. Variables related to socioeconomic and geographical dimensions of the urbanisation process were associated with greater prevalence of wheeze/asthma outcomes.ConclusionsEven small increases in urbanicity are associated with a higher prevalence of asthma in an area undergoing the urban transition. The use of a multidimensional urbanicity indicator has greater explanatory power than the widely used urban–rural dichotomy to improve our understanding of how the process of urbanisation affects the risk of asthma.

There is considerable interest as to potential protective effects of soil-transmitted helminths (STH) against allergy and allergic diseases. Here, we discuss findings of studies done of the effects of STH parasites on atopy and allergic diseases in Ecuador. While cross-sectional studies have consistently shown a reduced prevalence of allergen skin prick test (SPT) reactivity among infected schoolchildren, the removal of these infections by repeated deworming did not affect SPT prevalence over the short-term (ie, 12 months) but may have increased SPT prevalence over the long-term (ie, 15-17 years). In the case of allergic symptoms, cross-sectional studies have generally not shown associations with STH and intervention studies showed no impact on prevalence. However, a birth cohort suggested that early STH infections might reduce wheeze by 5 years. Allergic sensitization to Ascaris, however, explained a significant proportion of wheezing among rural schoolchildren. Studies of the effects of STH on immune and inflammatory responses indicated a potential role of STH in contributing to more robust regulation. The effects of STH on allergy are likely to be determined by history of exposure over the life-course and by interactions with a wide variety of other infectious and non-infectious factors.

Rationale: Exposures to geohelminths during gestation or early childhood may reduce risk of wheezing illness/asthma and atopy during childhood in tropical regions. Objectives: To investigate the effect of maternal and early childhood geohelminths on development of wheeze/asthma and atopy during the first 5 years of life. Methods: A cohort of 2,404 neonates was followed to 5 years of age in a rural district in coastal Ecuador. Data on wheeze were collected by questionnaire and atopy was measured by allergen skin prick test reactivity to 10 allergens at 5 years. Stool samples from mothers and children were examined for geohelminths by microscopy. Measurements and Main Results: A total of 2,090 (86.9%) children were evaluated at 5 years. Geohelminths were observed in 45.5% of mothers and in 34.1% of children by 3 years. Wheeze and asthma were reported for 12.6% and 5.7% of children, respectively, whereas 14.0% had skin test reactivity at 5 years. Maternal geohelminths were associated with an increased risk of wheeze (adjusted odds ratio, 1.41; 95% confidence interval, 1.06-1.88), whereas childhood geohelminths over the first 3 years of life were associated with reduced risk of wheeze (adjusted odds ratio, 0.70; 95% confidence interval, 0.52-0.96) and asthma (adjusted odds ratio, 0.60; 95% confidence interval, 0.38-0.94) but not skin prick test reactivity. The effects on wheeze/asthma were greatest with later age of first infection, were observed only in skin test-negative children, but were not associated with parasite burden or specific geohelminths. Conclusions: Although maternal exposures to geohelminths may increase childhood wheeze, childhood geohelminths during the first 3 years may provide protection through a nonallergic mechanism. Registered as an observational study (ISRCTN41239086).

AbstractMore than 2 billion people are infected with parasites globally, and the majority have coinfections. Intestinal protozoa and helminths induce polarizing CD4+ T-helper cell 1 (Th1) mediated cytokine responses within the host. Such immune polarization may inhibit the ability of the host to mount an adequate immune response for pathogen clearance to concurrent pathogens. The current study evaluated the plasma cytokine profile in Ascaris and Giardia coinfected children compared with Giardia- and Ascaris-only infected children. Fecal samples and blood samples were collected from asymptomatic 3-year-old children living in the district of Quininde, Ecuador. Stool samples that tested positive for Giardia lamblia-only, Ascaris lumbricoides-only, or G. lamblia and A. lumbricoides coinfections were confirmed by quantitative real-time polymerase chain reaction. Plasma samples from the study subjects were used to quantitate cytokines. A total of 39 patients were evaluated. Children with coinfection had a significant decrease in Th1 cytokine production, interleukin 2 (IL-2) (P < 0.05), IL-12 (P < 0.05), and tumor necrosis factor alpha (P < 0.05) compared with Giardia-only infected children. Coinfected children had an increase in IL-10/interferon gamma (IFN-γ) ratio compared with uninfected (P < 0.05) and Ascaris alone (P < 0.05). The increased IL-10/IFN-γ ratio in the setting of decreased Th1 cytokine response indicates Th2 polarization in the coinfected group. Reduced Th1 cytokines in children coinfected with Ascaris and Giardia may impair the host's ability to eradicate Giardia infection leading to chronic giardiasis.

Background: Asthma is the most prevalent chronic disease of childhood. Recently, we identified a critical window early in the life of both mice and Canadian infants during which gut microbial changes (dysbiosis) affect asthma development. Given geographic differences in human gut microbiota worldwide, we studied the effects of gut microbial dysbiosis on atopic wheeze in a population living in a distinct developing world environment. Objective: We sought to determine whether microbial alterations in early infancy are associated with the development of atopic wheeze in a nonindustrialized setting. Methods: We conducted a case-control study nested within a birth cohort from rural Ecuador in which we identified 27 children with atopic wheeze and 70 healthy control subjects at 5 years of age. We analyzed bacterial and eukaryotic gut microbiota in stool samples collected at 3 months of age using 16S and 18S sequencing. Bacterial metagenomes were predicted from 16S rRNA data by using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States and categorized by function with Kyoto Encyclopedia of Genes and Genomes ontology. Concentrations of fecal short-chain fatty acids were determined by using gas chromatography. Results: As previously observed in Canadian infants, microbial dysbiosis at 3 months of age was associated with later development of atopic wheeze. However, the dysbiosis in Ecuadorian babies involved different bacterial taxa, was more pronounced, and also involved several fungal taxa. Predicted metagenomic analysis emphasized significant dysbiosis-associated differences in genes involved in carbohydrate and taurine metabolism. Levels of the fecal short-chain fatty acids acetate and caproate were reduced and increased, respectively, in the 3-month stool samples of children who went on to have atopic wheeze. Conclusions: Our findings support the importance of fungal and bacterial microbiota during the first 100 days of life on the development of atopic wheeze and provide additional support for considering modulation of the gut microbiome as a primary asthma prevention strategy.

Introduction The urbanisation process has been associated with increases in asthma prevalence in urban and rural areas of low-income and middle-income countries (LMICs). However, although rural to urban migration and migration between cities are considered important determinants of this process, few studies have evaluated the effects of internal migration on asthma in urban populations of LMICs. The present study evaluated the effects of internal migration on the prevalence of wheeze in an urban area of Latin America.Methods We did a cross-sectional analysis of 2510 schoolchildren living in the city of Esmeraldas, Ecuador. Logistic regression was used to analyse associations between childhood wheeze and different aspects of migration among schoolchildren.Results 31% of schoolchildren were migrants. Rural to urban migrants had a higher prevalence of wheeze, (adj. OR=2.01,95% CI1.30 to 3.01, p=0.001) compared with non-migrants. Age of migration and time since migration were associated with wheeze only for rural to urban migrants but not for urban to urban migrants. Children who had migrated after 3 years of age had a greater risk of wheeze (OR 2.51, 95% CI 1.56 to 3.97, p=0.001) than non-migrants while migrants with less than 5 years living in the new residence had a higher prevalence of wheeze than non-migrants (<3 years: OR=2.34, 95% CI 1.26 to 4.33, p<0.007 and 3-5 years: OR=3.03, 95% CI 1.49 to 6.15, p<0.002).Conclusions Our study provides evidence that rural to urban migration is associated with an increase in the prevalence of wheeze among schoolchildren living in a Latin-American city. Age of migration and time since migration were important determinants of wheeze only among migrants from rural areas. A better understanding of the social and environmental effects of internal migration could improve our understanding of the causes of the increase in asthma and differences in prevalence between urban and rural populations.

Studies in developing countries (DCs) have frequently reported a lower prevalence of allergic diseases (ADs) in rural areas compared with urban settings, and this has been attributed to the protective effects of environmental exposures such as rural lifestyle.1von Hertzen L. Haahtela T. Disconnection of man and the soil: reason for the asthma and atopy epidemic?.J Allergy Clin Immunol. 2006; 117: 334-344Abstract Full Text Full Text PDF PubMed Scopus (94) Google Scholar Recent evidence from studies conducted in Africa and Asia showed that ADs are increasing in urban and even in rural settings, reducing the urban-rural prevalence gap.2Addo-Yobo E.O.D. Woodcock A. Allotey A. Baffoe-Bonnie B. Strachan D. Custovic A. Exercise-induced bronchospasm and atopy in Ghana: two surveys ten years apart.PLoS Med. 2007; 4: 0355-0360Crossref Scopus (85) Google Scholar, 3Selcuk Z.T. Demir A.U. Tabakoglu E. Caglar T. Prevalence of asthma and allergic diseases in primary school children in Edirne, Turkey, two surveys 10 years apart.Pediatr Allergy Immunol. 2010; 21: e711-e717Crossref PubMed Scopus (14) Google Scholar It has been hypothesized that temporal increases in the prevalence of ADs might be associated with urbanization processes, especially with the change from rural to more modern urban lifestyles.1von Hertzen L. Haahtela T. Disconnection of man and the soil: reason for the asthma and atopy epidemic?.J Allergy Clin Immunol. 2006; 117: 334-344Abstract Full Text Full Text PDF PubMed Scopus (94) Google Scholar Migration is an important component of the urbanization process and involves socioeconomic, environmental, and lifestyle changes in rural and urban populations. However, the effects of migration on ADs in urban and rural settings of DCs have not been explored.4Cooper P.J. Chico M.E. Vaca M.G. Rodriguez A. Alcântara-Neves N.M. Genser B. et al.Risk factors for asthma and allergy associated with urban migration: background and methodology of a cross-sectional study in Afro-Ecuadorian school children in Northeastern Ecuador (Esmeraldas-SCAALA Study).BMC Pulm Med. 2006; 6: 24Crossref PubMed Scopus (31) Google Scholar The impact of migration on ADs has been largely investigated by comparing populations that have migrated from DCs (presumed low risk for ADs) to developed countries (presumed high risk).5Cabieses B. Uphoff E. Pinart M. Antó J.M. Wright J. A systematic review on the development of asthma and allergic diseases in relation to international immigration: the leading role of the environment confirmed.PLoS One. 2014; 9: e105347Crossref PubMed Scopus (81) Google Scholar These studies have shown that being born in a country of low risk provides protection against asthma, but this protection may decline with the length of residence in the new environment.5Cabieses B. Uphoff E. Pinart M. Antó J.M. Wright J. A systematic review on the development of asthma and allergic diseases in relation to international immigration: the leading role of the environment confirmed.PLoS One. 2014; 9: e105347Crossref PubMed Scopus (81) Google Scholar Others studies have shown that age of migration and time since migration are associated with the risk of asthma and other ADs, often leading to a higher risk of atopy and allergy among migrants than among the local population.6Rottem M. Szyper-Kravitz M. Shoenfeld Y. Atopy and asthma in migrants.Int Arch Allergy Immunol. 2005; 136: 198-204Crossref PubMed Scopus (76) Google Scholar The Social Changes, Asthma and Allergy in Latin America (SCAALA) study has been investigating the effects of migration on the prevalence of ADs in schoolchildren living in rural and urban areas.4Cooper P.J. Chico M.E. Vaca M.G. Rodriguez A. Alcântara-Neves N.M. Genser B. et al.Risk factors for asthma and allergy associated with urban migration: background and methodology of a cross-sectional study in Afro-Ecuadorian school children in Northeastern Ecuador (Esmeraldas-SCAALA Study).BMC Pulm Med. 2006; 6: 24Crossref PubMed Scopus (31) Google Scholar We studied 4295 rural and 2510 urban children aged 5 to 16 years attending a convenience sample of schools in Esmeraldas province, Ecuador. Data on potential risk factors, migration (direction and distance of migration, age at migration, and time since migration), and wheeze, rhinitis, and eczema symptoms within the previous 12 months were collected using an investigator-administered questionnaire that included the core allergy questions of the International Study of Asthma and Allergies in Childhood (ISAAC phase II).4Cooper P.J. Chico M.E. Vaca M.G. Rodriguez A. Alcântara-Neves N.M. Genser B. et al.Risk factors for asthma and allergy associated with urban migration: background and methodology of a cross-sectional study in Afro-Ecuadorian school children in Northeastern Ecuador (Esmeraldas-SCAALA Study).BMC Pulm Med. 2006; 6: 24Crossref PubMed Scopus (31) Google Scholar Atopy was measured by skin prick testing to 7 aeroallergens. Results from the rural area showed that children who migrated during the first year of life had a greater risk of wheeze and rhinitis than did nonmigrant children and that children with a history of international migration (children from rural areas of Colombia) had a higher prevalence of rhinitis than did nonmigrant children (Table I). The study also evaluated the effects of maternal migration on allergic outcomes in children using the variables maternal history of migration and children living with one or no parent. These analyses suggested that children whose mothers had a history of migration had a greater risk of eczema compared with children whose mother did not, and children who did not live with any parent had more wheeze than did children living with both parents (Table I). The magnitude of the latter association was greater for all allergic symptoms among children of migrant mothers (Table II). No associations were observed for atopy (at least 1 positive allergen skin test result).Table IORs and 95% CIs for associations between migration variables and allergic symptoms adjusted for sex, age, and socioeconomic statusVariableCategoryNOR (95% CI)WheezeRhinitisEczemaDirection of migrationNM2964111Rural to rural5551.13 (0.84-1.52)1.02 (0.7-1.49)1.23 (0.82-1.83)Urban to rural7760.97 (0.74-1.27)1.18 (0.86-1.61)1.16 (0.81-1.66)Distance of migrationNM2964111National12630.99 (0.79-1.25)1.04 (0.79-1.38)1.21 (0.90-1.64)International681.71 (0.88-3.32)2.39 (1.16-4.92)∗P < .05.0.64 (0.16-2.66)Age at migration (y)NM2964111<12691.47 (1.02-2.12)∗P < .05.1.59 (1.03-2.46)∗P < .05.1.25 (0.73-2.14)1-55600.96 (0.71-1.31)1.18 (0.83-1.69)1.17 (0.78-1.75)>55020.88 (0.62-1.24)0.76 (0.48-1.19)1.16 (0.75-1.79)Time since migration (y)NM2964111<3 vs NM3830.98 (0.68-1.4)0.94 (0.6-1.49)0.96 (0.57-1.61)3-5 vs NM1970.56 (0.31-1.02)0.9 (0.48-1.69)1.53 (0.86-2.7)>5 vs NM7511.21 (0.94-1.58)1.26 (0.92-1.73)1.21 (0.85-1.73)Maternal history of migrationNo3314111Yes9811.22 (0.96-1.53)1.24 (0.93-1.65)1.88 (1.39-2.53)∗P < .05.Parents living in the child's houseBoth2490111One11461.07 (0.84-1.36)1.16 (0.87-1.54)1.21 (0.88-1.67)None6591.57 (1.2-2.05)∗P < .05.1.29 (0.92-1.81)1.27 (0.86-1.86)NM, No migrant; OR, odds ratio.Outcomes were defined as recent wheeze—reported wheezing during the previous 12 months; recent eczema—having a reported itchy rash with a flexural distribution in the previous 12 months; and recent rhinitis—nasal stuffiness or sneezing without a cold accompanied by itchy eyes in the previous 12 months.∗ P < .05. Open table in a new tab Table IIORs and 95% CIs for associations between allergic symptoms and parents living in the child's home (live with parents) stratified by maternal history of migration∗ORs adjusted for sex, age, and socioeconomic status.Allergic symptomLive with parentsMaternal history of migrationNoYesOR∗ORs adjusted for sex, age, and socioeconomic status.95% CIP valueOR∗ORs adjusted for sex, age, and socioeconomic status.95% CIP valueWheezeOne vs both10.76-1.34.9761.20.77-1.87.429None vs both1.441.06-1.95.022.171.25-3.77.006RhinitisOne vs both1.030.73-1.46.8581.460.85-2.52.171None vs both1.10.74-1.64.6272.071.05-4.08.036EczemaOne vs both0.960.63-1.46.8571.630.95-2.77.074None vs both1.030.64-1.65.9162.121.07-4.17.031OR, Odds ratio.∗ ORs adjusted for sex, age, and socioeconomic status. Open table in a new tab NM, No migrant; OR, odds ratio. Outcomes were defined as recent wheeze—reported wheezing during the previous 12 months; recent eczema—having a reported itchy rash with a flexural distribution in the previous 12 months; and recent rhinitis—nasal stuffiness or sneezing without a cold accompanied by itchy eyes in the previous 12 months. OR, Odds ratio. The present study is unique in investigating migrants within a rural area of a DC, where migrants come from urban and rural settings. In this setting, age at migration and international migration were important factors associated with a higher risk of ADs in rural populations. A novel observation was the effect of migrant status of the mother on the prevalence of ADs: children of migrant mothers not living with either parent had a 2-fold greater risk of all 3 ADs compared with children living with both parents. These data raise a question: Could it be that social effects of migration, such as absence of parents at home, are important determinants of the increase in ADs in rural populations of DCs? To answer this question, we need to consider some demographic patterns in these regions. It is well known that people in rural villages move to urban areas, temporally or permanently, in search of work to improve their quality of life. A high proportion of these rural migrants are single women who provide economic support for their families. Most of these women leave their children in the community of origin to be cared for by relatives. Some of these immigrants are able to settle in the city while others return to their rural communities.7Mujeres migrantes de América Latina y el Caribe: derechos humanos, mitos y duras realidades. Comisión Económica para América Latina y el Caribe, Santiago de Chile2005http://www.cepal.org/es/publicaciones/7200-mujeres-migrantes-de-america-latina-y-el-caribe-derechos-humanos-mitos-y-durasGoogle Scholar In the SCAALA rural population, 31% of the children and 23% of the mothers had a history of migration and 15% of the children lived with no parent. If the absence of parents at home (especially the mother) is an important determinant of the increase in ADs in DCs, then 2 migration trends that have occurred over recent decades might help us understand temporal trends in ADs. In the past, most economic migrants were young men, but now "feminization of migration" is a growing trend worldwide because of a greater demand for female labor.8Chammartin G. The feminization of international migration.Int Migr Program Int Labour Organ. 2002; (Available at:) (Accessed May 5, 2016): 37-40http://library.fes.de/pdf-files/gurn/00072.pdfGoogle Scholar Second, "circular migration" is a common phenomenon in regions that are undergoing high levels of urbanization, and it refers to repeated migrations between rural and urban areas due to improvements in transport and modern forms of communication.9Beguy D. Bocquier P. Zulu E.M. Circular migration patterns and determinants in Nairobi slum settlements.Demogr Res. 2010; 23: 549-586Crossref Scopus (79) Google Scholar Migration affects not only the individuals who migrate but also their family. Migration impacts on roles, support structures, and responsibilities of family members, resulting in changes in social and psychological factors. In the case of maternal migration, children who remain in their community may experience heightened levels of stress and depression because of separation from their primary carer. Psychological mechanisms have been proposed to explain how emotional factors, in the context of family, might affect the development of allergic diseases.10Kaugars A.S. Klinnert M.D. Bender B.G. Family influences on pediatric asthma.J Pediatr Psychol. 2004; 29: 475-491Crossref PubMed Scopus (166) Google Scholar For this reason, we propose that the absence of the parents at home, through temporary or permanent migration, may contribute to the increase in ADs in rural and urban populations of DCs. Finally, further analyses in different populations living in rural and urban areas evaluating the effects of migration on ADs are required. A better understanding of the social, psychological, and environmental effects of migration on ADs in DCs is required.

Background. Many studies have documented lower vaccine efficacy among children in low-income countries, compared with their counterparts in high-income countries. This disparity is especially apparent with respect to oral vaccines such as rotavirus and oral polio vaccines. One potential contributing factor is the presence of maternal antenatal helminth infections, which can modulate the infant's developing immune system.Methods. Using a multiplex immunoassay, we tested plasma immunoglobulin A (IgA) or immunoglobulin G (IgG) levels specific for antigens in 9 routinely administered childhood vaccines among 1639 children aged approximately 13 months enrolled in the ECUAVIDA (Ecuador Life) birth cohort study in Ecuador. We compared vaccine responses in 712 children of mothers who tested positive for helminth infections in the last trimester of pregnancy to responses in 927 children of mothers without helminth infection.Results. Plasma IgA levels specific for antigens in rotavirus vaccine and oral polio vaccine containing poliovirus serotypes 1 and 3 were all significantly higher in children of helminth-infected mothers, compared with children of uninfected mothers. Plasma IgG levels specific for diphtheria, tetanus, pertussis, measles, rubella, and Haemophilus influenzae type b vaccine antigens were comparable between the 2 groups.Conclusions. Antenatal maternal helminth infections were not associated with reduced antibody responses to infant vaccines, but rather with modestly increased IgA responses to oral vaccines.

We describe immune phenotypes (innate and adaptive cytokines) according to environmental exposure using latent class analysis. A total of 310 schoolchildren living in Ecuador were assayed for spontaneous cytokine production as well as mitogen (SEB)-stimulated cytokines in whole blood cultures. We collected data on environmental exposures by questionnaire and on intestinal parasites by examination of stool samples. Latent class analysis (LCA) was used to group children according to their innate (IL-6, IL-8, IL-10 and TNF-α) and adaptive (IL-5, IL-13, IL-17, IFN-γ and IL-10) cytokine profile. We also conducted multiple-group LCA and LCA with covariates to evaluate the effect of predictors on profile membership. We identified both hyporesponsive and Th2-modified immune phenotypes produced by peripheral blood leukocytes (PBLs) that were associated with intestinal worms and birth order, providing insights into how poor hygiene mediates immunologic effects on immune-mediated diseases.

Background: Maternal geohelminth infections during pregnancy may protect against allergy development in childhood.Objective: We sought to investigate the effect of maternal geohelminths on the development of eczema, wheeze, and atopy during the first 3 years of life.Methods: A cohort of 2404 neonates was followed to 3 years of age in a rural district in coastal Ecuador. Data on wheeze and eczema were collected by means of questionnaire and physical examination at 13, 24, and 36 months of age. Atopy was measured based on skin prick test (SPT) reactivity to 9 allergens at 36 months. Maternal stool samples were examined for geohelminths by microscopy. Data on potential confounders was collected after birth by questionnaire.Results: Geohelminths were observed in 45.9% of mothers. Eczema and wheeze were reported for 17.7% and 25.9%, respectively, of 2069 (86.1%) children with complete follow-up to 3 years, and allergen SPT reactivity to any allergen was present in 17.2% and to house dust mite in 8.7%. Maternal geohelminth infections were not significantly associated with eczema (adjusted odds ratio [OR], 1.26; 95% CI, 0.98-1.61), wheeze (adjusted OR, 1.02; 95% CI, 0.82-1.27), and SPT reactivity to any allergen (adjusted OR, 0.79; 95% CI, 0.61-1.01). In subgroup analyses maternal geohelminths were associated with a significantly reduced risk of SPT reactivity to mite and other perennial allergens, and maternal ascariasis was associated with an increased risk of eczema and reduced risk of SPT reactivity to all allergens.Conclusion: Our data do not support a protective effect of maternal infections with geohelminth parasites during pregnancy against the development of eczema and wheeze in early childhood, although there was evidence in subgroup analyses for a reduction in SPT reactivity to house dust mites and perennial allergens.