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The ECUAVIDA birth cohort is studying the impact of exposures to soil-transmitted helminth (STH) parasites and early-life microbial exposures on the development of atopy, allergic diseases and immune responses in childhood. A total of 2404 newborns were recruited between 2006 and 2009 in a public hospital serving the rural district of Quininde, Esmeraldas Province, in a tropical region of coastal Ecuador. Detailed measurements were done around the time of the birth, at 7 and 13 months and at 2 and 3 years, and data collection is ongoing at 5 and 8 years. Data being collected include questionnaires for: sociodemographic, lifestyle, psychosocial (at 4-6 years only) and dietary (at 6-7 years only) factors; childhood morbidity and clinical outcomes; stool samples for parasites; blood samples for DNA, measurements of vaccine responses and other measures of immune function/inflammation; and anthropometrics. Allergen skin prick test reactivity is done from 2 years and measures of airway function and inflammation at 8 years. [ABSTRACT FROM AUTHOR]

Background. In areas where intestinal helminth infections are endemic, infections by these parasites may protect against skin test-measured reactivity to allergens, and it has been suggested that interleukin (IL)-10 may mediate this effect. This study investigated whether IL-10 and populations of IL-10+ T cells may modulate atopy in children living in an area where intestinal helminth infections are endemic. Methods. Ecuadorian schoolchildren from rural communities were assessed for skin test-measured reactivity to Periplaneta americana allergen and Dermatophagoides pteronyssinus allergen. Blood samples were collected from 39 skin test-positive and 41 skin test-negative children, and peripheral-blood leukocytes were cultured in the presence of Ascaris lumbricoides antigen, to measure IL-10 protein and the frequency of T cell populations expressing intracellular IL-10. We also investigated whether these immunological factors affected the association between allergen-specific IgE and skin test-measured reactivity to aeroallergens. Results. There was no evidence of association between the level of A. lumbricoides-induced IL-10 protein or IL-10+ T cells and skin test-measured reactivity to allergens. The association between allergen-specific IgE and skin test-measured reactivity was not affected by the level of IL-10 protein or the frequency of IL-10+ T cells. Conclusions. The results of this study do not support the notion that IL-10 plays a role in modulating atopy in children living in a tropical area where intestinal helminth infections are endemic. [ABSTRACT FROM AUTHOR]

Studies have shown a strong inverse relationship between atopy and geohelminth infection, indicating that atopy may protect against geohelminth infection. Resistance to ascariasis in atopic individuals may occur through greater immunoglobulin E-mediated responses and expression of T helper cell type 2 (Th2) cytokines to parasite antigens. To investigate the effect that atopy has on the immune response to Ascaris antigens, school-age children were recruited from rural schools in Ecuador. Immunologic variables were compared between children stratified by atopic and/or A. lumbricoides-infection status; the variables included cytokine expression by peripheral-blood mononuclear cells (PBMCs) and histamine release in response to Ascaris antigens. Atopic children had both greater frequencies of PBMCs expressing interleukin (IL)-4 and IL-5 and enhanced histamine release, compared with those in nonatopic children. Stratification by atopic and A. lumbricoides-infection status revealed the greatest histamine and Th2 cytokine responses in the stratum of atopic, noninfected children. Multivariate regression analyses showed significant effects for atopic status but not for infection status on Th2 cytokine expression and histamine release. [ABSTRACT FROM AUTHOR]

Investigates the cytokine and antibody response to adult and larval stages of Ascaris lumbricoides in infected young adults living in an endemic area of Ecuador. Frequencies of peripheral blood mononuclear cells secreting interleukin (IL)-10, interferon-gamma, IL-4 and IL-5 in infected young adults; Levels of A. lumbricoides-specific antibodies in plasma from infected individuals.

Background: Most studies assessing pathophysiological heterogeneity in asthma have been conducted in high-income countries (HICs), with little known about the prevalence and characteristics of different asthma inflammatory phenotypes in low-and middle-income countries (LMICs). This study assessed sputum inflammatory phenotypes in five centres, in Brazil, Ecuador, Uganda, New Zealand (NZ) and the United Kingdom (UK).Methods: We conducted a cross-sectional study of 998 asthmatics and 356 non-asthmatics in 2016-20. All centres studied children and adolescents (age range 8-20 years), except the UK centre which involved 26-27 year-olds. Information was collected using questionnaires, clinical characterization, blood and induced sputum.Results: Of 623 asthmatics with sputum results, 39% (243) were classified as eosinophilic or mixed granulocytic, i.e. eosinophilic asthma (EA). Adjusted for age and sex, with NZ as baseline, the UK showed similar odds of EA (odds ratio 1.04, 95% confidence interval 0.37-2.94) with lower odds in the LMICs: Brazil (0.73, 0.42-1.27), Ecuador (0.40, 0.24-0.66) and Uganda (0.62, 0.37-1.04). Despite the low prevalence of neutrophilic asthma in most centres, sputum neutrophilia was increased in asthmatics and non-asthmatics in Uganda.Conclusions: This is the first time that sputum induction has been used to compare asthma inflammatory phenotypes in HICs and LMICs. Most cases were non-eosinophilic, including in settings where corticosteroid use was low. A lower prevalence of EA was observed in the LMICs than in the HICs. This has major implications for asthma prevention and management, and suggests that novel prevention strategies and therapies specifically targeting non-eosinophilic asthma are required globally. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background. Although norovirus is the most common cause of gastroenteritis, there are few data on the community incidence of infection/disease or the patterns of acquired immunity or innate resistance to norovirus. Methods. We followed a community-based birth cohort of 194 children in Ecuador with the aim to estimate (1) the incidence of norovirus gastroenteritis from birth to age 3 years, (2) the protective effect of norovirus infection against subsequent infection/disease, and (3) the association of infection and disease with FUT2 secretor status. Results. Over the 3-year period, we detected a mean of 2.26 diarrheal episodes per child (range, 0-12 episodes). Norovirus was detected in 260 samples (18%) but was not found more frequently in diarrheal samples (79 of 438 [18%]), compared with diarrhea-free samples (181 of 1016 [18%]; P = .919). A total of 66% of children had at least 1 norovirus infection during the first 3 years of life, and 40% of children had 2 infections. Previous norovirus infections were not associated with the risk of subsequent infection. All genogroup II, genotype 4 (GII.4) infections were among secretor-positive children (P < .001), but higher rates of non-GII.4 infections were found in secretor-negative children (relative risk, 0.56; P = .029). Conclusions. GII.4 infections were uniquely detected in secretor-positive children, while non-GII.4 infections were more often found in secretor-negative children. [ABSTRACT FROM AUTHOR]