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.
Bees are one of the most important creatures on Earth because of their pollination processes, which contribute to food security and ecosystem maintenance. The practice of apiculture is regarded as ...secondary. Nonetheless, producers find this activity appealing due to the added value of its products. Researchers have been paying attention to the genetic erosion processes of pollinators for decades. To propose a conservation plan for these insects, identification studies from individuals from those locations must be carried out in the same way because different environmental conditions promote individuals with distinct characteristics that are harder to see with the naked eye. A total of 45 Apis mellifera colonies were sampled from nine centers for rearing queens in the Camagüey province, Cuba. Wing geometric morphometric analysis was used to determine the ancestry and identify Africanization processes at different altitudes in managed honeybee populations on the island. A total of 350 reference wings were obtained from the pure subspecies: Apis mellifera mellifera, Apis mellifera carnica, Apis mellifera ligustica, Apis mellifera caucasia, Apis mellifera iberiensis, Apis mellifera intermissa, and Apis mellifera scutellata for the study. Our results showed that altitude influences wing shape; and that 96.0% (432) of the individuals were classified as Cuban hybrids, with a tendency to the formation of a new morphotype. In addition, a great similarity was found with the subspecies Apis mellifera mellifera, and it was confirmed that there is no Africanization due to the low presence of 0.44% (2) of this morphotype in the population under study. The greatest Mahalanobis distances were obtained for the comparisons between the center rearing of queens in the Camagüey province with the subspecies A. m. scutellata (Dsup.2 = 5.18); A. m. caucasia (Dsup.2 = 6.08); A. m. ligustica (Dsup.2 = 6.27); and A. m. carnica (Dsup.2 = 6.62). The well-defined pattern of wing shape produced by honeybee populations in Camagüey’s centers for queen rearing suggests a Cuban hybrid. Moreover, it is essential to note that the populations of bees under investigation lack Africanized morphotypes, indicating that Camagüey bees have not interacted with the African lineage.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Background
Early‐life exposures to geohelminths may protect against development of wheeze/asthma and atopy.
Objective
To study the effect of maternal geohelminths and infections in children during ...the first 5 years on atopy, wheeze/asthma and airways reactivity/inflammation at 8 years.
Methods
Birth cohort of 2404 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
1933 (80.4%) children were evaluated at 8 years. Geohelminths were detected in 45.8% of mothers and 45.5% of children to 5 years. Frequencies of outcomes at 8 years were as follows: 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 SPT prevalence (OR 0.72). Childhood Trichuris trichiura infections during the first 5 years were associated with reduced wheeze (OR 0.57) but greater parasite burdens with Ascaris lumbricoides at 5 years 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).
Maternal geohelminths protect 8‐year‐old children from the development of allergen skin prick test reactivity with strongest effects observed in infected children of infected mothers. Early childhood infections with Trichuris trichiura protect against wheeze at 8 years. Effects of geohelminths on wheeze/asthma and airways reactivity and inflammation at 8 years vary by parasite species and atopy.
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
and
coinfected children compared with
- and
-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
-only,
only, or
and
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) (
< 0.05), IL-12 (
< 0.05), and tumor necrosis factor alpha (
< 0.05) compared with
-only infected children. Coinfected children had an increase in IL-10/interferon gamma (IFN-γ) ratio compared with uninfected (
< 0.05) and
alone (
< 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
and
may impair the host's ability to eradicate
infection leading to chronic giardiasis.
Rural residence is protective against atopy and wheeze-rhinitis-eczema symptoms in developed countries, an effect attributed to farming and poor hygiene exposures. There are few data from developing ...countries addressing this question. We compared atopy and wheeze-rhinitis-eczema symptoms between urban and rural Ecuador, and explored the effects of farming and poor hygiene exposures.
We performed cross sectional studies of schoolchildren living in rural and urban Ecuador. Data on symptoms and farming/hygiene exposures were collected by parental questionnaire, atopy by allergen skin prick test reactivity and geohelminth infections by stool examinations.
Among 2526 urban and 4295 rural schoolchildren, prevalence was: atopy (10.0% vs 12.5%, p=0.06), wheeze (9.4% vs 10.1%, p=0.05), rhinitis (8.1% vs 6.4%, p=0.02) and eczema (5.9% vs 4.7%, p=0.06). A small proportion of symptoms were attributable to atopy (range 3.9-10.7%) with greater attributable fractions for respiratory symptoms observed in urban schoolchildren. Respiratory symptoms were associated with poor hygiene/farming exposures: wheeze with lack of access to potable water; and rhinitis with household pets, no bathroom facilities and contact with large farm animals. Birth order was inversely associated with respiratory symptoms. Area of residence and atopy had few effects on these associations.
Urban schoolchildren living in Ecuador have a similar prevalence of atopy, eczema and wheeze but a higher prevalence of rhinitis compared with rural children. Some farming and poor hygiene exposures were associated with an increase in the prevalence of wheeze or rhinitis while birth order was inversely associated with these symptoms.
Immune responses to oral vaccines are impaired in populations living in conditions of poverty in developing countries, and there is evidence that concurrent geohelminth infections may contribute to ...this effect. We vaccinated 48 children living in rural communities in Ecuador with a single oral dose of 100 mg of BCG Moreau RDJ and measured the frequencies of tuberculin-stimulated peripheral blood mononuclear cells expressing IFN-γ before and after vaccination. Vaccinated children had active ascariasis (n=20) or had been infected but received short- (n=13) or long-term (n=15) repeated treatments with albendazole prior to vaccination to treat ascariasis. All children had a BCG scar from neonatal vaccination. There was no evidence of a boosting of postvaccination IFN-γ responses in any of the 3 study groups. Our data provide support for the presence of a barrier to oral vaccination among children from the rural tropics that appeared to be independent of concurrent ascariasis.
Studies conducted in transitional communities from Africa and Asia have pointed to the process of urbanisation as being responsible for the increase in asthma prevalence in developing regions. In ...Latin America, there are few published data available on the potential impact of urbanisation on asthma prevalence. The aim of the present study was to explore how the process of urbanisation may explain differences in asthma prevalence in transitional communities in north-eastern Ecuador.
An ecological study was conducted in 59 communities in Esmeraldas Province, Ecuador. Indicators of urbanisation were grouped into three indices representing the processes associated with urbanisation: socioeconomic, lifestyle and urban infrastructure. Categorical principal components analysis was used to generate scores for each index and a fourth index--a summary urbanisation index--was derived from the most representative variables in each of the three indices. The authors analysed the associations between community asthma prevalence and the indices, as well as with each indicator variable of every group. The overall prevalence of asthma was 10.1% (range 0-31.4% between communities). Three of the four indices presented significant associations with community asthma prevalence: socioeconomic (r = 0.295, p = 0.023), lifestyle (r = 0.342, p = 0.008) and summary urbanisation index (r = 0.355, p = 0.006). Variables reflecting better socioeconomic status and a more urban lifestyle were associated with greater asthma prevalence.
These data provide evidence that the prevalence of asthma increases with increasing levels of urbanisation in transitional communities, and factors associated with greater socioeconomic level and changes towards a more urban lifestyle may be particularly important.
Conclusions Our data indicate that RV infection in our population is a risk factor for wheezing illness in under 7s while RSV infection is related more to ILI irrespective of wheeze.
BACKGROUND Asthma has emerged as an important public health problem of urban populations in Latin America. Epidemiological data suggest that a minority of asthma cases in Latin America may be ...associated with allergic sensitisation and that other mechanisms causing asthma have been overlooked. The aim of the present study was to investigate risk factors for atopic and non-atopic asthma in school-age children. METHODS A cross-sectional study was conducted among 3960 children aged 6-16 years living in Afro-Ecuadorian rural communities in Esmeraldas province in Ecuador. Allergic diseases and risk factors were assessed by questionnaire and allergic sensitisation by allergen skin prick reactivity. RESULTS A total of 390 (10.5%) children had wheeze within the previous 12 months, of whom 14.4% had at least one positive skin test. The population-attributable fraction for recent wheeze associated with atopy was 2.4%. Heavy Trichuris trichiura infections were strongly inversely associated with atopic wheeze. Non-atopic wheeze was positively associated with maternal allergic symptoms and sedentarism (watching television (>3 h/day)) but inversely associated with age and birth order. CONCLUSIONS The present study showed a predominance of non-atopic compared with atopic wheeze among schoolchildren living in a poor rural region of tropical Latin America. Distinct risk factors were associated with the two wheeze phenotypes and may indicate different causal mechanisms. Future preventive strategies in such populations may need to be targeted at the causes of non-atopic wheeze.
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