89 research outputs found
Risk factors for acute asthma in tropical America: a case-control study in the City of Esmeraldas, Ecuador.
BACKGROUND: Despite the high asthma rates described in Latin America, asthma risk factors in poor urban settings are not well established. We investigated risk factors for acute asthma among Ecuadorian children. METHODS: A matched case-control study was carried out in a public hospital serving a coastal city. Children with acute asthma were age- and sex-matched to non-asthmatics. A questionnaire was administered, and blood, as well as stool, and nasopharyngeal swabs were collected. RESULTS: Sixty cases and 119 controls aged 5-15 were evaluated. High proportions of cases were atopic with population-attributable fractions for atopy of 68.5% for sIgE and 57.2% for SPT. Acute asthma risk increased with greater titers of mite IgE (3.51-50 kU/l vs. 50kU/l vs. <0.70kU/l - OR 41.98, 95% CI: 8.97-196.39, p < 0.001). Asthma risk was significantly independently associated with bronchiolitis (adj. OR: 38.9, 95% CI 3.26-465), parental educational level (adj. OR 1.26, 95% CI: 1.08-1.46), and presence of sIgE (adj. OR: 36.7, 95% CI: 4.00-337), while a reduced risk was associated with current contact with pets (adj. OR: 0.07, 95% CI: 0.01-0.56). Rhinovirus infection was more frequent in cases (cases 35.6% vs. controls 7.8%, p = 0.002). None of the cases were on maintenance therapy with inhaled corticosteroids and most relied on emergency department for control. CONCLUSIONS: A high proportion of children presenting to a public hospital with acute asthma were allergic to mite, particularly at high IgE titer. Poor asthma control resulted in overuse of emergency care
Data on prevalence and risk factors associated with Toxocara spp infection, atopy and asthma development in Northeast Brazilian school children.
In the present article, we provide shortly, data on risk factors for acquiring Toxocara spp. infection and investigate possible associations between this infection with atopy and asthma in school children of a small town and its semi-rural areas of Northeast Brazil. The data set are composed by demographic, social and home environment variables. The detection of anti-Toxocara spp. IgG and specific IgE to aeroallergens was determined by ELISA and ImmunocAP/Phadiatrope systems, respectively. The data presented in this article are related to the article entitled "Risk factors for Toxocara spp. seroprevalence and its association with atopy and asthma phenotypes in school-age children in a small town and semi-rural areas of Northeast Brazil" (M.B. Silva, A.L. Amor, L.N. Santos, A.A. Galvão, A.V. Oviedo Vera, E.S. Silva et al., 2016) [1]
The epidemiology of soil-transmitted helminth infections in children up to 8 years of age: Findings from an Ecuadorian birth cohort.
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
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A prospective seroepidemiological study of toxocariasis during early childhood in coastal Ecuador: potential for congenital transmission and risk factors for infection.
BACKGROUND: Although Toxocara spp. infection has a worldwide distribution, to our knowledge, no data from birth cohorts have been reported in published studies on the potential for congenital transmission and determinants of infection in early childhood. METHODS: We followed 290 mother-infant pairs from birth to 5 years of age through periodic collection of data and samples at birth, 7 and 13 months and 2, 3 and 5 years of age. Data on potential risk factors and confounders were collected by maternal questionnaire. Blood for plasma was collected from the mother at time of birth and periodically from the child for detection of anti-Toxocara spp. immunoglobulin G (IgG) antibodies using a Toxocara canis larval excretory-secretory antigen-based enzyme-linked immunosorbent assay. Stool samples were collected from the mother around the time of birth and periodically from the child for microscopic detection of soil-transmitted helminths (STH). Associations between potential risk factors and Toxocara spp. seroprevalence and seroconversion were estimated using multivariable logistic regression and generalized estimating equations. RESULTS: Toxocara spp. seroprevalence was 80.7% in mothers and in children was 0%, 9.3%, 48.4%, 64.9%, and 80.9% at 7 months, 13 months, 2, 3 and 5 years, respectively. Risk factors significantly associated with increases in seroprevalence over the first 5 years of life in multivariable analyses were age [Odds ratio (OR) 2.06, 95% confidence interval (CI) 1.39-2.27, P < 0001], male sex (female vs. male: OR 0.66, 95% CI 0.48-0.89, P = 0.006), maternal ethnicity (non-Afro vs. Afro-Ecuadorian: OR 0.65, 95% CI 0.47-0.91, P = 0.011), lower maternal educational and socioeconomic level, and childhood STH (OR 2.29, 95% CI 1.51-3.47, P < 0.001). Seroconversion rates for infection were greatest at 2 years of age (3.8%/month). Factors associated significantly with seroconversion at 2, 3 or 5 years were childhood STH infection, male sex, and more frequent domestic cat exposure. CONCLUSIONS: Our data, from an area of high Toxocara spp. endemicity, indicate no congenital transmission but high rates of seroconversion after 13 months of age reaching maternal levels of seroprevalence by 5 years of age. Factors associated with seroprevalence and seroconversion included STH infections, domestic cats, maternal ethnicity, male sex, STH infections, and markers of greater poverty
Impact of early life geohelminths on wheeze, asthma, and atopy in Ecuadorian children at 8 years.
BACKGROUND: Early-lifeexposures to geohelminths may protect against development of wheeze/asthma and atopy. OBJECTIVE: 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. 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 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 SPT prevalence (OR 0.72).Childhood Trichuris trichiura infectionsduring the first 5 years were associated with reduced wheeze (OR 0.57) but greater parasite burdens with Ascaris lumbricoidesat 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-specificeffects 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)
Predicting site index from climate and soil variables for cork oak (Quercus suber L.) stands in Portugal
Site productivity, assessed through site index, was modelled using partial least
squares regression as a function of soil and climatic variables. Two alternative models were
developed: a full model, considering all available explanatory variables, and a reduced
model, considering only variables that can be obtained without digging a soil pit. The
reduced model was used for mapping the site index distribution in Portugal, on the basis of
existing digital cartography available for the whole country. The developed models indicate
the importance of water availability and soil water holding capacity for site index
value distribution. Site index was related to climate, namely evaporation and frost, and soil
characteristics such as lithology, soil texture, soil depth, thickness of the A horizon and soil
classification. The variability of the estimated values within the map (9.5–16.8 m with an
average value of 13.4 m) reflects the impact of soil characteristics on the site productivity
estimation. These variables should be taken into consideration during the establishment of
new plantations of cork oak, and management of existing plantations. Results confirm the
potential distribution of cork oak in coastal regions. They also suggest the existence of a
considerable area, located both North and South of the Tagus river, where site indices
values of medium (]13;15]) to high (]15;17]) productivity classes may be expected. The
species is then expected to be able to have good productivity along the northern coastal
areas of Portugal, where presently it is not a common species but where, according to
historical records, it occurred until the middle of the sixteenth century. The present
research focused on tree growth. Cork growth and cork quality distribution needs to be
further researched through the establishment of long term experimental sites along the distribution area of cork oak, namely in the central and northern coastal areas of the
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Impact of Long-Term Treatment with Ivermectin on the Prevalence and Intensity of Soil-Transmitted Helminth Infections
Soil-transmitted helminth (intestinal worm) infections are very common in developing countries and are an important cause of illness. Mass de-worming treatments of school children are an important strategy to reduce illness caused by these infections in communities without access to clean water and sanitation. Few studies have examined the effect of repeated mass treatments in the long-term in controlling these infections. The objective of the present study was to assess the impact of the drug ivermectin used for the control of onchocerciasis (river blindness), that has important effects against intestinal worms, on the epidemiology of intestinal worms in children when administered repeatedly for 15–17 years. We compared the epidemiology of infections between children living in communities that received ivermectin with communities that never received the drug. The data suggest that ivermectin has important differential effects on intestinal worms with a greater impact on infections with Trichuris trichiura and little impact on Ascaris lumbricoides and hookworms infections. Our data suggest that long-term ivermectin treatments may provide health benefits through effects on T. trichiura infections but that the addition of second de-worming drug such as albendazole may be required for the control of other intestinal worm infections
Asthma inflammatory phenotypes on four continents: most asthma is non-eosinophilic.
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
Principal components analysis based control of a multi-dof underactuated prosthetic hand
<p>Abstract</p> <p>Background</p> <p>Functionality, controllability and cosmetics are the key issues to be addressed in order to accomplish a successful functional substitution of the human hand by means of a prosthesis. Not only the prosthesis should duplicate the human hand in shape, functionality, sensorization, perception and sense of body-belonging, but it should also be controlled as the natural one, in the most intuitive and undemanding way. At present, prosthetic hands are controlled by means of non-invasive interfaces based on electromyography (EMG). Driving a multi degrees of freedom (DoF) hand for achieving hand dexterity implies to selectively modulate many different EMG signals in order to make each joint move independently, and this could require significant cognitive effort to the user.</p> <p>Methods</p> <p>A Principal Components Analysis (PCA) based algorithm is used to drive a 16 DoFs underactuated prosthetic hand prototype (called CyberHand) with a two dimensional control input, in order to perform the three prehensile forms mostly used in Activities of Daily Living (ADLs). Such Principal Components set has been derived directly from the artificial hand by collecting its sensory data while performing 50 different grasps, and subsequently used for control.</p> <p>Results</p> <p>Trials have shown that two independent input signals can be successfully used to control the posture of a real robotic hand and that correct grasps (in terms of involved fingers, stability and posture) may be achieved.</p> <p>Conclusions</p> <p>This work demonstrates the effectiveness of a bio-inspired system successfully conjugating the advantages of an underactuated, anthropomorphic hand with a PCA-based control strategy, and opens up promising possibilities for the development of an intuitively controllable hand prosthesis.</p
Between a Rock and a Hard Place: Habitat Selection in Female-Calf Humpback Whale (Megaptera novaeangliae) Pairs on the Hawaiian Breeding Grounds
The Au'au Channel between the islands of Maui and Lanai, Hawaii comprises critical breeding habitat for humpback whales (Megaptera novaeangliae) of the Central North Pacific stock. However, like many regions where marine mega-fauna gather, these waters are also the focus of a flourishing local eco-tourism and whale watching industry. Our aim was to establish current trends in habitat preference in female-calf humpback whale pairs within this region, focusing specifically on the busy, eastern portions of the channel. We used an equally-spaced zigzag transect survey design, compiled our results in a GIS model to identify spatial trends and calculated Neu's Indices to quantify levels of habitat use. Our study revealed that while mysticete female-calf pairs on breeding grounds typically favor shallow, inshore waters, female-calf pairs in the Au'au Channel avoided shallow waters (<20 m) and regions within 2 km of the shoreline. Preferred regions for female-calf pairs comprised water depths between 40–60 m, regions of rugged bottom topography and regions that lay between 4 and 6 km from a small boat harbor (Lahaina Harbor) that fell within the study area. In contrast to other humpback whale breeding grounds, there was only minimal evidence of typical patterns of stratification or segregation according to group composition. A review of habitat use by maternal females across Hawaiian waters indicates that maternal habitat choice varies between localities within the Hawaiian Islands, suggesting that maternal females alter their use of habitat according to locally varying pressures. This ability to respond to varying environments may be the key that allows wildlife species to persist in regions where human activity and critical habitat overlap
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