Conditional Cash Transfer Program and Leprosy Incidence: Analysis of 12.9 Million Families From the 100 Million Brazilian Cohort

Leprosy is a neglected tropical disease predominately affecting poor and marginalized populations. To test the hypothesis that poverty-alleviating policies might be associated with reduced leprosy incidence, we evaluated the association between the Brazilian Bolsa Familia (BFP) conditional cash transfer program and new leprosy case detection using linked records from 12,949,730 families in the 100 Million Brazilian Cohort (2007–2014). After propensity score matching BFP beneficiary to nonbeneficiary families, we used Mantel-Haenszel tests and Poisson regressions to estimate incidence rate ratios for new leprosy case detection and secondary endpoints related to operational classification and leprosy-associated disabilities at diagnosis. Overall, cumulative leprosy incidence was 17.4/100,000 person-years at risk (95% CI: 17.1, 17.7) and markedly higher in “priority” (high-burden) versus “nonpriority” (low-burden) municipalities (22.8/100,000 person-years at risk, 95% confidence interval (CI): 22.2, 23.3, compared with 14.3/100,000 person-years at risk, 95% CI: 14.0, 14.7). After matching, BFP participation was not associated with leprosy incidence overall (incidence rate ratio (IRR)_Poisson = 0.97, 95% CI: 0.90, 1.04) but was associated with lower leprosy incidence when restricted to families living in high-burden municipalities (IRR_Poisson = 0.86, 95% CI: 0.77, 0.96). In high-burden municipalities, the association was particularly pronounced for paucibacillary cases (IRR_Poisson = 0.82, 95% CI: 0.68, 0.98) and cases with leprosy-associated disabilities (IRR_Poisson = 0.79, 95% CI: 0.65, 0.97). These findings provide policy-relevant evidence that social policies might contribute to ongoing leprosy control efforts in high-burden communities.

Socioeconomic determinants of leprosy new case detection in the 100 Million Brazilian Cohort: a population-based linkage study

BACKGROUND

Although leprosy is recognised as a disease of poverty, there is little evidence on the specific socioeconomic factors associated with disease risk. To inform targeted strategies for disease elimination, we investigated socioeconomic markers of leprosy risk in Brazil.

METHODS

Socioeconomic data from the 100 Million Brazilian Cohort were linked to the Brazilian national disease registry (Sistema de Informação de Agravos de Notificação) for leprosy from Jan 1, 2007, to Dec 31, 2014. Using Poisson regression, we assessed the association of socioeconomic factors with risk of incident leprosy in the full cohort and in children (aged 0-15 years), by leprosy subtype and region of residence.

FINDINGS

In an analysis of 23 899 942 individuals including 18 518 patients with leprosy, increased levels of deprivation were associated with an increased risk of leprosy in Brazil. Directions of effect were consistent in children younger than 15 years and across disease subtypes. Individuals residing in regions with the highest poverty in the country (central-west, north, and northeast regions) had a risk of leprosy incidence five-to-eight times greater than did other individuals. Decreased levels of income and education and factors reflecting unfavourable living conditions were associated with an up to two-times increase in leprosy incidence (incidence rate ratio 1·46, 95% CI 1·32-1·62, for lowest vs highest quartile of income per capita; 2·09, 95% CI 1·62-2·72, for lowest vs highest level of education).

INTERPRETATION

Within the poorest half of the Brazilian population, the most deprived individuals have the greatest risk of leprosy. Strategies focusing on early detection and treatment in the poorest populations could contribute substantially to global disease control.

FUNDING

Medical Research Council, Wellcome Trust, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Brazil), the Conselho Nacional das Fundações Estaduais de Amparo à Pesquisa, Economic and Social Research Council, Biotechnology and Biological Sciences Research Council, Conselho Nacional de Desenvolvimento Científico e Tecnológico, and Fundação de Apoio à Pesquisa do Distrito Federal.

Genetic variants in 17q12-21 locus and childhood asthma in Brazil: Interaction with Varicella zoster virus seropositivity

BACKGROUND

Asthma is a complex disease with worldwide public health relevance, is related to environmental causes and a genetic predisposition. The chromosomal 17q12-21 locus has been consistently demonstrated to be associated with asthma risk. The effects of variants in the 17q12-21 locus on childhood asthma were first identified in a genome wide- association study. Since that time, those findings have been replicated in different populations but not in South American populations.

OBJECTIVE

This study aimed to investigate the role of variants in the 17q12-21 locus on asthma in a sample of Brazilian children.

METHODS

This was a cross-sectional study conducted on a cohort of 1247 children. These analyses used 50 Single Nucleotide Variants (SNVs) in the 17q12-21 locus were genotyped as part of a genome wide association study (GWAS).

RESULTS

Four SNVs (rs4065275, rs12603332, rs73985228 and rs77777702) were associated with childhood asthma. The rs73985228 exhibited the strongest association across the different genetic models (OR, 95%CI 2.8, 1.44-3.21, p < 0.01). In an analysis that was stratified by atopy, two SNVs (rs73985228 and rs2715555) were found to be associated with atopic and non-atopic asthma. For the first time, we observed a significant interaction with seropositivity for the Varicella zoster virus (for rs4065275, p = 0.02, and for rs12603332, p = 0.04); i.e., the association was found in those who were seropositive but not in those who were seronegative for this virus.

CONCLUSIONS

We confirmed the associations of variants in the 17q12-21 locus with atopic and non-atopic asthma and identified an interaction with seropositivity for the Varicella zoster virus.

Socioeconomic risk markers of leprosy in high-burden countries: A systematic review and meta-analysis

Over 200,000 new cases of leprosy are detected each year, of which approximately 7% are associated with grade-2 disabilities (G2Ds). For achieving leprosy elimination, one of the main challenges will be targeting higher risk groups within endemic communities. Nevertheless, the socioeconomic risk markers of leprosy remain poorly understood. To address this gap we systematically reviewed MEDLINE/PubMed, Embase, LILACS and Web of Science for original articles investigating the social determinants of leprosy in countries with > 1000 cases/year in at least five years between 2006 and 2016. Cohort, case-control, cross-sectional, and ecological studies were eligible for inclusion; qualitative studies, case reports, and reviews were excluded. Out of 1,534 non-duplicate records, 96 full-text articles were reviewed, and 39 met inclusion criteria. 17 were included in random-effects meta-analyses for sex, occupation, food shortage, household contact, crowding, and lack of clean (i.e., treated) water. The majority of studies were conducted in Brazil, India, or Bangladesh while none were undertaken in low-income countries. Descriptive synthesis indicated that increased age, poor sanitary and socioeconomic conditions, lower level of education, and food-insecurity are risk markers for leprosy. Additionally, in pooled estimates, leprosy was associated with being male (RR = 1.33, 95% CI = 1.06-1.67), performing manual labor (RR = 2.15, 95% CI = 0.97-4.74), suffering from food shortage in the past (RR = 1.39, 95% CI = 1.05-1.85), being a household contact of a leprosy patient (RR = 3.40, 95% CI = 2.24-5.18), and living in a crowded household (≥5 per household) (RR = 1.38, 95% CI = 1.14-1.67). Lack of clean water did not appear to be a risk marker of leprosy (RR = 0.94, 95% CI = 0.65-1.35). Additionally, ecological studies provided evidence that lower inequality, better human development, increased healthcare coverage, and cash transfer programs are linked with lower leprosy risks. These findings point to a consistent relationship between leprosy and unfavorable economic circumstances and, thereby, underscore the pressing need of leprosy control policies to target socially vulnerable groups in high-burden countries.

A genome-wide association study of asthma symptoms in Latin American children

Background

Asthma is a chronic disease of the airways and, despite the advances in the knowledge of associated genetic regions in recent years, their mechanisms have yet to be explored. Several genome-wide association studies have been carried out in recent years, but none of these have involved Latin American populations with a high level of miscegenation, as is seen in the Brazilian population.

Methods

1246 children were recruited from a longitudinal cohort study in Salvador, Brazil. Asthma symptoms were identified in accordance with an International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Following quality control, 1 877 526 autosomal SNPs were tested for association with childhood asthma symptoms by logistic regression using an additive genetic model. We complemented the analysis with an estimate of the phenotypic variance explained by common genetic variants. Replications were investigated in independent Mexican and US Latino samples.

Results

Two chromosomal regions reached genome-wide significance level for childhood asthma symptoms: the 14q11 region flanking the DAD1 and OXA1L genes (rs1999071, MAF 0.32, OR 1.78, 95 % CI 1.45–2.18, p-value 2.83 × 10⁻⁸) and 15q22 region flanking the FOXB1 gene (rs10519031, MAF 0.04, OR 3.0, 95 % CI 2.02–4.49, p-value 6.68 × 10⁻⁸ and rs8029377, MAF 0.03, OR 2.49, 95 % CI 1.76–3.53, p-value 2.45 × 10⁻⁷). eQTL analysis suggests that rs1999071 regulates the expression of OXA1L gene. However, the original findings were not replicated in the Mexican or US Latino samples.

Conclusions

We conclude that the 14q11 and 15q22 regions may be associated with asthma symptoms in childhood.

Electronic supplementary material

The online version of this article (doi:10.1186/s12863-015-0296-7) contains supplementary material, which is available to authorized users.

Effects of maternal geohelminth infections on allergy in early childhood

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.

Environmental indicators of intra-urban hetererogeneity

A large number of human diseases are related to poor access to water and sewer systems, inadequate solid waste management and deficient storm water drainage. The goal of this study was to formulate environmental sanitation indicators and classify sanitation conditions in specific sewer basins and their respective neighborhoods. The database used contains information on the following sanitation components in these areas: water supply, sewer systems, urban drainage, road pavement, building typology and public cleaning. Data was analyzed using cluster analysis. The key variable of each component was identified, and eight sewer basins and twenty-three neighborhoods were classified into the following categories: good, regular, and poor. The use of environmental sanitation indicators allows decision makers to identify critical areas and define priorities for improving environmental sanitation conditions.

Environmental indicators of intra-urban hetererogeneity

A large number of human diseases are related to poor access to water and sewer systems, inadequate solid waste management and deficient storm water drainage. The goal of this study was to formulate environmental sanitation indicators and classify sanitation conditions in specific sewer basins and their respective neighborhoods. The database used contains information on the following sanitation components in these areas: water supply, sewer systems, urban drainage, road pavement, building typology and public cleaning. Data was analyzed using cluster analysis. The key variable of each component was identified, and eight sewer basins and twenty-three neighborhoods were classified into the following categories: good, regular, and poor. The use of environmental sanitation indicators allows decision makers to identify critical areas and define priorities for improving environmental sanitation conditions.

Epidemiologists working together with anthropologists: lessons from a study to evaluate the epidemiological impact of a city-wide sanitation program

This paper discusses the role of qualitative approaches in epidemiological studies, beginning with a general discussion of epidemiological and anthropological methods. It focuses on a case study of the health impact of an environmental intervention carried out in Salvador, Bahia State, Brazil. Most of the precedent studies fields, based on primary date, use to devote little attention to the methodological and theorethical questions attached to long-term studies. Four specific aspects of this experience are highlighted: (a) drawing up epidemiological study; (b) construction of an observational instrument to measure hygiene habits; (c) an ethnographic study that was carried out before the epidemiological study; (d) observation of the effects of health intervention on health inequalities. Finally, the report details how the findings of qualitative and quantitative studies might be synthesized. It provides a critical overview of follow-up strategies, illustrated with proper examples whenever possible.

219 EXPRESSION PATTERN OF THE SUB-CORTICAL MATERNAL COMPLEX IN OVINE OOCYTES AND PRE-IMPLANTATION EMBRYOS

The sub-cortical maternal complex (SCMC) is a multi-protein complex located in the sub-cortex of the oocyte. In mouse, it assembles during oocyte growth and is essential for zygotes to progress beyond the first embryonic cell divisions (Li et al., 2008). At least 4 proteins contribute to the complex: oocyte expressed protein (OOEP), maternal antigen that embryo requires (MATER), transducin-like enhancer of split 6 (TLE6), and ES cell associated transcript 1 (ECAT1), all encoded by maternal effect genes. In mouse, the relative transcripts are degraded during meiotic maturation and ovulation, whereas the SCMC proteins persist in the early embryo. Whereas MATER expression has been studied in several species, the existence of the genes encoding the other components has been assessed in few mammalian species and their pattern of expression during pre-implantation development has been analysed only in mouse (Li et al. 2008 Dev. Cell 15, 416–425). In a previous work (Bebbere et al. 2008 Reprod. Fertil. Dev. 20, 908–915), we assessed MATER existence and pattern of expression in the ovine species. The aim of the present work was to assess the existence of OOEP, TLE6, and FILIA in the ovine species and to analyse the expression pattern of the 4 genes in the oocytes and during pre-implantation embryo development. Total RNA was isolated and reverse transcribed from pools of immature (GV) and in vitro matured (IVM) metaphase II (MII) oocytes, from in vitro fertilized and cultured (IVFC) embryos at the 2-, 4-, 8-, and 16-cell stage and from blastocysts. Three pools of 10 oocyte/embryos were analysed for each class. Primers were designed on the basis of the sequences conserved among orthologs and amplify intron-spanning regions. The PCR products were sequenced, and the alignment, performed with BLASTn, confirmed the homology with the orthologous genes present in public databases. Real-time PCR analysis revealed that all 4 transcripts are present at its highest level in the GV oocyte but decrease during embryo pre-implantation development with a gene-specific pattern. Conversely to the pattern of expression observed in mouse, all 4 transcripts persisted until the 8-cell stage embryo, disappearing only at the 16-cell stage. No transcripts were detected at the blastocyst stage. This study confirms the existence of transcripts related to SCMC also in the ovine species, but highlights species-specific patterns of expression in the 2 species, possibly related to the different time of activation of the embryo genome in mouse and in sheep. The observed expression patterns suggest an involvement of the protein complex in oocyte maturation and in the very first phases of life, possibly in the transition from the maternal to embryonic program of development.

Poverty, dirt, infections and non-atopic wheezing in children from a Brazilian urban center

BACKGROUND

The causation of asthma is poorly understood. Risk factors for atopic and non-atopic asthma may be different. This study aimed to analyze the associations between markers of poverty, dirt and infections and wheezing in atopic and non-atopic children.

METHODS

1445 children were recruited from a population-based cohort in Salvador, Brazil. Wheezing was assessed using the ISAAC questionnaire and atopy defined as allergen-specific IgE ≥ 0.70 kU/L. Relevant social factors, environmental exposures and serological markers for childhood infections were investigated as risk factors using multivariate multinomial logistic regression.

RESULTS

Common risk factors for wheezing in atopic and non-atopic children, respectively, were parental asthma and respiratory infection in early childhood. No other factor was associated with wheezing in atopic children. Factors associated with wheezing in non-atopics were low maternal educational level (OR 1.49, 95% CI 0.98-2.38), low frequency of room cleaning (OR 2.49, 95% CI 1.27-4.90), presence of rodents in the house (OR 1.48, 95% CI 1.06-2.09), and day care attendance (OR 1.52, 95% CI 1.01-2.29).

CONCLUSIONS

Non-atopic wheezing was associated with risk factors indicative of poverty, dirt and infections. Further research is required to more precisely define the mediating exposures and the mechanisms by which they may cause non-atopic wheeze.

Validation of epidemiological tools for eczema diagnosis in Brazilian children: the ISAAC's and UK Working Party's criteria

Background

Instruments for field diagnosis of eczema are increasingly used, and it is essential to understand specific limitations to make best use of their strengths. Our objective was to assess the validity of ISAAC and UK Working Party criteria for field diagnosis of eczema in children.

Methods

We performed a cohort study in urban Brazil. Parents/guardians of 1,419 children answered ISAAC phase II questionnaire. Children were examined for skin lesions (UKWP protocol). Two dermatologists examined most cases of eczema (according to ISAAC or UKWP), and a sample without eczema.

Results

Agreement between repeat questionnaires on the filter question was poor (kappa = 0.4). Agreement between the 2 dermatologists was fair (kappa = 0.6). False positive reports included scabies in 39% of ISAAC cases and 33% of UKWP cases. Sensitivity and PPV were low (ISAAC: 37.1% and 16.1%; UKWP: 28.6% and 23.8%). Specificity and NPV were high (ISAAC: 90.0% and 96.6%; UKWP: 95.3% and 96.2%). One-year prevalence of eczema was 11.3% (ISAAC), 5.9% (UKWP) and 4.9% (adjusted dermatologist diagnosis). Point prevalence of scabies (alone or not) was 43%, 33% and 18%, in eczemas according to ISAAC, to UKWP and to dermatologists. The reasons why children with eczema were not identified by ISAAC or UKWP were wrongly denying dry skin, itchy rash or personal history of atopic diseases. A limitation is that questionnaire was already validated in Brazil, but not field tested in this specific setting.

Conclusions

Studies using UKWP or ISAAC criteria should include a validation arm, to contribute to the understanding of potential limitations of their use in different contexts and to explore solutions. We list specific recommendations.

Impact of a citywide sanitation program in Northeast Brazil on intestinal parasites infection in young children

BACKGROUND

Sanitation affects health, especially that of young children. Residents of Salvador, in Northeast Brazil, have had a high prevalence of intestinal parasites. A citywide sanitation intervention started in 1996 aimed to raise the level of sewer coverage from 26% to 80% of households.

OBJECTIVES

We evaluated the impact of this intervention on the prevalence of Ascaris lumbricoides, Trichuris trichuria, and Giardia duodenalis infections in preschool children.

METHODS

The evaluation was composed of two cross-sectional studies (1998 and 2003-2004), each of a sample of 681 and 976 children 1-4 years of age, respectively. Children were sampled from 24 sentinel areas chosen to represent the range of environmental conditions in the study site. Data were collected using an individual/household questionnaire, and an environmental survey was conducted in each area before and after the intervention to assess basic household and neighborhood sanitation conditions. Stool samples were examined for the presence of intestinal parasites. The effect of the intervention was estimated by hierarchical modeling, fitting a sequence of multivariate regression models.

FINDINGS

The prevalence ofA. lumbricoides infection was reduced from 24.4% to 12.0%, T. trichuria from 18.0% to 5.0%, and G. duodenalis from 14.1% to 5.3%. Most of this reduction appeared to be explained by the increased coverage in each neighborhood by the sewage system constructed during the intervention. The key explanatory variable was thus an ecological measure of exposure and not household-based, suggesting that the parasite transmission prevented by the program was mainly in the public (vs. the domestic) domain.

CONCLUSION

This study, using advanced statistical modeling to control for individual and ecological potential confounders, demonstrates the impact on intestinal parasites of sanitation improvements implemented at the scale of a large population.

Reductions in the prevalence and incidence of geohelminth infections following a city-wide sanitation program in a Brazilian Urban Centre

Objective

In the city of Salvador, a large urban centre in Northeast Brazil, a city-wide sanitation intervention started in 1997, aimed at improving the sewerage coverage of households from 26% to 80%. Our aim was to study the impact of the intervention on the prevalence and incidence of geohelminths in the school-aged population.

Methods

The study comprised two comparable cohorts: the first assembled in 1997, before the intervention, and the second assembled in 2003, after the intervention. Both were sampled from 24 sentinel areas chosen to represent the different environmental conditions throughout the city. Copro-parasitological examinations were carried out on every individual from both cohorts, at baseline and nine months later. Demographic, socio-economic, and environmental data were collected using semi-structured questionnaires and environmental surveys. A hierarchical modelling approach fitting a sequence of Poisson multivariate linear models was undertaken to test the effect of the intervention variables on the prevalence and incidence rate ratios.

Findings

729 and 890 children aged 7–14 years (mean = 10.4 y, SD = 0.05 y) were analysed over the first and the second cohorts, respectively. The adjusted reductions of the prevalence and incidence rates at the second in relation to the first cohort were 27% and 34%, 25% and 32%, 33% and 26%, and 82% and 42% for geohelminths overall, Ascaris lumbricoides, Trichuris trichiura, and hookworm, respectively. Hierarchical modelling showed that a major part of each of these reductions was explained by the intervention.

Conclusion

Our results show that a city-wide sanitation program may reduce significantly the prevalence and incidence of geohelminths.

In the city of Salvador, a large urban centre in Northeast Brazil, a city-wide sanitation intervention started in 1997, aiming to improve the sewerage coverage of households from 26% to 80%. Our aim was to study the impact of the intervention on the prevalence and incidence of geohelminths in the school-aged population. The longitudinal study comprised two cohorts: from the beginning of 1997 to 1998, where data was collected before the intervention, and at the end of 2003 to 2004, after the intervention. Copro-parasitological examinations were carried out on every individual from both cohorts, at the start and nine months later. Demographic, socio-economic, and environmental data were collected using semi-structured questionnaires. The variables utilized to demonstrate the effects of intervention, when utilized together in a multivariate model, accounted for a 100% observed reduction in the prevalence ratio (PR) and incidence ratio (IR). As well as proving that the variables associated with the effect of the program intervention were mediators in this reduction, the reduction in the PR and IR between these periods demonstrated that modifications to the urban environment, particularly those associated with sanitary sewage systems, affected the health of the population, significantly reducing the prevalence of geohelminths.

87 HIGH HYDROSTATIC PRESSURE TREATMENT IMPROVES THE QUALITY OF IN VITRO-PRODUCED OVINE BLASTOCYSTS

High hydrostatic pressure (HHP) has been introduced into the field of embryology recently. It has been reported that a sublethal HHP could induce the synthesis of molecular chaperons to protect the embryos from other environmental stresses. The possible beneficial effect of HHP was examined on embryo vitrification, and improved cryotolerance has been achieved in HHP-treated mouse and bovine embryos. In the present study we evaluated, first, the behavior of in vitro-produced ovine blastocysts after treatment with 2 different HHP conditions. In the second part of the study, optimized pressure treatment was combined with a cryopreservation protocol. Day 7 in vitro-produced ovine blastocysts were loaded in 0.5-mL straws and pressure treated in a custom-made hydrostatic pressure chamber (Cryo-Innovation Ltd., Budapest, Hungary) according to the following conditions: -60 MPa, 70 min, 38°C; and -40 MPa, 70 min, 38°C. After HHP treatment, embryos were cultured for 24 h and their survival evaluated upon morphological appearance, re-expansion of the blastocoel, and hatching from the zona pellucida. Blastocysts were fixed and stained, observed with confocal microscope to evaluate blastocyst cell number, and mitotic and picnotic index. Untreated blastocysts were used as controls. On the basis of results obtained in this experiment, groups of blastocysts were exposed to 40 MPa for 70 min at 38°C and, following 2 h incubation after HHp treatment, were vitrified using cryotops. After warming, embryos were checked for re-expansion and hatching and finally fixed and stained as described for fresh embryos. Vitrified untreated blastocysts were used as controls. Results showed that the hatching rate of embryos treated at 40 MPa was significantly higher than that of 60 MPa-treated group (87.5 v. 0%; P < 0.01, chi-squared test) and similar to that of control embryos (85.3%) after 24 h culture. Blastocysts exposed at 40 MPa showed higher cell number compared with control embryos (161.3 ± 8.7 v. 123.9 ± 9.4, P < 0.01, ANOVA ± SD) and a lower picnotic index (PI: 1.3 ± 0.4% v. 3.8 ± 0.6%, P < 0.05). Similar re-expansion rate has been recorded between HHP treated and untreated (86.6 v. 89.6%) vitrified blastocysts as well as hatching rates (53.3 v. 48.3) and embryo cell number (131 ± 4.6 v. 139 ± 5.8). Conversely, HHP treatment significantly decreased picnotic index of vitrified treated embryos compared with control (2.3 ± 0.9 v. 4.8 ± 0.5, P < 0.05). We concluded that HHP treatment significantly improved the quality of in vitro-produced ovine blastocysts by increasing their cell number and reducing the proportion of picnosis. The HHP treatment exerted a positive effect in vitrified blastocysts, decreasing the number of picnotic nuclei. Further studies are needed to evaluate the possible beneficial effect at the molecular level of HHP treatment after vitrification and also to test if different interval times between HHP treatment and embryo cryopreservation could affect embryo response.

Giardia duodenalis infection and anthropometric status in preschoolers in Salvador, Bahia State, Brazil

The aim of this study was to estimate the association between Giardia duodenalis infection and anthropometric deficits, as measured by weight-for-age and height-for-age. This cross-sectional study included 629 children from 12 to 48 months of age, selected from 30 geographic areas in the city of Salvador, Bahia State, Brazil. Poisson regression and linear regression were used for the multivariate statistical analyses. G. duodenalis was diagnosed in 13.5% of the children. The children's breastfeeding duration and living conditions (garbage collection and paved streets or sidewalks) modified the effect of G. duodenalis infection on anthropometric status. Among infected children, there were statistically significant associations between weight deficit and shorter breastfeeding (PR=2.22; 95%CI: 1.56-3.14) and inadequate paving of streets and sidewalks (PR=2.00; 95%CI: 1.37-2.92), while height deficit was associated with deficient public garbage collection (PR=2.21; 95%CI: 1.31-2.51). In the linear regression, the association with the anthropometric indicators remained positive and statistically significant. The child's unhealthy living environment aggravated the negative effect of G. duodenalis infection on anthropometric status, and breastfeeding was a protective factor in the outcome.

Determinants of cognitive function in childhood: a cohort study in a middle income context

BACKGROUND

There is evidence that poverty, health and nutrition affect children's cognitive development. This study aimed to examine the relative contributions of both proximal and distal risk factors on child cognitive development, by breaking down the possible causal pathways through which poverty affects cognition.

METHODS

This cohort study collected data on family socioeconomic status, household and neighbourhood environmental conditions, child health and nutritional status, psychosocial stimulation and nursery school attendance. The effect of these on Wechsler Pre-School and Primary Scale of Intelligence scores at five years of age was investigated using a multivariable hierarchical analysis, guided by the proposed conceptual framework.

RESULTS

Unfavourable socioeconomic conditions, poorly educated mother, absent father, poor sanitary conditions at home and in the neighbourhood and low birth weight were negatively associated with cognitive performance at five years of age, while strong positive associations were found with high levels of domestic stimulation and nursery school attendance.

CONCLUSION

Children's cognitive development in urban contexts in developing countries could be substantially increased by interventions promoting early psychosocial stimulation and preschool experience, together with efforts to prevent low birth weight and promote adequate nutritional status.

A hierarchical model for studying risk factors for childhood diarrhoea: a case-control study in a middle-income country

OBJECTIVE

To identify factors associated with diarrhoea occurrence in children in a city in a middle-income country, with high access to water and sanitation.

METHODS

A case-control study in the city of Salvador, north-eastern Brazil was conducted from November 2002 to August 2004. The study population consisted of children presenting at a health facility. A total of 1688 cases of diarrhoea and 1676 controls were selected. Data collection was by a questionnaire and structured observation during home visits. The explanatory variables were grouped according to a conceptual model defined previously. Analysis was done using a hierarchical approach, to provide a more dynamic view of the transmission characteristics of childhood diarrhoea. Non-conditional logistic regression was used, and odds ratio and population-attributable fractions were estimated.

RESULTS

Socioeconomic factors contributed most to determining diarrhoea occurrence, followed by interpersonal contact, while factors related to food preparation, the environment and water and sanitation made a smaller contribution.

CONCLUSION

The findings indicate that the transmission of diarrhoea is influenced by factors from all hierarchical levels, with interpersonal transmission playing a relatively higher role than previously thought. This is compatible with a predominance of viruses and other agents spread by interpersonal routes including Shigella, Giardia and Cryptosporidium. Diarrhoea control strategies in similar settings (middle-income countries in which a large proportion of the population has access to water and sanitation) must give greater emphasis to policies geared towards reducing person-to-person transmission for the prevention of diarrhoea.

Effect of city-wide sanitation programme on reduction in rate of childhood diarrhoea in northeast Brazil: assessment by two cohort studies

BACKGROUND

A city-wide sanitation intervention was started in Salvador, Brazil, in 1997 to improve sewerage coverage from 26% of households to 80%. Our aim was to investigate the epidemiological effect of this city-wide sanitation programme on diarrhoea morbidity in children less than 3 years of age.

METHODS

The investigation was composed of two longitudinal studies done in 1997-98 before the intervention (the sanitation programme) and in 2003-04 after the intervention had been completed. Each study consisted of a cohort of children (841 in the preintervention study and 1007 in the postintervention study; age 0-36 months at baseline) who were followed up for a maximum of 8 months. Children were sampled from 24 sentinel areas that were randomly chosen to represent the range of environmental conditions in the study site. At the start of each study an individual or household questionnaire was applied by trained fieldworkers; an environmental survey was done in each area before and after introduction of the sanitation programme to assess basic neighbourhood and household sanitation conditions. Daily diarrhoea data were obtained during home visits twice per week. The effect of the intervention was estimated by a hierarchical modelling approach fitting a sequence of multivariate regression models.

FINDINGS

Diarrhoea prevalence fell by 21% (95% CI 18-25%)-from 9.2 (9.0-9.5) days per child-year before the intervention to 7.3 (7.0-7.5) days per child-year afterwards. After adjustment for baseline sewerage coverage and potential confounding variables, we estimated an overall prevalence reduction of 22% (19-26%).

INTERPRETATION

Our results show that urban sanitation is a highly effective health measure that can no longer be ignored, and they provide a timely support for the launch of 2008 as the International Year of Sanitation.

Risk factors for childhood diarrhea incidence: dynamic analysis of a longitudinal study

BACKGROUND

Several longitudinal studies have investigated factors associated with childhood diarrhea in developing countries. However, most studies have neglected important dynamic features of the longitudinal design and hierarchical interrelationships among the potential risk factors.

METHODS

We conducted a longitudinal study of 902 children, age 0 to 36 months at baseline, in a large urban center in northeastern Brazil. Diarrhea data were collected by following children from October 2000 until January 2002 with biweekly home visits. We used a dynamic time-to-event analysis to account for several longitudinal features. We applied an effect-decomposition strategy to quantify direct and indirect effects of risk factors grouped in different blocks.

RESULTS

Child's age and an autoregressive effect of past diarrhea episodes explained some of the decline of diarrhea incidence observed throughout the study (from more than 14 episodes to 2 episodes per child-year), a phenomenon already observed but not explained in other longitudinal diarrhea studies. We identified the following major diarrhea determinants: low socioeconomic status, poor sanitation conditions, presence of intestinal parasites, and absence of prenatal examination. The effect of socioeconomic status was mediated mostly by living and sanitation conditions.

CONCLUSION

Our study shows important advantages of applying a dynamic analysis approach to longitudinal observational studies of diarrhea or other acute diseases and highlights the complex interrelationships of diarrhea determinants. Our results confirm the importance of sanitation as a major determinant of child health in urban settings of developing countries.

Community-based monitoring of diarrhea in urban Brazilian children: incidence and associated pathogens

Community-based monitoring was conducted in order to investigate the occurrence of diarrhea in 'sentinel areas' of Salvador, Brazil, and to establish a preliminary profile of the most common pathogens present in children's diarrhea by screening stool samples. This report describes the results obtained from twice weekly home visits to identify and follow diarrhea episodes and testing of carer-requested stool sample collection over a 6-month period. Participants were selected from a large longitudinal study in 21 areas representing the city's poorer socioeconomic and sanitary conditions. Fecal samples were examined for the presence of pathogenic bacteria, viruses and protozoa. The mean incidence of diarrhea was 4.97 episodes per child-year, and longitudinal prevalence was 13.6 days per child-year (3.7%). Pathogens were found in 44% of the fecal samples examined. Bacteria were the most frequently encountered pathogens (isolated in 22% of samples), followed by protozoa (19.5%) and viruses (16%). Viral and bacterial pathogens were associated with episodes of severe diarrhea, while viral and protozoan pathogens were associated with longer episodes. The study demonstrated the importance of a public health monitoring system based on 'sentinel areas'.

Asymptomatic giardiasis and growth in young children; a longitudinal study in Salvador, Brazil

This study sought to assess the effect of giardiasis on growth of young children. In Salvador, northeast Brazil, 597 children initially aged 6 to 45 months were followed for a year in 1998/9, measured anthropometrically thrice, every 6 months, and monitored for diarrhoea prevalence twice weekly. Stool samples were collected and examined during the second round of anthropometry, and infected children were treated 39 days later, on average (S.D. 20 days). For each 6-month interval, the gains in z-scores of infected and uninfected children were compared, after adjustment for potential confounding factors, including longitudinal prevalence of diarrhoea. No significant difference was found for the first interval but in the second, the gain in adjusted height-for-age z-score was 0.09 less in infected than uninfected children, equivalent to a difference in height gain of 0.5 cm. The shortfall in growth was greater in children who remained free of diarrhoea, and was significantly correlated with the proportion of the second interval during which the child had remained untreated. We conclude that Giardia can impede child growth even when asymptomatic, presumably through malabsorption. This finding challenges the view that young children found to have asymptomatic giardiasis in developing countries should not be treated.

Childhood diarrhoea symptoms, management and duration: observations from a longitudinal community study

This study examined the evolution and duration of diarrhoea episodes observed in a community setting, with regard to symptoms and carers' responses. The study group comprised 1156 children, aged 0-36 months, who were followed-up with twice-weekly home visits in 30 sampling areas in the city of Salvador, northeast Brazil. A total of 2403 diarrhoea episodes (mean duration: 2.9 days) were recorded. The number of soft/liquid motions per day (3.6) did not vary significantly with duration, but other symptoms were more commonly reported in the longer episodes. However, when the data were analysed by day of the episode, rather than the episode's overall duration, the reported frequency of fever and vomiting declined significantly with time. During the course of an episode, rehydration, medication and care-seeking also showed a decline in frequency after the first or second week. As episodes continue, less rehydration and medical care are provided by carers, whereas they ought to be maintained because of the continued purging and cumulative effect of the symptoms. Since most cases of diarrhoea are managed at home, it is important to understand how to encourage better management of the longer episodes, which cause an increasing proportion of mortality in some countries.

Prevalence of diarrheagenic Escherichia coli in children with diarrhea in Salvador, Bahia, Brazil

We report the frequency of the different diarrheagenic Escherichia coli (DEC) categories isolated from children with acute endemic diarrhea in Salvador, Bahia. The E. coli isolates were investigated by colony blot hybridization with the following genes probes: eae, EAF, bfpA, Stx1, Stx2, ST-Ih, ST-Ip, LT-I, LT-II, INV, and EAEC, as virulence markers to distinguish typical and atypical EPEC, EHEC/STEC, ETEC, EIEC, and EAEC. Seven of the eight categories of DEC were detected. The most frequently isolated was atypical EPEC (10.1%) followed by ETEC (7.5%), and EAEC (4.2%). EHEC, STEC, EIEC, and typical EPEC were each detected once. The strains of ETEC, EAEC, and atypical EPEC belonged to a wide variety of serotypes. The serotypes of the others categories were O26:H11 (EHEC), O21:H21 (STEC), O142:H34 (typical EPEC), and O:H55 (EIEC). We also present the clinical manifestations and other pathogenic species observed in children with DEC. This is the first report of EHEC and STEC in Salvador, and one of the first in Brazil.

Risk factors for infection with Giardia duodenalis in pre-school children in the city of Salvador, Brazil

A cross-sectional study of 694 children aged 2 to 45 months selected from 30 clusters throughout the city of Salvador, Bahia (pop. 2.3 million) was carried out as part of a longitudinal study of diarrhoea in order to identify risk factors for infection with Giardia duodenalis. Variables studied included three social and demographic factors (such as mother's education and marital status), five relating to the peri-domestic environment (rubbish disposal, open sewers, paving of the street), seven relating to the home itself (house construction, susceptibility to flooding, water supply and sanitation) as well as a score for hygiene behaviour based on structured observation. After multivariate analysis using a hierarchical model, only four significant risk factors were found: (a) number of children in the household under five years (b) rubbish not collected from the house (c) presence of visible sewage nearby, and (d) absence of a toilet. All four were significant at the 1% level.

Childhood diarrhea and observed hygiene behavior in Salvador, Brazil

Brief biweekly home visits, made as part of a cohort study of diarrhea in young children under age 5 years that was carried out in Salvador, Brazil, in 1998-1999, were used as a low-cost way to collect structured observation data on domestic hygiene behavior. Field-workers were trained to check a list of 23 forms of hygienic or unhygienic behavior by the child or the child's caretaker, if any behaviors were seen during the visit. Children were grouped according to whether mainly unhygienic behavior or mainly hygienic behavior had been recorded. This permitted study of the determinants of hygiene behavior and of its role in the transmission or prevention of diarrheal disease. Observations were recorded on roughly one visit in 20. Households with adequate excreta disposal were significantly more likely to be in the "mainly hygienic" group. The prevalence of diarrhea among children for whom mainly unhygienic behavior was recorded was 2.2 times that among children in the "mainly hygienic" group. The relative risk for prevalence was 2.2 (95% confidence interval: 1.7, 2.8). The relative risk fell to 1.9 (95% confidence interval: 1.5, 2.5) after data were controlled for confounding, but the difference was still highly significant.

Sentinel areas: a monitoring strategy in public health

Available techniques for monitoring the health situation have proven insufficient, thus leading to a discussion of the need for their improvement based on new data collection strategies allowing for data use by local health systems. This article presents the methodological basis for a strategy to monitor health problems utilizing demarcated intra-urban spaces called "sentinel areas" to collect fundamental social, economic, behavioral, and biological data for public health that allow for a closer approach to the reality of complex social spaces. The authors present an experience that is being developed in Salvador, Bahia, Brazil, to evaluate the epidemiological impact of an environmental sanitation program. They discuss selection criteria for the areas and the potential uses of this strategy allowing for the rapid utilization of epidemiological resources by health services and the timely application of the results to reorient and enhance health intervention practices.

[Prevalence and intensity of infection by intestinal parasites in school-aged children in the City of Salvador (Bahia, Brazil)]

As part of a major study to evaluate the relationship between environmental changes and occurrence of the infection, prevalence and intensity of infection by intestinal parasites was studied in a sample of school children aged 7 to 14 years living in the City of Salvador. The prevalence of infection by at least one species of protozoa or helminth was 66.1%. Prevalence of infection by helminths increased with age. For all helminth species male children presented the highest prevalence.

Measuring the burden of common morbidities: sampling disease experience versus continuous surveillance

Longitudinal prevalence, the proportion of all days of observation that a given individual manifests symptoms of illness, is a measure of disease frequency that is easy to generate from daily morbidity data and has been shown to be strongly related to subsequent health outcome. It is hypothesized that this measure could be derived using a representative sample of days of observation rather than continuous surveillance. The authors use 1990-1991 data from a Brazilian supplementation trial comprising a year's daily records of the occurrence of diarrhea, fever, and cough in 906 children under 5 years of age to examine how many days of morbidity data need to be observed to rank subjects into quintiles of illness frequency. Systematic samples of the full data set, based on every 2nd, 3rd, 5th, 10th, 15th, 20th, and 30th day of data, are compared with the continuous record. For diarrhea and fever, estimates based on less than 72 days of observation result in over one fourth of individuals who should have been in the extreme quintiles of the morbidity distribution being misclassified, and over one fifth of all subjects appear (falsely) to suffer no morbidity. Estimates of longitudinal prevalence should be based on at least 72 days of observation.