Childhood stunting in Northeast Brazil: the role of Schistosoma mansoni infection and inadequate dietary intake

OBJECTIVE

To evaluate the relationship between stunting, Schistosoma mansoni infection and dietary intake in schoolchildren.

DESIGN

This is a cross-sectional study. Two stool samples were obtained from each child and examined quantitatively for the presence of S. mansoni, Ascaris lumbricoides and Trichuris trichiuria eggs. Information on dietary intake, and demographic, biologic and socioeconomic variables was elicited during the in-home survey. Logistic regression was used to evaluate the association between stunting (height for age < -2s.d.), parasitic infection and food consumption.

SETTING

The study was carried out in the city of Nazaré, located in the Recôncavo region of the State of Bahia, Northeastern Brazil.

SUBJECTS

The sample consisted of 461 children 7-14 y old, 228 boys and 233 girls, recruited from public schools.

RESULTS

Of the children studied, 55.1% presented with S. mansoni infection and 22.1% were stunted. The median protein, lipid and carbohydrates intake were 47.8, 36.0 and 248.2 g/day, respectively. The median caloric consumption was 1527.0 kcal (6388.97 kJ/day). The analysis indicated that children heavily infected (> or = 400 eggs/g of stool) with S. mansoni had a 2.74-fold (95% CI: 1.32-5.67) higher risk of stunting than uninfected children, and those with inadequate intake of lipid (< 36 g/day) had a 1.83-fold (95% CI: 1.05-3.20) increased risk of stunting compared to those with adequate diets.

CONCLUSION

Heavy S. mansoni infection and inadequate dietary intake of fat in schoolchildren play a significant and independent role in the development of stunting. This meaning that nutritional interventions in this age group in S. mansoni endemic areas must include the diagnosis and treatment of the infection associated with dietary measures.

SPONSORSHIP

This study was supported by the Thrasher Foundation. Sandra Maria Conceição Pinheiro is a National Council on Technological Development Scholarship Awardee (CNPq), #302228/81-0.

Lower prevalence of reported asthma in adolescents with symptoms of rhinitis that received neonatal BCG

BACKGROUND

BCG is a vaccine used against tuberculosis and leprosy and is an immunostimulant that primes T(H)1 lymphocytes to produce cytokines that antagonize atopy both in animal models and in man. Considering that atopy is the main risk factor for asthma, one can hypothesize that vaccination inducing T(H)1 responses, such as BCG, can be protective against asthma.

METHODS

OBJECTIVE

To estimate the association between neonatal BCG vaccination and prevalence of asthma among adolescents.

STUDY DESIGN

Cross-sectional study with schoolchildren aged 12-16 years. The presence of a scar compatible with BCG was used as a surrogate of neonatal vaccination. A self administered structured questionnaire was prepared based on that used by the International Study of Asthma and Allergies in Childhood. The prevalence of asthma was categorized according to the report of lifetime wheeze, lifetime asthma, lifetime asthma among those referring allergy and among those referring allergy and sneezing.

RESULTS

Neonatal BCG vaccination was not associated with the overall prevalence of reported wheezing or asthma. However, in the subgroup reporting current allergy and sneezing, neonatal BCG was associated with a 37% reduction of prevalence of lifetime asthma.

CONCLUSIONS

In the population we surveyed, neonatal BCG scar was associated with a reduction in the risk of asthma only in individuals with a past history suggestive of allergic rhinitis.

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.

Rates of adverse reactions to first and second doses of BCG vaccination: results of a large community trial in Brazilian schoolchildren

OBJECTIVE

To evaluate the incidence of adverse reactions to first and second bacille Calmette-Guérin (BCG) vaccination in schoolchildren.

SETTING AND DESIGN

Enhanced surveillance in a Brazilian trial. Suspected reactions were reported to a nurse who visited cases and completed a standard form.

RESULTS

Among 71341 schoolchildren studied, 33 reactions were reported. Of these, 25 fulfilled the criteria, resulting in a rate of one per 2854 vaccinations, with no deaths or BCG-osis. Reactions to second doses were more common than to first BCG vaccinations, but this difference was not statistically significant.

CONCLUSIONS

Adverse reactions to a second dose of BCG may be more frequent than reactions to a first dose, but they are still rare events.

A comparison of dual skin test with mycobacterial antigens and tuberculin skin test alone in estimating prevalence of Mycobacterium tuberculosis infection from population surveys

SETTING

City of Manaus, Amazonas, Brazil.

OBJECTIVE

To compare estimates of Mycobacterium tuberculosis infection prevalence obtained using traditional tuberculin skin test (TST) criteria and dual skin test (DST) data.

METHODS

A total of 1070 schoolchildren received DST with tuberculin and four environmental mycobacteria sensitins. Responses were classified as sensitin-dominant, tuberculin-dominant or non-dominant. Positive predictive values (PPV) were defined using 'narrow' and 'wide' standards based on DST responses. These predictive values were derived for each category of tuberculin indurations, and were used to calculate the prevalence estimates.

RESULTS

Using DST data, the estimates of M. tuberculosis prevalence for scar-negative children were 7.4% (M. avium) and 7.8% (M. scrofulaceum) using the 'narrow' standard, and 16.9% (M. avium) and 15.2% (M. scrofulaceum) using the 'wide' standard. The percentage with TST > or =10 mm was 11.5%. Scar-positive children had higher estimates using both the 10 mm cut-off and DST data.

CONCLUSION

In settings with a relatively low prevalence of M. tuberculosis infection and high cross-reactivity with environmental mycobacteria, DST can help to assess the validity of traditional thresholds for estimating the prevalence of M. tuberculosis infection. DST data with environmental antigens and tuberculin do not distinguish BCG-induced cross-reactivity.

Combined analysis of supernatant-based feeding bioassays and PCR as a first-tier screening strategy for Vip -derived activities in Bacillus thuringiensis strains effective against tropical fall armyworm

AIMS

To assess whether feeding bioassays using culture-supernatant proteins could be combined with PCR into a first-tier screening strategy for Vip3A-like genes efficient against tropical Spodoptera frugiperda.

METHODS AND RESULTS

Out of 12 Bacillus thuringiensis strains studied, the total protein concentrated from the culture supernatant of only the strain HD125 yielded a significantly increased armyworm mortality and an intense band of the predicted size for VIP3A protein in SDS-PAGE. However, PCR and sequencing data indicated Vip-like genes are ubiquitous in tropical B. thuringiensis isolates. Interestingly, the HD125 strain was also the only one displaying a single-band amplification pattern and the highest sequence identity to the reported Vip3A(a) gene.

CONCLUSIONS

Results suggest the insecticidal effectiveness of putative VIPs in B. thuringiensis isolates can be preliminarily estimated by the use of supernatant-derived total protein in feeding experiments, though only in a limited manner.

SIGNIFICANCE AND IMPACT OF THE STUDY

A simple and cost-effective first-tier screening strategy for VIP-derived activities in B. thuringiensis collections can be developed by combining PCR and feeding bioassays. Moreover, the employed primers showed to be useful as a tool for strains differentiation at DNA level, and for characterization and isolation of Vip-like genes in tropical B. thuringiensis germplasm.

Suplementação com vitamina A: impacto na morbidade e efeitos adversos

Este artigo apresenta uma síntese de dois estudos previamente publicados e que avaliaram diferentes aspectos dos efeitos da suplementação com mega-doses (100.000 ou 200.000 UI) de vitamina A em crianças pré-escolares. O primeiro é um ensaio comunitário, aleatório, duplo cego e placebo controlado, que demonstrou o efeito positivo da suplementação na redução da severidade dos episódios de diarréia. O segundo investigou os potenciais efeitos adversos da suplementação com mega-doses de vitamina A, oferecida conjuntamente com a vacinação em massa, utilizando um desenho de intervenção controlado e não randomizado. Seus resultados indicaram que a suplementação associada com as vacinas rotineiramente utilizadas na infância não elevou as taxas de efeitos adversos (diarréia, febre e vômito). São ainda discutidas as implicações dos resultados destes estudos, que contribuíram não somente para o avanço do conhecimento científico do campo em questão, como também têm fornecido evidências para justificar a implementação de políticas e ações específicas no campo da saúde e da nutrição, que por sua vez têm contribuído para gerar condições mais auspiciosas de sobrevivência na infância. Discute-se também a pertinência e a utilidade de desenhos de estudo com diferentes níveis de rigor metodológico na avaliação de intervenção em saúde.

Upward trend in the rate of detection of new cases of leprosy in the State of Bahia, Brazil

BACKGROUND

The worldwide fall in the rate of detection of new cases of leprosy has been partly attributed to the introduction of multidrug therapy and other improvements in control programs. However, the rate of detection of new cases has not decreased in Brazil.

METHODS

An analysis was made of the temporal distribution of 18,872 newly reported leprosy cases in Bahia, Brazil, from 1974 to 1997. Population denominators for the annual detection rate were obtained from population estimates based on the national census. Trends were presented by sex, date of birth, date of diagnosis, date of release, clinical form and by residence in areas which had notified cases in the 5 years prior to the rise in detection rate.

RESULTS

There was a marked increase in the new case detection rate (NCDR) in the State of Bahia, from 0.19 to 1.43 cases per 10,000 inhabitants during the study period, an increment of nearly 7% to 8% per year. This increase was also observed in people aged 14 years and younger. During this period tuberculoid and indeterminate forms have become predominant among women and younger people. The average age of male cases has shifted toward younger ages.

CONCLUSIONS

We interpret this pattern to mean that the increase in NCDR reflects a real increase in incidence of leprosy, whether or not accompanied by improved detection.

Sensitivity and specificity of BCG scar reading in Brazil

In a cross sectional survey within a community trial of BCG efficacy evaluation in Brazil, trained teams inspected children's upper arms and obtained information on BCG vaccination from guardian letters and vaccination cards. Nurses re-examined the sub-sample of children blindly. High agreement was found between the two scar readings (Kappa = 0.839). High sensitivity and low specificity was observed when guardian or card information was the gold standard. Sensitivity remained high when guardian and card information agreed. When disagreement occurred, sensitivity remained high and specificity was very low. BCG scar is a good indicator of BCG vaccination.

Skin test reactivity to mycobacterial antigens parallels the phylogenetic structure of their genus

SETTING

City of Manaus, Amazonas, Brazil.

OBJECTIVE

To explore the relationship between positivity to tuberculin and other environmental mycobacteria sensitins, according to a range of criteria and presence of BCG scar.

DESIGN

Dual skin testing with tuberculin and four mycobacterial sensitins, and BCG scar recording of 1070 schoolchildren aged 7-14. Four criteria for positivity were used: simple and dominant, with 5 and 10 mm cut-off points.

RESULTS

The standardised prevalence of reactions > or = 5 mm for BCG scar negative children was 58.3% for Mycobacterium avium, 54.2% for M. scrofulaceum, 26.8% for M. fortuitum, 17.9% for M. tuberculosis and 7.6% for M. kansasii. Correlations between tuberculin and each sensitin, for BCG scar negative children, were 0.47 for M. avium, 0.53 for M. scrofulaceum, 0.60 for M. kansasii and 0.22 for M. fortuitum (all with P < 0.01). BCG effect was particularly significant for tuberculin (odds ratio = 3.44 for reactions > or = 5 mm, P < 0.001) and influenced the balance between dominant/non-dominant reactions for all sensitins.

CONCLUSION

The correlation between tuberculin and each sensitin confirmed the separation of the rapidly (M. fortuitum) and slowly growing mycobacteria (M. tuberculosis, M. avium, M. scrofulaceum and M. kansasii). The influence of BCG on tuberculin reactions was more marked than on other mycobacterial sensitins.

[Epidemiology of dengue in Salvador-Bahia, 1995-1999]

Since 1981, Brazil has registered dengue epidemic and simultaneous circulation of the DEN-1 and DEN-2 serotypes in over 2,700 municipalities. In Salvador- Bahia, located in the Northeastern region of the Country, two epidemic outbreaks occurred in the years of 1995 and 1996, with further endemic spread of the disease. This study analyses the incidence of the virosis within this municipal area, from 1995 to 1999, considering, among other variables, its distribution in the Sanitary Districts and density of Aedes aegypti. Registers of notified cases and the city's Vectorial Control Program were used as data source. The incidence rate of notified cases of dengue in 1995 and 1996, which were 691.4 and 393.5 per 100,000 inhabitants, respectively, decreased to 65 per 100,000 inhabitants in 1998. In the poorer Sanitary Districts, this index reached figures of over 800 per 100,000 inhabitants. The Premise Index for Aedes aegypti reached 54.1% in one of the Districts. Bearing in mind the relevance of the re-emergence of dengue in the world, the authors discuss the possible factors which condition the virus introduction, its epidemiological presentation over the course of four years, and the effectiveness of the vectorial combat (eradication) program.

[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.

Lower hookworm incidence, prevalence, and intensity of infection in children with a Bacillus Calmette-Guérin vaccination scar

Bacillus Calmette-Guérin (BCG), the most common vaccine worldwide, has broad effects on the immune system. Hookworm infections are a major source of morbidity. In response to a preliminary report of BCG vaccination protection against nematodes in human immunodeficiency virus-infected adults, data from an ongoing prospective study were analyzed to determine the intensity (eggs per gram of stool), prevalence, and incidence of different helminths in children with and without a BCG vaccination scar. Adjusted prevalence and incidence ratios were estimated by using logistic regression. Children with a BCG vaccination scar were found to have statistically significantly lower hookworm prevalence (41%), incidence (37%), and mean egg counts (39%), after controlling for age, sex, and socioeconomic factors. There was no BCG association with incidence, prevalence, or intensity of infection with Schistosoma mansoni, Ascaris lumbricoides, or Trichuris trichiura. Such protection would have implications for public health and for research on mechanisms behind human immunological responses to hookworm.

Outbreak of aseptic meningitis associated with mass vaccination with a urabe-containing measles-mumps-rubella vaccine: implications for immunization programs

A mass immunization campaign with a Urabe-containing measles-mumps-rubella vaccine was carried out in 1997 in the city of Salvador, northeastern Brazil, with a target population of children aged 1-11 years. There was an outbreak of aseptic meningitis following the mass campaign. Cases of aseptic meningitis were ascertained through data collected from the records of children admitted to the local referral hospital for infectious diseases between March and October of 1997, using previously defined eligibility criteria. Vaccination histories were obtained through home visits or telephone calls. Eighty-seven cases fulfilled the study criteria. Of those, 58 cases were diagnosed after the vaccination campaign. An elevated risk of aseptic meningitis was observed 3 weeks after Brazil's national vaccination day compared with the risk in the prevaccination period (relative risk = 14.3; 95% confidence interval: 7.9, 25.7). This result was confirmed by a case series analysis (relative risk = 30.4; 95% confidence interval: 11.5, 80.8). The estimated risk of aseptic meningitis was 1 in 14,000 doses. This study confirms a link between measles-mumps-rubella vaccination and aseptic meningitis. The authors discuss the implications of this for the organization and planning of mass immunization campaigns.

[Tolerance to administration of massive doses of vitamin A associated to mass immunization of children in Northeast Brazil]

A follow-up study was carried out in two localities in the semi-arid region of the State of Bahia, Northeast Brazil, with the aim of identifying the occurrence and nature of possible acute side effects subsequent to vitamin A megadose supplement given together with mass immunization in children 6-59 months old. The sample consisted of 852 children, 416 from the county of Teofilandia who received vitamin A together with vaccines and 436 from Santa Barbara, who received only vaccine. In the 24 hours before immunization, children from both groups had similar incidences of diarrhea, fever, and vomiting. Anorexia was more prevalent in Teofilandia and remained so throughout the study period. The results suggest that acute side effects like diarrhea, vomiting, fever, or anorexia were not associated with the vitamin A dosage given with mass OPV, DPT, and measles immunization.

Schistosoma mansoni infection and nutritional status in schoolchildren: a randomized, double-blind trial in northeastern Brazil

Brazilian schoolchildren with mild- to moderate-intensity schistosome infections (<400 Schistosoma mansoni eggs/g stool) were randomly allocated to a treatment (oxamniquine) or placebo group in a double-blind fashion. Anthropometric measurements were made at baseline, 6 mo, and 1 y for 353 students. At baseline, the groups were not significantly different with respect to nutritional status or selected socioeconomic and biological characteristics, including anthropometric measures. One year later, significant differences were noted only in the nutritional status of boys treated for schistosome infection. Treated boys had greater measurements for weight, triceps skinfold thickness, midarm circumference, arm muscle area, and body mass index than untreated boys. They also showed significant increases over the year in weight, height, midarm circumference, and body mass index. The rates of improvement in weight and height were more accelerated in the first 6 mo after therapy than the last. These results indicate that, at least in boys, chronic S. mansoni infection at any intensity is detrimental to short-term growth and development.

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.

[Paternity in the perspective of a group of fathers]

Looking upon occidental silence which involves the paternity, we performed this research with the intention to conceive some associated aspects: the family role, birth of son expectation and father social role. For that, 7 fathers have been interviewed with ages between 21 and 45 years. This study allowed us observed that the paternity of the interviewed fathers is experienced by the father-son relationship preoccupation, kids education and the constant search of ways to experience the paternity as a form to be near of the kids and the wife.

Gender differences in growth of school-aged children with schistosomiasis and geohelminth infection

Light or moderate intensity infection with Schistosoma mansoni may contribute to growth deficits. We report on the effects of treatment for S. mansoni on growth and development in Brazilian schoolchildren. Anthropometric measurements were taken from 539 S. mansoni-infected children and their age- and sex-matched egg-negative controls between the ages of 7 and 15 years. The children as a whole exhibited chronic malnutrition, with growth retardation in height evident in 21% of the population. Infected children, however, were significantly smaller in height, weight, mid upper arm circumference (UAC), tricep skinfold (TSF), and subscapular skinfold (SSF) measurements than control children (P < 0.05). These differences were due primarily to a greater disparity between infected and egg-negative girls in height (P < 0.01), weight (P = 0.01), UAC (P = 0.O2), and TSF (P < 0.01). Nevertheless, girls demonstrated a better level of development and nutrition compared with boys. While infected boys were shorter and weighed less than controls, these differences were not significant. Growth and development in girls was negatively correlated with intensity of infection. Coinfection with S. mansoni and Trichuris appeared to act synergistically in the development of malnutrition.

[Nutritional status of pre-school children of the semi-arid region of Bahia (Brazil): II--Vitamin A deficiency]

A survey of 754 preschool children was undertaken in the urban areas of seven small towns of the semi-arid region of Bahia, Northeastern Brazil, to determine the prevalence of vitamin A deficiency, as well as its association with variables such as a age, family income, mother's schooling and dietary adequacy in vitamin A. Protein energy malnutrition and anemia were also studied and are reported separately. The clinical ophthalmological examination did not reveal any signs or symptoms of xerophthalmia amongst these children. In 563 children serum retinol was determined and the average value found was 20.3 micrograms/dl (SD = 10.8 micrograms/dl); the prevalence of deficient serum retinol (below 10.0 micrograms/dl) was of 15.3%. In all 7 localities studied, the prevalence of deficient retinol levels was above 5.0%, the criterion recommended by WHO for considering it a Public Health Problem. The distribution of serum retinol was similar between the sexes, but there was an age trend: the prevalence of deficient and low levels decreased with age. There was no association between deficient serum retinol and family income per capita or mother's education. Results from the 24 h food consumption survey revealed that only 8% of children had an adequate intake of vitamin A through the diet; 66% received less than 1/2 and 35% less than 1/4 of the recommended daily intake of vitamin A. Vitamin A deficiency should be considered a Public Health Problem in the region due to the high prevalence of deficient levels of serum retinol as well as the large dietary inadequacy.

[Nutritional and feeding status of preschool children in the semi-arid region of Bahia (Brazil): I. Anthropometric assessment]

A survey of 754 preschool children was undertaken in the urban areas of seven small towns of the semi-arid region of Bahia, Northeast Brazil. The study set out to determine the prevalence of weight and height deficits, as well as to correlate them with variables such as age, family income, mother's schooling and food consumption. A prevalence of 22.9% of Height for Age (HA) below -2.0 SD was found (stunting) and prevalence of 19.1% and 3.6% were determined, respectively for Weight for Age (WA) and Weight for Height (WH) below -2.0 SD (wasting). Regarding food consumption, only 6.8% of the children received a diet with an adequate energy supply for their age group in the previous day. There was a close association between inadequate HA and WA and family income per capita (p = 0.001 and p = 0.000, respectively). Children from families with income < 1/4 of the minimum wage per capita had twice the chance of being malnourished as compared with those from the > or = 1/2 minimum wage per capita stratum. The children included in this study showed prevalences of inadequate WH and WA significantly higher than those found in a national survey conducted in the same period (p = 0.047 and p = 0.000 respectively). This fact is surprising since in the last decade important reductions in child malnutrition and mortality were reported in the country as a whole; this may indicate that children from this region probably were not benefitted in the same way as the rest of the Brazilian child population.

Seroprevalence of HIV, HTLV-I/II and other perinatally-transmitted pathogens in Salvador, Bahia

Generation of epidemiological data on perinatally-transmitted infections is a fundamental tool for the formulation of health policies. In Brazil, this information is scarce, particularly in Northeast, the poorest region of the country. In order to gain some insights of the problem we studied the seroprevalence of some perinatally-transmitted infections in 1,024 low income pregnant women in Salvador, Bahia. The prevalences were as follow: HIV-1 (0.10%), HTLV-I/II (0.88%), T.cruzi (2.34%). T.pallidum (3.91%), rubella virus (77.44%). T.gondii IgM (2.87%) and IgG (69.34%), HBs Ag (0.6%) and anti-HBs (7.62%). Rubella virus and T.gondii IgG antibodies were present in more than two thirds of pregnant women but antibodies against other pathogens were present at much lower rates. We found that the prevalence of HTLV-I/II was nine times higher than that found for HIV-1. In some cases such as T.cruzi and hepatitis B infection there was a decrease in the prevalence over the years. On the other hand, there was an increase in the seroprevalence of T.gondii infection. Our data strongly recommend mandatory screening tests for HTLV-I/II, T.gondii (IgM), T.pallidum and rubella virus in prenatal routine for pregnant women in Salvador. Screening test for T.cruzi, hepatitis and HIV-1 is recommended whenever risk factors associated with these infections are suspected. However in areas with high prevalence for these infections, the mandatory screening test in prenatal care should be considered.

Uma concepção popular sobre a esquistossomose mansônica: os modos de transmissão e prevenção na perspectiva de gênero

Estudo sobre as concepções e práticas populares acerca da transmissão e prevenção das parasitoses, com ênfase para a esquistossomose mansônica. Explora a existência de um sistema popular de cuidados de saúde que mescla elementos da biomedicina e da medicina tradicional como forma de compreender e manejar os fenômenos de saúde/doença. Descreve as diferenças entre morbidade e sexo/gênero na concepção dos sujeitos entrevistados. Apresenta o discurso popular sobre as parasitoses, discutindo as dificuldades das ações de controle. Considera as contradições entre hábitos e valores culturais e as medidas de controle conhecidas, criticando a imprecisão das ações educativas nos programas oficiais de intervenção.

Esquistossomose mansônica no estado da Bahia, Brasil: tendências históricas e medidas de controle

Visando a contribuir para o aperfeiçoamento das estratégias de controle da esquistossomose mansônica, foram estudadas as modificações no padrão de distribuição das prevalências municipais no Estado da Bahia no período de 1950 a 1994, seus determinantes e o efeito da quimioterapia em larga escala. Verificou-se redução da prevalência média de esquistossomose para o estado como um todo, de 15,6% para 9,5%, no período de estudo. Não foram observadas modificações substanciais no padrão básico de distribuição espacial da prevalência. Entretanto, em municípios do oeste, sudoeste e litoral norte do estado, verificou-se aumento da prevalência, indicando o surgimento de novas áreas de transmissão. Comparando-se as variações das prevalências municipais de acordo com a utilização da quimioterapia em larga escala, verificou-se que houve redução na Bacia do Paraguaçu, onde vem sendo intensamente adotada tal medida, em proporção semelhante ao que foi observado para algumas áreas sem quimioterapia. As análises de correlação e regressão utilizadas não evidenciaram associação entre a quimioterapia e a variação da prevalência, observando-se correlações significativas entre esta última variável e a dinâmica populacional. Esses resultados indicam que a redução da prevalência de esquistossomose no estado não pode ser atribuída exclusivamente à utilização de quimioterapia, mas deve contemplar a articulação com os fatores relacionados à organização do espaço, que contribuem para diminuir o risco de transmissão. A forma incompleta e espacialmente desigual que caracteriza o processo de urbanização, aliada à intensa mobilidade da população, possibilita a disseminação da esquistossomose mansônica para novas áreas de transmissão, como evidenciado no Estado da Bahia.

Effect of vitamin A supplementation on diarrhoea and acute lower-respiratory-tract infections in young children in Brazil

A beneficial effect of periodic vitamin A supplementation on childhood mortality has been demonstrated, but the effect on morbidity is less clear. We investigated the effect of vitamin A supplementation on diarrhoea and acute lower-respiratory-tract infections (ALRI) in children from northeastern Brazil in a randomised, double-blind, placebo-controlled community trial. 1240 children aged 6-48 months were assigned vitamin A or placebo every 4 months for 1 year. They were followed up at home three times a week, and data about the occurrence and severity of diarrhoea and ALRI were collected. Any child with cough and respiratory rate above 40 breaths per min was visited by a paediatrician. The overall incidence of diarrhoea episodes was significantly lower in the vitamin-A-supplemented group than in the placebo group (18.42 vs 19.58 x 10(-3) child-days; rate ratio 0.94 [95% Cl 0.90-0.98]). The benefit of supplementation was greater as regards severe episodes of diarrhoea; the incidence was 20% lower in the vitamin A group than in the placebo group (rate ratio 0.80 [0.65-0.98]). With the standard definition of diarrhoea (> or = 3 liquid or semi-liquid stools in 24 h) the effect of vitamin A on mean daily prevalence did not reach significance, but as the definition of diarrhoea was made more stringent (increasing number of stools per day), a significant benefit became apparent, reaching for diarrhoea with 6 or more liquid or semi-liquid stools in 24 h a 23% lower prevalence. We found no effect of vitamin A supplementation on the incidence of ALRI. The reduction in severity of diarrhoea may be the most important factor in the lowering of mortality by vitamin A supplementation.

[Impact of Chagas' infection on some demographic characteristics: results of an ecological study]

This study aimed to analyze the impact of T. cruzi infection on some demographic characteristics in the State of Bahia. It is a place where Chagas' disease is endemic in general. In the endemic areas, similar infection rates were observed in males and females. However, males, mainly those aged 30 or more, had higher mortality rates than females. Analyses were conducted on a set of secondary data from several different sources. They included prevalence of T. cruzi infection, specific mortality related to Chagas' disease, and demographic characteristics. The data were aggregated at two different levels: municipality and homogeneous micro-regions. Significant positive correlations were observed between prevalence of T. cruzi infection and mortality rates. These indicators, in turn, were correlated with the proportion of widows and widowers in the population. Findings were higher for widows. In areas where prevalence of T. cruzi infection was 15% or greater, there were 22% more widows as compared to infection free areas. Places with high prevalence presented some skew in the age structure, and there was a consistent decrease in the proportion of males in the 35-44 age group. A possible confounding effect of migration on these finding was not demonstrated.

The dot map as an epidemiological tool: a case study of Schistosoma mansoni infection in an urban setting

In this paper dot maps are used as an epidemiological tool to describe the spatial patterns of cases, non-cases and some relevant risk factors associated with the occurrence of Schistosoma mansoni infection in an urban environment. The study was carried out in Santo Antonio de Jesus, a town in north-east Brazil with a population of around 45,000 inhabitants. The survey was targeted at all children aged between 12 years 8 months and 14 years 11 months who were living in the town at the time of the survey. An extensive questionnaire was used to collect information on each child and on family and household conditions; stool samples were also taken for quantitative examination. A computerized digitizer was used on a map (scale 1:4000) to create x and y coordinates for each child's household. The result was matched with individual data from the questionnaires and the stool examination. From this data base it was possible, by using a statistical package, to make epidemiological analyses and by using the statistical package associated with a geocartographic system package it was possible to dot plot selected values of defined variables. These techniques substantiated the findings on the risk factors at a local level and, as a consequence, improve our ability to define targeted actions towards local control of schistosomiasis.

Use of risk factors obtained by questionnaires in the screening for Schistosoma mansoni infection

Several social, environmental, and behavioral variables shown to be strongly associated with the level of Schistosoma mansoni infection were evaluated regarding their power to discriminate infected from noninfected children. Emphasis was placed on the identification of infected persons with high egg counts, who are at risk of developing the severe clinical forms of the disease. Data were collected in a survey carried out in a town (Santo Antonio de Jesus) in northeastern Brazil. The sample consisted of all children 12-14 years old living in the town. An extensive questionnaire was used to collect information on each child and on family and household conditions. Stool samples were taken for quantitative examination. The prevalence of S. mansoni infection was 31.0%. The risk factors were first analyzed one-by-one and then aggregated using logistic models. From the models, individual probabilities of being infected were estimated. The results were then used to produce relative operating characteristics curves. The model with highest discriminative power was that which included five risk factors, namely migratory status and four others related to water-contact activities. The ability to discriminate increased with an increase in the level of egg excretion. The conclusion is that the development of short questionnaires for large-scale screening for S. mansoni infection in endemic areas is realistic.

Geographical and socioeconomic factors relating to the distribution of Schistosoma mansoni infection in an urban area of north-east Brazil

A study was carried out in Santo Antonio de Jesus, a town in Bahia State, north-east Brazil, to determine the relationship between various biological, socioeconomic, behavioural, and geographical factors and the prevalence and intensity of Schistosoma mansoni infection. The town's population was around 45,000 and the study was targeted at all children born in 1970-71 who were living in the town at the time of the survey (August-November 1984). An extensive questionnaire was used to collect information on each child and on family and household conditions; samples of stools were also taken for examination (Kato-Katz method). A survey of water snails was also carried out and information on the distribution of their breeding sites was plotted on a map of the area. The overall prevalence of S. mansoni infection was 31.0%. Several variables that reflected different aspects of the population's way of life were strongly associated with the prevalence and the intensity of infection. Some of the findings are valuable for understanding the mechanisms involved in the occurrence of schistosomiasis and its distribution in urban locations as well as for defining high-risk groups, all of which are important for planning control strategies.

[Cause vs. prediction: history of bathing in rivers as a risk factor and predictor of infection by Schistosoma mansoni]

Através da análise das relações existentes entre as medidas de risco e as medidas de eficiência de testes de diagnóstico ou triagem, são discutidos os problemas e limitações concernentes ao uso de fatores de risco na predição da distribuição de efeitos (infecção, doença, cura) em uma população. Para ilustrar o tema, foi utilizada a associação, em crianças, entre a questão "você já tomou banhos em rios?", muito utilizada em anamneses clínicas ensinadas em diversas escolas médicas do Brasil, e a infecção pelo Schistosoma mansoni. A história de banhos em rios, enquanto um importante fator de risco, mostrou-se mau preditor da ocorrência da infecção esquistossomótica. A análise demonstrou que este achado é, em grande parte, devido a baixa freqüência de história negativa de banhos em rios. Porém, a possibilidade da utilização de fatores de risco isoladamente ou agrupados, com o objetivo de predição de efeitos, é possível e desejável. Apesar de pouco explorado nos seus aspectos práticos ou conceituais, esta área de conhecimento representa um importante ponto de convergência entre a epidemiologia das causas e a epidemiologia das intervenções.

Three-year prospective study of the evolution of Manson's schistosomiasis in north-east Brazil

A cross-sectional study of morbidity associated with Schistosoma mansoni infection in an area in North-East Brazil where the disease is endemic was carried out in 1974. The survey was repeated in 1977, before mass treatment with oxamniquine, providing a cohort of 210 individuals who had both examinations. The high prevalence of hepatomegaly (over 80%) and of splenomegaly (over 15%) contrasted with rates of 10% and 1%, respectively, in a non-endemic area. Over the 3-year period hepatomegaly spontaneously regressed in 13% of patients, and splenomegaly regressed in 56%, a phenomenon most common in older individuals with light infections. Those with heavy infections--ie, 500 or more eggs per g faeces, had an excess risk of splenomegaly of 19.6% and, of its persistence, of 61.5%. Thus, intensity of infection was a critical factor in liver and spleen involvement, and programmes of chemotherapy that reduce infection should mitigate the risk of schistosomal morbidity.

The effect of Schistosoma mansoni infection on child morbidity in the State of Bahia, Brazil. II--Analysis at the individual level

The present investigation was carried out on a sample of 840 children (5 to 16 years old) from ten small towns of the State of Bahia in northeastern Brazil. The objetive was to study, by using a cross sectional methodology, the evolution of schistosomiasis morbidity (hepatic and splenic enlargement) in children, and the role of the intensity of S. mansoni infection in this process. The children were analised in three age groups (5 to 8, to 12 and 13 to 16 years old) and classified as uninfected, mildly infected, moderately infected and heavily infected according to the number of eggs in the stool. In children aged 5 to 8 years, increasing egg counts were not associated with increasing frequencies of hepatic or splenic enlargement. In the 9 to 12 years old group and association was observed with the prevalence of hepatic enlargement, but not with the prevalence of spleen enlargement. In the oldest group, 13 to 16 years old, an association was observed with the prevalence of enlargement of both organs. It was evident that in this population schistosomiasis morbidity develops in the early period of life as a gradual process starting with liver enlargement and followed by spleen enlargement some years later. It was found that the intensity of infection has a fundamental role in this process, although there is a latent period of some years before clinical splenomegaly appears in moderate-heavily infected children. The Authors suggest that the prevalence of splenomegaly in the 13 to 16 years old group is a good measure of the community level of schistosomiasis morbidity and could be used to measure the impact of control programs.

The effect of Schistosoma mansoni infection on child morbidity in the state of Bahia, Brazil. I--Analysis at the ecological level

Esta investigação foi levada a efeito em 10 pequenas cidades do Estado da Bahia (Nordeste do Brasil), escolhidas através de um processo amostrai. O objetivo foi estudar as correlações entre as prevalências de hepatomegalia e esplenomegalia, em diferentes áreas, com a prevalência e a intensidade da infecção pelo S. mansoni nas mesmas áreas. Nossas conclusões são: a) a morbidade esquistossomótica (prevalências de hepatomegalia e esplenomegalia) foi diretamente correlacionada com a prevalência e a intensidade da infecção; b) a intensidade da infecção (medida pelo número de ovos nas fezes) mostrou ser um bom indicador do grau de morbidade, explicando a variação da morbidade entre as áreas melhor que a prevalência da infecção; c) a prevalência de esplenomegalia e o tamanho médio do fígado abaixo do rebordo costal na linha me dio-esternal são bom indicadores da prevalência e da intensidade da infecção pelo S. mansoni na comunidade. Nossas conclusões trazem a possibilidade da construção de equações de regressão definitivas entre indicadores de morbidade e indicadores de infecção, de tal forma que o valor de um possa ser usado para predizer o valor do outro.

Multiple causes of anaemia amongst children living near a lead smelter in Brazil

A prevalence study of anaemia was carried out amongst children, aged one to nine years, living near a lead smelter in Santo Amaro City, Northeast Brazil. It was found that the variation in haemoglobin levels was significantly associated with malnutrition and with the interaction between malnutrition and iron deficiency, but not with lead poisoning, iron deficiency, or hookworm infection, having allowed for the effects of age, area of residence, family per capita income and race. The effect of the interaction between malnutrition and iron deficiency on haemoglobin levels was most prominent amongst children aged one year and amongst those living in the most deprived area. The lack of demonstrable interaction between lead poisoning and iron deficiency in the causation of anaemia amongst these children is discussed.

Lead poisoning and hookworm infection as multiple factors in anaemia

A retrospective study was carried out in a rural area of north-eastern Brazil, to search for interactions between biological and chemical agents present in the environment as causes of anaemia. A lead smelter situated in a hookworm endemic area provided the opportunity to look at the effect of this double exposure in relation to laboratory defined anaemia, by comparing the odds ratios in different subgroups of 109 "cases" and 107 "controls". The subgroup with both hookworm infection and chronic lead poisoning--measured by the concentration of delta-ALA excreted in urine--had an odds ratio of developing anaemia five times greater than individuals with neither. Although a synergistic effect could not be demonstrated, the additive effect of the two conditions placed this group in a higher risk category.

A three year follow-up of chemotherapy with oxamniquine in a Brazilian community with endemic schistosomiasis mansoni

Oral oxamniquine was tested as a control strategy for endemic schistosomiasis in a rural area of Bahia, Brazil. Adults were treated with a single dose (12.5 to 15 mg per kg) and children (less than 12 years old) with a total of 20 mg per kg in two doses. The 191 (infected) persons treated represented 69% of the infected population in the study area. Follow-up stool examinations (Kato-Katz method) at one, 3, 6, 13, 25 and 33 months showed the cure rate declining from 80% at three months to 46% at 33 months. Over one half of those not cured showed a decrease in egg counts throughout the follow-up which, after 33 months, remained 66% below the pre-treatment levels. Stool examinations conducted on all study area residents during three years before chemotherapy showed the prevalence and intensity of Schistosoma mansoni infection to be high and stable. 33 months after the chemotherapy the prevalence was 41% and for infected individuals the geometric mean egg count was 121 epg, a decline of respectively 35% and 40% from pre-treatment levels for each index. Chemotherapy of infected persons with oxamniquine protected the community as a whole from high worm burdens for almost three years, although at this point the prevalence began to rise towards pretreatment levels.

Stability of faecal egg excretion in Schistosoma mansoni infection

Stability of Schistosoma mansoni egg excretion was studied in 23 residents of a rural endemic area in North-east Brazil where the over-all prevalence rate was 87% and the peak geometric mean egg excretion was 308 eggs/ml (Bell method) in the 10 to 14-year-old age group. Stool examinations by the Kato method were performed for three to four consecutive days each month for three consecutive months. Both raw and transformed data showed significant stability of S. mansoni egg excretion from day to day and month to month in this population. A single Kato examination detected 68% of individuals who were excreting more than 400 eggs per gramme. Although S. mansoni egg excretion is stable over time, identifying individuals with high egg excretion in endemic populations requires sensitive quantitative methods.