Estudio comparativo de la morbilidad por asma entre la población de distintas zonas de Bahía Blanca y la de toda la ciudad / Comparative study of the morbidity for asthma between the population of different zones of Bahía Blanca and that of the whole city

Antecedentes. En Bahía Blanca se incrementaron las industrias petroquímicas, las empresas cerealeras y el parque automotor. La Municipalidad realiza estudios epidemiológicos con el propósito de conocer la prevalencia de las enfermedades, determinar los factores de riesgo y comprobar diferencias y asociaciones. Se consideraron áreas de mayor riesgo para padecer enfermedad respiratoria a la zona de Ingeniero White (industrial-portuaria) y al centro, por estudios anteriores y por los resultados de mediciones de los contaminates comunes. Objetivo. Comparar las prevalencias de asma, síntomas indicadores de asma (SIA), rinitis, enfermedades de la piel y trastornos del oído en distitnas áreas, con la prevalencia observada en toda la ciudad. Metodolgía. Los estudios a comparar son de corte transversal por encuesta domiciliaria de propósitos múltiples. Se utilizó la estandarización indirecta ajustando por edad, para estimar una razón estandarizada de prevalencia relacionando la proporción de casos esperados en cada barrio, comparando con los casos hallados en la ciudad. Resultados. Las prevalencias de enfermedades respiratorias observadas en Ingeriero White y en el Centro fueron dos y 1,43 veces mayores a las esperadas, respectivamente. La prevalencia de asma fue superior a la esperada en los cuatro barrios, más notoriamente en Ingeniero White. Los SIA resultaron dos veces por encima de lo esperado en Ingeniero White y 1.27 vecen en el Centro. En esta zona los casos de rinitis, enfermedades de la piel e hipoacusias fueron cinco, cuatro y 3,5 veces superiores a los esperados. Conclusiones. Residir en Ingeniero White y en el Centro significa mayor riesgo para padecer asma, rinitis, enfermedades de la piel e hipoacusia. Se debe considerar el impacto de los contaminantes conocidos.

Estudio comparativo de la morbilidad por asma entre la población de distintas zonas de Bahía Blanca y la de toda la ciudad / Comparative study of the morbidity for asthma between the population of different zones of Bahía Blanca and that of the whole city

Antecedentes. En Bahía Blanca se incrementaron las industrias petroquímicas, las empresas cerealeras y el parque automotor. La Municipalidad realiza estudios epidemiológicos con el propósito de conocer la prevalencia de las enfermedades, determinar los factores de riesgo y comprobar diferencias y asociaciones. Se consideraron áreas de mayor riesgo para padecer enfermedad respiratoria a la zona de Ingeniero White (industrial-portuaria) y al centro, por estudios anteriores y por los resultados de mediciones de los contaminates comunes. Objetivo. Comparar las prevalencias de asma, síntomas indicadores de asma (SIA), rinitis, enfermedades de la piel y trastornos del oído en distitnas áreas, con la prevalencia observada en toda la ciudad. Metodolgía. Los estudios a comparar son de corte transversal por encuesta domiciliaria de propósitos múltiples. Se utilizó la estandarización indirecta ajustando por edad, para estimar una razón estandarizada de prevalencia relacionando la proporción de casos esperados en cada barrio, comparando con los casos hallados en la ciudad. Resultados. Las prevalencias de enfermedades respiratorias observadas en Ingeriero White y en el Centro fueron dos y 1,43 veces mayores a las esperadas, respectivamente. La prevalencia de asma fue superior a la esperada en los cuatro barrios, más notoriamente en Ingeniero White. Los SIA resultaron dos veces por encima de lo esperado en Ingeniero White y 1.27 vecen en el Centro. En esta zona los casos de rinitis, enfermedades de la piel e hipoacusias fueron cinco, cuatro y 3,5 veces superiores a los esperados. Conclusiones. Residir en Ingeniero White y en el Centro significa mayor riesgo para padecer asma, rinitis, enfermedades de la piel e hipoacusia. Se debe considerar el impacto de los contaminantes conocidos.(AU)

Prevalencia de enfermedad respiratoria en la población de la ciudad de Bahía Blanca / Prevalence of respiratory diseases in the population of the city of Bahia Blanca

Antecedentes. Se encuentran en el partido empresas químicas, petroquímicas y granarias. Están registrados 130.000 vehículos. Se realizaron estudios sobre prevalencia de enfermedades y factores de riesgo en distintas zonas . No se conoce la prevalencia de enfermedades respiratorias en la ciudad. Objetivos. Describir la frecuencia de asma, rinitis y factores de riesgo. Efectuar comparaciones. Metodología. Estudio de corte transversal por modalidad de encuesta de propósitos múltiples en hogares. Para la estimación del n se utilizó la prevalencia de asma ( 4 %), encontrada en estudios previos, un error absoluto de 0.8 % (ER=20 %) y un nivel de confianza del 95 %. Se efectuó un muestreo por conglomerados con submuestreo, con probabilidades proporcionales a su tamaño, aplicando el efecto de diseño (deff = 2). Se utilizó el cuestionario usado en otros estudios. Resultados. Se encuestaron 1447 viviendas, n = 4766 personas. El 18% refirió padecer algún tipo de enfermedad respiratoria. Rinitis 12,7% (607/4766), síntomas indicadores de asma (SIA) 3,4% (163/4766) y asma 2,6% (125/4766). El 19,8% padecía SIA con rinitis (OR = 3,57; IC95%: 2,30-5,54) y el 17,8% de los que referían asma padecían rinitis (OR = 3,04; IC95%: 1,83-5,07). La prevalencia de tabaquismo fue de 20%, encontrándose asociación entre inhalar humo y SIA. Se halló asociación entre obesidad y rinitis. Conclusiones. La prevalencia de asma y rinitis fue similar a la hallada en Argentina. La frecuencia de SIA fue notoriamente inferior. La prevalencia de asma en la ciudad sería del 6%. Se ratifica el subdiagnóstico de asma hecho que contribuye a los tratamientos inadecuados referidos. La comparación con los resultados de los estudios anteriores, ratificarán o no la existencia de áreas de mayor riesgo para padecer enfermedad respiratoria(AU)

Background. In the place there are chemical, petrochemical and granaries companies. There are registrered 130.000 vehicles. Studies were realized on prevalence of diseases and factors of risk in different zones. There is not known the prevalence of respiratory diseases in the city. Proposes. To describe the frequency of asthma, rinitis and factors of risk. To carry out comparisons. Methodology. Study of transverse cut for modality of survey of multiple proposes in homes. For the estimation of n there was in use the prevalence of asthma (4%), found in previous studies, a mean error of 0.8 % (ER = 20%) and a confidence level of 95%. A sampling was effected by conglomerates with subsampling, by proportional probabilities to its size, applying the effect of design (deff=2). The questionnaire applyed was used in other studies. Results. There were polled 1447 housings, n = 4766 persons. The 18% answered to suffer some kind of respiratory disease. Rhinitis: 12.7% (607/4766), Symptoms Indicators of Asthma (SIA): 3.4% (163/4766) and asthma: 2.6% (125/4766). The 19.8% was suffering SIA with rhinitis ­OR = 3.57 (95% CI: 2.30-5.54 )­ and 17.8% of those who were recounting asthma they were suffering rhinitis ­OR = 3.04 (95% CI: 1.83-5.07)­. The prevalence of smoking was 20%, being association between inhaling smoke and SIA. Association was situated among obesity and rhinitis. Conclusions. The prevalence of asthma and rhinitis was similar to found in Argentina. SIA's frequency was glaringly low. The prevalence of asthma in the city would be 6 %. There is corroborated the made subdiagnosis of asthma that its ratified to the inadequate above-mentioned treatments. The comparison with the results of the previous studies, they will corroborated or not the existence of areas of major risk to suffer respiratory disease. (AU)

Defining the burden of pneumonia in children preventable by vaccination against Haemophilus influenzae type b.

OBJECTIVES: To determine the burden of pneumonia requiring hospitalization in infants and young children preventable by vaccination against Haemophilus influenzae type b (Hib). DESIGN: Vaccination centers in Santiago, Chile, were randomly selected to administer PRP-T, an Hib conjugate vaccine, combined with diphtheria-tetanus toxoids-pertussis (DTP) vaccine or DTP alone. SUBJECTS: Infants who received > or =2 doses of DTP or DTP and Hib conjugate vaccine combined. MAIN OUTCOME MEASURES: Pneumonia episodes leading to hospitalization accompanied by indicators of likely bacterial infection including radiologic evidence of alveolar consolidation or pleural effusion, an elevated erythrocyte sedimentation rate (> or =40 mm/h) or bronchial breath sounds on auscultation. RESULTS: In participants age 4 to 23 months, PRP-T reduced the incidence of pneumonia associated with alveolar consolidation or pleural effusion by 22% (95% confidence interval, -7 to 43) from 5.0 to 3.9 episodes per 1000 children per year. When the pneumonia case definition included any of the following, alveolar consolidation, pleural effusion, erythrocyte sedimentation rate > or =40 mm/h or bronchial breath sounds, PRP-T provided 26% protection (95% confidence interval, 7 to 44) and prevented 2.5 episodes per 1000 children per year. CONCLUSIONS: Hib vaccine provides substantial protection against nonbacteremic pneumonia, particularly those cases with alveolar consolidation, pleural effusion or other signs of likely bacterial infection. Hib vaccination prevented approximately 5 times as many nonbacteremic pneumonia cases in infants as meningitis cases, thus indicating that the largest part of the effect of Hib vaccination might be undetectable by routine culture methods.

Duration of efficacy of Ty21a, attenuated Salmonella typhi live oral vaccine.

Currently, two different formulations of Ty21a live oral typhoid vaccine are commercialized. The enteric-coated capsule formulation was licensed based on results of three years of follow-up of a randomized, placebo-controlled, double-blind field trial in Area Occidente, Santiago, Chile, which demonstrated that three doses of this formulation, given on an every other day immunization schedule, conferred the best protection among several options evaluated. Subsequently, a liquid formulation (lyophilized vaccine organisms reconstituted with buffer and water into a vaccine cocktail) was commercialized after it was shown to provide superior protection than enteric-coated capsules over three years of follow-up in a randomized, placebo-controlled field trial in Area Sur Oriente and Area Norte, Santiago. Surveillance in the Area Occidente trial was continued for four additional years (i.e., total seven years of follow-up) and in the Area Sur Oriente/Area Norte trial for two additional years (i.e., a total of five years of follow-up). These additional surveillance data, which were analyzed to ascertain the longevity of protection conferred by these formulations of Ty21a, revealed that three doses of Ty21a in enteric-coated capsules (every other day schedule) conferred 67% protection over three years and 62% protection over seven years of follow-up, whereas three doses of liquid formulation (every other day schedule) elicited 77% protection over three years and 78% over five years of follow-up. Based on its excellent clinical acceptability, ease of oral administration, proven practicality in school-based mass immunization, and long-term efficacy enduring at least seven years, it is proposed that school-based immunization with Ty21a be utilized as a control measure in areas where the incidence of typhoid fever is high and Salmonella typhi are antibiotic-resistant.

Effect of small bowel bacterial overgrowth on the immunogenicity of single-dose live oral cholera vaccine CVD 103-HgR.

Several live oral vaccines (polio, bovine rotavirus, CVD 103-HgR cholera) are less immunogenic in developing than in industrialized countries. It was hypothesized that proximal small bowel bacterial overgrowth (common in children in less developed countries but rare in industrialized settings) diminishes the vibriocidal antibody response to CVD 103-HgR. In total, 202 fasting Santiago schoolchildren aged 5-9 years had lactulose breath H2 tests to detect proximal small bowel bacteria 1 day before ingesting CVD 103-HgR. Florid small bowel overgrowth was observed in 10 (5.6%) of 178 analyzable children. In children with florid overgrowth, vibriocidal seroconversion differed little from other children (60% vs. 67%), but the geometric mean titer was lower (160 vs. 368; P=.25). By logistic regression, increased peak breath H2 at small bowel time points was associated with diminished seroconversion (P=.04), as was the interaction of H2 value and weight (children >25 kg had lower seroconversion rates among subjects with heaviest overgrowth).

[Serum antibodies against hepatitis A virus among subjects of middle and low socioeconomic levels in urban area of Santiago, Chile]. / Anticuerpos séricos contra el virus hepatitis A en sujetos de nivel socioeconómico medio y bajo, en comunas urbanas de Santiago.

BACKGROUND: The epidemiology of hepatitis A virus (HAV) infection is closely associated to the level of hygiene and sanitation of the population. Newly industrialising areas experience a transition from high to intermediate endemicity, which is characterized by a shift in the exposure age to HAV, from early childhood to school ages or adolescence. AIM: To measure the prevalence of HAV antibodies in subjects living in urban Santiago. SUBJECTS AND METHODS: A HAV antibody survey in five medium and low socioeconomic level urban districts of northern Santiago, was conducted in 1996. Healthy subjects aged 1 to 39 years old were recruited from randomly selected households. RESULTS: Five hundred three subjects were studied. Anti HAV antibodies were found in 13.2, 29.5, 59.6, 78.1, 95.6 and 98.2% of individuals aged 1 to 4, 5 to 9, 10 to 14, 15 to 19, 20 to 29 and 30 to 39 years old, respectively. CONCLUSIONS: The profile of positive antibodies is compatible with an intermediate pattern of transmission of HAV. The current data supports the idea that infection is shifting towards older ages. A progressive increase in the number of susceptible school age children and teenagers is propitious for the occurrence of common source hepatitis A outbreaks.

Clinical acceptability and immunogenicity of a pentavalent parenteral combination vaccine containing diphtheria, tetanus, acellular pertussis, inactivated poliomyelitis and Haemophilus influenzae type b conjugate antigens in two-, four- and six-month-old Chilean infants.

BACKGROUND: In recent years additional parenteral vaccines have been recommended for routine immunization of infants in the US and elsewhere. The ability to administer multiple vaccines as a single injection without unacceptably increasing reactogenicity or decreasing immunogenicity of any component would offer many practical advantages. METHODS: A randomized, open, controlled trial was conducted to assess the tolerance profile and immunogenicity, as well as to identify potential antigenic interferences, resulting from administration of a parenteral combination vaccine for infants. The vaccine contains diphtheria and tetanus toxoids, acellular pertussis antigens (DTaP), enhanced inactivated poliovirus (eIPV) and Haemophilus influenzae type b-tetanus toxoid conjugate (PRP-T). Infants (n=711) were randomly assigned to receive 1 of 5 regimens as the primary series at 2, 4 and 6 months of age, by group: (1) DTaP plus oral polio vaccine (OPV); (2) DTaP plus eIPV (separate injections); (3) DTaP-eIPV combined as a single injection; (4) DTaP-eIPV combined, plus a separate injection of PRP-T; or (5) DTaP-eIPV combined and reconstituting PRP-T, as a single injection. At 3, 5 and 7 months Groups 1, 2 and 3 received PRP-T. At 12 months all infants received a booster dose of DTaP reconstituting PRP-T as a single injection, plus a separate injection of measles, mumps and rubella vaccine. Groups 2, 3, 4 and 5 received OPV at 7 months, and all infants received OPV at 13 months. Serum immune responses were measured to the primary series at 2 and 7 months and to the booster dose at 12 and 13 months. RESULTS: Reaction rates were similar among groups. In the primary series combining eIPV with DTaP decreased geometric mean titers (GMTs) to diphtheria, tetanus and pertussis. In addition concomitant PRP-T (either simultaneous or combined) with DTaP-eIPV lowered anti-PRP and further decreased tetanus GMTs. Nonetheless in 100% of infants protective titers were achieved against diphtheria and tetanus (>0.01 IU/ml each) and against the poliovirus types 1, 2 and 3 after eIPV (Groups 2 to 5); 99% of infants (Groups 4 and 5) had protective titers against PRP (> or = 0.15 microg/ml). After boosting with DTaP/PRP-T decreased GMTs to diphtheria and PRP antigens were observed in the groups that received DTaP and eIPV combined. Nonetheless protective titers to diphtheria, tetanus and PRP occurred consistently. In contrast concomitant PRP-T with DTaP-eIPV enhanced the pertussis GMTs. CONCLUSIONS: We conclude that combined DTaP, eIPV and PRP-T in a single injection is well-tolerated and elicits an acceptable immune response to each component.

No adverse impact on protection against pertussis from combined administration of Haemophilus influenza type b conjugate and diphtheria-tetanus toxoid-pertussis vaccines in the same syringe.

To assess whether combining a Haemophilus influenzae type b conjugate vaccine (PRP-T) and diphtheria-tetanus toxoid-pertussis (DTP) vaccine in a single syringe would impact adversely the antibody response and clinical protection conferred by pertussis vaccine, surveillance and a nested serosurvey were conducted among infants in a large-scale evaluation of PRP-T in Santiago. Infants received either combined PRP-T/DTP or DTP only at 2, 4, and 6 months of age. At 8 months, pertussis agglutinin, anti-pertussis toxin, and anti-filamentous hemagglutinin antibody levels in the PRP-T/DTP (137.7, 23.1, and 12.2, respectively) and DTP (142.9, 20.6, and 13.0, respectively) groups were comparable. The incidence of pertussis was similar among infants assigned to health centers administering combined PRP-T/DTP and those administering DTP alone (13.1 vs. 12.2 cases/10(5) child-years). Combined PRP-T/DTP vaccine did not diminish protection against pertussis.

Large scale, postlicensure, selective vaccination of Chilean infants with PRP-T conjugate vaccine: practicality and effectiveness in preventing invasive Haemophilus influenzae type b infections.

BACKGROUND: Haemophilus influenzae type b (Hib) conjugate vaccines have demonstrated an impressive impact in diminishing Hib disease in industrialized countries. However, their high cost prompts nonindustrialized countries to corroborate their effectiveness under local conditions before considering their programmatic implementation. Such a postlicensure evaluation of vaccine effectiveness was undertaken in Chile. METHODS: After its licensure in Chile polyribosylribitol phosphate-tetanus toxoid protein conjugate vaccine (PRP-T), combined with diphtheria-tetanus-pertussis vaccine, was introduced into the Expanded Program on Immunization schedules in 36 health centers throughout metropolitan Santiago for 12 months, whereas 35 similar health centers administered only diphtheria-tetanus toxoid-pertussis vaccine. Bacteriologic surveillance data for invasive Hib cases collected over the ensuing 30 months were analyzed. RESULTS: In an intent-to-vaccinate (effectiveness) analysis, PRP-T provided 90.2% protection (95% confidence interval, 74.5 to 100%) against invasive Hib disease (40 vs. 4 cases, P < 0.001). Vaccine effectiveness was 91.3% against meningitis (22 vs. 2 cases) and 80% against pneumonia and empyema (10 vs. 2 cases, P = 0.039). Vaccine efficacy among infants who received all three doses of PRP-T was 91.7% (95% confidence interval, 64.8 to 100%). CONCLUSIONS: Programmatic use of Hib conjugate vaccine administered in combination with diphtheria-tetanus-pertussis vaccine constitutes a highly effective and practical intervention in Chile, a newly industrializing country.

Epidemiologic studies of Escherichia coli diarrheal infections in a low socioeconomic level peri-urban community in Santiago, Chile.

The incidence of diarrhea due to six categories of diarrheogenic Escherichia coli was determined in two pediatric cohorts in a low socioeconomic level community in Santiago, Chile, with access to chlorinated water. An age cross-sectional cohort of 340 children aged birth to 47 months was assembled. A newborn cohort was assembled by enrolling 10-12 newborns monthly for 12 months. Episodes of diarrhea were detected by twice weekly household visits. E. coli from stool cultures of cases and matched controls were hybridized with DNA probes specific for enterotoxigenic, enteroinvasive, enteropathogenic, enterohemorrhagic, enteroaggregative, and diffuse adherence E. coli. Overall, the incidence of diarrhea was low (2.1 episodes/infant/year). Nevertheless, a putative E. coli enteropathogen was found in a large proportion of diarrheal episodes, particularly during the summer. In both cohorts, enterotoxigenic E. coli were important pathogens. Enteropathogenic E. coli were incriminated during the first year of life in the newborn cohort, where they were found significantly more often in cases (p = 0.021) than in controls; beyond this age, isolation rates were similar. In contrast, the relative risk of isolation of diffuse adherence E. coli increased with age in the age cross-sectional cohort, where, overall, the difference in rate of isolation between cases and controls was significant (p = 0.0024). Enteroinvasive and enterohemorrhagic E. coli were isolated infrequently. Enteroaggregative E. coli were encountered equally in cases and controls. Facile transmission of E. coli enteropathogens is occurring in this community despite the availability of potable water.

PIP: Researchers conducted an age cross sectional cohort analysis of 340 0-47 month old children and newborn cohort analysis of 144 newborns to determine the diarrheogenic Escherichia coli incidence in Santa Julia, a low socioeconomic community in Santiago, Chile. Children in the age cross sectional cohort had age, sex, and sector matched controls. The newborns had sex matched controls. A public health nurse or nurse auxiliary visited the household of each subject 2 times a week to detect diarrhea episodes. Between December 1986 and February 1990, the age cross sectional cohort had 1178 episodes of diarrhea and the newborn cohort had 674 episodes. The overall diarrhea incidence was only 2.1 episodes/child/year. An E. coli enteropathogen was isolated in many of these episodes, especially during the summer (e.g. enterotoxigenic E. coli [ETEC], 2.2 cases/month in summer vs. 0.4 cases/month in winter; p = .00001). Diffuse adherence E. coli (DAEC) and enteropathogenic E. coli (EPEC) infections also peaked in the summer. ETEC contributed greatly to diarrheal episodes in both cohorts. Among newborns, EPEC was isolated significantly more often in cases than controls during the 1st 12 months of life (6.7% vs. 2.5%; p = .021). After 1 year, however, E. coli isolation rates were essentially the same. On the other hand, in the age cross sectional cohort, the relative risk of isolation of DAEC rose with age (e.g., 1.1 for 0.11 months, 1.4 for 36-47 months, and 2.1 for = or 48 months). In the same cohort, DAEC infections were much more common in cases than controls (16.6% vs. 11.9%; p = .0024). Enteroinvasive and enterohemorrhagic E. coli were the most rarely isolated E. coli types. No difference in the isolation rate of enteroaggregative E. coli existed between cases and controls. Since most households in Santa Julia have access to potable water (68%) and an indoor toilet (64%), food contamination were likely the vehicles of E. coli transmission because more than 50% of households do not have a refrigerator.

Epidemiologic patterns of acute diarrhea and endemic Shigella infections in children in a poor periurban setting in Santiago, Chile.

To prepare a field site for evaluating preventive interventions against endemic shigellosis, the authors followed prospectively a cohort of 360 children (90 each of children aged 0-11, 12-23, 24-35, and 36-47 months) in Santa Julia, a low socioeconomic area in Santiago, Chile, from November 1986 through April 1989 with twice weekly household visits for diarrheal disease; infants replaced children who reached 60 months of age. Coprocultures on 2 consecutive days from children with diarrhea and from age-matched controls within the cohort were cultured for Shigella. Bacteriologic surveillance was also maintained in the health center and children's hospital serving Santa Julia. In this community, where all households had access to potable water (68% inside) and all but 3% had access to a toilet, but where there was marked crowding, the overall incidence of diarrheal disease in the cohort was low (2.26 episodes/12 child months of observation in children aged 0-11 months and 2.09 in those aged 12-23 months), yet Shigella infections were common. Shigella accounted for 10% of diarrheal episodes in the cohort (vs. 3.2% isolation rate in controls, p less than 0.0001). The incidence of shigellosis in children aged 12-47 months was 0.16 cases per 12 child months of observation; in the first 5 years of life, a child had a 67% chance of experiencing shigellosis. Shigella sonnei, Shigella flexneri 2a, and S. flexneri 6 caused greater than 79% of the infections. Shigella occurred more often in hospitalized cases of diarrhea than in age-matched cases detected in the health center or by household surveillance (p less than 0.0001). An initial episode of Shigella diarrhea did not diminish overall the risk of subsequent shigellosis but did confer 72% protection (p = 0.05) against illness due to the homologous serotype. The high rate of both S. sonnei and S. flexneri shigellosis in a population with a low background rate of diarrhea makes Santa Julia an appropriate site for assessing the efficacy and effectiveness of measures to reduce Shigella infections.