[Geospatial models for local health surveillance]. / Modelos geo-espaciales para la vigilancia local de la salud.

OBJECTIVES: To produce a geospatial model to evaluate lead exposure among school children from 6-8 years of age, in San Antonio Oeste, Rio Negro province, Argentina, an area contaminated by a foundry in the city center whose toxins were released into the open air. METHODS: The spatial analysis conducted from October-April 2006 included satellite interpretation and mapping of the data to geographically plot the information. Residences on dirt roads were included, as was the distance for each of the study children's homes and/or schools to the site identified as the source of the exposure. RESULTS: Blood samples taken from children attending schools within the area surrounding the source showed higher lead levels than that of children in other areas. These lead levels were associated with the proximity to the source and/or with living on a dirt road. The highest blood lead levels corresponded to the higher environmental lead levels. CONCLUSIONS: Spatial analysis was shown to be a useful tool for site analysis and risk management since it indicated a definitive association between elevated lead levels and the proximity to the source, and/or residing on a dirt road, connections which had not been revealed with traditional epidemiological analyses. The results provided the scientific evidence needed to begin implementing interventions regarding the sources of exposure and education aimed at promoting more hygienic dietary habits among the population.

Modelos geo-espaciales para la vigilancia local de la salud / Geospatial models for local health surveillance

OBJETIVOS: Generar un modelo geo-espacial para evaluar la exposición a plomo de escolares de 6 a 8 años, residentes de San Antonio Oeste, en la provincia de Río Negro, Argentina, localidad contaminada por una fundición en el casco de la ciudad y la acumulación a cielo abierto de sus residuos. MÉTODOS: El análisis espacial llevado a cabo de octubre a abril de 2006 incluyó la interpretación satelital y el georreferenciamiento de los datos para la espacialización de la información. Se tomó en cuenta la localización de las residencias sobre calles de tierra y la proximidad, desde el domicilio y/o la escuela de los niños bajo estudio, a los sitios-fuente como puntos de exposición. RESULTADOS: Las muestras de sangre tomadas a los niños en las escuelas en el área de influencia de alguna fuente, mostraron mayor abundancia de plombemias elevadas que las localizadas en otras áreas. Dichas plombemias se asociaron con la cercanía a alguna fuente y/o la ubicación de las residencias sobre calles de tierra. Los valores más altos de plomo en sangre correspondieron a mayores rangos de plomo ambiental. CONCLUSIONES: El análisis espacial constituyó una metodología complementaria útil para el análisis y la gestión de riesgo del sitio contaminado, al indicar una asociación positiva entre plombemias elevadas y la proximidad a la fuente, y/o el hecho de vivir en calles de tierra, que no se había hecho evidente mediante los análisis epidemiológicos tradicionales. Los resultados aportaron la evidencia científica necesaria para indicar la implementación de medidas de intervención directas sobre las fuentes de exposición y de educación, orientadas a fomentar hábitos dietéticos higiénicos en la población.

OBJECTIVES: To produce a geospatial model to evaluate lead exposure among school children from 6-8 years of age, in San Antonio Oeste, Rio Negro province, Argentina, an area contaminated by a foundry in the city center whose toxins were released into the open air. METHODS: The spatial analysis conducted from October-April 2006 included satellite interpretation and mapping of the data to geographically plot the information. Residences on dirt roads were included, as was the distance for each of the study children’s homes and/or schools to the site identified as the source of the exposure. RESULTS: Blood samples taken from children attending schools within the area surrounding the source showed higher lead levels than that of children in other areas. These lead levels were associated with the proximity to the source and/or with living on a dirt road. The highest blood lead levels corresponded to the higher environmental lead levels. CONCLUSIONS: Spatial analysis was shown to be a useful tool for site analysis and risk management since it indicated a definitive association between elevated lead levels and the proximity to the source, and/or residing on a dirt road, connections which had not been revealed with traditional epidemiological analyses. The results provided the scientific evidence needed to begin implementing interventions regarding the sources of exposure and education aimed at promoting more hygienic dietary habits among the population.

Pulsed-field gel electrophoresis, pertactin, pertussis toxin S1 subunit polymorphisms, and surfaceome analysis of vaccine and clinical Bordetella pertussis strains.

To add new insight to our previous work on the molecular epidemiology of Bordetella pertussis in Argentina, the prn and ptxS1 gene sequences and pulsed-field gel electrophoresis (PFGE) profiles of 57 clinical isolates obtained during two periods, 1969 to 1989 and 1997 to 2006, were analyzed. Non-vaccine-type ptxS1A was detected in isolates obtained since 1969. From 1989 on, a shift of predominance from the vaccine prn1 type to the nonvaccine prn2 type was observed. This was also reflected in a transition of PFGE group IV to group VI. These results show that nonvaccine B. pertussis strains are currently circulating. To analyze whether the observed genomic divergences between vaccine strains and clinical isolates have functional implications, protection assays using the intranasal mouse challenge model were performed. For such experiments, the clinical isolate B. pertussis 106 was selected as representative of circulating bacteria, since it came from the major group of the PFGE dendrogram (PFGE group VI). Groups of mice were immunized either with diphtheria-tetanus-whole-cell pertussis vaccine (ptxS1B prn1) or a vaccine prepared by us containing B. pertussis 106. Immunized mice were then challenged with a B. pertussis vaccine strain (Tohama, harboring ptxS1B and prn1) or the clinical isolate B. pertussis 106 (ptxS1A prn2). An adequate bacterial-elimination rate was observed only when mice were immunized and challenged with the same kind of strain. For further characterization, comparative proteomic profiling of enriched membrane proteins was done using three vaccine strains and the selected B. pertussis 106 clinical isolate. By matrix-assisted laser desorption ionization-time of flight mass spectrometry analysis, a total of 54 proteins were identified. This methodology allowed us to detect differing proteins among the four strains studied and, in particular, to distinguish the three vaccine strains from each other, as well as the vaccine strains from the clinical isolate. The differing proteins observed have cellular roles associated with amino acid and carbohydrate transport and metabolism. Some of them have been proposed as novel vaccine candidate proteins for other pathogens. Overall, the global strategy described here is presented as a good tool for the development of next-generation acellular vaccines.