RESUMO
Chagas disease is a lethal, neglected tropical disease. Unfortunately, aggressive insecticide-spraying campaigns have not been able to eliminate domestic infestation of Triatoma dimidiata, the native vector in Guatemala. To target interventions toward houses most at risk of infestation, comprehensive socioeconomic and entomologic surveys were conducted in two towns in Jutiapa, Guatemala. Given the exhaustively large search space associated with combinations of risk factors, traditional statistics are limited in their ability to discover risk factor interactions. Two recently developed statistical evolutionary algorithms, specifically designed to accommodate risk factor interactions and heterogeneity, were applied to this large combinatorial search space and used in tandem to identify sets of risk factor combinations associated with infestation. The optimal model includes 10 risk factors in what is known as a third-order disjunctive normal form (i.e., infested households have chicken coops AND deteriorated bedroom walls OR an accumulation of objects AND dirt floors AND total number of occupants ≥ 5 AND years of electricity ≥ 5 OR poor hygienic condition ratings AND adobe walls AND deteriorated walls AND dogs). Houses with dirt floors and deteriorated walls have been reported previously as risk factors and align well with factors currently targeted by Ecohealth interventions to minimize infestation. However, the tandem evolutionary algorithms also identified two new socioeconomic risk factors (i.e., households having many occupants and years of electricity ≥ 5). Identifying key risk factors may help with the development of new Ecohealth interventions and/or reduce the survey time needed to identify houses most at risk.
Assuntos
Animais Domésticos , Doença de Chagas/epidemiologia , Materiais de Construção/estatística & dados numéricos , Abrigo para Animais , Habitação/estatística & dados numéricos , Insetos Vetores , Triatoma , Algoritmos , Animais , Doença de Chagas/transmissão , Galinhas , Cães , Instalação Elétrica/estatística & dados numéricos , Características da Família , Guatemala/epidemiologia , Humanos , Higiene , Controle de Insetos , Inseticidas , Piretrinas , Fatores de Risco , Comportamento de Redução do Risco , Fatores SocioeconômicosRESUMO
OBJECTIVE: To estimate the prevalence of exposure to magnetic fields generated by transmission lines (TL) and characterize the exposed population. METHODS: Information about TL in the metropolitan region of São Paulo, Southeastern Brazil, was provided by the electricity companies and mapped out using geographic information system (GIS). Demographic and socioeconomic data were obtained from the 2000 Census and added to the GIS in another layer. Households and their inhabitants that were located at a distance from the TL that was sufficient to generate a magnetic field 0.3 microT (microteslas) were deemed to be exposed. The prevalence was estimated according to the area of the corridors of exposure along the TL. Two approaches were used to delimit the corridor width: one consisted of widths that were predefined by the TL voltage, and the other consisted of calculation of the magnetic field. The socioeconomic information on the exposed and non-exposed populations were compared by applying the two-proportion test (alpha= 5%). RESULTS: In the corridors with predefined widths, the prevalence of exposure was 2.4%, and in the calculated corridors, the prevalence was 1.4%. Both methods indicated higher prevalence of exposure among the younger population, and among individuals with lower education and income levels (p < 0.001). CONCLUSIONS: The prevalence of exposure to magnetic fields generated by TL in the metropolitan region of São Paulo was lower than what has been observed in other countries. The results indicate inequality in the exposure to magnetic fields in this urban area, with greater risk to vulnerable populations such as children and socioeconomically less favored individuals.
Assuntos
Instalação Elétrica/estatística & dados numéricos , Campos Eletromagnéticos , Exposição Ambiental/estatística & dados numéricos , Monitoramento de Radiação/estatística & dados numéricos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Brasil , Criança , Estudos Transversais , Exposição Ambiental/economia , Humanos , Pessoa de Meia-Idade , Monitoramento de Radiação/métodos , Fatores Socioeconômicos , Adulto JovemRESUMO
OBJETIVO: Estimar a prevalência de exposição aos campos magnéticos gerados por linhas de transmissão (LT) e caracterizar a população exposta. MÉTODOS: Informações sobre LT da Região Metropolitana de São Paulo foram fornecidas pelas concessionárias de energia e mapeadas usando sistema de informação geográfica (SIG). Dados demográficos e socioeconômicos foram obtidos por meio do Censo 2000 e incluídos no SIG em outra camada. Foram considerados expostos os domicílios e seus habitantes localizados a uma distância da LT suficiente para gerar um campo magnético 0,3 µT (microteslas). A prevalência foi estimada por meio da área de corredores de exposição ao longo das LT. A largura dos corredores de exposição se baseou em duas abordagens: uma consistiu em larguras pré-definidas pela tensão da LT e a outra por meio de cálculo do campo magnético. As informações socioeconômicas entre expostos e não expostos foram comparadas pela aplicação do teste de duas proporções (α= 5 por cento)...
OBJECTIVE: To estimate the prevalence of exposure to magnetic fields generated by transmission lines (TL) and characterize the exposed population. METHODS: Information about TL in the metropolitan region of São Paulo, Southeastern Brazil, was provided by the electricity companies and mapped out using geographic information system (GIS). Demographic and socioeconomic data were obtained from the 2000 Census and added to the GIS in another layer. Households and their inhabitants that were located at a distance from the TL that was sufficient to generate a magnetic field 0.3 µT (microteslas) were deemed to be exposed. The prevalence was estimated according to the area of the corridors of exposure along the TL. Two approaches were used to delimit the corridor width: one consisted of widths that were predefined by the TL voltage, and the other consisted of calculation of the magnetic field. The socioeconomic information on the exposed and non-exposed populations were compared by applying the two-proportion test (α= 5 percent)...
OBJETIVO: Estimar la prevalencia de exposición a los campos magnéticos generados por líneas de transmisión (LT) y caracterizar la población expuesta. MÉTODOS: Informaciones sobre LT de la Región Metropolitana de São Paulo (Sureste de Brasil) fueron providenciadas por las concesionarias de energía y mapeadas usando el sistema de información geográfica (SIG). Datos demográficos y socioeconómicos fueron obtenidos por medio del Censo 2000 e incluidos en el SIG en otra camada. Fueron considerados expuestos los domicilios y sus habitantes localizados a una distancia de la LT suficiente para generar un campo magnético 0,3 μT (microteslas). La prevalencia fue estimada por medio del área de corredores de exposición a lo largo de las LT. El ancho de los corredores de exposición se basó en dos abordajes: uno consistió en anchos pre-definidos por la tensión de la LT y la otra por medio del cálculo del campo magnético. Las informaciones socioeconómicas entre expuestos y no expuestos fueron comparadas por la aplicación de la prueba de dos proporciones (α=5 por ciento)...