Article

Uso do sensoriamento remoto para estudar a influência de alterações ambientais na distribuição da malária na Amazônia brasileira

Cadernos de Saúde Pública 01/2006; DOI: 10.1590/S0102-311X2006000300006
Source: DOAJ

ABSTRACT A construção da hidroelétrica de Tucuruí, no sudeste do Estado do Pará, Brasil, em 1981, impôs grandes mudanças ambientais, desmatamentos e migração para a região. O objetivo deste trabalho é verificar a influência destas mudanças na ocorrência da malária no Município de Jacundá, Pará, Brasil, utilizando-se técnicas de sensoriamento remoto e sistemas de informações geográficas. Os parâmetros utilizados para a construção dos mapas foram: distância das estradas, classe agrossilvopastoril, distância de coleções hídricas (rios, igarapés e do reservatório) e da área urbana do município. Neste estudo, verificou-se o caráter epidêmico da malária a partir da construção da barragem de Tucuruí. Sugere-se que o padrão sazonal da incidência está relacionado com o período de maior estabilidade das margens do reservatório e ocorrência de áreas alagadas, além de maior exposição de trabalhadores na época de colheita na região. Foi observado que a distribuição dos casos está relacionada com as formas de uso e ocupação da terra, principalmente em áreas de maior influência das estradas, locais onde se concentra grande parte da população.

Download full-text

Full-text

Available from: Maria Rita Donalisio, Sep 05, 2015
0 Followers
 · 
222 Views
 · 
59 Downloads
  • Source
    • "That high incidences are related to the fine-grained spatial association between natural preserved environments of the vector habitat altering with heavily modified man-made landscape patches, characterized by the high exposition and abundant vector presence. In this context, emphasize that the positive association between malaria incidence in the Amazon with deforestation [42,43] cannot be generalized, but may sharply differ or even be inverted as a function of observation scale and socio-environmental covariates. There is no evidence that malaria risk is elevated because of the presence of larger deforestation patches inside the settlement per se, but because these areas are characterized by elevated population fluxes and are frequently mining areas with man-made reproduction habitats favouring vector presence. "
    [Show abstract] [Hide abstract]
    ABSTRACT: In Brazil, 99% of the cases of malaria are concentrated in the Amazon region, with high level of transmission. The objectives of the study were to use geographic information systems (GIS) analysis and logistic regression as a tool to identify and analyse the relative likelihood and its socio-environmental determinants of malaria infection in the Vale do Amanhecer rural settlement, Brazil. A GIS database of georeferenced malaria cases, recorded in 2005, and multiple explanatory data layers was built, based on a multispectral Landsat 5 TM image, digital map of the settlement blocks and a SRTM digital elevation model. Satellite imagery was used to map the spatial patterns of land use and cover (LUC) and to derive spectral indices of vegetation density (NDVI) and soil/vegetation humidity (VSHI). An Euclidian distance operator was applied to measure proximity of domiciles to potential mosquito breeding habitats and gold mining areas. The malaria risk model was generated by multiple logistic regression, in which environmental factors were considered as independent variables and the number of cases, binarized by a threshold value was the dependent variable. Out of a total of 336 cases of malaria, 133 positive slides were from inhabitants at Road 08, which corresponds to 37.60% of the notifications. The southern region of the settlement presented 276 cases and a greater number of domiciles in which more than ten cases/home were notified. From these, 102 (30.36%) cases were caused by Plasmodium falciparum and 174 (51.79%) cases by Plasmodium vivax. Malaria risk is the highest in the south of the settlement, associated with proximity to gold mining sites, intense land use, high levels of soil/vegetation humidity and low vegetation density. Mid-resolution, remote sensing data and GIS-derived distance measures can be successfully combined with digital maps of the housing location of (non-) infected inhabitants to predict relative likelihood of disease infection through the analysis by logistic regression. Obtained findings on the relation between malaria cases and environmental factors should be applied in the future for land use planning in rural settlements in the Southern Amazon to minimize risks of disease transmission.
    Malaria Journal 11/2013; 12(1):420. DOI:10.1186/1475-2875-12-420 · 3.49 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Malaria is a disease with focal distribution. In Brazil, settlement and gold mining areas in the Legal Amazon region present a great concentration of cases. This paper analyzes the spatial distribution of malaria cases taking into consideration environmental and social factors in the Vale do Amanhecer settlement in the municipality of Juruena, Mato Grosso, Brazil. In 2005, 359 autochthonous cases were notified in the settlement. Using the Kernel method, areas of greater and lesser intensities of case numbers were identified. The areas of greater intensity presented 290 cases and those of lesser intensity, 64 cases. The intensity of distribution varied within the settlement, thus indicating areas of great intensity of cases favoring transmission, like gold mining areas. Therefore, although the settlement was considered to be the main focus for malaria, there were specific factors within it that, once identified, could contribute towards the disease control.
    Revista da Sociedade Brasileira de Medicina Tropical 02/2009; 42(1):47-53. DOI:10.1590/S0037-86822009000100010 · 0.94 Impact Factor
Show more