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.


Available from: Maria Rita Donalisio, Mar 31, 2015
  • Source
    [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: In the municipality of Manaus, intensification of the migratory process, along with precarious epidemiological and entomological surveillance, resulted in reintroduction of malaria transmission on the urban perimeter (in the eastern zone), in July 1988, after 13 years without any records of autochthonous disease. This study reports on the epidemiological situation relating to malaria and to the areas that were subjected to human actions (deforestation, human settlement, fish-rearing activity, etc) in Manaus, between 1986 and 2005. In this municipality, the population increase from 1986 to 2005 was 105.2%. This resulted from occupation of space, in the form of invasions and housing projects. From 2003, the increase in relation to 1986 was more than 2,000%. In these areas, there were increases in disease incidence. The annual parasitic index in the municipality ranged from low to medium risk and, between urban zones, it ranged from no risk to high risk. In the eastern, western and northern zones, which still contain areas with agricultural characteristics, there was greater receptivity and vulnerability to transmission.
    Revista da Sociedade Brasileira de Medicina Tropical 10/2009; 42(5):515-522. DOI:10.1590/S0037-86822009000500008 · 0.94 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We respond to Valle and Clark,(1) who assert that "conservation efforts may increase malaria burden in the Brazilian Amazon," because the relationship between forest cover and malaria incidence was stronger than the effect of the deforestation rate.(1) We contend that their conclusion is flawed because of limitations in their methodology that we discuss in detail. Most important are the exclusion of one-half the original data without a discussion of selection bias, the lack of model adjustment for either population growth or migration, and the crude classifications of land cover and protected areas that lead to aggregation bias.(1) Of greater significance, we stress the need for caution in the interpretation of data that could have profound effects on regional land use decisions.
    The American journal of tropical medicine and hygiene 11/2013; 90(4). DOI:10.4269/ajtmh.13-0323 · 2.53 Impact Factor