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Habitat suitability mapping of Anopheles darlingi in the surroundings of the Manso hydropower plant reservoir, Mato Grosso, Central Brazil.

Zeilhofer P, dos Santos ES, Ribeiro AL, Miyazaki RD, dos Santos MA - Int J Health Geogr (2007)

Bottom Line: Vector absence was associated with open vegetation formations such as grasslands and agricultural areas.We suppose that non-significant differences of vector incidences between rainy and dry seasons are associated with the availability of anthropogenic breeding habitat of the reservoir throughout the year.Vector presence is significantly increased in forested areas near reservoirs in bays protected from wind and wave action.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Geography, Federal University of Mato Grosso, Cuiabá, Brazil. pitalike@terra.com.br

ABSTRACT

Background: Hydropower plants provide more than 78 % of Brazil's electricity generation, but the country's reservoirs are potential new habitats for main vectors of malaria. In a case study in the surroundings of the Manso hydropower plant in Mato Grosso state, Central Brazil, habitat suitability of Anopheles darlingi was studied. Habitat profile was characterized by collecting environmental data. Remote sensing and GIS techniques were applied to extract additional spatial layers of land use, distance maps, and relief characteristics for spatial model building.

Results: Logistic regression analysis and ROC curves indicate significant relationships between the environment and presence of An. darlingi. Probabilities of presence strongly vary as a function of land cover and distance from the lake shoreline. Vector presence was associated with spatial proximity to reservoir and semi-deciduous forests followed by Cerrado woodland. Vector absence was associated with open vegetation formations such as grasslands and agricultural areas. We suppose that non-significant differences of vector incidences between rainy and dry seasons are associated with the availability of anthropogenic breeding habitat of the reservoir throughout the year.

Conclusion: Satellite image classification and multitemporal shoreline simulations through DEM-based GIS-analyses consist in a valuable tool for spatial modeling of A. darlingi habitats in the studied hydropower reservoir area. Vector presence is significantly increased in forested areas near reservoirs in bays protected from wind and wave action. Construction of new reservoirs under the tropical, sub-humid climatic conditions should therefore be accompanied by entomologic studies to predict the risk of malaria epidemics.

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Distance map for the average high water level of the reservoir at 278.5 m NN.
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Figure 4: Distance map for the average high water level of the reservoir at 278.5 m NN.

Mentions: Land cover classification was initially stratified in forest, savannah, cattle farming, crop farming/open soil and water. Only one small crop farming area was observed during field work. As this test site showed spectral signatures similar to recently reformed pastures, and as this land use is supposed to occupy less than 1 % of the reservoir influence area, pasture and crop farming areas were joined in one class in the final thematic layer. Proximity of sample points to waterbodies is already represented by the reservoir distance layer (Fig. 4). To minimize colinearity between explanatory data layers, percentages of water pixels in the 200 m radius around entomological sampling points were omitted.


Habitat suitability mapping of Anopheles darlingi in the surroundings of the Manso hydropower plant reservoir, Mato Grosso, Central Brazil.

Zeilhofer P, dos Santos ES, Ribeiro AL, Miyazaki RD, dos Santos MA - Int J Health Geogr (2007)

Distance map for the average high water level of the reservoir at 278.5 m NN.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1851006&req=5

Figure 4: Distance map for the average high water level of the reservoir at 278.5 m NN.
Mentions: Land cover classification was initially stratified in forest, savannah, cattle farming, crop farming/open soil and water. Only one small crop farming area was observed during field work. As this test site showed spectral signatures similar to recently reformed pastures, and as this land use is supposed to occupy less than 1 % of the reservoir influence area, pasture and crop farming areas were joined in one class in the final thematic layer. Proximity of sample points to waterbodies is already represented by the reservoir distance layer (Fig. 4). To minimize colinearity between explanatory data layers, percentages of water pixels in the 200 m radius around entomological sampling points were omitted.

Bottom Line: Vector absence was associated with open vegetation formations such as grasslands and agricultural areas.We suppose that non-significant differences of vector incidences between rainy and dry seasons are associated with the availability of anthropogenic breeding habitat of the reservoir throughout the year.Vector presence is significantly increased in forested areas near reservoirs in bays protected from wind and wave action.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Geography, Federal University of Mato Grosso, Cuiabá, Brazil. pitalike@terra.com.br

ABSTRACT

Background: Hydropower plants provide more than 78 % of Brazil's electricity generation, but the country's reservoirs are potential new habitats for main vectors of malaria. In a case study in the surroundings of the Manso hydropower plant in Mato Grosso state, Central Brazil, habitat suitability of Anopheles darlingi was studied. Habitat profile was characterized by collecting environmental data. Remote sensing and GIS techniques were applied to extract additional spatial layers of land use, distance maps, and relief characteristics for spatial model building.

Results: Logistic regression analysis and ROC curves indicate significant relationships between the environment and presence of An. darlingi. Probabilities of presence strongly vary as a function of land cover and distance from the lake shoreline. Vector presence was associated with spatial proximity to reservoir and semi-deciduous forests followed by Cerrado woodland. Vector absence was associated with open vegetation formations such as grasslands and agricultural areas. We suppose that non-significant differences of vector incidences between rainy and dry seasons are associated with the availability of anthropogenic breeding habitat of the reservoir throughout the year.

Conclusion: Satellite image classification and multitemporal shoreline simulations through DEM-based GIS-analyses consist in a valuable tool for spatial modeling of A. darlingi habitats in the studied hydropower reservoir area. Vector presence is significantly increased in forested areas near reservoirs in bays protected from wind and wave action. Construction of new reservoirs under the tropical, sub-humid climatic conditions should therefore be accompanied by entomologic studies to predict the risk of malaria epidemics.

Show MeSH
Related in: MedlinePlus