Analysis on the relationship between malaria epidemics and NOAA-AVHRR NDVI in Hainan province / 中华流行病学杂志

<p><b>OBJECTIVE</b>To explore the relationship between malaria epidemics and NOAA-AVHRR NDVI.</p><p><b>METHODS</b>Data on malaria were collected in all 19 counties in Hainan province from Feb, 1995 to Jan, 1996. Values regarding normalized difference vegetation index (NDVI)-related indicators including mean and maximum values of NDVI, the area proportion of NDVI values of 145- and 145+, months with NDVI values of 135+, 140+, 145+, 150+ of these counties in this period were all extracted from NOAA-AVHRR images, using ERDAS8.5 software. The coefficients of correlation of malaria incidences and these NDVI-related indicator values were then calculated with SPSS 11.0.</p><p><b>RESULTS</b>The incidence of malaria showed positive correlations to mean and maximum values of NDVI, the area proportion of NDVI values of 145+ and months with NDVI values of 135+, 140+, 145+, 150+ respectively, but having negative correlation to the area of NDVI values of 145-. The malaria epidemic regions were in accordance with those regions that the NDVI values of 145+ were continuing for 9 months or more.</p><p><b>CONCLUSION</b>Malaria prevalence was associated with NOAA-AVHRR NDVI value which could be considered to be use for malaria surveillance in Hainan province.</p>

Study on the distribution of malaria in Hainan province through spatial local interpolation technique / 中华流行病学杂志

<p><b>OBJECTIVE</b>To explore the spatial distribution of malaria in Hainan province.</p><p><b>METHODS</b>Maps of spatial distribution on malaria incidence in Hainan province from 1995 to 1999 were produced, using a spatial local interpolation technique in the ArcGIS 8.1 software. Cross-validation techniques were used to evaluate the fitness of the distribution maps.</p><p><b>RESULTS</b>The spatial distribution of malaria in Hainan province from 1995 to 1999 showed that the incidence of malaria in the southern part of Hainan province were higher than that in the north. In the south, the incidence of malaria in east coastal areas were higher than that of other parts, especially in Wuzhi and Yingge mountains. The prediction error of the cross-validation indicated that the spatial distribution maps of malaria in Hainan had good fitness of malaria incidence of Hainan province.</p><p><b>CONCLUSION</b>Spatial local interpolation technique seemed to be promising in describing the spatial distribution of malaria.</p>