Application of spatial analysis to the examination of dengue fever in Guayaquil, Ecuador

Dengue is the main viral disease transmitted by arthropods worldwide with over 50 million people infected yearly, especially in tropical and subtropical regions. In Ecuador epidemics of dengue erupted since 2000 with the appearance of the hemorrhagic form. However, studies in urban areas to better understand the spatial distribution of the disease are lacking. The objective of this study was to analyze the spatial distribution of reported cases of dengue fever in the city of Guayaquil (Ecuador) during the period from 2005 to 2009. Techniques of spatial statistics and GIS-Analysis are applied to characterize the geographical distribution of dengue incidence. Correlation analysis was used to determine hotspots of the distribution of the disease. This analysis revealed a significant spatial variation of disease incidence within the urban environment. Analysis of correlation indicated high spatial autocorrelation: Moran's I value was 0.37 (p<0.001). Preliminary results suggest a higher possibility of infection in places with already infected people. The results of this analysis suggest that dengue transmission in Guayaquil, Ecuador, is concentrated in local hotspots where strategies of prevention and control of the disease should be reinforced in order to avoid the spread of the epidemics to other areas of the city.