Regional analysis of the spread of dengue in South America

Extract of PALABRAS CLAVES: SIG, Dengue, Epidemiología Panorámica, Sensores Remotos

Lamfri Mario1, Quevedo Silvia, Rotela Camilo1, Scavuzzo Marcelo.  [1]

ABSTRACT

Even thou the goal of extermination of Aedes aegypti, the south American malaria and dengue vector, was near to be fulfill, after the 70s and in no more than 20 years, the region arrived to an hyper-endemic situation, with simultaneous circulation of 4 serotypes, frequent outbreaks with big amounts of cases and hemorrhagic dengue outbreaks. Do to that the need of understanding of witch factors are associated in a regional scale with the expansion of the epidemics and those that inhibit or avoid their development. In this work we present the results of space -time regional scale analysis of dengue outbreaks diffusion for south American countries with official notifications, and preliminary results of the relationship between DF incidence and macro-environmental biophysics factors estimated by remote sensors. To do this, it was necessary the creation of a Geographic Information System that integrates the epidemiological information from different countries sources, and macro-environmental information estimated by different space-time scale remote sensors, like the Normalized Difference Vegetation Index (NDVI), Land surface Temperature (LST), height over sea level from Digital Elevation Models (DEM) and Precipitations. At Sub-continental level, the generation notified DF cases GIS layers available for 1980-2005 period, made possible the retrospective and synoptic analysis of the illness at a regional level. It could be observed that altitude plays as a limitateing and inhibiting factor on vector-illness introduction and/or propagation on altitudinal floors over 1000 meters above sea level. At a time, this tool allows us to appreciate the gradual propagation space-time sense and magnitude over south American continent. Actually the typical tropical character of the illness was lost, that confined dengue at –1,45º Lat. S y –64,83º Long. O on 1982, showing an actual and sustain propagation to south west, confirming its introduction in subtropical zones with lower temperatures and less vegetal coverage, reaching latitudes of –33,75 S on 1998 and longitudes of –81,34 O on 1995. So, the hazardous of this results is that, if global and regional climate forecasts for next decades are taking in account, an increasing tendency of continental level dispersion is likely to happen, with all its consequences.

[1Instituto de altos estudios Espaciales “Mario Gulich”. Comisión Nacional de Actividades Espaciales (CONAE). Universidad Nacional de Córdoba. Argentina. e-mail: crotela at cett.conae.gov.ar