Eco-Epidemiology of Chagas Disease in northwestern Argentina: Application of fine resolution satellite data and wing morphometry to spatial analysis and control.

GÜRTLER R. E., M. C. CECERE, J. SCHACHTER-BROIDE, G. M. VAZQUEZ-PROKOPEC, J. P. DUJARDIN Y U. KITRON

Valencia-España

Congreso; 10. IX European Multicolloquium of Parasitology; 2004

Long-term studies of the process of reinfestation by T. infestans (or other triatomines) sufficiently detailed at the spatial level in a well-defined area have not been reported. As part of a longitudinal study on the eco-epidemiology and control of Chagas disease in northwestern Argentina initiated in 1985, we describe the spatio-temporal reinfestation patterns by T. infestans following a community-wide residual spraying with pyrethroid insecticides in rural northwestern Argentina conducted in 1992 (Gürtler et al., 1999). To this aim we used fine-resolution satellite imagery (derived from the Ikonos satellite, capable of creating 1-m2 panchromatic and 4-m2 multi-spectral images), Geographic Information Systems (GIS) and spatial statistics, combined with a 10-year long time series of triatomine reinfestation georeferenced at the domestic and peridomestic site level. GIS allow the integration of spatial and temporal information with satellite data to describe, understand and predict the potential distribution of arthropod vectors and transmission of pathogens (Kitron, 1998; Hay et al., 2000). Using global and local spatial statistics, we identified independent clusters of vector distribution in the northern and southern sections of the village. Moreover, this was also supported by wing geometric morphometry, which showed strong spatial structuring of T. infestans populations and suggested that recolonization could be traced back to a small geographic source. Application of focal spatial statistics allowed for the identification of T. infestans propagation epicenters. Targeted surveillance of key peridomestic sites, such as goat and pig corrals, using low-cost sensing devices and improved treatment regimes of actual epicenters and sites within 450 m of them are recommended to prevent the propagation of T. infestans.