Validation of a mapping and prediction model for human fasciolosis transmission in Andean very high altitude endemic areas using remote sensing data

The present paper aims to validate the usefulness of the Normalized Differe nce Vegetation Index (NDVI) obtained by satellite remote sensing for the de velopment of local maps of risk and For prediction of human fasciolosis in the Northern Bolivian Altiplano. The endemic area, which is located at very high altitudes (3800-4100 m) between Lake Titicaca and the valley of the c ity of La Pat, presents the highest prevalences and intensities of fasciolo sis known in humans. NDVI images of 1.1 km resolution from the Advanced Ver y High Resolution Radiometer (AVHRR) sensor on board the National Oceanic a nd Atmospheric Administration (NOAA) series of environmental satellites app ear to provide adequate information For a study area such as that of the No rthern Bolivian Altiplano. The predictive value of the remotely sensed map based on NDVI data appears to be better than that from forecast indices bas ed only on climatic data. A close correspondence was observed between real ranges of human fasciolosis prevalence at 13 localities of known prevalence rates and the predicted ranges of fasciolosis prevalence using NDVI maps. However, results based on NDVI map data predicted zones as risk areas where , in fact, field studies have demonstrated the absence of lymnaeid populati ons during snail surveys, corroborated by the absence of the parasite in hu mans and livestock. NDVI data maps represent a useful data component in lon g-term efforts to develop a comprehensive geographical information system c ontrol program model that accurately fits real epidemiological and transmis sion situations of human fasciolosis in high altitude endemic areas in Ande an countries. (C) 2001 Elsevier Science B.V. All rights reserved.