Space observations for monitoring vector diseases

Vector born diseases create the greatest burden in the world, because they are deadly and cover large area. World statistics indicates that vector diseases affect ½ of the world population in 140 countries. Every year 300-500 million clinical cases occur with 2-3 million fatalities. Children, old people and pregnant women are the most vulnerable targets. Africa is the most affected continent, which contributes 60 % of the global cases and 80% of death. Climate and ecosystems determines distribution of vector and weather affects timing, duration, area and intensity of outbreaks. In general warm and wet weather stimulated mosquitoes hatching, activity and the rate of diseases transmission to people. Such weather parameters as precipitation, temperature and relative humidity serve as the indicators of diseases and their development. However, weather station network is not dense enough especially in Africa for effective diseases monitoring. Therefore, satellite data have been used in recent years for global watch of vector diseases. New Vegetation health (VH), techniques have been developed and applied successfully for early detection and monitoring diseases from the operational environmental satellite. VH was developed from reflectance/emission measured by the Advanced Very High Resolution Radiometer (AVHRR) flown on NOAA polar-orbiting satellites since 1981. The calibrated measurements in the visible and near infrared wavelength were converted to the Normalized Difference Vegetation Index (NDVI) and in the infrared wavelength to brightness temperature (BT), which were expressed as a deviation from 30-year climatology. Three indices characterizing moisture (VCI), thermal (TCI) and vegetation health (VHI) conditions were produced and calibrated against in situ data. They were applied to identify vector disease early enough to mitigate their consequences. These results covering Africa, Asia and South America will be presented.