POTENTIAL MAPPING OF THE INFECTIOUS DISEASE TRANSMISSION VIA SPACEBORNE OBSERVATIONS

Infectious disease (ID) carried by water-bred vectors is a major public health issue over lake, coastal, and wetland regions in many tropical/subtropical countries. The transmission of such infectious disease primarily depends on both the variation of water extent and the environmental factors that affect intermediate hosts to propagate. In this study, we take the Schistosomiasis in Poyang Lake, China, as an example to quantify the possible spread area of Schistosoma japonicum, by estimating the extent of habitat for its intermediating host Oncomelania snails.This approach utilizes various spaceborne sensors for environmental surveillance, including European Space Agency’s (ESA)’s Envisat radar altimeter for water level, Moderate Resolution Imaging Spectroradiometer (MODIS) onboard NASA’s EOS platform for the 8-day sun reflectance (MOD09A1), 16-day Enhanced Vegetation Index (MOD13A1), and 8-day Land Surface Temperature (MOD11A2), to monitor variations in water level, water extent, vegetation coverage, and temperature in Poyang Lake lying on the Yangtze midstream basin. We first validate the outline of water area using MODIS Modified Normalized Difference Water Index (MNDWI). The delineation using MNDWI shows that Poyang Lake and surrounding basins have a seasonal change of water extent varying between 500 km² and 3400 km² during 2000–2011, corresponding well with previous studies using in situ gauge and radiometry/optical data sets. Based on former published geospatial constraints for snail’s habitat, we then build a preliminary model using satellite data to approximate potential high and low areas of snail’s habitat. This simulated extent quantitatively agrees well with official reports on snail habitat estimate. It also shows that spaceborne observations and in situ measurements can be well integrated as the first step of a monitoring system for improved analysis and potential early-warning of the epidemics.