Snail Density Estimation for Schistosomiasis Control by Integrating Field Survey and Multiscale Satellite Images

In a mountainous region of Sichuan Province, China, snails live along the edges of ditches in crop fields. People are infected through contact with the contaminated waters of natural rivers and irrigation systems. Infected human and animal stools are used as fertilizers in the crop fields, from which the disease can also be transmitted. Snail population is crucial for more refined analysis of schistosomiasis transmission and for the development of a control model. We focus on five land-use and land-cover categories to which the snail habitat and the water exposure activities of humans may be closely related. These are lowland crop, upland crop, terraced crop field, riverbed and residential area.