Figure 3. Hunan Province in 2002, showing that schistosomiasis is mainly confined to the area surrounding Dongting Lake. Areas in beige are classified as endemic for schistosomiasis. Areas in light green have fulfilled the transmission control criteria and are characterized by schistosomiasis infection rates <1% for humans and animals and a snail habitat reduction of >98%. Areas in dark green have fulfilled the criterion of interrupted transmission, which means that no new human or animal schistosomiasis cases occurred in successive years, and no snails were found for >1 year.