Four regions with different leptospirosis incidence and geographical locations in China.10,15 The A region (pink) is located in tropical or subtropical areas, where typhoons commonly occur, and it has moderate incidence. The B region (red), in which incidence is the highest, encompasses 13 provinces such as Sichuan, Yunan, Zhejiang, Jiangxi, Fujian and Anhui, and is located in the middle and lower Yangtze River regions. The C region (gray) comprises the temperate region located in the middle and lower areas of the Yellow River, with lower leptospirosis incidence. Meanwhile, no human leptospirosis has been reported in the D region (white), which has a dry climate.