Abstract: Wang Yajie, Gong Xiangdong, Yue Xiaoli, Li Jing Division of Sexually Transmitted Disease Epidemiology, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, National Center for Sexually Transmitted Disease Control, China Center for Disease Control and Prevention, Nanjing 210042, China Corresponding author: Gong Xiangdong, Email: gxdchina@163.com 【Abstract】 Objective To investigate the spatial distribution characteristics and patterns of congenital syphilis in China, and to make suggestions and recommendations for precise prevention of mother-to-child transmission of syphilis. Methods The geographic information system software ArcGIS 10.0 was used to conduct exploratory spatial data analysis on the basis of congenital syphilis cases reported from 31 provinces, autonomous regions and municipalities directly under the central government in 2010 and 2015. Results In 2015, a total of 7 251 congenital syphilis cases were reported, which decreased by 40.00% compared with the case number in 2010 （12 084 cases）. The global spatial autocorrelation analysis revealed a positive spatial autocorrelation in the number of reported cases at the county level in China between 2010 and 2015, with Global Moran′s I indices of 0.46 and 0.37, respectively. The degree of spatial clustering of congenital syphilis was lower in 2015 than in 2010. The local spatial autocorrelation analysis was further performed to output the hot-spot mappings of congenital syphilis at the county level in 2010 and 2015. In 2010, 207 hot-spot counties with a high number of congenital syphilis cases （> 12 cases） were identified, and these counties were mainly distributed in 3 core areas including southwest China （Chongqing, eastern Sichuan and northern Guizhou）, eastern China （southern Jiangsu, Zhejiang and northern Fujian）, and southern and central China （Guangxi, Guangdong and mid-east Hunan）. In 2015, 72 hot-spot counties with a high number of congenital syphilis cases（> 12 cases）were identified, and mainly distributed in 5 core areas including northwest China （western Xinjiang）, mid-east Qinghai, southwest and central China （Sichuan, Chongqing, Guizhou and Hunan）, eastern China （Jiangsu, Anhui）, and southern China and eastern China （Guangdong and Fujian）. Conclusions In Zhejiang, Shanghai, Guangdong, Guangxi, Sichuan and Chongqing, the number of hot-spot counties with a high reported congenital syphilis cases was significantly lower in 2015 than in 2010, suggesting that the prevention of mother-to-child transmission of syphilis had achieved a primary success. At present, hot-spots counties with a high number of congenital syphilis cases are mainly distributed in western Xinjiang, mid-east Qinghai, Sichuan, Chongqing, Guizhou and so on, Therefore, the prevention of mother-to-child transmission of syphilis should be strengthened in these areas.

Key words: Congenital syphilis, Case report, Geographic information system, Exploratory spatial analysis, Spatial autocorrelation, Hot spots mapping