title: Syphilis in the economic center of South China: results from a real-time, web-based surveillance program.
abstract: BACKGROUND
  Guangzhou is the economic center of South China, which is currently suffering an insidious re-emergence of syphilis. Syphilis epidemic in this area is a matter of serious concern, because of the special economic position of Guangzhou and its large migrant population. Therefore, a comprehensive analysis of surveillance data is needed to provide further information for developing targeted control programs.
  
  
  METHODS
  Case-based surveillance data obtained from a real-time, web-based system were analyzed. A hierarchical clustering method was applied to classify the 12 districts of Guangzhou into several epidemiological regions. The district-level annual incidence and clustering results were displayed on the same map to show the spatial patterns of syphilis in Guangzhou.
  
  
  RESULTS
  A total of 60,178 syphilis cases were reported during the period from 2005 to 2013, among which primary/secondary syphilis accounted for 15,864 cases (26.36 %), latent syphilis for 41,078 cases (68.26 %) and congenital syphilis for 2,090 cases (3.47 %). Moreover, primary/secondary syphilis burden slightly decreased from 17.5-18.0 cases per 100,000 people in the first years to 10.6 cases per 100,000 in 2013, with latent syphilis largely increasing from 18.5 cases per 100,000 to 43.4 cases per 100,000. Districts of Guangzhou could be classified into 3 epidemiological regions according to the syphilis burden over the last 3 years of the study period.
  
  
  CONCLUSIONS
  The burden of primary/secondary syphilis appears to be decreasing in recent years, whereas that of latent syphilis is increasing. Given the epidemiological features and the annual changes found in this study, it is suggested that future control programs should be more population-specific and spatially targeted.
authors.affiliation: Department of Medical Statistics and Epidemiology & Health Information Research Center & Guangdong Key Laboratory of Medicine, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, Guangdong Province, China. zhangwj35@mail2.sysu.edu.cn.
authors.forename: Wangjian
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Medical Statistics and Epidemiology & Health Information Research Center & Guangdong Key Laboratory of Medicine, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, Guangdong Province, China. dgdzc@hotmail.com.
authors.forename: Zhicheng
authors.initials: Z
authors.lastname: Du
authors.affiliation: Guangzhou Institute of Dermatology, Guangzhou, 510095, Guangdong Province, China. shaokait@163.com.
authors.forename: Shaokai
authors.initials: S
authors.lastname: Tang
authors.affiliation: Department of Medical Statistics and Epidemiology & Health Information Research Center & Guangdong Key Laboratory of Medicine, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, Guangdong Province, China. guopi.01@163.com.
authors.forename: Pi
authors.initials: P
authors.lastname: Guo
authors.affiliation: Guangzhou Institute of Dermatology, Guangzhou, 510095, Guangdong Province, China. xingdongye@21cn.com.
authors.forename: Xingdong
authors.initials: X
authors.lastname: Ye
authors.affiliation: Department of Medical Statistics and Epidemiology & Health Information Research Center & Guangdong Key Laboratory of Medicine, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, Guangdong Province, China. haoyt@mail.sysu.edu.cn.
authors.forename: Yuantao
authors.initials: Y
authors.lastname: Hao
mesh_terms: D000293:Adolescent; D000328:Adult; D002681:China / Q000453:epidemiology; D016000:Cluster Analysis; D005260:Female; D006801:Humans; D015994:Incidence; D020407:Internet; D008297:Male; D008875:Middle Aged; D016730:Program Development; D012306:Risk; D013587:Syphilis / Q000453:epidemiology*; D055815:Young Adult