title: [A study on early detection for seven infectious diseases].
abstract: OBJECTIVE
  To provide methods and alert thresholds which are scientific, sensitive, specific and practical for Early Warning System in Public Health Surveillance.
  
  
  METHODS
  Alert data was based on historical infectious diseases reports. Control chart was used to detect outbreaks or epidemics. An epidemic was defined by consulting Specialists. After calculating sensitivity, specificity, positive predictive value and describing receiver-operating characteristic curve (ROC), the optimal model and thresholds were chosen.
  
  
  RESULTS
  At 80 percentile, the sensitivities and the specificities of epidemic haemorragia fever, hepatitis A, dysentery, epidemic cerebrospinal meningitis and malaria were over 90%, and there was a high efficacy of early warning. At 90 percentile, the sensitivities and the specificities of tuberculosis and measles were over 85%, and there was a high efficacy of early warning also.
  
  
  CONCLUSIONS
  Control chart based on five years was chose as a essential method in early warning system. The alert threshold for epidemic haemorragia fever, hepatitis A, dysentery, epidemic cerebrospinal meningitis and malaria was 80 percentile. The alert threshold for tuberculosis and measles was 90 percentile.
authors.affiliation: Chinese Center for Disease Control and Prevention, Beijing 100050, China.
authors.forename: Wei-Zhong
authors.initials: WZ
authors.lastname: Yang
authors.forename: Hui-Xian
authors.initials: HX
authors.lastname: Xing
authors.forename: Han-Zhang
authors.initials: HZ
authors.lastname: Wang
authors.forename: Ya-Jia
authors.initials: YJ
authors.lastname: Lan
authors.forename: Qiao
authors.initials: Q
authors.lastname: Sun
authors.forename: Shi-Xiong
authors.initials: SX
authors.lastname: Hu
authors.forename: Wei
authors.initials: W
authors.lastname: Lü
authors.forename: Zheng-An
authors.initials: ZA
authors.lastname: Yuan
authors.forename: Yu-Xu
authors.initials: YX
authors.lastname: Chen
authors.forename: Bai-Qing
authors.initials: BQ
authors.lastname: Dong
mesh_terms: D002681:China / Q000453:epidemiology; D003141:Communicable Diseases / Q000453:epidemiology*; D016208:Databases, Factual; D018563:Disease Notification; D004405:Dysentery, Bacillary / Q000453:epidemiology; D004784:Environmental Monitoring / Q000379:methods*; D062665:Epidemiological Monitoring; D005260:Female; D006480:Hemorrhagic Fever with Renal Syndrome / Q000453:epidemiology*; D006506:Hepatitis A / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008585:Meningitis, Meningococcal / Q000453:epidemiology; D011159:Population Surveillance