title: Comparative evaluation of the diagnosis, reporting and investigation of malaria cases in China, 2005-2014: transition from control to elimination for the national malaria programme.
abstract: BACKGROUND
  The elimination of malaria requires high-quality surveillance data to enable rapid detection and response to individual cases. Evaluation of the performance of a national malaria surveillance system could identify shortcomings which, if addressed, will improve the surveillance program for malaria elimination.
  
  
  METHODS
  Case-level data for the period 2005-2014 were extracted from the China National Notifiable Infectious Disease Reporting Information System and Malaria Enhanced Surveillance Information System. The occurrence of cases, accuracy and timeliness of case diagnosis, reporting and investigation, were assessed and compared between the malaria control stage (2005-2010) and elimination stage (2011-2014) in mainland China.
  
  
  RESULTS
  A total of 210 730 malaria cases were reported in mainland China in 2005-2014. The average annual incidence declined dramatically from 2.5 per 100 000 people at the control stage to 0.2 per 100 000 at the elimination stage, but the proportion of migrant cases increased from 9.8 % to 41.0 %. Since the initiation of the National Malaria Elimination Programme in 2010, the overall proportion of cases diagnosed by laboratory testing consistently improved, with the highest of 99.0 % in 2014. However, this proportion was significantly lower in non-endemic provinces (79.0 %) than that in endemic provinces (91.4 %) during 2011-2014. The median interval from illness onset to diagnosis was 3 days at the elimination stage, with one day earlier than that at the control stage. Since 2011, more than 99 % cases were reported within 1 day after being diagnosed, while the proportion of cases that were reported within one day after diagnosis was lowest in Tibet (37.5 %). The predominant source of cases reporting shifted from town-level hospitals at the control stage (67.9 % cases) to city-level hospitals and public health institutes at the eliminate stage (69.4 % cases). The proportion of investigation within 3 days after case reporting has improved, from 74.6 % in 2010 to 98.5 % in 2014.
  
  
  CONCLUSIONS
  The individual case-based malaria surveillance system in China operated well during the malaria elimination stage. This ensured that malaria cases could be diagnosed, reported and timely investigated at local level. However, domestic migrants and overseas populations, as well as cases in the historically malarial non-endemic areas and hard-to-reach area are new challenges in the surveillance for malaria elimination.
authors.affiliation: Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China.
authors.forename: Jun-Ling
authors.initials: JL
authors.lastname: Sun
authors.affiliation: Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Zhou
authors.affiliation: Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China.|State Key Laboratory of Virology and College of Life Sciences, Wuhan University, Wuhan, 430072, China.
authors.forename: Qi-Bin
authors.initials: QB
authors.lastname: Geng
authors.affiliation: Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China.|Center of Clinical Laboratory, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Zi-Ke
authors.initials: ZK
authors.lastname: Zhang
authors.affiliation: Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China.
authors.forename: Can-Jun
authors.initials: CJ
authors.lastname: Zheng
authors.affiliation: School of Public Health and Social Work, Queensland University of Technology, Brisbane, Australia.
authors.forename: Wen-Biao
authors.initials: WB
authors.lastname: Hu
authors.affiliation: Research School of Population Health, College of Medicine, Biology and Environment, The Australian National University, Canberra, Australia.
authors.forename: Archie C A
authors.initials: ACA
authors.lastname: Clements
authors.affiliation: Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China.|Department of Geography and Environment, University of Southampton, Southampton, SO17 1BJ, UK.
authors.forename: Sheng-Jie
authors.initials: SJ
authors.lastname: Lai
authors.affiliation: Division of Infectious Diseases, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing, 102206, China. lizhongjiecdc@163.com.
authors.forename: Zhong-Jie
authors.initials: ZJ
authors.lastname: Li
mesh_terms: D002681:China / Q000453:epidemiology; D018563:Disease Notification; D006801:Humans; D015994:Incidence; D008288:Malaria / Q000453:epidemiology* / Q000469:parasitology / Q000517:prevention & control*; D010961:Plasmodium / Q000502:physiology
keywords: China; Elimination; Evaluation; Malaria; Surveillance