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

BackgroundThe 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.MethodsCase-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.ResultsA 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.ConclusionsThe 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.Electronic supplementary materialThe online version of this article (doi:10.1186/s40249-016-0163-4) contains supplementary material, which is available to authorized users.

Malaria in China, 2011–2015: an observational study

“…Data sources: The number of malaria cases were obtained from the Chinese malaria enhanced surveillance information system. 7 , 20 …”

“…Data sources: The malaria data were obtained from the Chinese malaria enhanced surveillance information system. 7 , 20 The geographical distribution of dominant Anopheles vectors of human malaria in China was obtained from the Malaria Atlas project. 32 The population data at national and sub-national level for each year were obtained from the national statistical bureau of China.…”

“…31 Data sources: The data of malaria cases were obtained from the Chinese malaria enhanced surveillance information system. 7 , 20 The estimated annual population at risk in 2011–2015 were extracted from the WHO annual world malaria reports for 2012–2016, 1 , 22 - 25 and the population data at national level for each year were obtained from the national statistical bureau of China. 31 The costs of malaria control in 2011–2015 were extracted from the WHO annual world malaria reports for 2012–2016, 22 - 25 the China annual report of malaria elimination, the national programme office for malaria of the Global Fund in China, and information publicly available through the Global Fund website.…”

“…Also, imported cases of malaria may have been misdiagnosed in malaria-free or hard-to-reach areas, even though the individual case-based malaria surveillance system in China operated well during the malaria elimination stage. 20 Third, the cost calculations did not include funding from governments at national and sub-national levels to support the salaries of health department staff at county level or above. These staff members were responsible for most of the malaria elimination activities (e.g.…”

“…This system was developed as a part of the national malaria elimination programme to actively collect demographic and epidemiological information, using the unified form for case investigation required by the Chinese technical scheme of malaria elimination. 7 , 20 Laboratory-confirmed malaria cases refer to patients with a positive result from one type of laboratory test. 21 Rapid diagnostic tests were the primary diagnostic tools in the remote villages, townships and counties.…”