Research
Spatial and temporal distribution of falciparum malaria in China
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* Corresponding authors: Linwei Tian linweit@cuhk.edu.hk - Qiyong Liu liuqiyong@icdc.cn
- † Equal contributors
1 National Institute for Communicable Disease Control and Prevention, China CDC; State Key Laboratory for Infectious Disease Prevention and Control, Beijing, PR China
2 Stanley Ho Centre for Emerging Infectious Diseases, School of Public Health, Chinese University of Hong Kong, Hong Kong SAR, PR China
3 National Malaria Office, National Institute for Parasitic Diseases, Shanghai, PR China
4 Yunnan Center for Disease Control and Prevention, Kunming, PR China
Malaria Journal 2009, 8:130 doi:10.1186/1475-2875-8-130
Published: 12 June 2009Abstract
Background
Falciparum malaria is the most deadly among the four main types of human malaria. Although great success has been achieved since the launch of the National Malaria Control Programme in 1955, malaria remains a serious public health problem in China. This paper aimed to analyse the geographic distribution, demographic patterns and time trends of falciparum malaria in China.
Methods
The annual numbers of falciparum malaria cases during 1992–2003 and the individual case reports of each clinical falciparum malaria during 2004–2005 were extracted from communicable disease information systems in China Center for Diseases Control and Prevention. The annual number of cases and the annual incidence were mapped by matching them to corresponding province- and county-level administrative units in a geographic information system. The distribution of falciparum malaria by age, gender and origin of infection was analysed. Time-series analysis was conducted to investigate the relationship between the falciparum malaria in the endemic provinces and the imported falciparum malaria in non-endemic provinces.
Results
Falciparum malaria was endemic in two provinces of China during 2004–05. Imported malaria was reported in 26 non-endemic provinces. Annual incidence of falciparum malaria was mapped at county level in the two endemic provinces of China: Yunnan and Hainan. The sex ratio (male vs. female) for the number of cases in Yunnan was 1.6 in the children of 0–15 years and it reached 5.7 in the adults over 15 years of age. The number of malaria cases in Yunnan was positively correlated with the imported malaria of concurrent months in the non-endemic provinces.
Conclusion
The endemic area of falciparum malaria in China has remained restricted to two provinces, Yunnan and Hainan. Stable transmission occurs in the bordering region of Yunnan and the hilly-forested south of Hainan. The age and gender distribution in the endemic area is characterized by the predominance of adult men cases. Imported falciparum malaria in the non-endemic area of China, affected mainly by the malaria transmission in Yunnan, has increased both spatially and temporally. Specific intervention measures targeted at the mobile population groups are warranted.