Epidemiological analysis of falciparum malaria reported in China,2005 - 2008

Objective To identify the epidemiological characteristics of falciparum malaria reported from 2005 through 2008 in China. Methods Using data derived from the Disease Reporting Information System of China Center for Disease Control, where imported cases referred only to those of falciparum malaria reported outside Yunnan and Hainan provinces, the spatial-temporal distribution and diagnosed cases of the population suffering from falciparum malaria in China were described in terms of relative numbers such as constituent ratios, and the situation in Yunnan and Hainan was compared to the other regions using the chi-square test, Kruskal-Wallis test and Watson-Willian test. Results The incidence rate of falciparum malaria in Yunnan and Hainan provinces showed a remarkably declining trend in recent years, in contrast to the slightly increasing one of imported cases in other regions (P0.001). The onset peak was present from April to June in Yunnan and Hainan rather than from May to August in other regions (P0.01). Farmers and migrant workers were the group primarily affected by this disease, the age of onset ranging between 20 and 40 years. The fatality rate (3.39%), mean onset-diagnosis interval (5 d) and proportion of revised report cards (52.30%) of falciparum malaria cases outside Yunnan and Hainan were significantly higher than those in the two provinces (0.76%,3 d and 11.91%, respectively; P0.01). However, the proportion of laboratory confirmed cases (78.18%) of the former was lower than that of the latter (92.64%, P0.001). Conclusion Despite its annually decreasing incidence in China in recent years, reported cases of falciparum malaria were accumulating outside Yunnan and Hainan in addition to low diagnostic capability. Therefore, health education and relevant training should be strengthened in non-prevalent areas to assist in early diagnosis and to improve the diagnostic capability in medical institutions, thereby reducing the fatality rate.