Characteristics of imported malaria cases from Association of Southeast Asian Nations countries to China, 2010–2019

  Objective  To understand the epidemiological characteristics of imported malaria cases from Association of Southeast Asian Nations (ASEAN) to China during 2010–2019 and provide evidence for the malaria prevention and control in post malaria elimination period in China.

  Methods  The incidence data of imported malaria from ASEAN countries to China from January 1, 2010 to December 31, 2019 were obtained from national notifiable infectious disease reporting system and national malaria surveillance system for statistical analysis with software ArcGIS 10.7.

  Results  During 2010–2019, a total of 5 041 imported malaria cases from ASEAN countries were reported in China, showing a decline in the proportion in total imported cases in China ( χ²=1627.63, P<0.05). The top three source countries of imported malaria cases were Myanmar (4 227 cases), Indonesia (354 cases) and Cambodia (245 cases). The proportions of tertian malaria, quartan malaria and ovale malaria cases increased, while the proportion of faciparum malaria cases decreased. The imported malaria cases from ASEAN countries were reported in 28 provinces of China, and 89% of all imported malaria cases from ASEAN countries were distributed in Yunnan (3 492 cases, 69.27%), Hunan (358 cases, 7.08%), Sichuan (287 cases, 5.69%), Guangxi (158 cases, 3.11%) and Guangdong (93 cases, 1.81%). Among the imported malaria cases from ASEAN countries in 10 provinces of China, 545 were foreigners, in whom 513 were from Myanmar. In the 10 provinces reporting the imported malaria cases from ASEAN countries, Yunnan province reported 528 cases, accounting for 96.88%. The imported malaria cases were reported all the year around from 2010 to 2019, and most cases were reported from April to August. The imported malaria cases in Chinese were mainly young male adults and the imported malaria cases in foreigners were mainly aged <34 years (76.33%).

  Conclusion  Although the incidence of the imported malaria from ASEAN countries showed a decline trend in China, the prevention of secondary transmission of malaria is still a priority. The potential of secondary malaria transmission will exist in in the areas with Anopheles mosquitoes due to the increased importation of tertian malaria from ASEAN countries. Some areas, such as Yunnan, have higher potential of secondary malaria transmission.