Epidemiological Characteristics, Risk Factors, and Countermeasures of Imported Malaria — China, 2017–2024

Introduction: This study aimed to analyze the epidemiological characteristics of imported malaria in China, identify transmission risks from the global malaria burden and China's international population exchanges, and propose a two-stage prevention and control strategy for overseas and post-entry periods of outbound personnel.Methods: A descriptive epidemiological analysis was performed on the National Infectious Disease Surveillance Information System, including the number of patients with imported malaria, Plasmodium species distribution, spatiotemporal patterns, demographic characteristics, and countries of infection origin.Results: Between 2017 and 2024, 16,571 patients with imported malaria, including 75 deaths, were reported, with a U-shaped temporal trend.The annual number of patients with imported malaria remained stable at 2,600-2,800 from 2017 to 2019, dropped to 798 in 2021, and rebounded to 3,155 in 2024.Plasmodium falciparum (10,593 patients) and Plasmodium vivax (3,288 patients) were the dominant species.P. falciparum was imported from Africa, whereas P. vivax was from Myanmar.Patients with imported malaria were distributed across China, with Yunnan, Guangdong, and Guangxi emerging as the top three provincial-level adminsitrative divisions (PLADs).The high-risk population was male overseas laborers aged 30-59.Severe illness and fatality rates among individuals with imported malaria remained low with no upward trend.Conclusion: The global malaria epidemic and China's international exchanges have increased the pressure on malaria importation.Strengthening multisectoral collaboration in health services for outbound personnel and improving targeted surveillance and treatment capacity in key post-entry areas are crucial to prevent severe illness, deaths, and secondary transmission and to consolidate China's malaria elimination achievements.China was certified malaria-free by the World Health Organization (WHO) in June 2021 after eliminating local mosquito-borne malaria transmission with no indigenous infections reported since 2017 (1).However, malaria remains a major global public health challenge, with the WHO reporting continuous growth in infections and deaths in recent years, especially in sub-Saharan Africa, where malaria transmission remains severe and uncontrolled.In 2024, the global infections exceeded 282 million, with an estimated 610,000 deaths, reflecting stagnant progress in elimination (2).Meanwhile, China's opening-up and the Belt and Road Initiative have significantly expanded international population mobility, including overseas laborers, cross-border traders, and project personnel.This intensified international exchange has brought persistent and increasing import pressure on China, making imported malaria the main threat to its elimination achievements (3).Malaria vectors are still widely distributed in former endemic areas, especially in southern border provincial-level administrative divisions (PLADs), such as Yunnan (4).Delayed diagnosis and treatment of imported malaria infections increase severe illness and death risk, leading to introduced transmission if mosquito-borne transmission conditions are met (5).In this context, analyzing the epidemiological characteristics of imported malaria in China from 2017 to 2024 based on national surveillance data is crucial for identifying key risk points, formulating scientific and targeted prevention strategies, and blocking reestablishment risk.This study aimed to systematically determine the temporal, spatial, and demographic distributions of imported malaria infections, providing evidence-based support for China CDC Weekly