关键词: 疟疾, 输入性病例, 新型冠状病毒感染, 安徽省, 湖北省, 河南省, 浙江省, 广西壮族自治区

Abstract: Objective　To examine the impact of COVID⁃19 pandemic on the epidemic status of imported malaria and national malaria control program in China, so as to provide insights into post⁃elimination malaria surveillance. Methods　All data pertaining to imported malaria cases were collected from Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region during the period from January 1, 2018 through December 31, 2021. The number of malaria cases, species of malaria parasites, country where malaria parasite were infected, diagnosis and treatment after returning to China, and response were compared before (from January 1, 2018 to January 22, 2020) and after the COVID⁃19 pandemic (from January 23, 2020 to December 31, 2021). Results　A total of 2 054 imported malaria cases were reported in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region during the period from January 1, 2018 to December 31, 2021, and there were 1 722 cases and 332 cases reported before and after the COVID⁃19 pandemic, respectively. All cases were reported within one day after definitive diagnosis. The annual mean number of reported malaria cases reduced by 79.30% in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region after the COVID⁃19 pandemic (171 cases) than before the pandemic (826 cases), and the number of monthly reported malaria cases significantly reduced in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region since February 2020. There was a significant difference in the constituent ratio of species of malaria parasites among the imported malaria cases in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region before and after the COVID⁃19 pandemic ([χ2] = 146.70, P < 0.05), and P. falciparum malaria was predominant before the COVID⁃19 pandemic (72.30%), while P. ovale malaria (44.28%) was predominant after the COVID⁃19 pandemic, followed by P. falciparum malaria (37.65%). There was a significant difference in the constituent ratio of country where malaria parasites were infected among imported malaria cases in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region before and after the COVID⁃19 pandemic ([χ2] = 13.83, P < 0.05), and the proportion of malaria cases that acquired Plasmodium infections in western Africa reduced after the COVID⁃19 pandemic that before the pandemic (44.13% vs. 37.95%; [χ2] = 4.34, P < 0.05), while the proportion of malaria cases that acquired Plasmodium infections in eastern Africa increased after the COVID⁃19 pandemic that before the pandemic (9.58% vs. 15.36%; [χ2] = 9.88, P = 0.02). The proportion of completing case investigation within 3 days was significantly lower after the COVID⁃19 pandemic than before the pandemic (96.69% vs. 98.32%; [χ2] = 3.87, P < 0.05), while the proportion of finishing foci investigation and response within 7 days was significantly higher after the COVID⁃19 pandemic than before the pandemic (100.00% vs. 98.43%; [χ2] = 3.95, P < 0.05). Conclusions　The number of imported malaria cases remarkably reduced in Anhui Province, Hubei Province, Henan Province, Zhejiang Province and Guangxi Zhuang Autonomous Region of China during the COVID⁃19 pandemic, with a decreased proportion of completing case investigations within 3 days. The sensitivity of the malaria surveillance⁃response system requires to be improved to prevent the risk of secondary transmission of malaria due to the sharp increase in the number of imported malaria cases following the change of the COVID⁃19 containment policy.

Key words: Malaria, Imported case, COVID?19, Anhui Province, Hubei Province, Henan Province, Zhejiang Province, Guangxi Zhuang Autonomous Region