Abstract:

Objective To investigate the epidemiological characteristics of malaria in Hebei Province from 2011 to 2019, and to provide a scientific basis for the surveillance and control of imported malaria after malaria elimination in the province. Methods The malaria epidemic data and individual case information in Hebei Province from 2011 to 2019 were collected from National Infectious Disease Surveillance Reporting and Management System and Information Management System for the Prevention and Treatment of Parasitic Disease, based on which the characteristics of the malaria epidemic were analyzed with descriptive epidemiological method. The characteristics of the malaria epidemic were analyzed with descriptive epidemiological methods. Results A total of 611 malaria cases were reported in Hebei Province from 2011 to 2019, with no local cases and cases transmitted from other provinces. All reported cases were imported from abroad, and no case of imported secondary malaria was detected. Among these cases, 571 (93.5%, 571/611) were imported from 34 African countries, mainly falciparum malaria (75.0%, 428/571). The top three source countries of imported cases were Angola (104 cases), Nigeria (76 cases), and Equatorial Guinea (60 cases). Six Asian countries contributed 34 cases (5.6%, 34/611), and among these, vivax malaria was the predominant type (70.6%, 24/34). The top three Asian source countries were Pakistan (14 cases), Myanmar (12 cases), and Cambodia (4 cases). In addition, three cases were imported from Oceania and two from South America. The cases were distributed across 129 counties (cities and districts) in 11 districts of the province, of which the highest number of imported cases were reported from the cities of Baoding (160 cases, 26.2%), Shijiazhuang (121 cases, 19.8%), Handan (89 cases, 14.6%) and Hengshui (58 cases, 9.5%), which accounted for 70.0% (428/611) of the total cases in the province. The imported cases were mainly male (598 cases), while only 13 female cases; mostly in the group aged 20-49 years, accounting for 86.1% (526/611); the majority (282 cases, 46.2%) were farmers, followed by migrant workers or workers (163 cases, 26.7%). Five deaths from malaria were reported from 2011 to 2019. During the nine years, 43.9% (268/611), 20.9% (128/611), and 6.5% (40/611) of patients visited three districts of Shijiazhuang, Beijing and Handan for medical care, respectively, which accounted for 71.4% (436/611) of the total cases. Since 2016, there has been a significant increase in malaria cases reported in Dezhou City, Shandong Province, where 84.4% (27/32) of patients were in Gucheng County, Hengshui City. The mean time period from onset to diagnosis was 5.4 days, with a median of 3.4 days. The shortest period was 0 days and the longest 70 days, among them the time period was ≤ 3 days in 307 patients (50.2%), 4-10 days in 232 patients (38.0%), and > 10 days in 72 patients (11.8%). There was a significant difference between years in the rate of confirmed diagnosis within 3 days from onset(χ² = 30.902, P < 0.01), but no significant difference in the rate of confirmed diagnosis within 10 days from onset(P > 0.05). Conclusion All cases of malaria reported in Hebei Province from 2011 to 2019 were imported from abroad, and no imported secondary malaria was reported.

Key words: Malaria, Imported case, Epidemiological characteristic, Hebei Province