Epidemiological characteristics of imported malaria after malaria elimination in Shanxi Province, 2019-2023

Abstract

Objective: To analyze the epidemiological characteristics of imported malaria cases from 2019 to 2023 after the elimination of malaria in Shanxi Province, and provide reference for formulating scientific and effective malaria prevention and control strategies in Shanxi Province. Methods: The data of imported malaria cases were collected China Information System for Disease Control and Prevention and National Parasitic Disease Control Information Management System in Shanxi Province, from 2019-2023. Descriptive epidemiological method and SPSS 26.0 statistical software were used for descriptive epidemiological statistical analysis. Results: A total of 51 malaria cases were reported in Shanxi Province in 2019-2023, all imported from abroad. Among them, there were 38 cases of falciparum malaria (74.51%), 6 cases of plasmodium ovale (11.77%), 5 cases of plasmodium vivax (9.80%), 1 case of plasmodium triticum malaria (1.96%), and 1 case of mixed infections (1.96%), with nodeaths; cases were predominantly males (94.12%, 48/51) and workers who went abroad for work (84.31%,43/51); the median age of onset was 37 years old; and there were imported cases every month, with no obvious peak of incidence; Taiyuan City reported the most cases, accounting for 72.55% (37/51) of the total number of cases,the source of infection of cases was mainly from Africa (96.08%), with the Democratic Republic of the Congo (16 cases), Nigeria (6 cases), Equatorial Guinea (5 cases), Mozambique (3 cases), and Republic of the Congo (3 cases) in that order; the median time between the onset of disease and first diagnosis, and the median time between first diagnosis and confirmation, were two times longer than that of first diagnosis, and the median time between first diagnosis and confirmation was two times longer than that of first diagnosis. The M(Q1, Q3) intervals from onset to first diagnosis and from first diagnosis to confirmed diagnosis were 2(0,4) days and 1(0,3) days, respectively, with statistically significant differences between different years from onset to first diagnosis (H=17.41, P=0.048), and from first diagnosis to confirmed diagnosis (H=20.82, P=0.010). A total of 101 146 blood tests for febrile patients were conducted in the province during the five years, with the minimum number of blood tests in 2020 (19 867 person-times) and the maximum number of blood tests in 2023 (20 778 person-times). Conclusions: After the elimination of malaria in Shanxi Province from 2019 to 2023, all malaria cases were imported from abroad, and it is still necessary to strengthen the surveillance of people traveling to and from malaria-endemic areas, implement the combination of medical treatment and prevention, and jointly prevent and control the occurrence of imported malaria.