[Epidemiological characteristics of imported malaria cases in Chengdu City from 2016 to 2023]

To investigate the epidemiological characteristics of imported malaria cases in Chengdu City, Sichuan Province from 2016 to 2023, so to provide insights into formulation of the malaria control strategy in the city.

All data pertaining to imported malaria cases reported in Chengdu City during the period from 2016 to 2023 were retrieved from the China Disease Prevention and Control Information System, and the epidemiological characteristics and diagnosis and treatment of imported malaria cases were analyzed.

A total of 463 imported malaria cases were reported in Chengdu City from 2016 to 2023, with Plasmodium falciparum malaria as the predominant type (71.27%, 330/463). Imported malaria cases returned from Africa (94.17%, 436/463), Asia (5.61%, 26/463), and South America (0.22%, 1/463), and were predominantly reported in May, June and December each year. Geographically, imported malaria cases were distributed across 20 counties (districts) in Chengdu City, with most cases (64.15%, 297/463) reported in Jinjiang District, and the male to female ratio of imported malaria cases was 21.05:1.00, with most cases diagnosed among migrant labors at ages of 20 to 50 years. There were 35.85% (166/463) of imported malaria cases seeking healthcare services on the day of disease onset, and cases with over 3 days of healthcare-seeking following disease onset were primarily farmers and labors at ages of 30 to 50 years. There were 456 imported malaria cases seeking healthcare services for the first time in domestic medical institutions following disease onset, and there were 341 cases with definitive diagnosis at the initial diagnosis (74.78%, 341/456). The domestic institutions with the highest proportion of correct malaria diagnosis at the initial diagnosis were county-level medical and health institutions (91.43%, 128/140), followed by city-level medical and health institutions (82.45%, 155/188), provincial-level medical and health institutions (80.00%, 44/55), and a low proportion of correct malaria diagnosis was seen in township healthcare centers (11.11%, 3/27), village healthcare clinics (0, 0/4) and individual doctors (0, 0/28).

Imported malaria cases in Chengdu City were primarily originated from Africa from 2016 to 2023, with P. falciparum malaria as the predominant type, and the malaria diagnostic capacity was low in grassroots healthcare institutions in the city. Intensified health education for malaria prevention and control targeting labors going to work in Africa and continuous improvements in the malaria diagnostic and treatment capability in healthcare institutions are recommended, in order to reduce the risk of re-establishment from imported malaria in Chengdu City.