Abstract:

Objective To analyze the epidemiological characteristics of imported malaria in Gansu Province, so as to provide reference for consolidating the gains in malaria elimination and formulating the prevention and control strategies for imported malaria. Methods Malaria epidemiological data and individual case reported in Gansu Province from 2016 to 2022 were collected through the Chinese Disease Prevention and Control Information System. Descriptive epidemiology was used to analyze statistical indicators, such as source of infection, infected species, monthly distribution, population distribution, regional distribution and diagnosis timeliness. Results Ninety-seven imported cases of malaria were reported in Gansu Province from 2016 to 2022, including 2 cases of relapses (1 in 2017 and 1 in 2022) and 1 death in 2017. There were 67 cases of Plasmodium falciparum infection (69.07%), 18 P. vivax infection (18.56%), 11 P. ovale infection (11.34%) and 1 mixed-infection (1.03%, caused by P. falciparum and P. malariae infection). The main source of imported cases was associated with African countries (80 cases, 82.47%) and Asian countries (10 cases, 10.31%). There are monthly case reports, with the highest number of reported cases occurring in January (13 cases), August (13 cases) and September (12 cases), which accounted for 39.18% of the totally reported cases. The average age of the reported cases was (36.7±10.1) years, and age group with the highest number of cases was 21-50 years old, accounting for 89.69% (87/97) of the total reported cases. The occupation was primarily involved in returned workers (82 cases, 84.54%). The region with the most reported cases was Chengguan District, Lanzhou City (30 cases, 30.93%). By current residence, the most reported cases were from Jinchuan District of Jinchang City (8 cases, 8.25%). The median between onset and diagnosis was 4.4 (2.4,7.5) days. Fifteen cases (15.46%) were treated on the day of onset, and 22 cases (22.68%) were treated within 1-2 days. Thirty-four cases (35.05%) underwent treatment within 3-7 days, and another 26 cases (26.80%) were treated more than 7 days after onset. Conclusion The malaria cases reported in Gansu Province from 2016 to 2022 were imported from overseas, mostly from Africa, and the predominant species was Plasmodium falciparum. Our findings suggest that in the post elimination stage of malaria, Gansu Province should strengthen monitoring of imported malaria, improve diagnostic capabilities, and consolidate the achievements of malaria elimination.

Key words: Imported malaria, Epidemiological characteristics, Gansu Province