Abstract:

This study aimed to reveal the epidemiological characteristics of imported malaria cases pre- and post-malaria elimination in Zigong by collecting and analyzing the imported malaria cases information and epidemiological data from January 2011 to July 2023. A total of 26 imported malaria cases were reported from 2011 to 2023, of which 61.5% (16/26) were falciparum malaria, 30.8% (8/26) were vivax malaria and 7.7% (2/26) were mixed infection of P. falciparum and P. ovale. All reported cases were imported with the residence time abroad of 62 days to 6 years. Most reported cases were returned from Africa (76.9%, 20/26), which showed peak epidemics in summer and winter and were distributed mainly in Fushun and Rongxian. The majority of imported malaria cases were male (92.3%, 24/26), of which 69.2% (18/26) were migrant workers whose ages were predominantly between 20 and 50. The median time interval between the return to China and the onset of symptoms was 7 days, with 88.0% (22/25) developing illness within 14 days after returning. The median time interval between the onset and the first visit was 1 day, with 80.8% (21/26) first visiting a doctor within 3 days after the onset of symptoms. A total of 84.6% (22/26) of the imported malaria cases were first visited by county-level medical units or above, with 69.2% (18/26) being diagnosed with malaria. It is suggested that early malaria diagnosis is yet to improve in the health service centres in Zigong. Improving the diagnostic ability of malaria, strengthening the health education on malaria prevention and control knowledge for labour exporting personnel, and monitoring the population who turned from high malaria prevalence areas are required to prevent the reemergence of malaria in Zigong.

Key words: Malaria, Zigong City, Epidemiological investigation