Characteristics of imported and domestic malaria cases in Gyeonggi Province, Republic of Korea.

Objectives: This study explored 11 years of malaria data from mandatory reporting in Gyeonggi Province, Korea, to provide information for prevention strategies by linkage to nationwide health claims data.

Methods: Reported malaria cases in Gyeonggi Province from 2011 to 2021 were linked to medical usage data from the National Health Insurance Database. Data about hospitalization, antibiotic prescription and duration, malarial species, and sociodemographic information of the cases were included.

Results: Between 2011 and 2021, a total of 3,011 malaria cases were reported, consisting of 2,828 domestic (93.9%) and 183 imported (6.1%) cases. Over 80% of the cases involved males, with the majority of patients being in their 20s. Both domestic and imported cases peaked between June and August over the years. Imported cases had a higher hospitalization rate (66.9%) compared to domestically-acquired cases (54.9%). There was a significant variation in treatment rates, with 80.7% of imported cases and 74.6% of domestic cases receiving treatment. For domestic cases, chloroquine combined with primaquine was the most commonly prescribed treatment (77.0%), while atovaquone-proguanil was frequently used for imported cases (25.9%). Plasmodium vivax was the predominant species in domestic cases (94.9%), whereas Plasmodium malariae was more common in imported cases (62.3%). The overall number of reported malaria cases declined following a sharp decrease in imported cases in 2020 and 2021.

Conclusion: Despite a decreasing trend in malaria cases reported in Gyeonggi Province, imported cases exhibited higher hospitalization rates and different antibiotic prescription and treatment patterns, reflecting the presence of a different malarial species.