[Malaria Vector Surveillance in 2024]

Effective malaria control requires early diagnosis, treatment, and vector mosquito management. In 2024, 94.1% of domestic malaria cases were reported in Seoul, Incheon, Gyeonggi, and Gangwon Provinces in the Republic of Korea. The Korea Disease Control and Prevention Agency annually surveys the mosquito density to provide vector information in malaria-risk areas.

In 2024, 76 sites, including the expanded malaria-risk areas, were surveyed from April to October. The collected mosquitoes were identified to species, and density was calculated as the trap index (TI), defined as the number of mosquitoes per trap per night. Anopheles mosquitoes were tested for infection of Plasmodium vivax by molecular method. The minimum infection rate (MIR) was calculated as (number of positive pools/number of tested mosquitoes)×1,000.

Cumulative TI reached 120.6 in 2024, showing a 66.6% increase than 2023 and a 59.3% increase from the 2020-2022 average. The first peak (TI 18.2) was observed at week 27. After a temporary drop in the rainy season, mosquito population was increased, followed by a rise in malaria cases after 5-6 weeks. Malaria-positive mosquitoes were detected in three pools (MIR=0.15) at 31st, 32nd, and 34th weeks in Paju-si. Although the number of positive pools is the same as in 2023 (MIR=0.21), MIR decreased due to increasing of Anopheles density.

Vector surveillance is a core strategy for malaria elimination. To reduce incidence in endemic regions, it is essential to respond promptly to advisory/warning issued based on continuous monitoring, and implement vector control measures.