[Monitoring Japanese Encephalitis Vector Mosquitoes (Culex tritaeniorhynchus) in the Republic of Korea, 2022]

Division of Vectors and Parasitic Diseases in the Korea Disease Control and Prevention Agency (KDCA) supervises projects with the Institute of Health & Environment Research to monitor the occurrence of Culex tritaeniorhynchus, a vector of Japanese encephalitis (JE). Mosquitoes were collected by operating black light traps at 11 collection areas across the country from April to October 2022, and the number of collected mosquitoes was calculated daily occurrence (mosquitoes/trap/day). Cx. tritaeniorhynchus was first collected on April 11, 2022 from Busan, which led to the warning of precautions against JE. On July 23, 2022, a national warning was issued. Because more than 50% of the collected mosquitoes in Busan were Cx. tritaeniorhynchus. In the 2022 collection period, 116,340 mosquitoes of 18 species were collected. Of them, 20,340 were Cx. tritaeniorhynchus, indicating a 16% increase from 2021 when 17,528 mosquitoes were collected. The appearance of Cx. tritaeniorhynchus is gradual from June and persists until October, occurring in a high density between July and September. The southern area was denser than the northern area, and the population density of Cx. tritaeniorhynchus was the highest in Gyeongnam. These results were posted on the KDCA website (http://www.kdca.go.kr) to aid in the prevention and control of Japanese encephalitis.