A seasonal chigger-borne disease surveillance program was established at Geoje in March, April, October, and November, 2023. Three species of 45 wild rodents were collected by using Sherman traps, including Apodemus agrarius (Species Ratio; SR 88.9%), Crocidura spp. (SR 8.9%), Micromys minutus (SR 2.2%) in Geoje, 2023. A total of 2,597 chiggers were collected from three species of the rodents in Geoje. The chigger mites were collected from A. agrarius (Chigger Index; CI 64.9) and C. spp. (CI 0.3) for Geoje. In the collection environments, a total number of 734, 659, 172, 520, and 512 chiggers were collected from a reservoir, a ditch, a rice paddy, a field, and a hill, respectively. In the results of the isolation of Orientia tsutsugamushi from the chigger mites, no pathogens were detected from the DNA of the 62 pools of the mites using a Polymerase Chain Reaction method in 2023.
A tick survey was conducted to monitor ticks using tick traps attached dry ice method at each four sites in Ulju and Gimhae counties, Gyeongsangnam-do from April to November, 2023. Two species belonging to one genera were collected with tick traps. A total of 1,064 ticks were collected as Haemaphysalis longicornis (Trap Index; TI 11.0), Haemaphysalis flava (TI <0.1) in Ulju and A total of 843 ticks were collected as Haemaphysalis longicornis (Trap Index; TI 8.7), Haemaphysalis flava (TI 0.1) in Gimhae 2023. Haemaphysalis longicornis was the most frequently collected, representing 99.2% in Ulju, 98.9% in Gimhae. In the collection environments, a total number of 685, 268, 64, and 47 ticks were collected from a glassland, a copse, a mountain path, and a grave of Ulju a total number of 469, 216, 83, and 75 ticks were collected from a glassland, a copse, a Grave, and a mountain path of Gimhae respectively. In the results of the isolation of Severe Fever with Thrombocytopenia Syndrome (SFTS) from the ticks, no pathogens were detected from RNA of 101 pools (Ulju), 98 pools (Gimhae) of the ticks using a Polymerase Chain Reaction method in 2023.
About 1 billion cases of vector-borne infectious diseases occur every year, of which more than 1 million is dead in worldwide. Japanese encephalitis and malaria continue to occur, and infectious diseases such as dengue fever being imported aborad have been increasing significantly due to the increasing number of overseas travelers in Korea. The Korea Disease Control and Prevention Agency has established local centers to monitor pathogen vector population density related to chimate change at 16 locations. We collected 59,389 mosquitoes in traps at 36 collection sites in 30 urban regions and migratory bird habitats in 2023. The trap index was 34.6, and the predominant mosquito species were the Culex pipiens complex, Aedes albopictus, Armigeres subalbatus, Aedes vexans, and Ochlerotatus Koreacus. The mosquitoes were pooled into 4,371 pools to monitor flavivirus infection. In flavivirus dietection, no virus was detected.