PHWR Public Health Weekly Report

Objectives: This study aims to prevent the introduction and establishment of overseas-origin infectious disease vectors associated with climate change and increasing international travel and trade by assessing the current status of vector surveillance at international points of entry in the Republic of Korea (ROK).
Methods: Mosquito surveillance was conducted at 40 major international airports and seaports in the ROK across 16 collection cycles from March to November 2025. Adult mosquitoes were collected using Biogents (BG)-Sentinel traps, light-emitting diode (LED) black-light traps, and Gravid traps. All specimens were morphologically identified to the species level and subsequently screened for six major viral pathogens using multiplex real-time reverse transcription polymerase chain reaction.
Results: A total of 37,544 mosquitoes representing 18 species were collected during the surveillance period. Although the overall mosquito population decreased by 21.6% compared with the previous year, species diversity increased by the detection of three additional species. Culex pipiens was the dominant species, accounting for 64.4% of all collected specimens, with its peak annual density observed in September (28.8%). Regional analysis showed that the highest Trap Index (T.I.) was recorded in the Capital region (104.6), whereas species richness was greatest in Gyeongnam Province (15 species). With respect to trapping efficiency, the BG-Sentinel trap (T.I.=75) demonstrated a significantly higher capture performance the than LED black-light traps. None of the mosquito samples tested positive for any of the six targeted viral pathogens.
Conclusions: The observed increase in mosquito species diversity at airports suggests a higher risk of invasive vector introduction through air travel. Accordingly, differentiated surveillance strategies are required: seaports should prioritize monitoring population density trends, whereas airports should focus on the early of invasive mosquito species at points of entry, thereby strengthening national preparedness against the spread of vector-borne diseases.

Objectives: This report analyzes the screening status and care cascade following the 2025 introduction of national hepatitis C virus (HCV) screening for 56-year-olds as a measure to eliminate HCV and evaluates the impact of this program on the national infectious disease surveillance system.
Methods: This study analyzed data from 537,726 individuals aged 56 who participated in the national health screening program in 2025 and the data from 329 reported cases of HCV in the same age group from the Korea Disease Control and Prevention Agency. Antibody positivity and the care cascade were calculated using data from the National Health Insurance Service, and diagnosis pathways and reported cases were compared across age groups.
Results: In 2025, the screening rate for 56-year-olds was 70.5%, with an antibody positivity rate of 0.8%. Data analysis found that there were about twice as many cases reported for this age group as the average for the entire 50s age group. Of these cases, 57.6% were identified through health screenings, confirming the effectiveness of the national program in detecting previously undiagnosed cases; however, only 44.9% of those with antibodies underwent confirmatory testing, and only 18.0% of the estimated confirmed cases initiated treatment.
Conclusions: The recently introduced national HCV screening for 56-year-olds has been effective in detecting previously undiagnosed cases. To enhance linkage to treatment and achieve the World Health Organization goal of eliminating HCV, the management system must be improved by implementing measures such as introducing reflex testing and strengthening case management through follow-up epidemiological investigations to improve linkage to care.

Objectives: Military units are highly vulnerable to infectious disease outbreaks because of communal living and frequent field training, yet military infectious disease education remains largely theory-based, limiting practical response capacity. This study aimed to (1) assess current practices and educational needs in military field settings, (2) develop a scenario-based education and training program reflecting the military context, and (3) provide evidence for a standardized prevention and management system through pilot testing and satisfaction surveys.
Methods: Focus group interviews (FGIs) were conducted with 37 completers of the 2025 military epidemiological investigator course to identify field practices and needs. Based on the findings, problem-based learning (PBL) materials were developed for seven infectious diseases. A tabletop-exercise pilot was delivered to 40 Navy and Air Force infection control personnel, and field applicability was evaluated through post-training self-report questionnaires and qualitative feedback. A civilian–government–military advisory board provided stepwise consultation throughout.
Results: FGIs identified four major barriers: guideline ambiguity, insufficient resources and tools, excessive workload from dual reporting, and rapid knowledge decay after short training. In the pilot, 95–100% of participants (n=40) responded positively across all six self-reported criteria, including competency, military relevance, and educational efficiency. Qualitative feedback identified procedural clarity and cross-unit experience sharing as key satisfaction drivers.
Conclusions: Field-oriented, scenario-based PBL can strengthen military infectious disease response beyond theory alone. This requires standardizing military epidemiological investigation and reporting, institutionalizing routine provision and operation of essential resources, and establishing a standing civilian–government–military body and joint practical training to offset military-only resource constraints.