Objectives
This study investigated a cluster of secondary human-to-human transmission of severe fever with thrombocytopenia syndrome (SFTS) in a hospital setting, focusing on infection risk factors and the role of personal protective equipment (PPE).
Methods
A descriptive epidemiological investigation was conducted following the death of an index patient with laboratory-confirmed SFTS. A total of 27 close contacts, including healthcare workers and a funeral director, were monitored for symptoms. Suspected cases underwent real-time reverse transcription polymerase chain reaction testing. Clinical features, PPE use, and exposure histories were analyzed. The Fisher exact test was used to assess associations between PPE use and infection. Viral genotyping and sequence analyses were performed to evaluate transmission routes.
Results
The index patient deteriorated rapidly and died after repeated cardiopulmonary resuscitation (CPR), during which 8 secondary cases occurred. Most infections were identified among individuals involved in CPR or postmortem care without adequate PPE. Although not statistically significant, infection rates were higher among those who did not wear masks or who used low-filtration masks. Proper use of gloves, gowns, and goggles was associated with lower infection rates. Cycle threshold values in secondary cases (range, 34–39) were higher than in the index case (14.07), suggesting lower viral loads. Sequence analysis demonstrated 99.6%–100% homology between the index and secondary cases; all isolates were genotype B, indicating direct transmission.
Conclusion
This study provides molecular and epidemiological evidence of nosocomial SFTS transmission. Inadequate PPE use during aerosol-generating procedures likely facilitated infection, underscoring the importance of strict adherence to PPE protocols and reinforced infection control practices.

Objectives
Scrub typhus, caused by Orientia tsutsugamushi, is a climate-sensitive vector-borne disease with high incidence in the Republic of Korea. This study examined long-term epidemiological trends and changing meteorological influences in the context of climate change.
Methods
A retrospective time-series study was conducted using national surveillance data on 149,289 scrub typhus cases (2001–2024) across 4 surveillance phases. Temporal trends in age-standardized incidence rates were evaluated using Joinpoint regression. Associations between monthly meteorological variables and incidence were assessed with Spearman correlation analysis and time-series regression analysis using distributed lag non-linear models.
Results
The national incidence increased until 2017 and has decreased since 2018, whereas the AAPC rebound to 4.32% during phase IV (2019–2024). The proportion of female cases decreased, while that of adults ≥70 years increased significantly. In phase IV, the average annual percent change increased in central and urban regions. The lag effect of meteorological factors lengthened from 4 to 6 months, with mean temperature (Tmean) and relative humidity (RH) representing the primary predictors. Phase III (2013–2018) displayed the highest cumulative relative risk (RR) for Tmean at 25.2 °C (RR, 5.86; 95% confidence interval [CI], 2.56–13.42), whereas in phase IV, only moderate RH (58%) remained significantly associated with incidence (RR, 1.68; 95% CI, 1.29–2.20).
Conclusion
Over the past 2 decades, the influence of meteorological factors on scrub typhus has shifted, with recent years marked by greater uncertainty under increasing climate variability and instability. For timely risk prediction and targeted prevention, adaptive surveillance systems that integrate dynamic climate indicators—capturing the intensity, frequency, and variability of extreme weather events—are needed.

Objectives
In March 2023, an alternative school in the Republic of Korea reported 12 cases of shigellosis. This study aims to analyze the epidemiological characteristics in order to determine the cause of the cluster outbreak of shigellosis and to develop prevention strategies. Methods: This study focused on 12 patients with confirmed Shigella infection and investigated their demographics, clinical features, epidemiology, diagnostics, and antimicrobial susceptibility. Following the identification of Shigella, we conducted follow-up rectal smear cultures to manage patients, implementing isolation and control measures. Results: This study investigated the emergence of multidrug-resistant Shigella following missionary activities in Cambodia, documenting a cluster infection within an alternative school in Daejeon, the Republic of Korea. The outbreak affected 56 participants, resulting in the confirmation of 12 cases. The incidence rates varied by gender and occupation, with higher rates among males and teachers. All 12 cases demonstrated multidrug resistance. Challenges included delayed pathogen confirmation and suboptimal adherence to isolation criteria. The incident prompted revisions in the criteria for isolation release, focusing on symptom resolution. The study underscores the necessity for strengthened surveillance, educational initiatives focusing on prevention in endemic areas, and improved oversight of unlicensed educational establishments. Conclusion: Successful response strategies included swift situation assessment, collaborative efforts, effective infection control measures, and modified criteria for isolation release. Continued surveillance of multidrug-resistant strains is recommended, especially in regions with a high prevalence.