PHWR Public Health Weekly Report

Vol.18 No.45, November 20, 2025 Article TypeQuickStatsReview & PerspectiveSurveillance Report

• Surveillance Report 2025-11-20

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  Identification of Culex quinquefasciatus Highlights the Need for Strengthened Vector Mosquito Surveillance in the Republic of Korea

  Ji-Young Kwon , Bo-Ram Yun , Gi-hun Kim , Hyeon-Seok Oh , Jung-Won Ju , Jin-Suk Im , Jae-Hyeon Park , Chang-Jun Lee , Wook-Gyo Lee , Jae-Uk Seol , YoungMin Yun , Jiro Kim , GyeongRok Kim , TaeGyu Lee , Hee-Il Lee

  Public Health Weekly Report 2025; 18(45): 1779-1789 https://doi.org/10.56786/PHWR.2025.18.45.1

  

  

  Abstract

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  Objectives: We investigated the presence of subtropical mosquito vectors that may become established in the Republic of Korea (ROK) owing to climate change. Comprehensive surveillance was conducted on Jeju Island, a region with a subtropical climate with active external entry routes, where the risk of subtropical mosquito introduction and establishment is increasing.
  Methods: In July 2025, adult mosquitoes were collected from 47 sites across Jeju Island using BG-Sentinel traps baited with carbon dioxide, in collaboration with Honam Regional Center for Disease Control, the Jeju Institute of Health and Environment, Jeju National University, and Cheju Halla University. A total of 147 mosquitoes, morphologically classified as belonging to the Culex pipiens complex, were subjected to genetic analyses for species identification. The collected specimens were screened for major mosquito-borne viruses, including the Japanese encephalitis, West Nile, Zika, Dengue, Chikungunya, and Yellow fever viruses.
  Results: Cx. quinquefasciatus is morphologically very similar to the Cx. pipiens complex, making it difficult to distinguish based on external characteristics. In addition, the cytochrome c oxidase subunit I marker alone was insufficient for clear species differentiation. Therefore, through multiplex molecular analyses incorporating nuclear gene markers such as acetylcholinesterase-2, a total of 11 Cx. quinquefasciatus individuals were identified from five collection sites. Furthermore, all specimens tested negative for six major mosquito-borne viruses.
  Conclusions: This study provides the first official report confirming the presence of subtropical mosquitoes on Jeju Island, ROK. These findings highlight the need to strengthen vector surveillance systems and refine public health strategies to address the potential establishment and northward expansion of subtropical mosquito species due to ongoing climate change and reveal an increased risk of exotic species introduction.

• Surveillance Report 2025-11-20

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  Trends in the Serotype Distribution of Salmonella enterica Isolated from Patients with Diarrhea in the Republic of Korea from 2022 to 2024

  Hyun Ju Jeong , Eunkyung Shin , Junyoung Kim , Jaeil Yoo

  Public Health Weekly Report 2025; 18(45): 1790-1812 https://doi.org/10.56786/PHWR.2025.18.45.2

  

  

  Abstract

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  Objectives: This study aimed to analyze and provide information on the distribution of Salmonella serotypes identified through the Enteric Pathogens Active Surveillance Network (Enter-Net) and outbreak investigations in the Republic of Korea (ROK) from 2022 to 2024.
  Methods: The isolates from domestic residents and outbreaks were collected using the Enter-Net, and serotyping was performed.
  Results: In total, 2,817 Salmonella isolates were identified, including 2,786 domestic cases and 31 imported cases, encompassing 131 distinct serotypes. The predominant serotypes were Salmonella Enteritidis (837 isolates, 29.7%), S. Typhimurium (327, 11.6%), S. I 4,[5],12:i:- (S. Typhimurium variant) (295, 10.5%), S. Infantis (258, 9.2%), S. Thompson (208, 7.4%), and S. Bareilly (160, 5.7%). The primary serotypes associated with the outbreaks were found to be S. Enteritidis, S. Typhimurium, and S. Thompson, whereas the leading serotypes among imported cases were S. Enteritidis, S. Rissen, and S. Weltevreden. Monthly isolation rates increased from May, coinciding with higher temperatures, and remained elevated throughout November, regardless of the serotype.
  Conclusions: Analysis of Salmonella isolates from domestic waterborne and foodborne infections between 2022 to 2024 showed an increased proportion of S. Enteritidis, decline of S. Typhimurium and S. I 4,[5],12:i:-.

• Review & Perspective 2025-11-20

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  Overview of PCR-based Diagnostic Assays for Emerging Infectious Disease Pathogens

  Yu Jeong Ahn , Chaewon Jung , Jee Eun Rhee , Eun-Jin Kim

  Public Health Weekly Report 2025; 18(45): 1813-1832 https://doi.org/10.56786/PHWR.2025.18.45.3

  

  

  Abstract

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  Objectives: Continuous genetic variation in pathogens enhances their infectious potential and promotes the emergence of infectious disease outbreaks, highlighting the need for diagnostic technologies capable of broad-range detection. Herein, we introduce pan-polymerase chain reaction (pan-PCR) and multiplex PCR assays to identify the causative agents of emerging or unknown infectious diseases.
  Methods: To introduce the research, development, and practical applications of pan-PCR and multiplex PCR assays for pathogen diagnosis, a comprehensive review was conducted. The review focused on recent domestic and international institutional reports and academic literature on public health and PCR-based diagnostic methods. Literature published since the coronavirus disease 2019 pandemic was included.
  Results: Both technologies have been recognized as core diagnostic approaches to effectively respond to emerging and unknown infectious diseases. Pan-PCR uses conserved gene regions for the initial screening of unknown pathogens, whereas multiplex PCR is used to simultaneously identify specific pathogens, including co-infection cases. These two technologies could be utilized complementarily to identify the causative agents of emerging infectious diseases.
  Conclusions: Pan-PCR and multiplex PCR show promise as key diagnostic platforms to facilitate proactive responses in the face of infectious disease threats in the future. The simultaneous use of both technologies, capitalizing on their respective strengths in versatility and specificity, is likely to improve diagnostic capabilities for emerging or unknown infectious diseases and strengthen public health surveillance.

• QuickStats 2025-11-20

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  Trends in the Proportion of Adolescents Engaged in Physical Activities, 2015–2024

  Yangha Kim

  Public Health Weekly Report 2025; 18(45): 1833-1834 https://doi.org/10.56786/PHWR.2025.18.45.4

  

  

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