Epidemiology and Health

Original article

The association between the consumption of raw Kudoa septempunctata–infected farmed Paralichthys olivaceus and gastrointestinal symptoms: Jihye An, En-Joo Jung, Soon-Ok Lee, Jong-Hoon Choi, Jung Hee Kim, Sung-Jong Hong, Sung-Hee Hong, Jung-Wong Ju, Hyungjun Kim, Kwang-Pil Ko; Epidemiol Health. 2026;e2026003. Published online January 19, 2026; DOI: https://doi.org/10.4178/epih.e2026003 [Accepted]

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Abstract PDF: Abstract
OBJECTIVES
Kudoa septempunctata has been identified as the causative agent of food poisoning following the consumption of raw farmed Paralichthys olivaceus. However, cohort studies providing robust evidence for an association between K. septempunctata and gastrointestinal symptoms remain limited. This prospective cohort study investigated the association between the consumption of K. septempunctata–infected farmed P. olivaceus and the occurrence of gastrointestinal symptoms.
METHODS
Individuals who purchased raw farmed P. olivaceus between 2020 and 2021 were selected as the study population. Study data included 2 rounds of questionnaire surveys administered before and after consumption, 2 muscle specimens obtained from each purchased fish, and human biological specimens collected from individuals who developed gastrointestinal symptoms within 24 hours after consumption. Data were analyzed using the chi-square test and t-test, and the association between consumption of K. septempunctata–infected farmed P. olivaceus and gastrointestinal symptoms was evaluated using relative risk estimates between exposure groups.
RESULTS
The relative risk of gastrointestinal symptoms associated with exposure to K. septempunctata–infected P. olivaceus ranged from 71.2 (95% CI, 27.0–178.6) to 124.5 (95% CI, 43.5–355) across the 2 case definitions. A strong and statistically significant association was observed between exposure to K. septempunctata–infected P. olivaceus and the development of acute gastrointestinal symptoms.
CONCLUSIONS
These findings indicate both an association and a causal relationship between consumption of K. septempunctata–infected farmed P. olivaceus and the onset of gastrointestinal symptoms.; Summary

Original Article

A large-scale norovirus outbreak associated with kimchi consumption across multiple schools in a Korean city in 2024: Eunkyung Park, Sumi Cho, Eunyoung Kim, Jung Im Park, Ju-Hyung Lee, Jin Gwack; Epidemiol Health. 2025;47:e2025057. Published online October 3, 2025; DOI: https://doi.org/10.4178/epih.e2025057

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Abstract Summary PDF Supplementary Material: Abstract
OBJECTIVES
Norovirus is a major global concern for foodborne outbreaks. We investigated a large-scale norovirus outbreak in a Korean city to identify the source of infection and implement control measures.
METHODS
A retrospective cohort study was conducted. Data were collected from questionnaires and laboratory test results, along with an environmental investigation. Human and environmental samples were obtained.
RESULTS
The overall attack rate was 20.2%, with 862 cases among 4,276 individuals exposed across 24 affected schools. Norovirus GII.17 was detected in symptomatic individuals, asymptomatic food handlers, and cabbage kimchi products. Kimchi consumption was significantly associated with illness (relative risk, 3.85; 95% confidence interval [CI], 3.12 to 4.74) and was confirmed as the outbreak source. In multivariate logistic regression, both high school status (odds ratio [OR], 1.49; 95% CI, 1.11 to 2.00) and kimchi consumption (OR, 5.56; 95% CI, 4.24 to 7.30) emerged as significant risk factors.
CONCLUSIONS
Kimchi contamination likely occurred either through ingredients or food handlers during the manufacturing process. This study provides key insights for prevention and rapid response to norovirus outbreaks, emphasizing the vulnerability of school food services. We highlight the importance of stringent food safety practices and routine training for food handlers, particularly in manufacturing facilities, given the role of asymptomatic carriers.; Summary

Korean summary
학교를 중심으로 발생한 대규모 노로바이러스 유행에 대한 역학조사 결과 오염된 김치가 원인으로 추정되었다. 이번 유행은 학교 등 단체 음식을 제공하는 식품 제조 과정에서 식재료 위생 및 무증상 조리종사자에 대한 관리의 중요성을 시사한다.

Key Message
An epidemiological investigation into a large-scale norovirus outbreak associated with 24 schools identified contaminated kimchi as the likely source. The outbreak underscores the critical need for proper hygiene management of food ingredients and effective control of asymptomatic food handlers during the preparation of mass meals in institutional settings such as school food services.

Epidemiologic Investigation

Salmonellosis outbreaks linked to eggs at 2 gimbap restaurants in Korea: Jun Suk Eun, Joohyun Han, Ji-Hyun Lim, Eunkyung Shin, Junyoung Kim, Da-Jung Ko, Jaeil Yoo, Sungil Kim, Jin Sook Kim, Jung Sub Park, Ji-Hyuk Park; Epidemiol Health. 2024;46:e2024036. Published online March 7, 2024; DOI: https://doi.org/10.4178/epih.e2024036

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8 Crossref

Abstract Summary PDF Supplementary Material

Abstract

OBJECTIVES
Salmonellosis outbreaks occurred at 2 restaurants 2 days apart, and an epidemiological investigation was conducted to determine whether the outbreaks were connected.

METHODS

Case studies were conducted for both outbreaks. Stool samples were collected from individuals, and food samples were collected from the restaurants. Pulsed-field gel electrophoresis (PFGE) and whole-genome sequencing analyses were performed on outbreak-related Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) isolates. Traceback investigations were also conducted for the ingredients from gimbap restaurants A and B.

RESULTS

In total, 106 people from gimbap restaurant A and 5 from gimbap restaurant B met the case definition. Salmonella Enteritidis was detected in samples from 2 food handlers, 22 patients, and 1 food (iceberg lettuce) at gimbap restaurant A and from 1 patient at gimbap restaurant B. According to PFGE, all isolates were identified as SEGX01.089. The molecular typing of all isolates showed the same pattern, and the genetic distance was close according to phylogenetic analysis. Eggs were the only food ingredient that was supplied to both gimbap restaurants.

CONCLUSIONS

The outbreaks were caused by Salmonella Enteritidis, and the source of infections was suspected to be contaminated eggs. To prevent foodborne outbreaks of Salmonella, restaurants should heat eggs sufficiently, and egg farms need to establish management systems that prevent Salmonella infections.

Summary

Korean summary
동일한 도시의 두 식당에서 2일 간격으로 살모넬라감염증 유행이 발생하여, 원인을 확인하고 두 유행 간에 연관이 있는지를 규명하기 위해 역학조사를 시행하였다. 병원체에 대한 유전자형 분석과 식재료 역추적조사 결과를 바탕으로 두 유행은 Salmonella Enteritidis에 의해 발생하였고, 감염원은 동일한 농장에서 공급된 오염된 계란으로 추적하였다.

Key Message
Salmonellosis outbreaks occurred at 2 restaurants in the same city 2 days apart, and epidemiological investigations were conducted to identify the causes and determine whether the outbreaks were connected. Based on the genetic characterization of the pathogens and traceback investigation of the food ingredients, the outbreaks were caused by Salmonella Enteritidis and the source of infection was traced to contaminated eggs, which were supplied from the same farm.

Citations

Citations to this article as recorded by

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Journal of Innovation Food and Animal Science (JIFAS).2025; 1(2): 43. CrossRef
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