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 Investigations

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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9 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

Bacteriophage emulsion for prevention of Salmonella contamination in eggshells
Su Jin Jo, Sang Guen Kim, Sib Sankar Giri, Sung Bin Lee, Jae Hong Park, Mae Hyun Hwang, Da Sol Park, Eun Jae Park, Se Chang Park
International Journal of Food Microbiology.2026; 445: 111470. CrossRef
Emergency department outcomes of children with non-typhoidal Salmonella gastroenteritis: a single-center cohort study with adult comparators
Da Som Hwang, Hwan Sun Moon, Min-Jung Kim, So-Hyun Paek
Pediatric Emergency Medicine Journal.2026; 13(1): 1. CrossRef
Bactericidal Efficacy of Sodium Hypochlorite on Eggshells Contaminated with Three Salmonella Serovars
Min-Ho Park, Seok-Jin Cho, Kyoung-Seong Choi
Pathogens.2026; 15(2): 133. CrossRef
Gompertz-derived growth kinetics of Salmonella enterica serovar Bareilly inoculated in precooked ingredients for Gimbap
Jae-Hyun Yoon, Hyunji Song, Euijin Choo, Sun-Young Lee
Food Science and Biotechnology.2025; 34(10): 2353. CrossRef
Emergence of Distinct Salmonella enterica Serovar Enteritidis Lineage since 2020, South Korea
Eunkyung Shin, Tae-Min La, Jaeil Yoo, Junyoung Kim, Ji-Yeon Hyeon
Emerging Infectious Diseases.2025;[Epub] CrossRef
A Novel Lytic Salmonella Phage Harboring an Unprecedented Tail-Protein Domain Combination Capable of Lysing Cross-Host-Transmitted Salmonella Strains
Ling Zhang, Mingqiang Guo, Xiaoyu Ma, Wei Wang, Wanpeng Ma, Yifan Liu, Junxiang Wei, Zhanqiang Su
Foods.2025; 14(16): 2850. CrossRef
Significant reduction in norovirus outbreaks and secondary transmission of acute gastroenteritis in Seoul schools following the COVID-19 pandemic: a retrospective epidemiological study
Euncheol Son, Young-Hoon Kim
Journal of Yeungnam Medical Science.2025; 42: 65. CrossRef
FOOD SAFETY CONSIDERATIONS OF EGGSHELL POWDER FOR FOOD APPLICATIONS: A REVIEW
Suci Apsari Pebrianti, Zahra Naelal Mounaya Insanullah, Nadia Raihan, Ririn Rosalina Trinita
Journal of Innovation Food and Animal Science (JIFAS).2025; 1(2): 43. CrossRef
2019–2022년 국내 수인성‧식품매개감염병 원인세균 병원체 감시현황
문의 홍, 은경 신, 준영 김, 재일 유
Public Health Weekly Report.2024; 17(45): 1941. CrossRef

Epidemiological investigation of a food-borne outbreak in a kindergarten, Jeju Province, Korea: Kyoung Mi Kim, Eun Suk Cho, Seong Bae Ahn, Eun Ok Kang, Jong-Myon Bae; Epidemiol Health. 2023;45:e2023047. Published online April 17, 2023; DOI: https://doi.org/10.4178/epih.e2023047

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2 Web of Science
2 Crossref

Abstract Summary PDF Supplementary Material

Abstract

OBJECTIVES
On Monday, September 6, 2021, at a kindergarten in Jeju Province, a large number of children vomited and developed food poisoning symptoms, and this necessitated an epidemiological investigation.

METHODS

The team surveyed symptoms and food intake history of kindergarten children, teachers, and workers who ate lunch between September 2 (Thursday) and September 6 (Monday), excluding weekends. In addition to rectal swabs, environmental samples from preserved foods, cooking utensils, drinking water, and refrigerator handles were collected. Pulsed field gel electrophoresis (PFGE) for genetic fingerprint analysis was also performed.

RESULTS

There were 19 cases among 176 subjects, which indicated an attack rate of 10.8%. The epidemic curve showed a unimodal shape, and the average incubation period was 2.6 hours. While no food was statistically significant in food intake history, the analysis of 35 rectal smear samples detected Bacillus cereus in 7 children, 4 teachers, and 1 cooking staff. Enterotoxins were also detected in 12 samples. Out of 38 environmental samples, B. cereus and enterotoxins were detected in the morning snack cereal, lunch bean sprouts, and afternoon snack steamed potatoes on Monday, September 6th. The result of the PFGE test on 10 isolates of B. cereus showed that there was no genetic homology.

CONCLUSIONS

Our results indicated that this outbreak was simultaneously caused by various strains of B. cereus from the environment.

Summary

Korean summary
모 유치원에서 제공한 급식 취식아동에서 발열이 없고 구토형의 주증상인 식중독이 발생되었다. 평균 잠복기 2.6시간 (최소 0.8, 최대 4.5시간)이며, 인체 및 환경 검체에서 바실러스 세레우스 균이 분리되었다. 이에 해당 집단발생은 구토형 바실러스 세레우스 감염증에 의한 식중독을 결론지었다.

Key Message
A large number of children in a kindergarten vomited suddenly. The average incubation period was 2.6 hours (min 0.8, max 4.5 hours) with uni-modal shape in the epidemic curve. Bacillus cereus and entertoxin were detected in rectal smear and environmental samples.

Citations

Citations to this article as recorded by

Significant reduction in norovirus outbreaks and secondary transmission of acute gastroenteritis in Seoul schools following the COVID-19 pandemic: a retrospective epidemiological study
Euncheol Son, Young-Hoon Kim
Journal of Yeungnam Medical Science.2025; 42: 65. CrossRef
Surge of acute gastroenteritis outbreaks due to rising norovirus GII.4 transmission in Seoul childcare centers and kindergartens in 2022 compared to 2019–2021
Euncheol Son, Young-Hoon Kim
Archives of Virology.2024;[Epub] CrossRef

Investigation of a human brucellosis outbreak in Douz, Tunisia, 2018: Nejib Charaa, Rabaa Ghrab, Aicha Ben Othman, Mohamed Makhlouf, Hejer Ltaief, Nissaf Ben Alaya, Mohamed Chahed; Epidemiol Health. 2022;44:e2022048. Published online May 18, 2022; DOI: https://doi.org/10.4178/epih.e2022048

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349 Download
7 Web of Science
5 Crossref

Abstract Summary PDF

Abstract

OBJECTIVES
In 2017, the incidence of human brucellosis in Tunisia was 9.8 per 100,000 population. In the Douz district, 2 cases were reported in March 2018. Prior to that date, the last indigenous cases to be reported in Douz had been in 2015. This study aimed to identify the source of this new contamination and recommend control interventions.

METHODS

This case-control study included residents of Douz who presented with clinical symptoms of brucellosis and had a subsequent Wright test antibody titer ≥ 1/160. The controls were neighbors of the infected cases who had a negative Rose Bengal test. Univariate and multivariate analyses were performed to estimate the odds ratios of risk factors. Goats belonging to the cases and controls were actively screened.

RESULTS

Twenty-five infected cases and 52 uninfected controls were enrolled. All infected cases had consumed goat milk and 92% had purchased it from the same breeder. Consumption of goat milk from this breeder (adjusted odds ratio [aOR], 30.78; 95% confidence interval [CI], 6.47 to 235.91) and overall consumption of raw goat milk (aOR, 14.84; 95% CI, 2.04 to 310.44) were independent risk factors for brucellosis. The breeder had 18 goats, 5 of which were smuggled from a neighboring country. Three of those goats were diagnosed with brucellosis.

CONCLUSIONS

Consumption of raw milk from smuggled sick goats was the main risk factor in this outbreak. The sick goats were slaughtered and an education campaign was conducted. Vaccination, control of cross-border animal movements, and control of goat milk sales must be strengthened to prevent the spread of brucellosis in southwestern Tunisia.

Summary

Key Message
Human brucellosis, despite being a major economic and health problem and the availability of proven control methods, is still endemic in North African countries. The scarcity of epidemiological data, under-reporting, certain weaknesses in surveillance systems and the lack of well-conducted outbreak investigations, contribute to this endemic state. This field epidemiological investigation of a human brucellosis outbreak highlighted the importance of serological surveillance, the slaughter of infected animals, vaccination, control of animal movements across borders and pasteurization of milk in the fight against this disease.

Citations

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Frontiers in Microbiology.2023;[Epub] CrossRef

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