Epidemiology and Health

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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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.

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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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.

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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3 Web of Science
2 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

Citations to this article as recorded by

Long ignored but making a comeback: a worldwide epidemiological evolution of human brucellosis
Zhiguo Liu, Liping Gao, Miao Wang, Min Yuan, Zhenjun Li
Emerging Microbes & Infections.2024;[Epub] CrossRef
Native circulating Brucella melitensis lineages causing a brucellosis epidemic in Qinghai, China
Hongmei Xue, Zhijun Zhao, Jianling Wang, Li Ma, Jiquan Li, Xuxin Yang, Lingling Ren, Liqing Xu, Zhiguo Liu, Zhenjun Li
Frontiers in Microbiology.2023;[Epub] CrossRef

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