| Deog-Yong Lee | 7 Articles |
 <b>Objectives</b><br/>On February 16, 2022, 12 cases of hepatitis E virus (HEV) infection were reported in a food manufacturing factory in Korea. The aim of this study was to identify additional cases and to determine the source of this HEV outbreak. Methods: This study was an in-depth investigation of 12 HEV immunoglobulin M (IgM)-positive cases and their demographic, clinical, and epidemiological characteristics. On-site specimens were collected from the environment and from humans, and a follow-up investigation was conducted 2 to 3 months after the outbreak. Results: Among 80 production workers in the factory, 12 (15.0%) had acute HEV infection, all of whom were asymptomatic. The follow-up investigation showed that 3 cases were HEV IgMpositive, while 6 were HEV IgG-positive. HEV genes were not detected in the HEV IgM-positive specimens. HEV genes were not detected in the food products or environmental specimens collected on-site. HEV was presumed to be the causative pathogen. However, it could not be confirmed that the source of infection was common consumption inside the factory. Conclusion: This was the first domestic case of an HEV infection outbreak in a food manufacturing factory in Korea. Our results provide information for the future control of outbreaks and for the preparation of measures to prevent domestic outbreaks of HEV infection.
The rotavirus vaccine is a live vaccine, and there is a possibility of infection by the virus strain used in the vaccine. We investigated the process of determining whether an infection was caused by the vaccine strain in a severe complex immunodeficiency (SCID) patient with rotavirus infection. The patient was vaccinated with RotaTeq prior to being diagnosed with SCID. The testing process was conducted in the following order: confirming rotavirus infection, determining its genotype, and confirming the vaccine strain. Rotavirus infection was confirmed through enzyme immunoassay and VP6 gene detection. G1 and P[8] were identified by multiplex polymerase chain reaction for the genotype, and G3 was further identified using a single primer. By detecting the fingerprint gene (WC3) of RotaTeq, it was confirmed that the detected virus was the vaccine strain. Genotypes G1 and P[8] were identified, and the infection was suspected of having been caused by rotavirus G1P[8]. G1P[8] is the most commonly detected genotype worldwide and is not included in the recombinant strains used in vaccines. Therefore, the infection was confirmed to have been caused by the vaccine strain by analyzing the genetic relationship between VP4 and VP7. Rotavirus infection by the vaccine strain can be identified through genotyping and fingerprint gene detection. However, genetic linkage analysis will also help to identify vaccine strains.
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<p>This study aimed to determine the presence of SARS-CoV-2 on surfaces frequently touched by COVID-19 patients, and assess the scope of contamination and transmissibility in facilities where the outbreaks occurred. In the course of this epidemiological investigation, a total of 80 environmental specimens were collected from 6 hospitals (68 specimens) and 2 “mass facilities” (6 specimens from a rehabilitation center and 6 specimens from an apartment building complex). Specific reverse transcriptase-polymerase chain reaction targeting of RNA-dependent RNA polymerase, and envelope genes, were used to identify the presence of this novel coronavirus. The 68 specimens from 6 hospitals (A, B, C, D, E, and G), where prior disinfection/cleaning had been performed before environmental sampling, tested negative for SARS-CoV-2. However, 2 out of 12 specimens (16.7%) from 2 “mass facilities” (F and H), where prior disinfection/cleaning had not taken place, were positive for SARS-CoV-2 RNA polymerase, and envelope genes. These results suggest that prompt disinfection and cleaning of potentially contaminated surfaces is an effective infection control measure. By inactivating SARS-CoV-2 with disinfection/cleaning the infectivity and transmission of the virus is blocked. This investigation of environmental sampling may help in the understanding of risk assessment of the COVID-19 outbreak in “mass facilities” and provide guidance in using effective disinfectants on contaminated surfaces.</p>
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<p>Human norovirus are major causative agent of nonbacterial acute gastroenteritis. In general, genogroup (G) II.4 is the most prominent major genotype that circulate in human population and the environment. However, a shift in genotypic trends was observed in Korea in December 2014. In this study, we investigated the trend of norovirus genotype in detail using the database of Acute Diarrhea Laboratory Surveillance (K-EnterNet) in Korea. GII.17 has since become a major contributor to outbreaks of norovirus-related infections and sporadic cases in Korea, although the reason for this shift remain unknown.</p>
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Human noroviruses are major causative agents of food and waterborne outbreaks of nonbacterial acute gastroenteritis. In this study, we report the epidemiological features of three outbreak cases of norovirus in Korea, and we describe the clinical symptoms and distribution of the causative genotypes. The incidence rates of the three outbreaks were 16.24% (326/2,007), 4.1% (27/656), and 16.8% (36/214), respectively. The patients in these three outbreaks were affected by acute gastroenteritis. These schools were provided unheated food from the same manufacturing company. Two genotypes (GII.3 and GII.4) of the norovirus were detected in these cases. Among them, major causative strains of GII.4 (Hu-jeju-47-2007KR-like) were identified in patients, food handlers, and groundwater from the manufacturing company of the unheated food. In the GII.4 (Hu-jeju-47-2007KR-like) strain of the norovirus, the nucleotide sequences were identical and identified as the GII.4 Sydney variant. Our data suggests that the combined epidemiological and laboratory results were closely related, and the causative pathogen was the GII.4 Sydney variant strain from contaminated groundwater.
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Norovirus GII.4 is recognized as a worldwide cause of nonbacterial outbreaks. In particular, the GII.4 variant occurs every 2–3 years according to antigenic variation. The aim of our study was to identify GII.4 variants in outbreaks in Korea during 2004–2012. Partial VP1 sequence of norovirus GII.4-related outbreaks during 2004–2012 was analyzed. The partial VP1 sequence was detected with reverse transcription-polymerase chain reaction, seminested polymerase chain reaction, and nucleotide sequence of 312-314 base pairs for phylogenetic comparison. Nine variants emerged in outbreaks, with the Sydney variant showing predominance recently. This predominance may persist for at least 3 years, although new variants may appear in Korea.
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<b>Objective</b><br/>
In this study, the factors that induced a decrease in the incidence of typhoid fever were analyzed. Based on the study results, we propose a quantitative and concrete solution to reduce the incidence of typhoid fever.<br/><b>Methods</b><br/>
We analyzed the incidence and fatality rate of typhoid fever in Korea. Tap water service rate and the number of pharmacies, which affect the incidence rate of typhoid fever, were used as environmental factors.<br/><b>Results</b><br/>
To prevent typhoid fever in the community, it is necessary to provide clean tap water service to 35.5% of the population, with an individual requiring 173 L of clean water daily. Appropriate access to clean water (51% service coverage, 307 L) helped the population to maintain individual hygiene and food safety practices, which brought about a decrease in the incidence of typhoid fever, and subsequently a decrease in fatality rate, which was achieved twice. During the 8-year study period, the fatality rate decreased to 1% when the population has access to proper medical service.<br/><b>Conclusion</b><br/>
The fatality rate was primarily affected by the availability of medical services as well as by the incidence of typhoid fever. However, an analysis of the study results showed that the incidence of typhoid fever was affected only by the availability of clean water through the tap water system.
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