Rotavirus genotypes in children under five years hospitalized with diarrhea in low and middle-income countries: Results from the WHO-coordinated Global Rotavirus Surveillance Network.

Rotavirus is the most common pathogen causing pediatric diarrhea and an important cause of morbidity and mortality in low- and middle-income countries. Previous evidence suggests that the introduction of rotavirus vaccines in national immunization schedules resulted in dramatic declines in disease burden but may also be changing the rotavirus genetic landscape and driving the emergence of new genotypes. We report genotype data of more than 16,000 rotavirus isolates from 40 countries participating in the Global Rotavirus Surveillance Network. Data from a convenience sample of children under five years of age hospitalized with acute watery diarrhea who tested positive for rotavirus were included. Country results were weighted by their estimated rotavirus disease burden to estimate regional genotype distributions. Globally, the most frequent genotypes identified after weighting were G1P[8] (31%), G1P[6] (8%) and G3P[8] (8%). Genotypes varied across WHO Regions and between countries that had and had not introduced rotavirus vaccine. G1P[8] was less frequent among African (36 vs 20%) and European (33 vs 8%) countries that had introduced rotavirus vaccines as compared to countries that had not introduced. Our results describe differences in the distribution of the most common rotavirus genotypes in children with diarrhea in low- and middle-income countries. G1P[8] was less frequent in countries that had introduced the rotavirus vaccine while different strains are emerging or re-emerging in different regions.

The first reported hepatitis E outbreak in a food manufacturing factory: Korea, 2022.

OBJECTIVES: 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. CONCLUSIONS: 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 laboratory test procedure to confirm rotavirus vaccine infection in severe complex immunodeficiency patients.

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.

Non-Polio Enteroviruses from Acute Flaccid Paralysis Surveillance in Korea, 2012-2019.

The risk of polio importation and re-emergence persists since epidemic polio still occurs in some countries, and the resurgence of polio occurring almost 20 years after polio eradication was declared in Asia has been reported. We analyzed the results of acute flaccid paralysis (AFP) surveillance in Korea to assess the quality of AFP surveillance and understand the etiology of non-polio enterovirus (NPEV)-associated central nervous system diseases in a polio-free area. We investigated 637 AFP patients under 15 years of age whose cases were confirmed during 2012-2019 by virus isolation, real-time reverse transcription polymerase chain reaction, and VP1 gene sequencing. Among the 637 AFP cases, NPEV was detected in 213 (33.4%) patients, with the majority observed in EV-A71, with 54.9% of NPEV positives. EV-A71 has been shown to play a role as a major causative agent in most neurological diseases except for Guillain-Barré syndrome (GBS), acute disseminated encephalomyelitis (ADEM), and meningitis. This study provides information on the AFP surveillance situation in Korea and highlights the polio eradication stage in the monitoring and characterization of NPEV against the outbreak of neurological infectious diseases such as polio.

Nationwide seroprevalence of hepatitis A in South Korea from 2009 to 2019.

Hepatitis A, an acute type of hepatitis caused by the hepatitis A virus, occurs worldwide. Following the 2009 hepatitis A epidemic in South Korea, patient outbreak reports were collectively converted to an "all-patient report" in 2011, and national immunization programs were introduced for children in 2015. In this study, we aimed to analyze the changes and characteristics of hepatitis A antibody titers in South Korea following the epidemic. The results of hepatitis A antibody tests performed at clinical laboratories from 2009 to 2019 were analyzed based on year, age, region, sex, and medical institution. The average 2009-2018 positive anti-hepatitis A virus immunoglobulin G rate was 51.8%, but it increased (56.06%) in 2019. Significantly different antibody-positive rates were observed based on age: <10 years, 54.5%; 20-29 years, 19.5%; ≥50 years, almost 100%. The positive rate of individuals in their teens and 20s gradually increased, whereas that of those in their 30s and 40s gradually decreased. Males had higher antibody-positive rates than females, and samples from higher-level general hospitals exhibited higher antibody rates. The positive anti-hepatitis A virus immunoglobulin M rates gradually decreased after 2009 and were <1% after 2012. However, a high positive rate of 3.69% was observed in 2019 when there was an epidemic. Anti-hepatitis A virus immunoglobulin G-positive rates were similar throughout the year, but the anti-hepatitis A virus immunoglobulin M-positive rates increased from January, peaked in April, and decreased from July, exhibiting distinct seasonality. This is considered to be related to groundwater pollution during the spring drought season. The introduction of the "all-patient report" and national vaccination program for children has had an effective influence on hepatitis A management. However, for hepatitis A prevention, policy considerations for high-risk age groups with low antibody-positive rates will be necessary.

Trends in acute viral gastroenteritis among children aged ≤5 years through the national surveillance system in South Korea, 2013-2019.

Acute gastroenteritis is a global public health concern. This study aimed to analyze the trend and characteristics of acute viral gastroenteritis through a national surveillance network. Enteric viruses were detected in 9510 of 31,750 (30.1%) cases assessed from 2013 to 2019 by EnterNet. The most prevalent pathogens were norovirus (15.2%) and group A rotavirus (9.7%); most infections were reported in 2017 (34.0%). Norovirus and rotavirus coinfections were the most common. Norovirus infections were prevalent among 1-year-old children (1835 out of 9510 cases) during winter, and group A rotavirus infections were common during spring. Seasonality was not observed among enteric adenovirus, astrovirus, and sapovirus. The prevalent viral genotypes detected included norovirus GII.4, enteric adenovirus F41, astrovirus genotype 1, and sapovirus GI.1. However, changes in enteric virus trends were noted during the study period. Norovirus prevalence extended into spring, and new genotypes of enteric adenovirus, astrovirus, and sapovirus were identified. These surveillance data elucidate enteric virus epidemiological characteristics.

A Different Epidemiology of Enterovirus A and Enterovirus B Co-circulating in Korea, 2012-2019.

BACKGROUND: Enteroviruses (EVs) occur frequently worldwide and are known to be associated with a broad spectrum of clinical manifestations from mild syndromes to neurological disease. To understand the epidemiology of EV in Korea, we characterized EV-infected cases during 2012-2019 based on national surveillance. METHODS: We collected specimens from patients with suspected EV infections and analyzed the data using real-time reverse-transcription polymerase chain reaction and VP1 gene sequencing. RESULTS: Among the 18 261 specimens collected, EVs were detected in 6258 (34.3%) cases. Although the most common EV types changed annually, EV-A71, echovirus 30, coxsackievirus B5, coxsackievirus A6, and coxsackievirus A10 were commonly identified. Among the human EVs, the case numbers associated with the 2 major epidemic species (EV-A and EV-B) peaked in the summer. While EV-A species affected 1-year-old children and were associated with herpangina and hand, foot, and mouth disease, EV-B species were mostly associated with neurologic manifestations. The highest incidence of EV-B species was observed in infants aged <12 months. Feces and respiratory specimens were the most predictive of EV infection. Specimens collected within 5 days of symptom onset allowed for timely virus detection. CONCLUSIONS: EV-A and EV-B species co-circulating in Korea presented different epidemiologic trends in clinical presentation, affected subjects, and seasonality trends. This study could provide information for the characterization of EVs circulating in Korea to aid the development of EV antivirals and vaccines, as well as public health measures to control enteroviral diseases.

Outbreak associated with Rotavirus G11,P[25] in Korea in 2018.

We here report the first outbreak caused by rotavirus G11,P[25] in Korea in 2018, representing a case of re-assortment with pig-derived rotavirus. The genotype constellation was identical to the virus identified in Korea in 2012 as G11-P[25]-I12-R1-C1-M1-A1-N1-T1-E1-H1. The infection source was not known exactly but it must be considered infection from swine.

An Outbreak Associated with Sapovirus GI.3 in an Elementary School in Gyeonggi-do, Korea.

On October 4, 2018, an outbreak of gastroenteritis associated with sapovirus occurred among elementary school students in Gyeonggi-do, Korea. Epidemiologic studies were conducted in a retrospective cohort approach. Using self-administered questionnaires, we collected information on symptoms and food items consumed. Of the 999 subjects, 17 developed patients that met the case definition. The main symptom was vomiting (100%), and the symptomatic age was 6-12 years. Positive samples were identified by conventional reverse transcription polymerase chain reaction for sequencing. They were classified into genotype GI.3 by phylogenetic analysis. This is the first report of an outbreak associated with sapovirus GI.3 in Korea.

Detection of Novel Coronavirus on the Surface of Environmental Materials Contaminated by COVID-19 Patients in the Republic of Korea.

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.

Plasmid-mediated transfer of CTX-M-55 extended-spectrum beta-lactamase among different strains of Salmonella and Shigella spp. in the Republic of Korea.

We screened 10 CTX-M-55-producing Shigella and Salmonella isolates from a national surveillance in Korea. The blaCTX-M-55 was located on the IncI1 (n=5), IncA/C (n=4) and IncZ (n=1) plasmids, downstream of ISEcp1, IS26-ISEcp1 and ISEcp1-IS5 sequences, respectively. These results indicate that CTX-M-55 has disseminated to other bacteria by lateral plasmid transfer.

Emergence of Norovirus GII.17-associated Outbreak and Sporadic Cases in Korea from 2014 to 2015.

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.

Public health significance of major genotypes of Salmonella enterica serovar Enteritidis present in both human and chicken isolates in Korea.

Salmonella enterica serovar Enteritidis is one of the most common serotypes implicated in Salmonella infections in both humans and poultry worldwide. It has been reported that human salmonellosis is mainly associated with the consumption of poultry products contaminated with serovar Enteritidis. The present study was to extensively analyze the public health risk of serovar Enteritidis isolates from chickens in Korea. A total of 127 chicken isolates were collected from clinical cases, on-farm feces, and chicken meat between 1998 and 2012 and 20 human clinical isolates were obtained from patients with diarrhea between 2000 and 2006 in Korea. To characterize the isolates from chickens and humans, we compared the pulsed-field gel electrophoresis (PFGE) patterns and multilocus variable-number tandem-repeat analysis (MLVA) profiles of the isolates. We further characterized representative isolates of different genotypes using a DNA microarray. PFGE revealed 28 patterns and MLVA identified 16 allelic profiles. The DNA microarray showed high genetic variability in plasmid regions and other fimbrial subunits of the isolates although the virulence gene contents of isolates from the same source and/or of the same genotype were unrelated. PFGE and MLVA showed that major genotypes were present in both human and chicken isolates. This result suggests that chickens in Korea pose a significant risk to public health as a source of serovar Enteritidis as has been noted in other countries.

Genome Sequence of Bacteriophage GG32, Which Can Infect both Salmonella enterica Serovar Typhimurium and Escherichia coli O157:H7.

We report here a new virulent Salmonella enterica serovar Typhimurium (S Typhimurium) bacteriophage, GG32, which was isolated from the Guem River in the Republic of Korea. The strain can infect both S Typhimurium and Escherichia coli (E. coli) O157:H7 and may be a good candidate for a bio-control agent.

Complete Genome Sequence of Bacteriophage MA12, Which Infects both Campylobacter jejuni and Salmonella enterica Serovar Enteritidis.

Here, we announce the complete genome sequence of Salmonella enterica serovar Enteritidis (S Enteritidis) bacteriophage MA12, a 41-Kb chromosome. The strain can infect both Campylobacter jejuni (C. jejuni) and S Enteritidis and can be used in phage therapy experiments with poultry and poultry meat.

Norovirus in benign convulsions with mild gastroenteritis.

BACKGROUND: Benign convulsions with gastroenteritis (CwG) are defined as afebrile convulsions accompanying symptoms of gastroenteritis without evidence of laboratory derangement. Although the main pathogen has been known as rotavirus, since the introduction of rotavirus vaccine, associated viruses with CwG may have changed. Thus, we evaluated the viral association of CwG for patients admitting for recent 2.5 years. METHODS: All patients hospitalized for CwG between November 2012 and May 2015 were included in our study. Stool specimens were tested with reverse transcription polymerase chain reaction for detecting norovirus and astrovirus and with enzyme immunoassay for rotavirus and enteric adenovirus. Clinical data was gathered via chart review. RESULTS: Fifty patients were included. Except four patients who failed to collect stool samples, 46 patients were tested. Causative diarrheal viruses were detected in 38 patients and they were 29 norovirus, four rotavirus, four adenovirus, and one astrovirus. Norovirus was commonly identified during the months of November and December. No difference of the clinical characteristics and laboratory value was noted according to the number of seizure episodes. CONCLUSIONS: Norovirus is a common pathogen in CwG. Understanding the viral associations can facilitate recognition of CwG.

Rapid Emergence and Clonal Dissemination of CTX-M-15-Producing Salmonella enterica Serotype Virchow, South Korea.

The prevalence of cefotaxime-resistant Salmonella enterica serotype Virchow has dramatically increased in South Korea since the first isolation in 2011. Of 68 isolates collected over 10 years, 28 cefotaxime-resistant isolates harbored the bla(CTX-M-15) extended-spectrum ß-lactamase gene and were closely related genetically, demonstrating the clonal dissemination of CTX-M-15-producing Salmonella Virchow in South Korea.

Emergence of Norovirus GII.4 variants in acute gastroenteritis outbreaks in South Korea between 2006 and 2013.

BACKGROUND: New emerging strains of noroviruses (NoVs) often increase acute gastroenteritis (AGE) outbreaks worldwide. OBJECTIVE: We analyzed the epidemiological features and genotypic patterns of NoVs in AGE outbreaks. STUDY DESIGN: To elucidate the public health impact of NoVs during AGE outbreaks in South Korea, a molecular and epidemiological investigation was performed with 318 AGE outbreaks reported from the Gyeonggi province of South Korea during the period from 2006 to 2013. RESULTS: NoVs were associated with 102 (32.1%) of the AGE outbreaks. Epidemiological data revealed that the majority of NoV outbreaks were in the student group (47.1%), and the majority of AGE patients were identified in schools (68.8%). NoV genogroup (G) II strains were associated with 94 (92.2%) of the NoV outbreaks, and GII.4 strains were predominantly associated with 57.6% (n=49) of NoV GII outbreaks. Four GII.4 variants (2006b, 2007, 2009 and 2012 variants) emerged and showed different contributions to NoV outbreak activity. The 2006b variant was predominantly associated with NoV outbreaks during the early years of the study period, and was subsequently displaced by the New Orleans 2009 variant, and most recently by the Sydney 2012 variant. In addition, the GII.2, GII.14, and GII.17 strains have recently been often associated with NoV AGE outbreaks. CONCLUSIONS: The emergence of new NoV GII.4 variants significantly affected the NoV outbreak activity in South Korea during the period from 2006 to 2013. The surveillance for new emerging strains affecting NoV outbreak activity should be intensified to develop an adequate policy to prevent further NoV outbreaks.

Characterization of Salmonella enterica serovar Typhimurium and Salmonella enterica serovar 4,[5],12:i:- isolates from pigs presenting with diarrhea in Korea.

Between 2011 and 2012, a total of 896 pig fecal samples were collected from nine provinces in Korea, and 50 salmonella enterica susp. enterica serovar Typhimurium (S. Typhimurium) was isolated. The characteristics of the 50 strains were analyzed, and 4 strains were identified as Salmonella enterica subsp. enterica serovar 4,[5],12:i:-. Salmonella 4,[5],12:i:- could not be distinguished from S. Typhimurium through phage typing, antimicrobial resistance testing or multiple-locus variable-number tandem repeat analysis (MLVA). However, among the four Salmonella 4,[5],12:i:- strains, one (KVCC-BA1400078) was identified as a Salmonella 4,[5],12:i:- clone isolated from humans in the United States, and another (KVCC-BA1400080) was identified as DT193, which has been primarily isolated from humans and animals in European countries. The presence of Salmonella 4,[5],12:i:- in Korea poses a significant threat of horizontal transfer between pigs and humans.

Three gastroenteritis outbreaks in South Korea caused by the consumption of kimchi tainted by norovirus GI.4.

BACKGROUND: In April 2013, outbreaks of acute gastroenteritis were reported at three schools in Jeonju, South Korea. Epidemiological investigations were performed to characterize the outbreaks and implement appropriate control measures. MATERIALS AND METHODS: Retrospective cohort studies were performed at these schools. Stool and environmental samples were collected for bacterial and viral assessment. A food supplier of the schools, food company X, was inspected, and samples of cabbage kimchi and groundwater were tested for norovirus by real-time reverse-transcriptase polymerase chain reaction. The relatedness of the detected norovirus strains was evaluated by phylogenetic analysis. RESULTS: Of the 3347 questionnaires distributed, 631 (attack rate: 18.9%) met the case definition. Among the consumed food items, kimchi products (i.e., cabbage and fresh kimchi) were significantly associated with illness. The kimchi products were supplied by food company X. Among stool samples from 95 students and 34 food handlers at the 3 schools, 39 (41.1%) and 14 (41.2%) samples, respectively, were positive for norovirus. The samples of groundwater and cabbage kimchi at food company X were positive for norovirus. The predominant genotype of norovirus detected in the patient, groundwater, and cabbage kimchi samples, GI.4, shared high nucleotide identity. CONCLUSIONS: Kimchi products tainted with norovirus GI.4 from contaminated groundwater were linked to the acute gastroenteritis outbreaks. Therefore, kimchi manufacturers in South Korea should apply chlorine disinfection when using groundwater. Moreover, more stringent sanitation requirements and strict regulations for food companies are recommended.