Genomic Analysis and Tracking of SARS-CoV-2 Variants in Gwangju, South Korea, From 2020 to 2022.

BACKGROUND: Since severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported in Wuhan, China, in December 2019, it has spread rapidly, and many coronavirus disease (COVID-19) cases have occurred in Gwangju, South Korea. Viral mutations following the COVID-19 epidemic have increased interest in the characteristics of epidemics in this region, and pathogen genetic analysis is required for infection control and prevention. METHODS: In this study, SARS-CoV-2 whole-genome analysis was performed on samples from patients with COVID-19 in Gwangju from 2020 to 2022 to identify the trends in COVID-19 prevalence and to analyze the phylogenetic relationships of dominant variants. B.41 and B.1.497 prevailed in 2020, the early stage of the COVID-19 outbreak; then, B.1.619.1 mainly occurred until June 2021. B.1.617.2, classified as sublineages AY.69 and AY.122, occurred continuously from July to December 2021. Since strict measures to strengthen national quarantine management had been implemented in South Korea until this time, the analysis of mutations was also able to infer the epidemiological relationship between infection transmission routes. Since the first identification of the Omicron variant in late December 2021, the spread of infection has been very rapid, and weekly whole-genome analysis of specimens has enabled us to monitor new Omicron sublineages occurring in Gwangju. CONCLUSIONS: Our study suggests that conducting regional surveillance in addition to nation-level genomic surveillance will enable more rapid and detailed variant surveillance, which will be helpful in the overall prevention and management of infectious diseases.

Impact of COVID-19 Pandemic Restrictions on Respiratory Virus Patterns: Insights from RSV Surveillance in Gwangju, South Korea.

The social restriction measures implemented due to the COVID-19 pandemic have impacted the pattern of occurrences of respiratory viruses. According to surveillance results in the Gwangju region of South Korea, respiratory syncytial virus (RSV) did not occur during the 2020/2021 season. However, there was a delayed resurgence in the 2021/2022 season, peaking until January 2022. To analyze this, a total of 474 RSV positive samples were investigated before and after the COVID-19 pandemic. Among them, 73 samples were selected for whole-genome sequencing. The incidence rate of RSV in the 2021/2022 season after COVID-19 was found to be approximately three-fold higher compared to before the pandemic, with a significant increase observed in the age group from under 2 years old to under 5 years old. Phylogenetic analysis revealed that, for RSV-A, whereas four lineages were observed before COVID-19, only the A.D.3.1 lineage was observed during the 2021/2022 season post-pandemic. Additionally, during the 2022/2023 season, the A.D.1, A.D.3, and A.D.3.1 lineages co-circulated. For RSV-B, while the B.D.4.1.1 lineage existed before COVID-19, both the B.D.4.1.1 and B.D.E.1 lineages circulated after the pandemic. Although atypical RSV occurrences were not due to new lineages, there was an increase in the frequency of mutations in the F protein of RSV after COVID-19. These findings highlight the need to continue monitoring changes in RSV occurrence patterns in the aftermath of the COVID-19 pandemic to develop and manage strategies in response.

Re-Emergence of HMPV in Gwangju, South Korea, after the COVID-19 Pandemic.

The non-pharmaceutical interventions implemented to prevent the spread of COVID-19 have affected the epidemiology of other respiratory viruses. In South Korea, Human metapneumovirus (HMPV) typically occurs from winter to the following spring; however, it was not detected for two years during the COVID-19 pandemic and re-emerged in the fall of 2022, which is a non-epidemic season. To examine the molecular genetic characteristics of HMPV before and after the COVID-19 pandemic, we analyzed 427 HMPV-positive samples collected in the Gwangju area from 2018 to 2022. Among these, 24 samples were subjected to whole-genome sequencing. Compared to the period before the COVID-19 pandemic, the incidence rate of HMPV in 2022 increased by 2.5-fold. Especially in the age group of 6-10 years, the incidence rate increased by more than 4.5-fold. In the phylogenetic analysis results, before the COVID-19 pandemic, the A2.2.2 lineage was predominant, while in 2022, the A2.2.1 and B2 lineage were observed. The non-pharmaceutical interventions implemented after COVID-19, such as social distancing, have reduced opportunities for exposure to HMPV, subsequently leading to decreased acquisition of immunity. As a result, HMPV occurred during non-epidemic seasons, influencing the age distribution of its occurrences.

Viral detection from negative mumps cases with respiratory symptoms in Gwangju, South Korea in 2021.

Mumps is the second-most reported infectious disease in South Korea; however, due to the low pathogen confirmation rate in laboratory diagnoses, we proposed a method for reevaluating the high incidence rate via the laboratory verification of other viral diseases. In 2021, 63 cases of pharyngeal or cheek mucosal swabs of suspected mumps cases in Gwangju, South Korea, were assessed for causative pathogens using massive simultaneous pathogen testing. More than one respiratory virus was detected in 60 cases (95.2%), 44 (73.3%) of which were codetected. Human rhinovirus was detected in 47 cases, followed by human herpesvirus (HHV)6 in 30; HHV4 (17), human bocavirus (17), HHV5 (10), and human parainfluenza virus 3 (6) were also detected. Our findings suggest the need for further investigations on the pathogenesis of diseases mimicking mumps, which are considered to aid with appropriate public health responses, treatment, and the prevention of infectious disease outbreaks.

Effects of Eriobotrya japonica Water Extract on Alcoholic and Nonalcoholic Fatty Liver Impairment.

The aim of this study was to investigate the potential protective effects of the hot water extract of Eriobotrya japonica (EJW) on EtOH- or free fatty acid (FFA)-induced fatty liver injury in vitro. HepG2/2E1 cells were exposed to EtOH and HepG2 cells were exposed to a mixture of FFAs (oleic acid:palmitic acid, 2:1) to stimulate oxidative stress and to induce lipid accumulation, respectively. Antioxidant activity was significantly increased and lipid accumulation was inhibited in cells pretreated with EJW compared to those in cells exposed to EtOH or FFA only. Also, 5'adenosine monophosphate (AMP)-activated protein kinase (AMPK) and acetyl-coenzyme A carboxylase (ACC) phosphorylations were considerably increased, indicating activation of AMPK. Furthermore, EJW reduced the messenger RNA (mRNA) expression of lipogenesis-associated factors such as ACC, sterol regulatory element binding protein-1c (SREBP-1c), and fatty acid synthase (FAS), and increased mRNA expression related to components of the fatty acid ß-oxidation pathway, such as AMPK, carnitine palmitoyltransferase 1 (CPT-1), and peroxisome proliferator-activated receptor alpha (PPARα). These results suggest that EJW possessed potential preventive effects against both EtOH- and FFA-induced fatty liver disease by alleviation of oxidative stress and lipid accumulation in hepatocytes.

Water Extract of Curcuma longa L. Ameliorates Non-Alcoholic Fatty Liver Disease.

Our aim was to investigate whether hot water extract (CLW) of Curcuma longa L. could prevent non-alcoholic fatty liver disease (NAFLD). HepG2 cells were treated with free fatty acid (FFA) mixture (oleic acid: palmitic acid, 2:1) for 24 h to stimulate in vitro fatty liver. In addition, C57BL/6 mice were fed 60 kcal% high-fat (HF) diet for eight weeks to induce fatty liver in vivo. Intracellular reactive oxygen species (ROS) and malondialdehyde (MDA) productions were increased by FFA and HF-diet, but supplementation with CLW significantly decreased these levels. CLW treatment ameliorated antioxidant activities that were suppressed by exposure to the FFA and HF-diet. Cluster of differentiation 36 (CD36) and fatty acid transport proteins (FATP2 and FATP5) were increased in HF-diet groups, while CLW suppressed their expression levels. Moreover, sterol regulatory element-binding protein-1c (SREBP-1c), acetyl-coenzyme A carboxylase (ACC), and fatty acid synthase (FAS) expression levels were down-regulated in the CLW groups compared to HF-diet groups. On the other hand, 5' adenosine monophosphate-activated protein kinase (AMPK), Peroxisome proliferator-activated receptor alpha (PPAR-α), and carnitine palmitoyltransferase 1 (CPT-1) expressions were up-regulated in the CLW groups. HF-diet fed mice showed high hepatic triglycerides (TG) content compared to the normal diet mice. However, the administration of CLW restored the hepatic TG level, indicating an inhibitory effect against lipid accumulation by CLW. These results suggest that CLW could be a potentially useful agent for the prevention of NAFLD through modulating fatty acid uptake.