Six amino acids of VP1 switch along with pandemic of CV-A6-associated HFMD in Guangxi, southern China, 2010–2017

Epidemiological and Genetic Characterization of Coxsackievirus A6-Associated Hand, Foot, and Mouth Disease in Gwangju, South Korea, in 2022

Coxsackievirus A6 (CV-A6) has emerged as the predominant causative agent of hand, foot, and mouth disease (HFMD) in young children. Since the declaration of coronavirus disease 2019 (COVID-19) as a global pandemic, the incidence of infectious diseases, including HFMD, has decreased markedly. When social mitigation was relaxed during the COVID-19 pandemic in 2022, the re-emergence of HFMD was observed in Gwangju, South Korea, and seasonal characteristics of the disease appeared to have changed. To investigate the molecular characteristics of enterovirus (EV) associated with HFMD during 2022, 277 specimens were collected. Children aged younger than 5 years accounted for the majority of affected individuals. EV detection and genotyping were performed using real-time RT-PCR and nested RT-PCR followed by sequence analysis. The EV detection rate was found to be 82.3%, and the main genotype identified was CV-A6. Sixteen CV-A6 samples were selected for whole genome sequencing. According to phylogenetic analysis, all CV-A6 strains from this study belonged to the sub-genotype D3 clade based on VP1 sequences. Analysis of 3D polymerase phylogeny showed that only the recombinant RF-A group was identified. In conclusion, circulating EV types should be continuously monitored to understand pathogen emergence and evolution during the post-pandemic era.

Diversity of Human Enterovirus Co-Circulations in Five Kindergartens in Bangkok between July 2019 and January 2020

Human enterovirus causes various clinical manifestations in the form of rashes, febrile illness, flu-like illness, uveitis, hand-foot-mouth disease (HFMD), herpangina, meningitis, and encephalitis. Enterovirus A71 and coxsackievirus are significant causes of epidemic HFMD worldwide, especially in children aged from birth to five years old. The enterovirus genotype variants causing HFMD epidemics have been reported increasingly worldwide in the last decade. We aim to use simple and robust molecular tools to investigate human enteroviruses circulating among kindergarten students at genotype and subgenotype levels. With the partial 5'-UTR sequencing analysis as a low-resolution preliminary grouping tool, ten enterovirus A71 (EV-A71) and coxsackievirus clusters were identified among 18 symptomatic cases and 14 asymptomatic cases in five kindergartens in Bangkok, Thailand, between July 2019 and January 2020. Two occurrences of a single clone causing an infection cluster were identified (EV-A71 C1-like subgenotype and coxsackievirus A6). Random amplification-based sequencing using MinION (Oxford Nanopore Technology) helped identify viral transmission between two closely related clones. Diverse genotypes co-circulating among children in kindergartens are reservoirs for new genotype variants emerging, which might be more virulent or better at immune escape. Surveillance of highly contagious enterovirus in communities is essential for disease notifications and controls.

Coxsackievirus A6 Infection Causes Neurogenic Pathogenesis in a Neonatal Murine Model

Coxsackievirus A6 (CVA6), a member of species A enterovirus, is associated with outbreaks of hand-foot-and-mouth disease and causes a large nationwide burden of disease. However, the molecular pathogenesis of CVA6 remains unclear. In the present study, we established a suckling Institute of Cancer Research (ICR) mouse infection model to explore the neural pathogenicity of CVA6. Five-day-old mice infected with CVA6 strain F219 showed lethargy and paralysis, and died 5 or 6 days after infection via IM injection. Cerebral edema and neuronal cell swelling were observed in the infected brain tissue, and we found that the CVA6 VP1 antigen could co-localize with GFAP-positive astrocytes in infected mouse brain using an immunofluorescence assay. CVA6 strain F219 can also infect human glioma (U251) cells. Transcriptome analysis of brain tissues from infected mice and infected U251 cells showed that significantly differentially expressed genes were enriched in antiviral and immune response and neurological system processes. These results indicate that CVA6 could cause neural pathogenesis and provide basic data for exploring the mechanism of how host-cell interactions affect viral replication and pathogenesis. Importance: Coxsackievirus A6 (CVA6) surpasses the two main pathogens, enterovirus 71 (EV-A71) and coxsackievirus A16 (CVA16), which are the leading pathogens causing HFMD in many provinces of China. In our study, CVA6 infection caused neurogenic pathogenesis in a neonatal murine model, manifesting as cerebral edema and neuronal cell swelling, CVA6 VP1 antigen could co-localize with GFAP-positive astrocytes in the infected mouse brain. Based on CVA6-infected brain tissue and U251 cell transcriptome analysis, we found upregulated antiviral and immune response-related genes such as Zbp1, Usp18, Oas2, Irf7, Ddx60, Ifit3, Ddx58, and Isg15, while the neurological system process-related genes were downregulated, including Fcrls, Ebnrb, Cdk1, and Anxa5.

Local immune dysregulation and subsequent inflammatory response contribute to pulmonary edema caused by Enterovirus infection in mice

Pulmonary edema that comes on suddenly is the leading cause of mortality in hand-foot-and-mouth disease (HFMD) patients; however, its pathogenesis is still largely unclear. A range of research suggest immunopathogenesis during the occurrence of pulmonary edema in severe HFMD patients. Herein, to investigate the potential mechanism of immune dysregulation in the development of pulmonary edema upon Enterovirus (EV) infection, we established mouse infection models for Enteroviruses (EVs) including Coxsackievirus (CV) A6, Enterovirus A71 (EVA71), and CVA2 exhibiting a high incidence of pulmonary edema. We found that EVs infection induced an immune system disorder by reducing the numbers of pulmonary and circulatory T cells, B cells, macrophages, and monocytes and increasing the numbers of lung neutrophils, myeloid-derived suppressor cells (MDSCs), and activated T cells. In addition, the concentrations of C-X-C motif chemokine ligand 1 (CXCL-1), tumor necrosis factor-alpha, monocyte chemoattractant protein-1, and interleukin 6 were increased in EV-infected lungs. Moreover, we found that EVs replication in mice lungs lead to apoptosis of lung cells and degradation of tight junction proteins. In conclusion, EVs infection likely triggered a complexed immune defense mechanism and caused dysregulation of innate immune cells (MDSCs, neutrophils, monocytes, and macrophages) and adaptive cellular immunity (B cells, T cells). This dysregulation increased the release of cytokines and other inflammatory factors from activated immune-related cells and caused lung barrier damage and pulmonary edema.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020)

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created as revised from J-SSCG 2016 jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in September 2020 and published in February 2021. An English-language version of these guidelines was created based on the contents of the original Japanese-language version. The purpose of this guideline is to assist medical staff in making appropriate decisions to improve the prognosis of patients undergoing treatment for sepsis and septic shock. We aimed to provide high-quality guidelines that are easy to use and understand for specialists, general clinicians, and multidisciplinary medical professionals. J-SSCG 2016 took up new subjects that were not present in SSCG 2016 (e.g., ICU-acquired weakness [ICU-AW], post-intensive care syndrome [PICS], and body temperature management). The J-SSCG 2020 covered a total of 22 areas with four additional new areas (patient- and family-centered care, sepsis treatment system, neuro-intensive treatment, and stress ulcers). A total of 118 important clinical issues (clinical questions, CQs) were extracted regardless of the presence or absence of evidence. These CQs also include those that have been given particular focus within Japan. This is a large-scale guideline covering multiple fields; thus, in addition to the 25 committee members, we had the participation and support of a total of 226 members who are professionals (physicians, nurses, physiotherapists, clinical engineers, and pharmacists) and medical workers with a history of sepsis or critical illness. The GRADE method was adopted for making recommendations, and the modified Delphi method was used to determine recommendations by voting from all committee members. As a result, 79 GRADE-based recommendations, 5 Good Practice Statements (GPS), 18 expert consensuses, 27 answers to background questions (BQs), and summaries of definitions and diagnosis of sepsis were created as responses to 118 CQs. We also incorporated visual information for each CQ according to the time course of treatment, and we will also distribute this as an app. The J-SSCG 2020 is expected to be widely used as a useful bedside guideline in the field of sepsis treatment both in Japan and overseas involving multiple disciplines.