Transient constrictive pericarditis following coxsackievirus A4 infection as a rare cause of acute mediastinitis: A case report.

Background: Transient constrictive pericarditis (TCP) is a distinct constrictive pericarditis (CP) subtype characterized by acute pericardial inflammation and transient constrictive physiology. If left untreated, it may progress to irreversible CP requiring pericardiectomy. However, making an early diagnosis of TCP remains difficult. Case presentation: A 51-year-old man presented with fever, chest pain, and dyspnea following preceding flu symptoms. An initial investigation suggested right-sided heart failure. Laboratory results revealed elevated inflammatory markers and hepatic enzyme levels. Echocardiography revealed pericardial effusion with a normal ejection fraction and diastolic ventricular septal bounce suggestive of pericardial constriction. Computed tomography suggested acute descending mediastinitis with pericarditis and pleuritis; however, detailed examinations ruled out this possibility. The constellation of increased serological inflammation, pericardial thickness/effusion, and constrictive physiology suggested TCP, confirmed by cardiac magnetic resonance (CMR) and hemodynamic studies. CMR also revealed coexistent myocarditis. After a thorough assessment for the cause of TCP, a viral etiology was suspected. Paired serology for virus antibody titers revealed a significant increase only in coxsackievirus A4 (CVA4) titers. With prompt anti-inflammatory treatment, the patient's pericardial structure and function and concomitant inflammation of the surrounding tissues were nearly completely recovered, leading to a final diagnosis of TCP caused by CVA4. The subsequent clinical course was uneventful without recurrence at the 1-year follow-up. Conclusions: Here we described the first case of TCP caused by CVA4 concurrent with mediastinitis, myocarditis, and pleuritis, all of which were successfully resolved with anti-inflammatory treatment. Acute mediastinitis secondary to TCP is rare. This case highlights the clinical importance of assessing pericardial diseases as a source of acute mediastinitis and considering CVA4 as an etiology of TCP. An evaluation including multimodal cardiac imaging and serology for virus antibody titers may be useful for an exploratory diagnosis of TCP in right-sided heart failure patients with pericardial effusion.

An outbreak of a novel recombinant Coxsackievirus A4 in a kindergarten, Shandong province, China, 2021.

In 2021, twenty children exhibiting influenza-like illnesses were reported from a kindergarten in Shandong Province, China. Eleven genomes of Coxsackievirus A4 (CV-A4) were obtained from the pediatric cases, sharing <93% genome sequence identities with known CV-A4 strains. Further analyses suggested potential genetic recombination in the P3 region of the novel strains.

Pathogen identification and genotyping of two cluster outbreaks of herpangina in children in Dapeng New District， Shenzhen / 上海预防医学

ObjectiveTo determine the pathogenic characteristics and genotype of two outbreaks of herpangina in children in Dapeng New District， Shenzhen， in May 2021. MethodsA total of five throat swabs from children in the two outbreaks of herpangina were collected and examined for common enteroviruses by real-time PCR. The VP1 region was further amplified by nested RT-PCR. The CLUSTAL W program in MEGA7 software was used to conduct the alignment and reconstruct a phylogenetic tree. ResultsThe pathogen causing the 2 cluster outbreaks of herpangina was coxsackievirus A4 （CVA4）. The sequences of CVA4 VP1 genes revealed that a nucleotide identity of 92% between the strains in the two outbreaks. The three CVA4 strains isolated in kindergarten A had the closest phylogenetic relationship with that isolated in Shenzhen in 2018（MN840533）， with the nucleotide identity of 98.11%. The two strains in kindergarten B had the closest phylogenetic relationship with CVA4 strain isolated in Sichuan in 2018（MW178763）， with the nucleotide identity of 97.88%. The phylogenetic tree showed that all five CVA4 strains in this study belonged to the C2 genotype. ConclusionThe C2 genotype of CVA4 is the causative agent in both outbreaks of herpangina.

Surveillance of pathogens causing hand, foot and mouth disease and analysis of coxsackievirus A4 VP1 gene in Yunnan Province from 2018 to 2020 / 中华微生物学和免疫学杂志

Objective:To investigate the predominant types of enteroviruses and the characteristics of the VP1 gene of coxsackievirus A4 (CVA4) causing hand, foot and mouth disease (HFMD) in Yunnan Province from 2018 to 2020.Methods:Throat swab and stool samples were collected from HFMD cases and tested by real-time quantitative PCR for nucleic acid detection. The samples positive for enterovirus nucleic acids were used for viral isolation and sent to the National Center for Disease Control and Prevention. The VP1 gene of the isolated strains was sequenced and analyzed.Results:From 2018 to 2020, a total of 21 757 HFMD samples were collected, 16 457 (75.64%) of which were positive for enteroviruses. Altogether 533 strains were isolated from 4 114 positive samples that were selected for viral isolation, including 89 strains of enterovirus 71 (EVA71, 16.70%), 180 strains of coxsackievirus A16 (CVA16, 33.77%), 76 strains of CVA10 (14.26%), 118 strains of CVA6 (22.14%), 26 strains of CVA4 (4.88%) and 44 strains of other types (8.26%). HFMD occurred mainly in children under five years old with higher incidence in males than in females (1.35∶1). The incidence of HFMD reached the peak in the second and third quarters. In Yunnan Province, CVA4 mainly circulated in Qujing and Kunming, and was sporadically detected in Wenshan and Honghe. The VP1 gene was 915 bp in length. Twenty-six CVA4 strains belonged to C2 subtype, which were genetically far from the prototype strain AY421762-HighPoint. Mutations in the VP1 gene were found at multiple sites including 18, 23, 34, 102, 148, 164, 200, 262, 174, 275, 285 and 303. These strains showed 80.4%-99.0% homology in nucleotide sequence and 95.6%-99.0% in amino acid sequence. Nucleotide mutations were mostly synonymous mutations.Conclusions:CVA16, CVA6, EVA71 and CVA10 were the predominant enteroviruses causing HFMD in Yunnan Province from 2018 to 2020. The prevalence of CVA4 was also worthy of attention. CVA4 isolates in Yunnan Province belonged to C2 subtype, mainly circulating in the east and southeast of Yunnan Province and gradually becoming a cocirculating predominant strain. Long-term dynamic monitoring would be of great public health significance for improving the sensitivity of HFMD early warning.

A neonatal murine model of coxsackievirus A4 infection for evaluation of vaccines and antiviral drugs.

Coxsackievirus A4 (CVA4) infection can cause hand, foot and mouth disease (HFMD), an epidemic illness affecting neonatal and paediatric cohorts, which can develop to severe neurological disease with high mortality. In this study, we established the first ICR mouse model of CVA4 infection for the evaluation of inactivated vaccines and antiviral drug screening. The CVA4 YT226R strain was selected to infect the neonatal mice and three infectious factors were optimized to establish the infection model. The 3-day-old neonatal mice exhibited clinical symptoms such as hind limb paralysis and death. The severe inflammatory reactions were closely related to the abnormal expression of the acute phase response proinflammatory cytokine IL-6 and an imbalance in the IFN-γ/IL-4 ratio. Importantly, the inactivated CVA4 whole-virus vaccine induced humoral immune responses in adult females and the maternal antibodies afforded mice complete protection against lethal dose challenges of homologous or heterologous CVA4 strains. Both IFN-α2a and antiserum inhibited the replication of CVA4 and increased the survival rates of neonatal mice during the early stages of infection. This neonatal murine model of CVA4 infection will be useful for the development of prophylactic and therapeutic vaccines and for screening of antiviral drugs targeting CVA4 to decrease morbidity and mortality.

Genome Analysis of Coxsackievirus A4 Isolates From Hand, Foot, and Mouth Disease Cases in Shandong, China.

Coxsackievirus A4 (CVA4) is one of the most prevalent pathogens associated with hand, foot and mouth disease (HFMD), an acute febrile illness in children, and is also associated with acute localized exanthema, myocarditis, hepatitis and pancreatitis. Despite this, limited CVA4 genome sequences are currently available. Herein, complete genome sequences from CVA4 strains (n = 21), isolated from patients with HFMD in Shandong province, China between 2014 and 2016, were determined and phylogenetically characterized. Phylogenetic analysis of the VP1 gene from a larger CVA4 collection (n = 175) showed that CVA4 has evolved into four separable genotypes: A, B, C, and D; and genotype D could be further classified in to two sub-genotypes: D1 and D2. Each of the 21 newly described genomes derived from isolates that segregated with sub-genotype D2. The CVA4 genomes displayed significant intra-genotypic genetic diversity with frequent synonymous substitutions occurring at the third codon positions, particularly within the P2 region. However, VP1 was relatively stable and therefore represents a potential target for molecular diagnostics assays and also for the rational design of vaccine epitopes. The substitution rate of VP1 was estimated to be 5.12 × 10-3 substitutions/site/year, indicative of ongoing CVA4 evolution. Mutations at amino acid residue 169 in VP1 gene may be responsible for differing virulence of CVA4 strains. Bayesian skyline plot analysis showed that the population size of CVA4 has experienced several dynamic fluctuations since 1948. In summary, we describe the phylogenetic and molecular characterization of 21 complete genomes from CVA4 isolates which greatly enriches the known genomic diversity of CVA4 and underscores the need for further surveillance of CVA4 in China.

Complete genome characteristics of coxsackievirus A4 isolated from Taian, 2017-2018 / 中华实验和临床病毒学杂志

Objective@#To analyze the genetic characteristics of Coxsackievirus A4 isolated from Taian, 2017-2018.@*Methods@#Sixty throat swab samples of the children who visited Taian Maternal and Child Health Hospital during the year 2017-2018 and were diagnosed as hand, foot and mouth disease, were collected and aseptically inoculated. Fluorescent quantitative PCR analysis was performed using the universal primer for enteroviruses. The high-throughput sequencing was applied to the enterovirus-positive samples, and the full-length genome sequences of the viruses were obtained. Phylogenetic analysis was performed using Mega5.05 and RaxML respectively, and sequence homology and amino acid mutation sites were also analyzed using Mega5.05.@*Results@#Four whole genome sequences of CV-A4 isolated from infants aged 17-19 months old were obtained. Phylogenetic analysis of the full length CV-A4 genomes showed that apart from MG550920/AA/Henan/2016, the remaining CV-A4 strains from China (97.2%), including the four strains from Taian, fell within Group 3. The VP1 genes could be classified into four genotypes and 98.5% of the Chinese strains belonged to genotype D, and the four strains from Taian belonged to D2. It was notable that the Taian isolate A1/Taian is closely related to two strains C179 and C062 from Australia both in the complete genome and the VP1 gene, as well as one strain YT184R isolated from Yantai in 2016 by us. Compared with the prototype CV-A4 strain High Point, 18 amino acid mutations were found in the P1 region.@*Conclusions@#Both phylogenetic trees estimated using the complete genome and the VP1 gene sequences revealed that the four CV-A4 isolates from Taian fell within the same clade with the majority of CV-A4 strains circulating in China. Compared with the prototype CV-A4 strain, several amino acid variations have occurred in the P1 region, which warrants further investigation.

Multiple transmission chains of coxsackievirus A4 co-circulating in China and neighboring countries in recent years: Phylogenetic and spatiotemporal analyses based on virological surveillance.

Coxsackievirus A4 (CV-A4) has been reported frequently in association with many infectious diseases and cases of hand, foot, and mouth disease potentially associated with CV-A4 infection are also identified. This study summarized the Shandong CV-A4 strains isolated from 25years acute flaccid paralysis surveillance, with an emphasis on exploring the phylogenetic analyses and spatiotemporal dynamics of CV-A4 at the global scale. We sampled 43 CV-A4 isolates and utilized VP1 gene to construct phylogenetic trees. Further extensive Bayesian phylogeographic analysis was carried out to investigate the evolution of CV-A4 and understand the spatiotemporal diffusion around the world using BEAST and SPREAD software. Phylogenetic trees showed that CV-A4 emerged to be more active in recent decades and multiple transmission chains were co-circulating. The molecular clock analysis estimated a mean evolutionary rate of 6.4×10-3 substitutions/site/year, and the estimated origin of CV-A4 around 1944. The phylogeographic analyses suggested the origin of CV-A4 could be in the USA, however regional dissemination was mainly located around the Asia-Europe region. The spatiotemporal dynamics of CV-A4 exhibited frequent viral traffic among localities, and virus from Shandong province seemed to have played a central role in spreading around China and neighboring countries. Our phylogenetic description and phylogeographic analyses indicate the importance of large spatial- and temporal-scale studies in understanding epidemiological dynamics of CV-A4, particularly the diffusion routes will be of great importance to global control efforts.

Molecular epidemiology of HFMD-associated pathogen coxsackievirus A4 in Fujian Province, 2011-2014 / 中国人兽共患病学报

To analyze the epidemiology,genetic variation and genetic evolution of coxsackievirus A4 (CVA4) in patients with hand,foot and mouth disease in Fujian,the virus isolates were molecular typed and amplified the whole VP1 region by RT-PCR,then the genetic variation and evolution were studied.The results showed that 33 CVA4 cases (8.1％) were confirmed from the 407 non-EV71 non-CVA16 HFMD cases in Fujian Province during 2011 and 2014,accounting for 31 cases in 2012 and 2 cases in 2014.Compared with common characteristics of the HFMD epidemic,no specificity in the distribution of CVA4 cases was found between gender and age groups.Sequence analysis of VP1 nucleotide sequences of Fujian CVA4 isolates showed that the nucleotide and amino acid sequences similarity were 92.6 ％-100 ％ and 95.7 ％-100 ％ respectively,low similarity with the prototype (83.7％-85.4％,96.1％-99.0％) and abroad isolates (82.1％-89.1％,90.4％-99.6％) both in nucleotide and amino acid sequences,high similarity with domestic isolates both in nucleotide and amino acid sequences,with the similarity of 87.9％ 99.2 ％ and 96.1％-100 ％.The results from phylogenetic tree showed that the genetic distance between Fujian CVA4 isolates and the prototype and abroad strains was far,and the genetic distance was close to domestic isolates in China.The distribution of the phylogenetic trees of Fujian CVA4 strains showed multiple branches.Therefore,CVA4 is the major HFMD associated-pathogen other than EV71,CVA 16,CVA6,and CVA10 in Fujian Province from 2011 to 2014.CVA4 strains from Fujian Province is co-circulating and co-evolving with other domestic isolates.There is existence of multiple closely related CVA4 transmission chains in various regions of Fujian.

Molecular epidemiology of HFMD-associated pathogen coxsackievirus A4 in Fujian Province, 2011-2014 / 中国人兽共患病学报

To analyze the epidemiology,genetic variation and genetic evolution of coxsackievirus A4 (CVA4) in patients with hand,foot and mouth disease in Fujian,the virus isolates were molecular typed and amplified the whole VP1 region by RT-PCR,then the genetic variation and evolution were studied.The results showed that 33 CVA4 cases (8.1％) were confirmed from the 407 non-EV71 non-CVA16 HFMD cases in Fujian Province during 2011 and 2014,accounting for 31 cases in 2012 and 2 cases in 2014.Compared with common characteristics of the HFMD epidemic,no specificity in the distribution of CVA4 cases was found between gender and age groups.Sequence analysis of VP1 nucleotide sequences of Fujian CVA4 isolates showed that the nucleotide and amino acid sequences similarity were 92.6 ％-100 ％ and 95.7 ％-100 ％ respectively,low similarity with the prototype (83.7％-85.4％,96.1％-99.0％) and abroad isolates (82.1％-89.1％,90.4％-99.6％) both in nucleotide and amino acid sequences,high similarity with domestic isolates both in nucleotide and amino acid sequences,with the similarity of 87.9％ 99.2 ％ and 96.1％-100 ％.The results from phylogenetic tree showed that the genetic distance between Fujian CVA4 isolates and the prototype and abroad strains was far,and the genetic distance was close to domestic isolates in China.The distribution of the phylogenetic trees of Fujian CVA4 strains showed multiple branches.Therefore,CVA4 is the major HFMD associated-pathogen other than EV71,CVA 16,CVA6,and CVA10 in Fujian Province from 2011 to 2014.CVA4 strains from Fujian Province is co-circulating and co-evolving with other domestic isolates.There is existence of multiple closely related CVA4 transmission chains in various regions of Fujian.

Adult-onset Kawasaki disease (mucocutaneous lymph node syndrome) and concurrent Coxsackievirus A4 infection: a case report.

INTRODUCTION: Kawasaki disease (KD) most commonly develops in infants, although its specific cause is still unclear. We report here a rare case of adult-onset KD which revealed to be concurrently infected by Coxsackievirus A4. CASE PRESENTATION: The patient was a 37-year-old Japanese man who presented with fever, exanthema, changes in the peripheral extremities, bilateral non-exudative conjunctival injection, and changes in the oropharynx, signs that meet the diagnostic criteria for KD defined by the Centers for Disease Control and Prevention. In this case, the patient had a significantly high antibody titer for Coxsackievirus A4, which led us to presume that the occurrence of KD was concurrent Coxsackievirus A4 infection. CONCLUSION: We reported a very rare case of KD which suggests that the disease can be concurrent Coxsackievirus A4 infection. Although KD is an acute childhood disease, with fever as one of the principal features, KD should also be considered in the differential diagnosis when adult patients present with a fever of unknown cause associated with a rash.