Coxsackievirus A6 Polymorphic Exanthem in Israeli Children

Evolutionary and Genetic Recombination Analyses of Coxsackievirus A6 Variants Associated with Hand, Foot, and Mouth Disease Outbreaks in Thailand between 2019 and 2022

Coxsackievirus (CV)-A6 infections cause hand, foot, and mouth disease (HFMD) in children and adults. Despite the serious public health threat presented by CV-A6 infections, our understanding of the mechanisms by which new CV-A6 strains emerge remains limited. This study investigated the molecular epidemiological trends, evolutionary dynamics, and recombination characteristics of CV-A6-associated HFMD in Thailand between 2019 and 2022. In the HFMD patient samples collected during the 4-year study period, we identified enterovirus (EV) RNA in 368 samples (48.7%), of which CV-A6 (23.7%) was the predominant genotype, followed by CV-A4 (6%), EV-A71 (3.7%), and CV-A16 (3.4%). According to the partial viral protein (VP) 1 sequences, all these CV-A6 strains belonged to the D3 clade. Based on the viral-RNA-dependent RNA polymerase (RdRp) gene, four recombinant forms (RFs), RF-A (147, 84.5%), RF-N (11, 6.3%), RF-H (1, 0.6%), and newly RF-Y (15, 8.6%), were identified throughout the study period. Results from the similarity plot and bootscan analyses revealed that the 3D polymerase (3Dpol) region of the D3/RF-Y subclade consists of sequences highly similar to CV-A10. We envisage that the epidemiological and evolutionarily insights presented in this manuscript will contribute to the development of vaccines to prevent the spread of CV-A6 infection.

Clinical characteristics of 68 children with atypical hand, foot, and mouth disease caused by coxsackievirus A6: a single-center retrospective analysis

BACKGROUND

Hand, foot, and mouth disease (HFMD) caused by coxsackievirus A6 (CV-A6) has become prevalent in many parts of the world. It is commonly referred to as atypical HFMD which more likely to present as bullous lesions. Compared with traditional HFMD, its misdiagnosis rate is relatively high, which brings difficulties to clinical diagnosis. We retrospectively analyze the clinical characteristics of children with HFMD with bullous lesions caused by CV-A6.

METHODS

The study included 68 children with atypical HFMD caused by CV-A6 who were hospitalized from 2018 to 2020. Data of the children including age, sex, month of HFMD onset, the morphologies and distribution of rashes, the details of fever, the presence or absence of onychomadesis, and laboratory test results were analyzed and compared between an infant group (<1 year), a toddler group (1-<3 years), and a preschool group (3-<6 years).

RESULTS

Of the 68 children, 67 were younger than 5 years old, with a male to female ratio of 1.62:1. The disease peaked in the period from June to September. With 75.0% of the infant group had more than three kinds of rashes; 95.0% of the preschool group had rashes in more than five locations. These differences were statistically significant (P<0.05). All children had fever. The peak fever in the toddler group was lower (P=0.033). No critical cases were observed in any of the groups. Of the 61 children who were successfully followed up, 68.9% developed onychomadesis within 2-3 weeks. The proportion of cases with abnormal liver function was 83.3%, 41.7%, and 10.0% in the infant, toddler, and preschool groups (P<0.001). The proportion of cases with increased serum creatine kinase MB isoenzyme (CK-MB) were significantly higher in the toddler group (P<0.05).

CONCLUSIONS

Atypical HFMD caused by CV-A6 infection usually occurred in children under 5 years old. The morphologies of the rashes in the infant group changed more, while the rashes in the preschool group was more widely distributed. The incidence of critical cases was low. More than half of the cases can develop onychomadesis in the recovery period. Organ damage was relatively mild in the preschool group.

Viral panniculitis in a patient with disseminated opportunistic Enterovirus infection

Infection-induced panniculitis has been described in association with a broad range of microorganisms. Among those, viral panniculitis represents a minor category, with only a few anecdotal reports in the literature documenting viral infection in the subcutaneous fat. Herein, we report a woman in her 30s with seropositive rheumatoid arthritis on rituximab and prednisone, who presented with a 6-month history of progressive multisystem manifestations, including unintentional weight loss, fever, fatigue, myopathy, pancreatitis, and sensorineural hearing loss. She had indurated plaques on her thighs characterized by predominantly lobular panniculitis with chronic lymphohistiocytic inflammation. Molecular studies performed at the Centers for Disease Control and Prevention identified evidence of Enterovirus group with the highest identity of Coxsackievirus A9. Enterovirus RNA was also detected in the cerebrospinal fluid and muscle. Based on the findings, a diagnosis of disseminated enteroviral infection in the setting of B-cell depletion was rendered. To the best of our knowledge, this represents the first reported case of viral panniculitis with documentation of Coxsackievirus A9 in the skin. Since rituximab may be used for the treatment of autoimmune dermatological diseases, familiarity of the potential occurrence of severe enteroviral infections in the setting of immunosuppressive treatment is important for dermatopathologists.

Acute exanthemas: a prospective study of 98 adult patients with an emphasis on cytokinic and metagenomic investigation

BACKGROUND

Acute exanthemas (AEs) are frequently seen; they can be caused by drugs or viruses but often the cause is unknown.

OBJECTIVES

To describe the clinical, virological and histological aspects of AEs and explore their cytokinic and metagenomic profiles.

METHODS

This prospective study examined 98 patients with AE, from February to July 2014. Clinical data were recorded in a standardized chart. Virological investigation and skin biopsies were performed. In addition, blood and skin samples were analysed for cytokines and then by a shotgun metagenomic approach. We identified five groups of patients: those with maculopapular exanthemas (MPEs) that were virally induced (group 1); those with drug-induced MPEs (group 2), those with MPEs that were both viral and drug induced (group 3), those with idiopathic MPEs (group 4) and those with pityriasis rosea (group 5).

RESULTS

A virus was identified in 29 cases (human herpesvirus 6, 72%). Cytokinic analysis of the skin (n = 23 MPEs) showed higher levels of interferon-γ and interleukin-1 receptor-α in viral MPEs, higher interleukin-33 levels in idiopathic MPEs, and higher macrophage inflammatory protein 1α levels in drug-induced MPEs. By metagenomics analysis (n = 10 MPEs), viruses identified with routine practice methods were not found in group 1 (n = 4 MPEs). However, Enterovirus A was detected in two cases, especially in a group 1 patient for whom metagenomic analysis rectified the diagnosis of the culprit agent.

CONCLUSIONS

Human herpesvirus 6 was the virus most frequently identified, and histology did not discriminate MPEs. In addition, the level of interleukin-33 seen in idiopathic MPEs suggests that an environmental factor may be the trigger for these. The results bring into question the utility of routine polymerase chain reaction analysis and viral serology for determining cause in AE. What's already known about this topic? Acute exanthemas, especially maculopapular exanthemas, are a frequent reason for patients consulting emergency and dermatology departments. It is difficult to evaluate the aetiology of acute exanthema based on the clinical aspects. Few data are available on the investigations needed in routine practice, and no prospective series have been published. What does this study add? Our study provides a global and prospective description of acute exanthemas. Cytokine analysis could help to investigate the pathophysiology of idiopathic eruptions. Metagenomic analysis provides new insights about the value of routine practice virological investigations. We show for the first time the feasibility of metagenomics analysis in the skin, which results question the interest of routine PCR and viral sérologies for the exploration of such acute exanthemas.

Molecular characteristic analysis for the VP1 region of coxsackievirus A6 strains isolated in Jiujiang area, China, from 2012 to 2013

BACKGROUND

Enterovirus 71 (EV-A71) and Coxsackievirus A16 (CV-A16) are the most common causative agents causing hand, foot, and mouth disease (HFMD). However, coxsackievirus A6 (CV-A6), previously largely ignored, became the predominant pathogen in China in 2012. The objective of this study is to investigate the genetic characteristics and molecular epidemiology of HFMD caused by CV-A6 to guide the diagnosis and treatment of the disease, as well as disease prevention.

MATERIAL AND METHODS

A total of 138 suspected HFMD cases were enrolled in this study and analyses based on complete VP1 nucleotide sequences were performed to determine the evolutionary trajectory of emerging CV-A6.

RESULTS

Among 138 samples in Jiujiang, 125 (90.58%) were positive for enterovirus, the most frequently presented serotypes were CV-A6 (77, 61.60%), CV-A16 (28, 22.40%), EV-A71 (6, 4.80%) and untyped enteroviruses (14, 11.20%). Seventy-seven CV-A6 positive specimens were analyzed for the complete VP1 sequences by sequencing and 36 representative isolates were selected to perform nucleotide sequence similarity analysis. The results showed that 36 strains isolated from HFMD patients were clustered closely to the mainland China and were far from prototype strain CV-A6/Gdula (AY421764) and other international subtypes. Moreover, phylogenetic analysis of the VP1 gene revealed that 36 circulating strains were not significantly concentrated in one branch, but were widely distributed in each branch.

CONCLUSIONS

Continuous surveillance of HFMD etiological agents other than EV-A71 and CV-A16 is necessary. CV-A6 is emerging as the most common pathogen causing HFMD. Closely monitoring the magnitude and trend of CV-A6 epidemic and the trend of pathogenic spectrum changes can provide scientific basis for this disease prevention and control to the department of disease control.