Complete genome sequence analysis of human echovirus 30 isolated during a large outbreak in Guangdong Province of China, in 2012

Clinical, Laboratory, and Molecular Epidemiology of an Outbreak of Aseptic Meningitis Due to a Triple-Recombinant Echovirus in Ashburton, New Zealand

Here, we describe a small enterovirus outbreak including nine cases of aseptic meningitis in a New Zealand hospital in 2017. Most patients had a lymphocytic predominance in the CSF, their length of stay was short, and there were no paediatric cases or ICU admissions. VP1 genotyping revealed that the outbreak was caused by an echovirus E30 strain closely related to strains reported from the US, UK, Brazil, and Denmark. They all form a separate cluster within lineage “h”, which leads to the proposal of establishing a new lineage tentatively named “j” for this group of echovirus E30 strains. However, whole genome sequencing and reference mapping to echovirus E30 sequences showed very poor mapping of reads to the 3′ half of the genome. Further bioinformatic analysis indicated that the causative agent of this outbreak might be a mosaic triple-recombinant enterovirus composed of echovirus E6, echovirus E11, and echovirus E30 genome segments.

Analysis of enterovirus genotypes in the cerebrospinal fluid of children associated with aseptic meningitis in Liaocheng, China, from 2018 to 2019

BACKGROUND

Aseptic meningitis is most often caused by enteroviruses (EVs), but EVs associated with aseptic meningitis have not yet been reported in Liaocheng. The aim of this study was to determine the prevalence and genetic characteristics of EVs causing aseptic meningitis in children in Liaocheng.

METHODS

We reviewed the epidemiological and clinical characteristics of 504 paediatric cases of aseptic meningitis in Liaocheng from 2018 to 2019 and analysed the phylogeny of the predominant EV types causing this disease.

RESULTS

A total of 107 children were positive for EV in cerebrospinal fluid samples by nested PCR. Most of the positive patients were children 13 years old or younger and had symptoms such as fever, headache and vomiting (P < 0.05). The seasons with the highest prevalence of EV-positive cases were summer and autumn. The 107 EV sequences belonged to 8 serotypes, and echovirus types 18, 6 and 11 were the three dominant serotypes in Liaocheng during the 2-year study period. Phylogenetic analyses demonstrated that the E18 and E6 isolates belonged to subgenotype C2, while the E11 isolates belonged to subgenotype D5. VP1 analysis suggested that only one lineage of these three types was cocirculating in the Liaocheng region.

CONCLUSIONS

This study demonstrated the diverse EV genotypes contributing to a large outbreak of aseptic meningitis in Liaocheng. Therefore, large-scale surveillance is required to assess the epidemiology of EVs associated with aseptic meningitis and is important for the diagnosis and treatment of aseptic meningitis in Liaocheng.

Clinical features of aseptic meningitis with varicella zoster virus infection diagnosed by next-generation sequencing: case reports

BACKGROUND

The aseptic meningitis caused by varicella zoster virus (VZV) reactivation was less described in the literature, most of which were detected by means of polymerase chain reaction. The authors presented 4 adult immunocompetent patients with acute aseptic meningitis with VZV infection diagnosed by next-generation sequencing (NGS).

CASE PRESENTATION

Four patients were admitted to the hospital with headache and fever between March 2018 and August 2019. The median ages were 37 years (range 22-52 years). The median symptoms onset to clinic time was 3.5 days (range 3-6 days). Two patients had signs of meningeal irritation. Rash occurred after the meningitis symptoms in 1 patient (time from meningitis symptoms to rash, 2 days). No other sign or symptom was reported. The brain Magnetic resonance imaging and electroencephalography were normal in all patients. Cerebrospinal fluid (CSF) samples were obtained at a median of 4 days (range 3-7 days) from the meningitis symptoms onset. Opening pressure of lumbar puncture after admission were high in these cases (median 256 mm H₂O; range 165-400 mm H₂O). White blood cell counts and protein levels were significantly elevated in CSF samples (median 317 × 10^6/L, range 147-478 × 10^6/L; median 1.41 g/L, range 0.57-1.79 g/L). The cytology of CSF demonstrated a lymphocytic pleocytosis, and most multinuclear cells. The culture of CSF was negative for all 4 cases, while T-cell spot test was positive for 2 cases, who were administrated with anti-tuberculosis treatment for suspicious tuberculous meningitis. NGS of CSF (the Vision Medical Research Institute) detected specific sequences of VZV in the 4 cases within 72 h after admission. The inappropriate treatment were stopped while acyclovir were continued intravenously for 10-14 days. All patients recovered completely.

CONCLUSIONS

VZV is an infectious agent that causes aseptic meningitis in immunocompetent adults and could not be accompanied by skin manifestations. The NGS of CSF is a rapid detection for the identification and differentiation of meningitis in patients, which is of great importance for providing the rapid and accurate diagnosis and the targeted antimicrobial therapy for central nervous system infection.

Recombination in Enteroviruses, a Multi-Step Modular Evolutionary Process

RNA recombination is a major driving force in the evolution and genetic architecture shaping of enteroviruses. In particular, intertypic recombination is implicated in the emergence of most pathogenic circulating vaccine-derived polioviruses, which have caused numerous outbreaks of paralytic poliomyelitis worldwide. Recent experimental studies that relied on recombination cellular systems mimicking natural genetic exchanges between enteroviruses provided new insights into the molecular mechanisms of enterovirus recombination and enabled to define a new model of genetic plasticity for enteroviruses. Homologous intertypic recombinant enteroviruses that were observed in nature would be the final products of a multi-step process, during which precursor nonhomologous recombinant genomes are generated through an initial inter-genomic RNA recombination event and can then evolve into a diversity of fitter homologous recombinant genomes over subsequent intra-genomic rearrangements. Moreover, these experimental studies demonstrated that the enterovirus genome could be defined as a combination of genomic modules that can be preferentially exchanged through recombination, and enabled defining the boundaries of these recombination modules. These results provided the first experimental evidence supporting the theoretical model of enterovirus modular evolution previously elaborated from phylogenetic studies of circulating enterovirus strains. This review summarizes our current knowledge regarding the mechanisms of recombination in enteroviruses and presents a new evolutionary process that may apply to other RNA viruses.

Molecular characterization of echovirus 30 isolates from Poland, 1995-2015

Echovirus 30 (E30) is one of the most frequently identified enterovirus and a major cause of meningitis in children and adults. To investigate the genetic variability and relationship of E30 isolated from specimens of aseptic meningitis cases that occurred in Poland over a period of 20 years, sequences of VP1 gene were determined and genetic analysis was performed. From 1995 to 2015, 124 E30 were isolated using RD cells, and 58 isolates were sequenced and characterized by phylogenetic analysis of partial VP1 region (793 nt). In general, nucleotide sequence divergence in pairwise comparisons among Polish E30 isolates ranged from 0.0 to 15.0 %. The phylogenetic analysis revealed that E30 circulating in Poland since 1995 belong to two unique groups: Group I, characterized by high divergence (up to 13.1 %), segregated in four subgroups, and showed strong temporal circulation of E30. Group II, detected in Poland in 2013-2014, was closely correlated with two meningitis outbreaks and formed a separate genetically homogeneous group. Phylogenetic analysis revealed that strains from Poland had the closest genetic relationship with not only the isolates previously identified in Europe (Belarus, France, Germany, Italy, Russia) but also those in other parts of the world (Australia, China). Sequences of outbreak isolates were grouped in group II together with those from Russia and China isolated during 2010-2013. The identification of five distinct viral lineages during 1995-2015 confirmed the high E30 genetic diversity which may be an essential precondition for the emergence of new strains responsible for further potential aseptic meningitis outbreaks.

Elucidation of echovirus 30's origin and transmission during the 2012 aseptic meningitis outbreak in Guangdong, China, through continuing environmental surveillance

An aseptic meningitis outbreak occurred in Luoding City of Guangdong, China, in 2012, and echovirus type 30 (ECHO30) was identified as the major causative pathogen. Environmental surveillance indicated that ECHO30 was detected in the sewage of a neighboring city, Guangzhou, from 2010 to 2012 and also in Luoding City sewage samples (6/43, 14%) collected after the outbreak. In order to track the potential origin of the outbreak viral strains, we sequenced the VP1 genes of 29 viral strains from clinical patients and environmental samples. Sequence alignments and phylogenetic analyses based on VP1 gene sequences revealed that virus strains isolated from the sewage of Guangzhou and Luoding cities matched well the clinical strains from the outbreak, with high nucleotide sequence similarity (98.5% to 100%) and similar cluster distribution. Five ECHO30 clinical strains were clustered with the Guangdong environmental strains but diverged from strains from other regions, suggesting that this subcluster of viruses most likely originated from the circulating virus in Guangdong rather than having been more recently imported from other regions. These findings underscore the importance of long-term, continuous environmental surveillance and genetic analysis to monitor circulating enteroviruses.

Recombination among human non-polio enteroviruses: implications for epidemiology and evolution

Human enteroviruses (EV) belong to the Picornaviridae family and are among the most common viruses infecting humans. They consist of up to 100 immunologically and genetically distinct types: polioviruses, coxsackieviruses A and B, echoviruses, and the more recently characterized 43 EV types. Frequent recombinations and mutations in enteroviruses have been recognized as the main mechanisms for the observed high rate of evolution, thus enabling them to rapidly respond and adapt to new environmental challenges. The first signs of genetic exchanges between enteroviruses came from polioviruses many years ago, and since then recombination has been recognized, along with mutations, as the main cause for reversion of vaccine strains to neurovirulence. More recently, non-polio enteroviruses became the focus of many studies, where recombination was recognized as a frequent event and was correlated with the appearance of new enterovirus lineages and types. The accumulation of multiple inter- and intra-typic recombination events could also explain the series of successive emergences and disappearances of specific enterovirus types that could in turn explain the epidemic profile of circulation of several types. This review focuses on recombination among human non-polio enteroviruses from all four species (EV-A, EV-B, EV-C, and EV-D) and discusses the recombination effects on enterovirus epidemiology and evolution.

The role of enterovirus 71 and coxsackievirus A strains in a large outbreak of hand, foot, and mouth disease in 2012 in Changsha, China

BACKGROUND

During 2012, Changsha experienced a large outbreak of hand, foot, and mouth disease (HFMD), resulting in 25,438 cases, including 42 severe cases and eight deaths.

METHODS

Seven hundred and forty-six clinical specimens were collected from hospital-based surveillance for HFMD in 2012. The detection and genotyping of enterovirus were performed by real-time RT-PCR and sequencing of the VP1 regions; phylogenetic analysis was performed based on the VP1 sequences.

RESULTS

A total of 545 (73.1%) enterovirus-positive samples were identified, with the most frequently presenting serotype being enterovirus 71 (EV-71; n=364, 66.8%), followed by coxsackievirus A16 (CV-A16; n=84, 15.4%), CV-A6 (n=22, 4.0%), and CV-A10 (n=19, 3.5%). Most of the affected patients were children aged ≤5 years (n=524, 96.1%). EV-71 was the major pathogen in the severe and fatal cases (n=22, 78.6%). Phylogenetic analysis of VP1 gene sequences showed the EV-71 isolates to belong to subgenotype C4a, and the CV-A16 isolates to belong to subgenotype B1. The Changsha CV-A6 and CV-A10 circulating strains were homologous to strains circulating in other areas of mainland China.

CONCLUSIONS

Our results demonstrate that EV-71 was the primary causative agent responsible for the HFMD outbreak in Changsha in 2012, and the co-circulation of other coxsackievirus A strains posed a potential risk to public health.

Prevalence of nonpolio enteroviruses in the sewage of Guangzhou city, China, from 2009 to 2012

The human-pathogenic viruses in urban sewage have been extensively monitored to obtain information on circulating viruses in human communities. Enteroviruses (EVs) excreted by patients who present with diverse clinical syndromes can remain infectious in the environment for several weeks, and limited data on circulating environmental EVs are available. A 4-year (2009 to 2012) surveillance study was conducted to detect nonpolio enteroviruses (NPEVs) in the urban sewage of Guangzhou city, China. After the viruses in the sewage samples were concentrated and isolated, molecular identification was used to detect and type the NPEVs. During the 4-year study, 17 different NPEV serotypes were identified in the sewage of Guangzhou city. The most common serotypes were echovirus 11 (ECHO11), ECHO6, ECHO7, and ECHO12 and coxsackie group B viruses 5 (CVB5) and CVB3. The predominant serotypes were influenced by spatial and temporal factors and differed each year. CVB5 was commonly detected in 2009 and 2010 but was rarely isolated in 2011 and 2012. In contrast, CVB3 was not observed in 2009 and 2010 but was increasingly detected in 2011 and 2012. Our study provides an overview of the serotype distribution and circulation patterns of NPEVs in the sewage of Guangzhou, China. In the absence of a systematic EV disease surveillance system, the detection and characterization of sewage-borne NPEVs will help us better understand the changes in EV disease trends and the epidemic background of circulating EVs, which could help interpret the EV trends and warn of future outbreaks in this area.