First epidemic of aseptic meningitis due to echovirus type 13 among Spanish children

Neurotropic enteroviruses (Picornaviridae: Enterovirus): predominant types, basis of neurovirulence

Enteroviruses are one of the most common causative agents of infectious diseases of the central nervous system. They are characterized by genetic variability, the ability to infect a wide range of cells, including brain microglial cells and astrocytes, and persist in the central nervous system tissue, causing delayed and chronic diseases. The review presents data on the basis of neurovirulence of non-polio enteroviruses and the most common pathogens causing enteroviral neuroinfections.

Genomic surveillance of enterovirus associated with aseptic meningitis cases in southern Spain, 2015-2018

New circulating Enterovirus (EV) strains often emerge through recombination. Upsurges of recombinant non-polio enteroviruses (NPEVs) associated with neurologic manifestations such as EVA71 or Echovirus 30 (E30) are a growing public health concern in Europe. Only a few complete genomes of EVs circulating in Spain are available in public databases, making it difficult to address the emergence of recombinant EVs, understand their evolutionary relatedness and the possible implication in human disease. We have used metagenomic (untargeted) NGS to generate full-length EV genomes from CSF samples of EV-positive aseptic meningitis cases in Southern Spain between 2015 and 2018. Our analyses reveal the co-circulation of multiple Enterovirus B (EV-B) types (E6, E11, E13 and E30), including a novel E13 recombinant form. We observed a genetic turnover where emergent lineages (C1 for E6 and I [tentatively proposed in this study] for E30) replaced previous lineages circulating in Spain, some concomitant with outbreaks in other parts of Europe. Metagenomic sequencing provides an effective approach for the analysis of EV genomes directly from PCR-positive CSF samples. The detection of a novel, disease-associated, recombinant form emphasizes the importance of genomic surveillance to monitor spread and evolution of EVs.

[Enterovirus meningitis in a child of one month in source of infection]

OBJECTIVE

To describe a rare case of enterovirus disease with meningitis in an infant.

MATERIAL AND METHODS

Summary of medical records of the child and his mother were used.

RESULTS AND CONCLUSION

The medical history, characteristics of the clinical picture, the composition of the cerebrospinal fluid (CSF) for laboratory confirmed Coxsackie B_1-6 with meningitis in the infant, aged 1 month, and his mother, 40 years old, the source of which were older children who had the infection in the form of a «minor illness», are presented. Enterovirus RNA was detected by PCR in pleocytosis 984/3 on the 4th (in a child) and cytosis 18/3 on the 5th day (in a mother) in the two-wave course of the disease. Data on clinical forms of enterovirus infection in children, aged 0-12 months, the frequency of cases and clinical signs of enterovirus meningitis in infants are considered.

[Enterovirus infections and meningitis in children]

OBJECTIVE

To compare clinical characteristics in children with enterovirus infections (EVI) and meningitis with detailed characteristics of the changes in the content of cerebrospinal fluid (CSF) confirmed in the laboratory.

MATERIAL AND METHODS

The results of examinations of 97 children, aged from 2.5 to 15 years, 3 adolescents and 1 adult female patient with EVI were analyzed. Enterovirus RNA isolation and detection in feces and CSF was performed using PCR.

RESULTS AND CONCLUSION

Enterovirus RNA in CSF was detected in 44 children, including 3 patients with cytosis (5-7-19 cells in 3 mm3). The frequency and severity of symptoms in 42 patients with EVI and meningitis, 14 children with EVI without meningitis and 8 patients with ICD-10 «Meningitis unspecified» are presented. The initial CSF pleocytosis in 1-3 day (4-5 day for two-wave course) in EVI and meningitis was <100 in 4, from 100 to 1000 in 33, >1000 (max 3036) cells in 3 mm3 in 5 patients, including 15 with the predominance of neutrophils (from 77 to 97% in cytosis 114-2300 cells in 3 mm(3)). In the peripheral blood, leukocytosis 10.9-13.8×10(9)/л was noted in 12 children and leukocytosis 14.4-18.7×10(9)/л with the «left shift» in 7. Most of the children (n=37) with EVI and meningitis were discharged from the hospital within 10-17 days. The authors suggest the importance of including the variety of clinical presentations of EVI in the additional item «B10 Enterovirus infections» in upcoming ICD-11.

Molecular characterization of echovirus 13 uncovering high genetic diversity and identification of new genotypes in Pakistan

Echovirus 13 (E-13) is reported worldwide and is mostly related to aseptic meningitis but it is also isolated from cases of acute flaccid paralysis (AFP). Unfortunately, all studies conducted on non polio enterovirus in Pakistan only confirm E-13 isolation based on microneutralization assay but there is lack of molecular epidemiological data on this serotype. In this study, 113 stool samples were collected from AFP patients during 2008-2010. An enterovirus primer mediated real-time reverse transcriptase polymerase chain reaction, a standard microneutralization assay and sequencing of viral protein 1 gene (VP1) identified the predominant serotype E-13. For molecular characterization, genetic relationship between 12 clinical isolates of echovirus 13 was investigated by partial sequencing of viral protein 1 gene. These strains, combined with related sequences from GenBank were divided phylogenetically into two different genogroups A and B (>30% divergence) and were found genetically distinct from the circulating strains in the world. Additionally, phylogenic grouping pattern revealed that the study strains clustered into three distinct subgroups (A3, A7 and B3) having >23% nucleotide divergence representing three new genotypes. The genotype A7 seems to be restricted geographically. In conclusion, the current study provides an overview of the molecular epidemiology and evolution of E-13 in the country. This study strongly suggests that enterovirus surveillance system should be established in the country to determine the temporal and geographical trends and disease pattern of different enterovirus serotypes in the community.

Enteroviruses in Spain over the decade 1998-2007: virological and epidemiological studies

BACKGROUND

Human enteroviruses (HEV) are the commonest cause of viral meningitis as well as other pathologies, therefore HEV characterization is important both in patient management and epidemiological investigation.

OBJECTIVES

A 10-year study of patients with enteroviral infection was carried out in Spain to determine the underlying etiology.

STUDY DESIGN

HEV were fully typed by microneutralisation tests and/or molecular methods.

RESULTS

A collection of 86404 clinical samples were studied in several Spanish laboratories. These were collected from patients with different syndromes, mainly aseptic meningitis (AM), fever, respiratory diseases and acute flaccid paralysis. Of these, 6867 HEV were obtained. At the National Poliovirus Laboratory 2814 were serotypically characterised. Among non-polio enteroviruses, the eight main serotypes were Echovirus 30 (25%), Echovirus 6 (12.4%), Echovirus 13 (8.3%), Echovirus 11 (7.4%) and Echovirus 9 (4.7%), followed by Coxsackievirus B5 (4.2%) and Echovirus 7 and Coxsackievirus A9 (3.7%) each. In AM cases, Echovirus 30 was identified in 39% of them, followed by Echovirus 6 (14%). However, Echovirus 6 was mainly associated with respiratory disease (17%), followed by Echovirus 11 (10%). On the other hand, Echovirus 30, Echovirus 11 and Echovirus 6 contributed equally with 12% of each serotype in the cases of fever.

CONCLUSIONS

The present report complements previous data (Trallero et al.(13)), with the results of HEV incidence in Spain from 1998 to 2007. The surveillance described in this study provided valuable information as to which serotypes are in circulation, the emergence of new HEV and association with clinical manifestations.

Epidemiology of enterovirus types causing neurological disease in Austria 1999-2007: detection of clusters of echovirus 30 and enterovirus 71 and analysis of prevalent genotypes

Between 1999 and 2007 1,388 stool specimens from patients with acute flaccid paralysis or aseptic meningitis were submitted to the Austrian reference laboratory for poliomyelitis. Samples (201) yielded non-poliovirus enterovirus in culture. One hundred eighty-one viruses were available for typing and 78 isolates which remained serologically untyped were further analyzed by CODEHOP-PCR and sequencing of the VP1 gene and the 5'-untranslated region (5'-UTR). Typing revealed an Echovirus 30 outbreak in northwestern Austria in 2000, which was in accordance with the situation in Europe, and no dramatic seasonal changes of Coxsackie viruses were observed. In 2002/2003 a small outbreak of enterovirus 71 (EV71), affected 12 patients in the province of Styria. This virus was identified as genotype C1 and appeared to be genetically distinct from the isolates observed in 2001/2002 in Vienna. In 2004 two unrelated cases occurred in Lower Austria, which were identified as genotype C4, which has been described associated with high mortality most recently in China. In contrast to the situation in Asia the detected EV71 cases were not associated with hand-foot-mouth disease, but with serous meningitis only. This was surprising as a recent publication suggested a reduced neurovirulence of C1 genotype in children in Norway, presumably due to alterations in 5'-UTR and polymerase gene. However, comparing the 5'-UTR of the Austrian isolates and established virulent reference strains to the Norwegian isolate and an attenuated EV71 laboratory strain we did not find an indication that the genotype C1 possesses a RNA structure in its 5'-UTR leading to reduced neurovirulence.

Enterovirus detection as a result of West Nile virus surveillance

In this 2005 study from the Los Angeles County Public Health Department Laboratory, Los Angeles, CA, cerebrospinal fluid specimens submitted for West Nile virus (WNV) serologic testing were also tested for enterovirus by real time reverse transcription-polymerase chain reaction and culture. Approximately 10% of the WNV- specimens were positive for enterovirus. Altered consciousness and muscle weakness were more common with WNV infection. Results provide compelling evidence that laboratory testing is a necessary adjunct to clinical diagnosis for accurate discrimination among the various possible etiologic agents of febrile and central nervous system disease.

Surveillance of enteroviruses in France, 2000–2004

In the context of poliomyelitis eradication, a reinforced sentinel laboratory network for surveillance of enteroviruses (RSE) was implemented in France in January 2000, and the purpose of this report is to describe the results of the five first years of surveillance. From 2000 to 2004, the RSE laboratory network performed detailed surveillance of the circulating enteroviruses. No wild-type poliovirus was isolated from humans during the 5 years of surveillance, although two imported vaccine polioviruses were detected. During the same period, Sabin-like polioviruses were identified on five occasions in the sludge from sewage treatment plants, but no wild-type poliovirus was found. Over the 5 years of surveillance, information was collected from 192,598 clinical samples, including 39,276 cerebrospinal fluid specimens, of which 14.7% were positive for enteroviruses, 45,889 stool samples (4.3% positive for enteroviruses), 70,330 throat swabs (2.2% positive) and 14,243 sera (1.4% positive). The ten main nonpolio enteroviruses typed were as follows, in decreasing order of frequency: E-30, E-13, E-6, CV-B5, E-11, CV-B4, E-9, E-7, CV-B1, and CV-B2. During the year 2000, an outbreak of aseptic meningitis due to three main enteroviruses (echoviruses type 30, 13, and 6) was monitored. Continued surveillance of enteroviruses is important to alert physicians and public health officials to changes in disease trends. Although the geographical coverage of the RSE network as well as the percentage of enteroviruses identified must be improved, the large number of samples tested for enteroviruses shows the ability of virology laboratories to detect the circulation of enteroviruses and to report the possible identification of poliovirus (wild-type, vaccine-derived, or Sabin-like).

Molecular epidemiology of echoviruses 11 and 13, based on an environmental surveillance conducted in Toyama Prefecture, 2002-2003

Nineteen echovirus 11 (E11) and 12 E13 isolates were isolated from three rivers in Toyama Prefecture, Japan, during an environmental surveillance conducted from April 2002 to March 2003. The nucleotide sequences of E13 isolates were closely related to those from patients with aseptic meningitis, with less than 1.3% divergence in the VP1 region of the viral capsid gene, and belonged to the same clade responsible for a worldwide outbreak that started in 2000. In contrast, E11 isolates were clustered into three genomic groups and were not closely related to echovirus strains isolated from patients. These results suggest that the combination of both virus isolation from environmental sources and phylogenetic analysis could be complementary assessment approaches to trace prevalent and minor circulating enteroviruses in the human population.

Enterovirus meningitis in Brazil, 1998-2003

Acute viral infections of the central nervous system (CNS) such as acute flaccid paralysis, meningitis, and encephalitis, are responsible for a high morbidity, particularly in children. Non-Polio enteroviruses (NPEV) are known to be responsible for over 80% of viral meningitis in which the etiologic agent is identified. In the present study, we show the frequency of enterovirus meningitis in Brazil from December 1998 to December 2003. Enterovirus were isolated from 162 (15.8%), of a total of 1,022 cerebrospinal fluid (CSF) specimens analyzed. Echovirus 30 was identified in 139 of these isolates (139/162-85.2%). Other identified enteroviruses were: Coxsackievirus B5 (3.7%), Echovirus 13 (3.7%), Echovirus 18 (3%), Echovirus 6 (1.2%), Echovirus 25 (1.2%), Echovirus 1 (0.6%), and Echovirus 4 (0.6%). Patients's age ranged from 28 days to 68 years old. The most frequent symptoms were fever (77%), headache (69.5%), vomiting (71.3%), neck stiffness (41.3%), convulsion (7.1%), and diarrhea (3.7%). Although, the majority of the patients recovered without any complication or permanent squeal, five deaths occurred. Throughout the surveillance period, five viral meningitis outbreaks were confirmed: four in the Southern Brazil and one in the Northeast Brazil. Echovirus 30 was responsible for four out of the five outbreaks while Echovirus 13 caused the fifth one. Besides the outbreaks, 734 sporadic cases were also identified during the study period and 59 of these were positive for virus isolation (8%). Echovirus 30 accounted for 70% of the isolates. Our results showed that Echovirus 30 was the most prevalent etiological agent of viral meningitis in Brazil, causing both outbreaks and sporadic cases.

Red de Laboratorios del Plan de Erradicación de la Poliomielitis (1998-2003): 6 años de vigilancia de parálisis flácida aguda en España

INTRODUCTION

Worldwide poliomyelitis eradication was proposed in 1988 by the World Health Organization (WHO), based on reaching and maintaining high vaccination coverage and on implementing effective poliovirus infection surveillance systems.

METHODS

In Spain the surveillance system focuses on active searching for acute flaccid paralysis cases through a nine-laboratory network, coordinated by the National Poliovirus Laboratory (NPL) in the National Center of Microbiology, and supported by Autonomous Community epidemiologists. Additionally, the Network sends enterovirus isolation data from other syndromes. The Laboratory Network is responsible for the primary virological study, while the NPL characterizes all polioviruses and the most epidemiologically relevant non-polio enteroviruses.

RESULTS

A total of 54,533 samples were studied during the six-year period, and enteroviruses were detected in 9%. All the polioviruses isolated (n = 196), were characterized as Sabin-like (poliovirus vaccine), and among the non-polio enteroviruses, the most frequent was Echovirus 30. A total of 3% of the samples studied corresponded to the 268 acute flaccid paralysis cases or their contacts.

DISCUSSION

According to the results and the WHO virological classification, Spain can be considered polio-free. However, the geographic situation of our country may facilitate the introduction of wild polioviruses that can give rise to imported poliomyelitis. Hence, the laboratory network should actively continue to participate in all the proposed WHO strategies, particularly maintenance of the poliomyelitis eradication infrastructures, and continuing monitoring and vaccination.

Molecular phylogeny of VP1, 2A, and 2B genes of echovirus isolates: epidemiological linkage and observations on genetic variation

Phylogenetic relationships between 37 echovirus clinical isolates, most of them originating from an aseptic meningitis outbreak during 2001 in Greece, were investigated by RT-PCR and sequencing. The generic primers 292 and 222 were used to amplify about 300 bp of the 5' end of VP1 while primers EUG3a, 3b, 3c, and EUC2 amplified the entire coding sequence of the 2A and 2B genes. Phylogenetic trees were constructed for each genomic region using the clinical isolates' sequences and those of the prototype echoviruses in order to investigate the correlation of part of VP1 with the serotype as well as the genetic variation of the echovirus genome in 2A and 2B. The phylogenetic grouping pattern of the clinical isolates revealed that there is a correlation of serotype and genotype in the part of VP1 that was investigated, while this pattern is disrupted in the adjacent genomic regions that were sequenced. Sequence analysis of the adjacent 2A and 2B genes provided a different pattern of phylogenetic relationships and strong evidence of epidemiological linkage of most of the clinical isolates.

Evaluation of seroneutralization and molecular diagnostic methods for echovirus identification

In this study we compared the identification results of 41 echovirus clinical isolates using RIVM pools (National Institute for Public Health and the Environment RIVM, Bilthoven, The Netherlands) and reverse transcription-polymerase chain reaction (PCR) assays. Primer pair UG52-UC53 amplified a 433-bp segment in the 5' untranslated region. Restriction enzyme HpaII was used for subgrouping of our isolates into 2 different genetic clusters. Amplification of 315 bp that is located in 5' end of VP1 gene as well as of a long genomic fragment (1452 bp) including the VP1 3' end, the entire coding sequence of 2A, 2B, and the 5' moiety of the 2C-coding region was achieved by the application of PCR protocols with primers 292-222 and EUG2a, 2b, 2c-EUC2, respectively. Phylogenetic trees were constructed for the 5' end as well as for the 3' end of VP1 gene using nucleotide sequences derived from sequencing of clinical isolates and homologous sequences of all echovirus serotypes. The phylogenetic grouping pattern of the clinical isolates revealed a correlation of serotype and genotype either in the 5' or in the 3' end of the VP1 gene that was investigated in the present study claiming that they can be either used for molecular typing of echoviruses.

Clinical spectrum in hospitalized children with echovirus type 13 infection

BACKGROUND

The aim of this study was to investigate the clinical spectrum of echovirus type 13 (E13) infection in hospitalized children.

METHODS

From April to August 2002, prospective viral surveillance was performed for hospitalized patients (aged 10 days to 14 years) irrespective of their presenting symptoms and severity. Medical records of laboratory-confirmed echovirus 13 infection were reviewed.

RESULTS

Of the 41 patients analyzed, the median age was 3.4 years and 30% of them were less than 1 year of age. The male:female ratio was 1.6:1. The main clinical features were non-specific febrile illness (nine patients), gastroenteritis (seven), bronchitis (seven), aseptic meningitis (16) and idiopathic thrombocytopenic purpura (two). Each age group had their representative symptoms: less than 1 year of age, non-specific febrile illness; from 1 to 6 years of age, enterocolitis and bronchitis; more than 6 years of age, aseptic meningitis.

CONCLUSION

The representative symptoms of E13 infection in hospitalized patients were variable but strongly associated with age distribution. It was of interest to note that two patients developed idiopathic thrombocytopenic purpura along with the infection.

Outbreak of echovirus 13 infection among Lithuanian children

The aim of this study was to investigate an outbreak of enterovirus infection in Lithuania in 2001, as well as the clinical presentation and outcome of the disease. Thirty children aged 1 month to 15 years were referred to hospital with suspected enterovirus infection during the period August-October 2001. Echovirus 13 (EV-13) was isolated from eight (26.7%) cases. No other pathogens were detected. Infection presented predominantly as viral meningitis, and rarely as a febrile illness with rash. The outcome was good for all patients. This is the first report of EV-13 from Lithuania.

Analysis of the serotype and genotype correlation of VP1 and the 5' noncoding region in an epidemiological survey of the human enterovirus B species

The sequence identity of the enterovirus VP1 gene has been shown to correlate with the serotype concept. Enterovirus molecular typing methods are therefore often based on sequencing of the VP1 genomic region and monophyletic clustering of VP1 sequences of a homologous serotype. For epidemiological surveillance, 342 enterovirus samples obtained from patients with aseptic meningitis in Belgium from 1999 to 2002 were first diagnosed as being enterovirus positive by amplification of the 5' noncoding region (5'NCR) by reverse transcription (RT)-PCR. Subsequently, samples were molecularly typed by RT-nested PCR amplification and sequencing of a portion of the VP1 gene. Phylogenetic analyses were performed to investigate enteroviral evolution and to examine the serotype and genotype correlation of the two genomic regions. Our typing results demonstrated echovirus 30, echovirus 13, echovirus 18, and echovirus 6 to be the most predominant types. Echoviruses 13 and 18 were considered to be emerging human serotypes since 2000 and 2001, respectively, as they had been rarely reported before. Several serotypes existed as multiple genotypes (subtypes) from 1999 to 2002, but genomic differences mainly resided at synonymous sites; these results strongly suggest that the subtypes exhibit similar antigenic properties. Phylogenetic analyses confirmed that VP1 is an adequate region for molecular typing. Serotype-specific clusters are not observed commonly in phylogenetic trees based on the 5'NCR, and the phylogenetic signal in the 5'NCR was found to be particularly low. However, some substructure in the 5'NCR tree made a tentative prediction of the enterovirus type possible and was therefore helpful in PCR strategies for VP1 (e.g., primer choice), provided some background knowledge on the local spectrum of enteroviruses already exists.

Emergence of echovirus type 13 as a prominent enterovirus

In 2001, increased activity of the rarely detected enterovirus echovirus type 13 (E13) was observed in the United States. This article describes the epidemiologic, clinical, and genetic characteristics of E13 activity in the United States in 2001, compared with E13 activity abroad in 2000-2002. In the United States, E13 accounted for 376 (24%) of the 1584 enterovirus isolates reported in 2001 (29% of the reported isolates had a known serotype), compared with 74 isolates reported during 1970-2000. Five states reported aseptic meningitis outbreaks associated with E13, for a total of 521 cases. All characterized E13 isolates from the United States, Europe, Asia, and Oceania recovered in 2000-2002 were at least 95% identical to each other in VP1 capsid gene sequence, but they were genetically distinct from E13 isolates recovered before 2000. Continued surveillance of enteroviruses is important to alert physicians and public health officials to changes in disease trends and to improve efficiencies of clinical intervention.

Molecular analysis of echovirus 13 isolates and aseptic meningitis, Spain

Echovirus 13 (EV13), considered rare, was reported worldwide in 2000, mostly related to aseptic meningitis outbreaks. In Spain, 135 EV13 isolates were identified. The genetic relationships between 64 representative strains from Spain and other reported isolates from the United States, Germany, Italy, Japan, and Sweden were described by analyzing the partial sequence of the major capsid protein (VP1) gene. The strains from Spain were clearly identified as EV13 (79.5% similarity with the EV13 reference strain) and were grouped phylogenetically into two different clusters (by origination on either the Iberian Peninsula or Canary Islands). Isolates from Germany from 2000 clustered with the Canary Islands group. The isolates from other countries obtained before 2000 were genetically distant. Changes in EV13 coding sequence involved several differences in the C-terminal extreme of the VP1 protein. Part of the neutralizing antigenic site III has been described in this genome region in poliovirus and swine vesicular disease virus.