Predominant enteroviral serotypes causing meningitis

Developmental outcomes in cerebrospinal fluid proven enteroviral meningitis in neonates > 32 weeks of gestation

AIM

The aim of this study is to assess the short-term and long-term (1 year) outcomes of cerebrospinal fluid (CSF) confirmed enteroviral meningitis in neonates > 32 weeks of gestation.

METHODS

A retrospective audit of neonates admitted between 1 July 2002 to 30 June 2012.

RESULTS

Thirty-three neonates were diagnosed with enteroviral meningitis based on a positive CSF enteroviral PCR. Physical growth and neurodevelopmental outcomes at 1 year corrected for prematurity were available for 24 infants. All infants were alive at 1 year. The median weight, length and head circumference at 1 year were in the 72nd, 62nd and 78th centile and were comparable with the birth parameters. The mean general quotient (GQ) was 98.5 (SD 7.1) and was not significantly different from the population mean of 100.2 (P = 0.27). None of the infants had a GQ > 2SD below the population mean. Neurological recovery was complete in the 24 neonates assessed except one, who developed cerebral palsy, epilepsy and progressive hydrocephalus requiring ventriculoperitoneal shunt at 1 year.

CONCLUSION

Neonatal enteroviral meningitis was associated with optimal growth and neurodevelopment in the majority of the infants at 1 year corrected for prematurity. Longer term studies are needed to better define developmental outcomes.

Épidémie estivale de méningites à entérovirus en 2005: expérience d'un service de pédiatrie générale

OBJECTIVE

To describe the clinical and biological characteristics of children presenting with enteroviral (EV) meningitis in a French paediatric unit during summer 2005.

METHODS

Retrospective study of children with EV meningitis from May to September 2005, diagnosed by PCR and/or viral culture in cerebrospinal fluid (CSF), serum or throat.

RESULTS

We reported 99 cases of EV meningitis (96 confirmed and 3 probable). The sex ratio was 2/1, and the median age was 5 years. Peak incidence was reached during the second week of July. The predominant symptom was meningism. ENT (16%), digestive (10%), cutaneous (15%) or respiratory (4%) symptoms were rare. Blood leucocyte count found a predominance of neutrophils (73%), and lymphopenia in half of the children. The mean value of CRP was 25,5 mg/l. The median leukocyte count in CSF was 65 cells/mm(3), with a prevalence of neutrophils in 60% of cases. Pleiocytosis was absent in 20 children. CSF protein level was increased in 20% of cases. The rate of hospitalization was 57,5%. Intravenous antibiotic treatment, initiated among 18 patients, was stopped in 66,6% of the cases on reception of PCR result. The latter result was obtained in 2,3 days on average.

CONCLUSION

The epidemic of 2005 EV meningitis was as widespread as that of summer 2000. Characteristics of these meningitis are strong proportion of CSF without pleiocytose and high prevalence of neutrophils in blood and CSF.

Phylogenetic Analysis of Echovirus 11 in the 3′ End of the VP1

OBJECTIVE

Echovirus 11 is one of the most frequently isolated enterovirus serotypes, causing a wide range of clinical diseases. We studied the genetic diversity in the 3' end of the VP1 gene of strains from different geographical origin in the world.

METHODS

The sequences in the 3' end of the VP1 of 11 Tunisian isolates were determined and aligned with the published sequences to establish a phylogenetic profile.

RESULTS

The grouping of the sequences was similar to what was previously reported by analyzing the whole VP1 gene with 4 genogroups, designated A-D, and 5 lineages in genogroup D. All Tunisian strains belonged to genogroup D, together with other sequences mainly from the USA and Europe. Contrary to the sequences from the USA isolated during the last 3 decades, which mostly belonged to the D4 lineage, those from Tunisia belonged to different lineages within genogroup D according to their isolation date: isolates from the early 1990s belonged to D3, those of the mid 1990s to D4 and the most recent ones to D5.

CONCLUSION

Our findings further widen the interest of partial sequencing in the VP1 to study the molecular epidemiology of echovirus 11 and indicate that the genetic evolution of circulating strains may differ from one country to another according to the region's epidemiological specificities.

Analysis of the genetic and the corresponding antigenic variability of the VP1 3' end of ECHO virus type 11 and ECHO virus type 30

The enteroviruses (EV), RNA viruses belonging to the Picornaviridae family, have a high genetic variability due to the absence of the efficient proofreading and post replicative repair activities associated with the RNA polymerase. In the present work, we studied the genetic and the antigenic variability of ECHO virus types 11 (E11) and 30 (E30), which are the most isolated echoviruses serotypes in clinical and environmental samples. We established on the 3' end of the VP1 gene, consensus sequences of E11 and E30 by alignment of 67 E11 and 247 E30 published sequences in GenBank. Our results of sequences comparison showed that the majority of the mutational sites are situated on the third nucleotide of the codon. These mutations were without consequence on the antigenic sequences of the VP1 protein. Thus, E11 and E30 have a high genetic variability (1/3 of the nucleotides are variable), but a relative antigenic conservation. The analysis of the intertypic antigenic variability between E11 and E30 was obtained by the alignment of the corresponding amino acids sequences relative to the N-terminal part of the VP1 protein. Two discriminating parts were highlighted, probably representing antigenic sites for neutralisation antibodies.

Epidemiological study of non-polio enterovirus neurological infections in children in the region of Monastir, Tunisia

The epidemiological, virological, and clinical syndromes of 86 children younger than 13 years suspected of having neurological diseases and admitted to Fattouma Bourguiba Hospital of Monastir from January 2002 to November 2003 were analyzed. The presence of enterovirus was studied in cerebrospinal fluid (CSF) samples by reverse transcription-polymerase chain reaction (RT-PCR) and by isolation on cell culture. Sixty-one (71%) specimens were positive by RT-PCR, whereas 45 (52.3%) were detected by cell culture. Eighty percent (n = 36) of cultured enteroviruses were identified, whereas 20% were untyped. Echoviruses were isolated most frequently, with 32 cases (71.1%) in children. Echovirus 6 was the most commonly identified serotype (22.2%), followed by echovirus 13 (20%). The highest incidence on neurological infection (19.6%) occurred in children less than 6 months of age. The infected children were predominantly male (62.3%). Enteroviruses were detected in all the period of the year with the highest rate in the spring and summer months. Aseptic meningitis was the most commonly diagnosed disease (49%).

Pesquisa de enterovírus em casos de síndrome de meningite asséptica de Belém, PA

Com o objetivo de isolar e identificar os sorotipos de enterovírus, agentes etiológicos mais freqüentes da síndrome de meningite asséptica, foram estudadas amostras de líquor de pacientes da unidade de saúde de referência da Cidade de Belém-PA, do período de março de 2002 a março de 2003. As amostras foram inoculadas em cultivos celulares RD e HEp-2, e as positivas identificadas por neutralização ou imunofluorescência indireta. De 249 amostras, 33 (13,2%) foram positivas sendo 57,6% (n=19) em pacientes menores de 11 anos (p<0,03) e predominantemente (72,7%) naqueles do sexo masculino (p<0,008). Os sorotipos isolados foram: Echovírus 30 (n=31), Coxsackievírus B5 (n=1) e Echovírus 30 e 4. Em conclusão, estudos deste tipo servem também para melhor compor o quadro nacional, ainda pouco definido, sobre os agentes enterovirais mais prevalentes em casos de SMA.

Human enterovirus isolates from an outbreak typed using heteroduplex mobility analysis

Genotyping and serotyping of enteroviruses is important for epidemiological, prognostic, and therapeutic reasons. In this study clinical isolates of enterovirus 71 during an outbreak of childhood meningoencephalitis in Sydney, Australia were identified using heteroduplex mobility analysis (HMA) of products from RT-PCR amplification of the 5' untranslated region. Five enterovirus 71 isolates shared identical heteroduplex patterns and nucleotide sequences in the 5' untranslated region. A sixth isolate exhibited minor differences in heteroduplex pattern and sequencing confirmed the isolate varied by 1% at the nucleotide level. The use of multiple reference strains and the analysis of heteroduplex patterns increased the confidence of isolate identification, and allowed identification of strain variation which could be subsequently further analyzed using sequencing. HMA can be used to accurately distinguish identical and variant isolates derived from sporadic cases and clustered infections with enteroviruses, including those causing serious infections.

[Neuromeningeal enterovirus infections in Tunisia: epidemiology, clinical presentation, and outcome of 26 pediatric cases]

Non-polio enteroviruses are the most common identified cause of viral neuromeningeal infections following the introduction of the mumps and polio vaccines.

OBJECTIVE

The aim of this study was to describe the epidemiology, clinical presentation, and the outcome of enteroviral infections of the CNS.

METHOD AND PATIENTS

We performed a prospective study on 41 children admitted for viral neuromeningeal infections in the pediatric department of Monastir between December 2001 and November 2002. Enteroviruses were detected from cerebrospinal fluid by RT-PCR.

RESULTS

This study showed that enteroviruses were responsible for 63.4% of the infections. The mean age of patients was 6.1 years. Aseptic meningitis was diagnosed in 14 cases and encephalitis in 10. The most frequent symptom was fever (61.5%), followed by seizures (42.3%), and confusion (23%). On follow-up, all patients with meningitis had recovered without sequels. Neurological complications in patients with encephalitis were epilepsy (3 cases), cerebral palsy (2 cases), and mental retardation (1 case).

CONCLUSION

This study confirmed that enteroviruses were the most common cause of viral infections of the CNS. Common use of RT-PCR can have a significant impact on the outcome of patients with enterovirus infections.

An approach based on RFLP assay to investigate outbreaks of enteroviral meningitis

BACKGROUND

Enteroviruses (EV) circulate worldwide and are a major cause for annual epidemics of meningitis in humans. During the last two decades, echovirus type 30 (E-30) has revealed to be one of the most prevalent enteroviruses at the origin of epidemics of EV meningitis.

OBJECTIVES

To design an approach to timely investigate epidemics due to EV. To apply this strategy to the outbreak of meningitis due to E-30 that occurred at the end of year 2000 in Marseilles, France.

STUDY DESIGN

The approach consisted to (i) determine whether the epidemic was caused by a dominant strain; (ii) identify the dominant strain by sequencing the first isolates during the outbreak; (iii) identify a restriction enzyme, capable to produce an Restriction fragment length polymorphism (RFLP) profile characteristic for the dominant strain, for rapid identification based on RFLP analysis of PCR products.

RESULTS AND CONCLUSIONS

A total of 394 samples were tested; 258 (corresponding to 177 patients) were positive for the presence of EV by cell culture and/or RT-PCR. Sequence analysis of a 785-bp PCR product (including the 5' end of the VP1 gene) performed for the 30 first isolates permitted to identify a RFLP profile that was specific of the dominant strain after enzymatic cleavage by Bst X1. This RFLP profile was observed in 246 out of 258 PCR products. This method of typing is rapid, simple and inexpensive, and may be applied for the epidemiological typing of EV in epidemic situations.

A retrospective clinical, laboratory and outcome analysis in 43 cases of acute aseptic meningitis

Forty-three consecutive cases of acute aseptic meningitis (AAM) presenting within a 24-months period were retrospectively analysed with respect to clinical symptomatology, cerebrospinal fluid (CSF) findings, clinical course, treatment and outcome. Nineteen of the 43 AAM cases (44%) were caused by enterovirus, one by HIV (2%), two by Varicella zoster virus (5%), three due to herpes simplex virus I (7%), two due to herpes simplex virus II (5%), one due to Central European encephalitis virus (2%), and in 15 patients (35%) the aetiology of AAM remained unknown. Headache (100%) and fever (93%) were the presenting symptoms in the majority of cases. Signs of preceding infection were predominantly gastrointestinal in the enterovirus subgroup, but were inconsistently observed in the other subgroups. CSF findings at the first lumbar tap on admission generally revealed lymphomonocytic pleocytosis of less than 500 cells per micro l, mild to moderately elevated protein and normal lactate and glucose levels. Initial therapy consisted of an empirical antiviral and antibiotic regimen until a serological diagnosis was available. Acyclovir, effective only in herpes family viruses, was initially administered to all AAM cases. Effective therapy for other viral pathogens are not broadly available and treating AAM of unknown aetiology imposes a particular problem. The average hospitalization time ranged from 16 to 31 days. Patients were either discharged home (72%) or transferred to a rehabilitation centre (28%). The outcome was good (40%) to fair (51%) in the majority of cases.

Genetic diversity of echovirus 30 during a meningitis outbreak, demonstrated by direct molecular typing from cerebrospinal fluid

Echovirus 30 is one of the enterovirus serotypes isolated most frequently in meningitis cases. The genetic diversity of echovirus 30 was investigated in patients hospitalised during an outbreak in 2000 in Clermont-Ferrand, France. A nested reverse transcription-PCR (RT-PCR) assay was developed for qualitative analysis of the echovirus 30 VP1 encoding sequence directly from cerebrospinal fluid. The viral sequences obtained for 22 patients were compared with those of virus isolates obtained from nine patients with echovirus 30 meningitis admitted to hospital in 1996-1997 and with echovirus 30 sequences from international databases. In 2000, meningitis cases were caused by two virus variants (C3 and C4) distinct genetically from the other two variants (C1 and C2) identified during the period 1996-1997. A detailed phylogenetic analysis established that the C1, C2, and C3 variants had close relatives among viruses previously identified in other geographical areas. The C4 variant had not been described earlier. The genomic differences observed between the four echovirus 30 variants arose at synonymous sites indicating that the viruses shared similar antigenic sites in the VP1 encoding sequence. Overall, these observations suggest wide circulation of different echovirus 30 variants and periodic importation of new viruses. The apparent displacement observed between virus variants did not result from a selective advantage caused by antigenic variation.

Development and evaluation of a 'real-time' RT-PCR for the detection of enterovirus and parechovirus RNA in CSF and throat swab samples

A two-step reverse transcriptase TaqMantrade mark duplex PCR (RT-PCR) assay was developed using the ABI 7700 Sequence Detection System for the detection of enterovirus (EV) and parechovirus type 1 and 2 (PEV) RNA from samples of cerebrospinal fluid (CSF) and throat swabs. Using sequence-specific fluorescent dye labeled probes and continuous 'real-time' monitoring, PCR amplified product accumulation was measured. Based on limiting dilutions, the TaqMantrade mark enterovirus and parechovirus RT-PCR showed an increase of two orders of magnitude compared to cell culture with sensitivity of 100% (7/7) when assessed using enterovirus cell culture positive samples (CSF, TS). The assays were specific for enterovirus and parechovirus and did not amplify a wide selection of virus and bacterial isolates. RNA was amplified from 22 enterovirus serotypes: coxsackie A7, A9, A21; coxsackie B2, B3, B4, B5; echovirus 2, 4, 6, 7, 9, 11, 13, 17, 18, 19, 30, 31; poliovirus types 1, 2, and 3, and parechovirus types 1 and 2. The assay was used to assess the incidence of enterovirus and parechovirus RNA in cell culture negative CSF and throat swab samples (n = 200). An additional 33 (15.9%) enterovirus and 2 (1%) parechovirus were identified as positive by RT-PCR. Also, of 100 CSF samples from suspected cases of meningococcal meningitis submitted for meningococcal PCR testing, 59 (59%) were enterovirus and 2 (2%) parechovirus 1 and 2 were positive by RT-PCR. The TaqMantrade mark duplex assay offers a more rapid and sensitive alternative to conventional cell culture for the diagnosis of enterovirus and parechovirus infection. Closed tube real-time detection using the ABI Sequence Detection System obviates the need for post-PCR manipulation, which reduces hands on time and eliminates the risk of contamination from amplified PCR product.

Enteroviral meningitis in Northern Jordan: prevalence and association with clinical findings

During the summer-autumn of 1999, 390 specimens of cerebrospinal fluid were taken from infants and children younger than 15 years of age. They were suspected of having meningitis and were admitted to Princess Rahma Hospital, Northern Jordan. They were investigated for the presence of enteroviruses using shell vial culture and indirect immunofluorescence assays. Most cases (46.9%) occurred in children younger than 1 year of age in which males represented 71.9%. The common symptoms were fever, vomiting, and headache. Enteroviruses were isolated from 32 (8.2%) cases, coxsackievirus B types 2, 4, and 5 from 15 (46.9%) cases, and echovirus 9 (31.3%) was the most common identified serotype. The virus isolation rate was directly proportional to the number of leukocytes in the cerebrospinal fluid. However, enteroviral isolation was demonstrated in 4 (12.5%) of 32 cerebrospinal fluid specimens without pleocytosis. Leukocyte differential count revealed a predominance of polymorphonuclear cells in 71.4% of the cases. Hospitalization ranged from 1 day to 25 days with a mean of 7 days. The majority of enterovirus-infected patients (88.9%) were treated with at least one type of antibiotic. These results emphasize the importance of shell vial culture assay for diagnosing enteroviruses, especially in laboratories that do not have access to advanced techniques such as polymerase chain reaction.

Epidemiological survey of neonatal non-polio enterovirus infection in the Netherlands

The epidemiological, virological, and clinical data of 119 infants less than 30 days of age with enteroviral infection collected from January 1993 to November 1995 by the diagnostic virology laboratories were analyzed retrospectively. Ninety-eight isolates (83%) were obtained in the period of May 1 to December 1 with a peak in the summer months. Sixty-five percent (n = 78) of neonates became ill within the first 2 weeks of life. Echoviruses and Coxsackie virus type B were isolated most frequently, in 77 (65%) and 29 (24%) infants, respectively. Diagnosis was made by viral isolation from stool, nasopharyngeal swab, cerebrospinal fluid, and blood. One hundred four (87%) infants developed fever and 25 (21%) infants had diarrhea. A clinical diagnosis of sepsis was made in 42 (35%) infants and meningitis was diagnosed in 28 (24%) cases. The great majority of sepsis cases (36/86%) occurred in infants less than 15 days of age. In conclusion, non-polio enteroviruses (especially echoviruses) are a common and underreported cause of neonatal infection in the Netherlands in the summer months and are associated with a clinical diagnosis of sepsis or meningitis cases in the first 2 weeks of life in a high proportion of cases.

Aseptic meningitis in Germany associated with echovirus type 13

BACKGROUND

Echoviruses are the commonest cause of aseptic meningitis. Echovirus type 13 which has not been isolated in Germany over a long period of time was the predominant enterovirus serotype associated with different local outbreaks of aseptic meningitis in Germany in 2000.

METHODS

Virus isolation was performed from cerebrospinal fluid and stools. In order to study the genetic relationship of echovirus type 13 isolates, sequence analysis of a part of VP1 (~300 nt) was carried out. Isolates from different geographic regions were compared to each other as well as to elder viruses (prototype strain from 1953, four isolates from 1965-1986).

RESULTS

Overall, 55 isolates of echovirus type 13 were obtained from different parts of Germany. It was shown that the new isolated strains have a very high degree of homology on the nucleotide level (> 98%)) but differ significantly from the old strains (76-85%).

CONCLUSIONS

a) Rare enterovirus serotypes can cause serious illness.b) The molecular drift has also been shown for other enterovirus serotypes.

Nosocomial transmission of echovirus 30: molecular evidence by phylogenetic analysis of the VP1 encoding sequence

We investigated six cases of enterovirus infection in a neonatal unit. The index patient, a 5-day-old boy, was admitted with aseptic meningitis due to echovirus 30 (E30). Secondary infections with E30 occurred in five babies. Comparison of the complete VP1 sequences showed that the isolates recovered from the index patient and his mother were closely related to those recovered from the five babies with secondary infections, demonstrating a nosocomial transmission of the virus. In the phylogenetic tree reconstructed from the VP1 sequences, the isolates formed a monophyletic cluster related to an E30 strain collected in June 1997 during an outbreak of aseptic meningitis.

Genomic variations in echovirus 30 persistent isolates recovered from a chronically infected immunodeficient child and comparison with the reference strain

Seven sequential isolates of echovirus type 30 (EV30) were recovered over 22 months from a child with severe combined immune deficiency syndrome. The nucleotide sequences of the 5' halves of the genomes (4,400 nucleotides) of the first (S1) and last (S7) isolates were determined and compared with that of the EV30 Bastianni reference strain, also determined in this study. In genome regions P1 and P2, 101 variations were identified between the two isolates. Synonymous differences far outnumbered nonsynonymous differences. Amino acid changes affected both capsid and nonstructural polypeptides (particularly 2B). The VP1 nucleotide sequences of the seven isolates were determined to analyze genome evolution during the chronic infection. In the phylogenetic tree, the seven isolates were directly related to the prototype strain in an individual monophyletic group, strongly suggesting that the chronic infection in the child arose from a single persistent EV30 isolate. Four lineages were observed in the persistent isolates. Isolates S2, S4, S5, and S6 were close relatives of one another, whereas isolates S1 and S3 formed individual lineages. Isolate S7, distantly related to all other isolates, formed the fourth lineage. These findings suggest the quasispecies nature of the genomes of the seven sequential EV30 isolates. Grouping of persistent isolates on the basis of replicative capacities was consistent with phylogenetic relationships. Overall, the results indicate that genetically related EV30 variants with different replicative capacities coexisted in a carrier state, probably in the gastrointestinal tract, during the infection of the child.

Cerebrospinal fluid testing for the diagnosis of central nervous system infection

The central nervous system (CNS) is susceptible to bacterial, viral, and fungal infections, and prion diseases. Examination of the cerebrospinal fluid (CSF) is crucial in diagnosing these infections. Cerebrospinal tests may directly identify an organism and its nucleic acid and surface constituents by culture, polymerase chain reaction (PCR), or antigen detection. Alternatively, antibody to an organism may be identified in CSF by enzyme-linked immunosorbent assay (ELISA), Western blot, or complement fixation assay. This article discusses how these CSF tests are performed and addresses the sensitivity and specificity of such tests for the diagnosis of selected CNS infections.