Echoviruses are a major cause of aseptic meningitis in infants and young children in Kuwait

Enterovirus characterized from cerebrospinal fluid in a cohort from the Eastern United States

BACKGROUND

Enteroviruses (EVs) are predominant causes of a spectrum of neurological diseases. To better understand the origins of the outbreaks of disease associated with EV, it is essential to develop an efficient surveillance system that identifies the circulating EVs and correlate their genomic evolution with the disease presentations.

METHODS

The clinical presentations of patients with positive EV from cerebrospinal fluid (CSF) between 2014 and 2022, diagnosed at the Johns Hopkins Medical Microbiology Laboratory, were compared from year to year. EV typing and whole genome sequencing were performed and correlated to the spectrum of disease.

RESULTS

A total of 95 CSF specimens were positive for EV between 2014 and 2022. The percentage positivity ranged from the lowest of 1.1% in 2020 to the highest of 3.2% in 2015. The median ages declined from 22 years in 2014 to less than one year starting in 2016 to 34 in 2022. Typing using VP1 sequencing revealed that E30 and E6 were associated with meningitis in adults but coxsackieviruses (CVs-B3 and B5) were detected from pediatric patients with fever. Whole genome sequencing revealed multiple recombination events. In 2020, a recombinant CV-A9 was detected in a CSF sample associated with unusual presentation of sepsis, profound acute bilateral sensory neural hearing loss, and myofasciitis.

CONCLUSIONS

EV genomic surveillance is needed for a better understanding of the genetic determinants of neurovirulence. Whole genome sequencing can reveal recombination events missed by traditional molecular surveillance methods.

Epidemiological characteristics and climatic variability of viral meningitis in Kazakhstan, 2014-2019

Background

The comprehensive epidemiology and impact of climate on viral meningitis (VM) in Kazakhstan are unknown. We aimed to study the incidence, in-hospital mortality and influence of climatic indicators on VM from 2014 to 2019.

Methods

Nationwide electronic healthcare records were used to explore this study. ICD-10 codes of VM, demographics, and hospital outcomes were evaluated using descriptive statistics and survival analysis.

Results

During the 2014-2019 period, 10,251 patients with VM were admitted to the hospital. 51.35% of them were children, 57.85% were males, and 85.9% were from the urban population. Enteroviral meningitis was the main cause of VM in children. The incidence rate was 13 and 18 cases per 100,000 population in 2014 and 2019, respectively. Case fatality rate was higher in 2015 (2.3%) and 2017 (2.0%). The regression model showed 1°C increment in the daily average temperature might be associated with a 1.05-fold (95% CI 1.047-1.051) increase in the daily rate of VM cases, 1hPa increment in the average air pressure and 1% increment in the daily average humidity might contribute to a decrease in the daily rate of VM cases with IRRs of 0.997 (95% CI 0.995-0.998) and 0.982 (95% CI 0.981-0.983), respectively. In-hospital mortality was 35% higher in males compared to females. Patients residing in rural locations had a 2-fold higher risk of in-hospital death, compared to city residents. Elderly patients had a 14-fold higher risk of in-hospital mortality, compared to younger patients.

Conclusion

This is the first study in Kazakhstan investigating the epidemiology and impact of climate on VM using nationwide healthcare data. There was a tendency to decrease the incidence with outbreaks every 5 years, and mortality rates were higher for Russians and other ethnicities compared to Kazakhs, for males compared to females, for elder patients compared to younger patients, and for patients living in rural areas compared to city residents. The climatic parameters and the days of delay indicated a moderate interaction with the VM cases.

Epidemiological and etiological characteristics of viral meningitis for hospitalized pediatric patients in Yunnan, China

BACKGROUND

Viral infection is the most common cause of aseptic meningitis. The purpose of this study was to identify the viruses responsible for aseptic meningitis to better understand the clinical presentations of this disease.

METHOD

Between March 2009 and February 2010, we collected 297 cerebrospinal fluid specimens from children with aseptic meningitis admitted to a pediatric hospital in Yunnan (China). Viruses were detected by using "in house" real-time quantitative polymerase chain reaction or reverse-transcription real-time quantitative polymerase chain reaction from these samples. Phylogenetic analyses were conducted using the Molecular Evolutionary Genetic Analysis version 7.0 software, with the neighbor-joining method.

RESULTS

Viral infection was diagnosed in 35 of the 297 children (11.8%). The causative viruses were identified to be enteroviruses in 25 cases (71.4%), varicella-zoster virus in 5 cases (14.3%), herpes simplex virus 1 in 2 cases (5.7%), and herpes simplex virus 2, Epstein-Barr virus, and human herpesvirus 6 in 1 case each (2.9% each). Of the enteroviruses, coxsackievirus B5 was the most frequently detected serotype (10/25 cases; 40.0%) and all coxsackievirus B5 strains belonged to C group.

CONCLUSIONS

In the study, a causative virus was only found in the minority of cases, of them, enteroviruses were the most frequently detected viruses in patients with viral meningitis, followed by varicella-zoster virus and herpes simplex virus. Our findings underscore the need for enhanced surveillance and etiological study of aseptic meningitis.

Molecular characterization of enterovirus detected in cerebrospinal fluid and wastewater samples in Monastir, Tunisia, 2014-2017

Background

Enteroviruses (EVs) are considered the main causative agents responsible for aseptic meningitis worldwide. This study was conducted in the Monastir region of Tunisia in order to know the prevalence of EV infections in children with meningitis symptoms. Detected EV types were compared to those identified in wastewater samples.

Methods

Two hundred CSF samples collected from hospitalized patients suspected of having aseptic meningitis for an EV infection between May 2014 and May 2017 and 80 wastewater samples collected in the same time-period were analyzed. EV detection and genotyping were performed using PCR methods followed by sequencing. Phylogenetic analyses in the 3′-VP1 region were also carried-out.

Results

EVs were detected in 12% (24/200) CSF and in 35% (28/80) wastewater samples. EV genotyping was reached in 50% (12/24) CSF-positive samples and in 64% (18/28) sewage. Most frequent types detected in CSF were CVB3, E-30 and E-9 (25% each). In wastewater samples, the same EVs were identified, but also other types non-detected in CSF samples, such as E-17,CVA9 and CVB1 from EV species B, and EV-A71 and CVA8 from EV-A, suggesting their likely lower pathogenicity. Phylogenetic analysis showed that within the same type, different strains circulate in Tunisia. For some of the EV types such as E-9, E-11 or CVB3, the same strains were detected in CSF and wastewater samples.

Conclusions

Epidemiological studies are important for the surveillance of the EV infections and to better understand the emergence of certain types and variants.

Enteroviral Infections in the First Three Months of Life

Enteroviruses (EVs) are an important source of infection in the paediatric age, with most cases concerning the neonatal age and early infancy. Molecular epidemiology is crucial to understand the circulation of main serotypes in a specific area and period due to their extreme epidemiological variability. The diagnosis of EVs infection currently relies on the detection of EVs RNA in biological samples (usually cerebrospinal fluid and plasma, but also throat swabs and feces) through a polymerase chain reaction assay. Although EVs infections usually have a benign course, they sometimes become life threatening, especially when symptoms develop in the first few days of life. Mortality is primarily associated with myocarditis, acute hepatitis, and multi-organ failure. Neurodevelopmental sequelae have been reported following severe infections with central nervous system involvement. Unfortunately, at present, the treatment of EVs infections is mainly supportive. The use of specific antiviral agents in severe neonatal infections has been reported in single cases or studies including few neonates. Therefore, further studies are needed to confirm the efficacy of these drugs in clinical practice.

Etiology, Clinical Phenotypes, Epidemiological Correlates, Laboratory Biomarkers and Diagnostic Challenges of Pediatric Viral Meningitis: Descriptive Review

Meningitis is an inflammation of the brain and spinal cord meninges caused by infectious and non-infectious agents. Infectious agents causing meningitis include viruses, bacteria, and fungi. Viral meningitis (VM), also termed aseptic meningitis, is caused by some viruses, such as enteroviruses (EVs), herpesviruses, influenza viruses, and arboviruses. However, EVs represent the primary cause of VM. The clinical symptoms of this neurological disorder may rapidly be observed after the onset of the disease, or take prolonged time to develop. The primary clinical manifestations of VM include common flu-like symptoms of headache, photophobia, fever, nuchal rigidity, myalgia, and fatigue. The severity of these symptoms depends on the patient's age; they are more severe among infants and children. The course of infection of VM varies between asymptomatic, mild, critically ill, and fatal disease. Morbidities and mortalities of VM are dependent on the early recognition and treatment of the disease. There were no significant distinctions in the clinical phenotypes and symptoms between VM and meningitis due to other causative agents. To date, the pathophysiological mechanisms of VM are unclear. In this scientific communication, a descriptive review was performed to give an overview of pediatric viral meningitis (PVM). PVM may occasionally result in severe neurological consequences such as mental retardation and death. Clinical examinations, including Kernig's, Brudzinski's, and nuchal rigidity signs, were attempted to determine the clinical course of PVM with various success rates revealed. Some epidemiological correlates of PVM were adequately reviewed and presented in this report. They were seen depending mainly on the causative virus. The abnormal cytological and biochemical features of PVM were also discussed and showed potentials to distinguish PVM from pediatric bacterial meningitis (PBM). The pathological, developmental, behavioral, and neuropsychological complications of PVM were also presented. All the previously utilized techniques for the etiological diagnosis of PVM which include virology, serology, biochemistry, and radiology, were presented and discussed to determine their efficiencies and limitations. Finally, molecular testing, mainly PCR, was introduced and showed 100% sensitivity rates.

High rate of human enteroviruses among clinically suspected meningitis cases at selected Hospitals in Addis Ababa, Ethiopia

BACKGROUND

Because of limited infrastructure and skilled human capital, the etiology of meningitis is rarely identified in developing countries like Ethiopia. This results in unnecessary antibiotics use, economic crisis, hospitalization, and related nosocomial infections. Thus, we aimed to assess the epidemiology of human enteroviruses (HEVs) among clinically suspected meningitis cases in Addis Ababa, Ethiopia.

METHOD

A cross-sectional study was conducted from January to August 2020 at selected Hospitals in Addis Ababa, Ethiopia. Reverse transcriptase-polymerase chain reaction (RT-PCR) was conducted on cerebrospinal fluid (CSF) collected from 146 clinically suspected meningitis and bacterial culture-negative patients. SPSS v 21.0 was used for data analysis and bivariate correlation was done for the association between variables of interest.

RESULTS

HEVs were detected in 39 (26.7%) of the 146 clinically suspected meningitis cases. Most of the HEVs cases 28 (71.9%) were detected in younger-aged infants less than 1 year. The most commonly observed clinical manifestations were vomiting (75.5%) followed by fever (56.8%) and impaired consciousness or irritability (50.7%). The mean length of hospital stay for patients with enteroviral meningitis was 9 days. Many patients with HEVs were recovered with sequelae (46.2%), and HEVs has contributed for one out of the nine meningeal deaths (11.1%).

CONCLUSIONS

HEVs were found to be the commonest cause of morbidity and mortality in all age groups. Many of the patients were mistreated with antibiotics and hospitalized. The detection of HEVs in 26.7% of clinically suspected meningitis cases indicated the need for molecular tests in investigating the etiology of meningitis. Therefore, we suggest the introduction of molecular tests as a routine practice in referral hospitals and the need to further characterize circulating HEVs strains.

Epidemiology Profile of Viral Meningitis Infections Among Patients in Qatar (2015-2018)

Background: Little is known about the etiology of meningitis in the MENA region, including Qatar. Viral agents are considered the major cause for meningitis worldwide. Here, we present primary data about the etiology and clinical and demographic characteristics of viral meningitis (VM) in Qatar between 2015 and 2018.

Methods: We retrospectively collected data from Hamad Medical Corporation (HMC), which provides about 80% of healthcare services in Qatar. Data were collected for the period between 2015 and 2018. During this time period, 6,705 specimens were collected from patients with suspected meningitis attending HMC and primary healthcare centers. These specimens were tested for a panel of viruses using the “FTD Viral meningitis” multiplex real-time PCR kit that detects Adenovirus (ADV), Human herpesvirus 1&2 (HSV1 and HSV2), Epstein–Barr virus (EBV), Enteroviruses (EV), Cytomegalovirus (CMV), Varicella zoster virus (VZV), and Parechovirus (PV).

Results: Only 10.9% (732/6,705) of all suspected meningitis cases were caused by viral agents. 60.9% of the reported cases were males, compared to 39.1% in females. Most of the infections (73.9%) were reported in children younger than 10 years of age. EV were identified as the main causative agent (68.7%), followed by EBV (7.5%) and ADV (6.8%). Other viral agents including VZV, PV, HSV-1, and HSV-2 were also detected with a lower frequency. Confirmed VM were more prevalent among Qatari subjects compared to other nationalities. We observed no specific seasonality of viral agents, but a slight rise was recorded during the spring seasons (March to June). Fever (59.4%, 435/732) and acute central nervous system (CNS) infection (15.6%, 114/732) were initial symptoms of most cases.

Conclusion: This is the first report about the molecular epidemiology of VM in Qatar. In line with the international records, our data showed that EV is responsible for 68.7% of Qatar's VM cases. Further studies are needed to genotype and serotype the identified viruses.

Molecular epidemiology of enteroviruses and predominance of echovirus 30 in an Iranian population with aseptic meningitis

Human enteroviruses are the most prevalent causes of aseptic meningitis worldwide. However, despite such predominancy, defining the enteroviral etiology of aseptic meningitis remains a diagnostic dilemma for the clinician in Iran. Therefore, this study was conducted to characterize the prevalence and clinical significance of enteroviral aseptic meningitis as well as the predominant enterovirus serotypes among patients with aseptic meningitis in the South of Iran.Cerebrospinal fluid (CSF) specimens were obtained from 73 patients with aseptic meningitis (52.1% males and 47.9% females), ages ranging from 1 month to 88 years. Following the extraction of nucleic acid, the detection of enteroviruses was performed by RT-PCR, targeting the 5' untranslated region of the genome, and sequencing. Enteroviruses were found in 46.6% of samples (34/73). The most predominant serotype was echovirus 30, followed by coxsackievirus B5 and poliovirus type 1 Sabin strain. The enterovirus infections were more prevalent among female patients (58.8%) and those below 5 years of age (52.9%). Although enterovirus infections were observed throughout the year, the infections were more prevalent during autumn with fever as the predominant clinical symptom. The outcomes revealed that enteroviruses are significant causes of aseptic meningitis in the South of Iran, while suspected cases of aseptic meningitis are usually monitored by bacterial culture and biochemical testing of CSF samples. Therefore, the etiology remains unknown in most cases. Molecular detection of viral pathogens should be included as a common approach in the screening of patients with aseptic meningitis to prevent unnecessary treatment and to improve clinical management.

Viral meningitis: an overview

Meningitis is a serious condition that affects the central nervous system. It is an inflammation of the meninges, which is the membrane that surrounds both the brain and the spinal cord. Meningitis can be caused by bacterial, viral, or fungal infections. Many viruses, such as enteroviruses, herpesviruses, and influenza viruses, can cause this neurological disorder. However, enteroviruses have been found to be the underlying cause of most viral meningitis cases worldwide. With few exceptions, the clinical manifestations and symptoms associated with viral meningitis are similar for the different causative agents, which makes it difficult to diagnose the disease at early stages. The pathogenesis of viral meningitis is not clearly defined, and more studies are needed to improve the health care of patients in terms of early diagnosis and management. This review article discusses the most common causative agents, epidemiology, clinical features, diagnosis, and pathogenesis of viral meningitis.

Cerebrospinal fluid inflammatory markers in children with aseptic meningitis

Aseptic meningitis is one of the most common inflammatory disorders of the meninges of the central nervous system (CNS). The aim of our study was to investigate the cytokine profiles in the CSF and in the serum of children with aseptic meningitis to determine their role in CNS inflammation. Sixty-eight (68) children were kept under observation. Cytokine profile of CSF and blood (based on the results of determining of IL-1β, IL-4, IL-10, TNF-α levels) and procalcitonin in children were revealed, meningitis severity were estimated by AMSS score. It was found that in the majority of patients with aseptic meningitis, the levels of IL-1β, TNF-α, IL-10 in CSF were increased and exceeded the serum cytokines levels. The severe course of meningitis was characterized by significantly higher concentrations of IL-1β and TNF-α in CSF, which was confirmed by positive correlation between AMSS score and IL-1β concentration (r=0.46, p<0.01), IL-10 (r=0.32, p<0.01), TNF-α (r=0.62, p<0.05). The IL-10/TNF-α ratio was – 17.8. PCT level in CSF was within normal limits in the majority of patients with meningitis. Increasing of anti-inflammatory cytokine levels in aseptic meningitis contributes to preventing of excessive inflammatory/immune responses in the brain. This can cause a longer diseases course and a longer recovery period. This can an indicate active production of cytokines in the central nervous system due to intrathecal inflammation and activation of immune responses caused by viral infection, but not due to penetration across the blood-brain barrier.

Comparison of clinical and laboratory characteristics during two major paediatric meningitis outbreaks of echovirus 30 and other non-polio enteroviruses in Germany in 2008 and 2013

Viral meningitis is mainly caused by non-polio enteroviruses (NPEV). Large-scale data on the clinical characteristics between different outbreaks within the same region are lacking. This study aimed to analyse a possible influence of the circulating NPEV genotype on the disease outcome of affected children. A retrospective cohort study analysing two major outbreaks of NPEV meningitis in Germany in 2008 and 2013 was conducted in cooperation with the National Reference Centre for Poliomyelitis and Enteroviruses (NRC PE) and five German children's hospitals. A total of 196 patients with laboratory-confirmed NPEV meningitis were enrolled. In 2008, children with NPEV meningitis had significantly higher fever and showed more behavioural changes and less back pain. To better define typical findings in echovirus 30 (E-30) meningitis, patients were split into the following three groups: E-30 positive patients, patients with "Non E-30" infection and patients with "Untyped" NPEV infection. E-30 positive patients were significantly older and their disease course was more acute, with early admission to but also early discharge from hospital. E-30 positive patients showed a significantly higher rate of headache and meningism, and a lower rate of diarrhoea and clinically defined septicaemia when compared to the others. Regarding laboratory testing, E-30 positive patients presented with significantly elevated peripheral blood neutrophil counts when compared to patients with "Non E-30" or "Untyped" NPEV infection. In conclusion, E-30 meningitis in children shows a characteristic pattern of clinical features. To further characterise NPEV strains worldwide, continuous surveillance and typing of NPEV strains causing central nervous system disease is warranted.

Molecular detection and genotyping of enteroviruses from CSF samples of patients with suspected sepsis-like illness and/or aseptic meningitis from 2012 to 2015 in West Bank, Palestine

BACKGROUND

Human enteroviruses (HEVs) are the most frequently reported cause of aseptic meningitis with or without CSF pleocytosis in childhood. Rapid detection and genotype of HEVs is essential to determine the causative agent and variant causing sepsis-like illness and/or aseptic meningitis.

AIM

To investigate the molecular epidemiology of enteroviruses (EVs) among patients with sepsis-like illness and/or aseptic meningitis admitted to three major hospitals in West Bank, Palestine from 2012 to 2015.

METHODS

During the study period, 356 CSF samples were collected from patients with sepsis-like illness and/or aseptic meningitis. Two RT-nested PCR assays targeting a partial part of 5'UTR for direct diagnosis and the VP1 region for genotyping by sequence analysis of the viral genome were used.

RESULTS

HEV RNA was detected in 66 of 356 (18.5%) of CSF samples. Age distribution showed that 64% (42/66) were infants (<1 year), 18% were children between 1 and 5 years old, 12% were children between 5 and 10 years old, and 6% were more than 10 years old. Of the 66 EV cases, 12 were successfully genotyped. Five different EV genotypes were identified. All of them belonged to HEV-B species. The study showed that echovirus 6 genotype accounted for 42% of the sequenced cases. The HEV infections in the present study tended to show slight seasonal pattern with more cases occurring during spring and summer, yet still significant numbers were also reported in fall and winter seasons.

CONCLUSION

HEV was isolated from a significant number of children with sepsis-like illness and/or aseptic meningitis. In addition, the molecular method utilized for direct diagnosis and genotyping of HEV from CSF revealed that more than one HEV type circulated in the West Bank, Palestine during the study period.

Childhood meningitis in Kuwait in the era of post pneumococcal conjugate vaccination: A multicenter study

This is a retrospective study to evaluate epidemiology and etiologies of childhood meningitis in Kuwait after the routine introduction of the pneumococcal conjugate vaccine. The data was collected from 196 patients in the period of 2010-2014. Aseptic meningitis accounted for 51% of the cases, bacterial meningitis accounted for 29% cases and partially treated meningitis were 20%. Organisms causing bacterial meningitis were: Streptococcus pneumoniae 40.4%, Neisseria meningitidis 17.6%, Haemophilus spp. 12.2%, other gram positive or negative 19.3%, and Group B Streptococcus 8.8%. The hospitalization was complicated by admission to the ICU in 16.3% patients. Sequelae on discharge were seen in 4%, and 2.5% died of complications of meningitis. In children with pneumococcal meningitis, 48% were admitted to the ICU, 35% were discharged with sequelae and 13% died. In the era of post pneumococcal conjugate vaccination, S. pneumoniae remains the leading cause of bacterial meningitis with the greatest morbidity and mortality.

Molecular identification of human enteroviruses associated with aseptic meningitis in Yunnan province, Southwest China

Human enteroviruses (EVs) are the major causative agents of aseptic meningitis. In this study, a total of 524 children were admitted to the children Kunming hospital (continental China) for aseptic meningitis manifestations in 2009 and 2010. An EV infection was diagnosed in 85/524 children (16.2 %) and the viruses detected were assigned to 16 serotypes. Most serotypes belonged to the enterovirus B species. Echovirus 9 was predominant (24.7 %), followed by coxsackievirus B5 (23.5 %) and then echovirus 30 (16.5 %). Echovirus 9 was firstly identified as the predominant serotype in sporadic aseptic meningitis which occurred in Yunnan, Southwest China. This work indicates the need to perform large-scale surveillance to gain a better insight into the epidemiology of enteroviruses associated with aseptic meningitis in China.

Echovirus serotypes circulating in Malaysia from 2002 to 2013

OBJECTIVE

To identify the circulating serotypes of human echovirus in Malaysia from 2002 to 2013.

METHODS

A total of 31 retrospective samples from non-polio acute flacid paralysis, hand-food-and-mouth disease, viral meningitis and enterovirus cases were subjected to amplification of partial VP1 gene by RT-PCR.

RESULTS

Sequencing and phylogenetic analysis of the partial sequences identified presence of human echovirus and human coxsackie viruses. It was found that echovirus 11 was the commonly circulating serotype followed by echovirus 6, echovirus 7, echovirus 3, echovirus 9, echovirus 30 and echovirus 1 in decreasing order. Additionally two types of human coxsackie virus isolates were detected which were coxsackie A24 and B3.

CONCLUSIONS

From the findings, there is a possibility that echovirus 11 is the predominant serotype among Malaysian patients with echovirus infection. However, a larger sample size will yield a more confident result to support this evidence.

Study of the Frequency of Herpesvirus Infections Among Patients Suspected Aseptic Meningitis in the West of Iran

Background:

Aseptic meningitis is the most common type of meningitis and is characterized by meningeal inflammation that is not linked to identifiable bacterial pathogens in cerebrospinal fluid (CSF).

Objectives:

This study aimed to evaluate the frequency of aseptic meningitis caused by herpesviruses, namely herpes simplex types I and II (HSV-1, HSV-2), Epstein-Barr virus (EBV), cytomegalovirus (CMV) and varicella-zoster virus (VZV).

Patients and Methods:

A total of 196 CSF samples were collected from patients with suspected meningitis. All samples were smear- and culture-negative for bacterial pathogens. The biochemical and cytological findings of CSF samples were also recorded. DNA was extracted from samples and PCR with specific primers was carried out to detect viruses.

Results:

The 196 samples derived from 100 (52%) men and 96 (48%) women ranging in age from one day to 86 years with an average age of 32.3 ± 25.3 years. Of them, 8 (4.08%) samples yielded positive results, including 5 (2.55%) cases of VZV infection and 3 (1.53%) cases of HSV-1 infection. No cases of HSV-2, CMV or EBV infection were detected. CSF protein and glucose levels among positive cases were all in the normal range.

Conclusions:

The results indicate a considerable rate of herpesvirus infection in patients with aseptic meningitis, and that VZV is the most common herpesvirus to cause infection followed by HSV-1. Our results also showed that a moderate increase in the WBC count and predominance of lymphocytes can be valuable clues in diagnosing viral meningitis. Given the different approaches of drug therapy in bacterial and viral meningitis, use of molecular methods is necessary in hospitals to rapidly discriminate between them.

Acute meningoencephalitis associated with echovirus 9 infection in Sri Lanka, 2009

The aetiology of acute meningoencephalitis in Sri Lankan children and adults is poorly understood. This study was carried out to determine pathogens responsible for meningoencephalitis in Sri Lanka. A hospital-based cross-sectional study was performed using cerebrospinal fluid samples (22 adult and 17 pediatric) collected from August to December 2009 from patients clinically diagnosed with acute meningoencephalitis at two tertiary care hospitals in Sri Lanka. Routine microbiology for bacterial pathogens together with in-house RT-PCR and PCR assays for the detection of dengue viruses, Japanese encephalitis virus, West Nile virus, chikungunya virus, enteroviruses, mumps virus, measles virus, herpes simplex viruses types 1 and 2, and varicella zoster virus were performed. Bacterial pathogens were not isolated from any patient specimens. However, from nine of the paediatric patients aged 1 month to 10 years (mean age 5.2 years) echovirus 9 (E-9; family Picornaviridae, genus Enterovirus,species Enterovirus B ) was detected by RT-PCR. All nine patients presented with fever, six had headache, and seven had vomiting. Neck stiffness indicating meningitis was present in six of the patients. Phylogenetic analysis of partial VP1 and VP4-VP2 genes showed these E-9 strains to be most closely related to E-9 strains detected in CSF from Korea and France in 2005 and 2006. The remaining patients were negative for all other viruses tested. E-9 was the most common cause of acute meningoencephalitis in the tested paediatric population from Sri Lanka in 2009, which likely reflects circulation of this E-9 strain between Europe and Asia over several years.

Viral diseases of the central nervous system

Virus-induced diseases of the central nervous system (CNS) represent a significant burden to human health worldwide. The complexity of these diseases is influenced by the sheer number of different neurotropic viruses, the diverse routes of CNS entry, viral tropism, and the immune system. Using a combination of human pathological data and experimental animal models, we have begun to uncover many of the mechanisms that viruses use to enter the CNS and cause disease. This review highlights a selection of neurotropic viruses that infect the CNS and explores the means by which they induce neurological diseases such as meningitis, encephalitis, and myelitis.

Molecular epidemiology of enterovirus B77 isolated from non polio acute flaccid paralytic patients in Pakistan during 2013

Human enteroviruses are associated with various clinical syndromes and severe neurological disorders. The aim of this study was to determine the molecular epidemiology of non polio enteroviruses and their correlation with acute flaccid paralysis (AFP) patients living in Khyber Pakhtunkhwa (KP) and Federally Administered Tribal Areas (FATA) of Pakistan. The stool samples collected from these patients were used for isolation of non polio enteroviruses (NPEVs). Out of 38 samples, 29 (76.3%) were successfully typed by microneutralization assay into eleven serotypes including echovirus (E)-3 (5.3%), E-7 (2.6%), E-11 (13.2%), E-12 (7.9%), E-13 (10.5%), E-20 (7.9%), E-27 (5.3%), E-29 (10.5%), E-30 (7.9%), E-33 (2.6%), coxsackievirus (CV) B5 (2.6%) and nine isolates (23.7%) remained untyped which were confirmed as NPEVs by real time RT-PCR. Complete VP1 genetic sequencing data characterized untypeable isolates into enterovirus B77 (EV-B77). Moreover, molecular phylogenetic analysis classified these viruses into two new genotypes having high genetic diversity (at least 17.7%) with prototype. This study provides valuable information on extensive genetic diversity of EV-B77 genotypes. Although, its association with neurological disorder has not yet been known but isolation of nine EV-B77 viruses from AFP cases highlights the fact that they may have a contributing role in the etiology of AFP. In addition, it is needed to establish enterovirus surveillance system and laboratory diagnostic facilities for early detection of NPEVs that may cause poliomyelitis like paralysis especially in the situation when we are at the verge of polio eradication.

Molecular characterisation of enteroviruses and clinical findings from a cluster of paediatric viral meningitis cases in Tshwane, South Africa 2010-2011

BACKGROUND

Human enteroviruses (HEVs) are the most common viral pathogen associated with paediatric aseptic meningitis. From October 2010 to February 2011 a cluster of HEV-associated meningitis cases was identified in paediatric patients who had presented at two large tertiary hospitals in Pretoria in the Tshwane Metropolitan Area, Gauteng, South Africa (SA).

OBJECTIVES

The aim of this study was to review the clinical features and to characterise the HEV strains associated with this cluster of meningitis cases.

STUDY DESIGN

In this retrospective study HEVs, detected by real time reverse transcription-polymerase chain reaction in acute phase cerebrospinal fluid specimens from 30 patients with aseptic meningitis, were characterised and the clinical presentations of these patients were described.

RESULTS

Fever (83%), headache (70%) and vomiting (67%) were the most prominent symptoms with signs of meningeal irritation recorded in 67% of the patients. There was a neutrophil predominance in the cerebrospinal fluid of 57% of the patients with pleocytosis. Based on partial nucleotide sequence analysis of the HEV viral protein 1 gene, echovirus (E) serotype 4 (E-4) was identified in 80% (24/30) of specimens with E-9 (3/30) and coxsackie virus B5 (1/30) detected less frequently.

CONCLUSION

In this cluster of aseptic meningitis cases E-4 was the predominant strain with E-9, and to a lesser extent other HEVs, identified less frequently.

Frequency of enterovirus detection in blood samples of neonates admitted to hospital with sepsis-like illness in Kuwait

This study investigated the role of enteroviruses in sepsis-like illness among neonates in Kuwait. Serum samples from 139 consecutive neonates presenting with sepsis-like illness during a three and a half-year-period whose blood cultures were negative for bacterial pathogens were tested. Enterovirus RNA was detected by single-step reverse-transcription PCR (RT-PCR). Specific genotypes were identified by direct DNA sequencing of enteroviral genome. Serotype-specific antibodies in serum samples from some selected patients were detected by virus neutralization test using coxsackievirus B types (CBVs). All 139 neonates presented with sepsis-like illness and blood samples were uniformly negative for aerobic/anaerobic bacterial cultures. Fifty-six (40%) neonates had further complications of sepsis including carditis (n = 34) and multi-organ involvement (n = 22). Enterovirus RNA was detected by RT-PCR in 34 of 139 (24%) serum samples which is among the highest frequency reported so far in non-epidemic settings. Genotyping identified CBVs as most common enteroviruses, causing 19 of 34 (56%) enteroviral sepsis episodes in neonates. Of 34 carditis cases, 18 were positive for CBVs by serotyping including all 10 enterovirus RNA-positive samples. Only one fatality was observed due to liver failure in a neonate with hepatitis. Our data showed that enteroviruses are responsible for 24% of neonatal sepsis cases due to non-bacterial causes in Kuwait. The data indicate that enteroviruses should be considered in the differential diagnosis of sepsis-like illness among neonates, particularly those with negative blood cultures for bacterial pathogens.

Differential TLR7-mediated expression of proinflammatory and antiviral cytokines in response to laboratory and clinical enterovirus strains

Enteroviruses (EVs) are single stranded RNA viruses associated with many serious diseases. The exact mechanism by which an EV is able to evade innate immunity and cause tissue damage still remain unknown. Toll-like receptor 7 (TLR7) mediates the activation of type I interferon genes and the development of inflammatory cytokine response. The main aim of the study was to explore the antiviral activity and the pattern of cytokine expression in human embryonic kidney cells (HEK-293 cells) expressing TLR7 protein following challenging with laboratory and clinical EV strains. The TLR7 open reading frame was cloned into the pcDNA3.1/nV5-DEST™ expression vector, followed by transfection into HEK-293 cells. TLR7- and mock-transfected cells were infected with laboratory and clinical strains of CVB1 and CVB5. The levels of cytokines (IL-6, IL-8, TNF-α, IFN-α and IFN-β) were measured by ELISA. The EV RNA concentrations were measured by real-time RT-PCR, and normalized against GAPDH RNA concentrations. The clinical EV strains were more effective activators of cytokines production in TLR7-transfected cells than the laboratory EV strains. The inhibition of EV replication in TLR7-transfected cells was correlated to the production of type I IFNs. The cytopathic effects observed in TLR7-transfected cells were correlated to the levels of IL-6 and TNF-α. The results suggest a clear segregation between laboratory and clinical EV strains on the basis of their cytokine induction ability, and a possible role of TLR7-induced proinflammatory cytokines in the pathogenesis of EV infection.

Prevalence of viruses in stool of premature neonates at a neonatal intensive care unit

AIM

Premature neonates represent a population highly vulnerable to infection. This study aims to profile viral colonisation of gut and the associated clinical manifestations among premature neonates admitted to a neonatal intensive care unit (NICU) in Australia.

METHODS

In a cohort of 75 premature neonates born at less than 32 weeks gestation, who were followed for 4 weeks following admission to a NICU in Sydney, Australia, multiplex polymerase chain reaction assays were used to determine viral presence in stool, and clinical data were examined.

RESULTS

Overall, viral RNA or DNA was detected in 24/419 (5.7%) of specimens, including norovirus genogroup 2 (1.9%), enterovirus (1.2%), herpes simplex virus-2 (1.2%), cytomegalovirus (0.7%), Epstein-Barr virus (0.5%) and rotavirus (0.2%). Viral infection was detected in 13/75 (17%) of premature neonates at some time point, including five (7%) neonates shedding more than one type of virus in stool. A higher rate of infection was observed among premature neonates with intrauterine growth restriction (56%) compared with those infants born appropriate for gestational age (12%. P = 0.006).

CONCLUSION

The overall viral detection rate in stool of 5.7% (affecting 17% of neonates) indicates viral infections are an important health risk for premature infants in NICU.

Recombinant VP1 protein expressed in Pichia pastoris induces protective immune responses against EV71 in mice

Human enterovirus 71 (EV71) is one of the major causative agents of hand, foot and mouth disease and is also associated with serious neurological diseases in children. Currently, there are no effective antiviral drugs or vaccines against EV71 infection. VP1, one of the major immunogenic capsid proteins of EV71, is widely considered to be the candidate antigen for an EV71 vaccine. In this study, VP1 of EV71 was expressed as a secretory protein with an N-terminal histidine tag in the methylotrophic yeast Pichia pastoris, and purified by Ni-NTA affinity chromatography. Immunogenicity and vaccine efficacy of the recombinant VP1 were assessed in mouse models. The results showed that the recombinant VP1 could efficiently induce anti-VP1 antibodies in BALB/c mice, which were able to neutralize EV71 viruses in an in vitro neutralization assay. Passive protection of neonatal mice further confirmed the prophylactic efficacy of the antisera from VP1 vaccinated mice. Furthermore, VP1 vaccination induced strong lymphoproliferative and Th1 cytokine responses. Taken together, our study demonstrated that the yeast-expressed VP1 protein retained good immunogenicity and was a potent EV71 vaccine candidate.

Echovirus 30 induced neuronal cell death through TRIO-RhoA signaling activation

BACKGROUND

Echovirus 30 (Echo30) is one of the most frequently identified human enteroviruses (EVs) causing aseptic meningitis and encephalitis. However the mechanism underlying the pathogenesis of Echo30 infection with significant clinical outcomes is not completely understood. The aim of this investigation is to illustrate molecular pathologic alteration in neuronal cells induced by Echo30 infection using clinical isolate from young patient with neurologic involvement.

METHODOLOGY/PRINCIPAL FINDINGS

To characterize the neuronal cellular response to Echo30 infection, we performed a proteomic analysis based on two-dimensional gel electrophoresis (2-DE) and MALDI-TOF/TOF Mass Spectrophotometric (MS) analysis. We identified significant alteration of several protein expression levels in Echo30-infected SK-N-SH cells. Among these proteins, we focused on an outstanding up-regulation of Triple functional domain (TRIO) in Echo30-infected SK-N-SH cells. Generally, TRIO acts as a key component in the regulation of axon guidance and cell migration. In this study, we determined that TRIO plays a role in the novel pathways in Echo30 induced neuronal cell death.

CONCLUSIONS/SIGNIFICANCE

Our finding shows that TRIO plays a critical role in neuronal cell death by Echo30 infection. Echo30 infection activates TRIO-guanine nucleotide exchange factor (GEF) domains (GEFD2) and RhoA signaling in turn. These results suggest that Echo30 infection induced neuronal cell death by activation of the TRIO-RhoA signaling. We expect the regulation of TRIO-RhoA signaling may represent a new therapeutic approach in treating aseptic meningitis and encephalitis induced by Echo30.

Enterovirus infections of the central nervous system

Enteroviruses (EV) frequently infect the central nervous system (CNS) and induce neurological diseases. Although the CNS is composed of many different cell types, the spectrum of tropism for each EV is considerable. These viruses have the ability to completely shut down host translational machinery and are considered highly cytolytic, thereby causing cytopathic effects. Hence, CNS dysfunction following EV infection of neuronal or glial cells might be expected. Perhaps unexpectedly given their cytolytic nature, EVs may establish a persistent infection within the CNS, and the lasting effects on the host might be significant with unanticipated consequences. This review will describe the clinical aspects of EV-mediated disease, mechanisms of disease, determinants of tropism, immune activation within the CNS, and potential treatment regimes.