Human Parechovirus 3: The Most Common Viral Cause of Meningoencephalitis in Young Infants

Respiratory Arrest in a Late Preterm Infant Presenting for a 2-Week Well-Visit

A 13-day-old, late preterm male, born appropriate for gestational age, presented to the pediatric clinic for his routine 2-week well visit with less than 1-day history of decreased oral intake and lethargy. During the baby's well exam, he acutely decompensated and required resuscitation and transfer to the emergency department, where he was intubated for frequent apneic events. He was admitted to the NICU for management and further workup. Physical examination and initial laboratory tests were unremarkable. An EEG demonstrated electrographic and clinical seizures. His initial MRI was unremarkable, and infection studies revealed the diagnosis. We review the patient's initial presentation, evaluation, hospital course, and the long-term implications of his diagnosis.

Hybrid capture shotgun sequencing detected unexpected viruses in the cerebrospinal fluid of children with acute meningitis and encephalitis

PURPOSE

Investigation of undiagnosed cases of infectious neurological diseases, especially in the paediatric population, remains a challenge. This study aimed to enhance understanding of viruses in CSF from children with clinically diagnosed meningitis and/or encephalitis (M/ME) of unknown aetiology using shotgun sequencing enhanced by hybrid capture (HCSS).

METHODS

A single-centre prospective study was conducted at Sant Joan de Déu University Hospital, Barcelona, involving 40 M/ME episodes of unknown aetiology, recruited from May 2021 to July 2022. All participants had previously tested negative with the FilmArray Meningitis/Encephalitis Panel. HCSS was used to detect viral nucleic acid in the patients' CSF. Sequencing was performed on Illumina NovaSeq platform. Raw sequence data were analysed using CZ ID metagenomics and PikaVirus bioinformatics pipelines.

RESULTS

Forty episodes of M/ME of unknown aetiology in 39 children were analysed by HCSS. A significant viral detection in 30 CSF samples was obtained, including six parechovirus A, three enterovirus ACD, four polyomavirus 5, three HHV-7, two BKV, one HSV-1, one VZV, two CMV, one EBV, one influenza A virus, one rhinovirus, and 13 HERV-K113 detections. Of these, one sample with BKV, three with HHV-7, one with EBV, and all HERV-K113 were confirmed by specific PCR. The requirement for Intensive Care Unit admission was associated with HCSS detections.

CONCLUSION

This study highlights HCSS as a powerful tool for the investigation of undiagnosed cases of M/ME. Data generated must be carefully analysed and reasonable precautions must be taken before establishing association of clinical features with unexpected or novel virus findings.

Shotgun metagenomics to investigate unknown viral etiologies of pediatric meningoencephalitis

INTRODUCTION

Meningoencephalitis in children poses a diagnostic challenge, as etiology remains unknown for most of patients. Viral metagenomics by shotgun sequencing represents a powerful tool for investigating unknown viral infections related to these cases.

PATIENTS AND METHODS

In a two-year, reference-centre, retrospective study, we investigated the usefulness of viral metagenomics of cerebrospinal fluid (CSF) for the diagnosis of viral infectious meningoencephalitis in forty seven pediatric patients, forty of them previously tested negative with a routine neurologic panel of viral targets that included herpesvirus 1-3 and enterovirus. We enhanced the detection by targeting viral sequences by hybrid capture. Raw sequence data was analysed using three bioinformatics pipelines.

RESULTS

Out of forty remaining children with meningoencephalitis of unknown viral etiology, a significant detection of viral nucleic acid by shotgun sequencing was found in twenty one, which was confirmed in ten of them by specific PCR: seven human endogenous retrovirus K113 (HER K113), one parechovirus 3, one human herpesvirus 5 (HHV5); one enterovirus B (Echovirus 9). The remaining eleven CSF were not confirmed by PCR: three rotavirus, one human herpesvirus 7 (HHV7), one influenza A, one mastadenovirus C, one sindbis virus, one torque teno virus, one human immunodeficiency virus 1 (HIV-1), one human alphaherpesvirus 3 (HHV3), one human alphaherpesvirus 2 (HHV2).

CONCLUSIONS

Underutilization of currently available meningitis-encephalitis diagnostic techniques such as BioFire® FilmArray® is the main cause of undiagnosed cases of meningoencephalitis. However, in this study we detected uncommon viruses that should be considered, including virus, rotavirus, sindbis virus, influenza A virus and HHV7. No other viral sequences that could be readily linked to CNS inflammation were detected. Some findings may stem from reagent or sample contamination, as seen with papillomavirus; for others, the clinical relevance of the virus remains uncertain and should be substantiated by further studies, as is the case with endogenous retrovirus K113 virus. Online bioinformatics pipeline CZID represents a valuable tool for analysing shotgun sequencing data in cases of neurological conditions with unknown etiology. Altogether, this study highlights the potential of shotgun sequencing in identifying previously unknown viral neuropathogens and sheds light on the interpretation issues related to its application in clinical microbiology.

Human parechovirus encephalitis in infants: a retrospective single-center study (2017-2022)

Parechoviruses cause a spectrum of clinical presentations ranging from self-limited to severe encephalitis. In July 2022, state health departments across the USA received an increase in reports of PeV infections among infants. A retrospective cohort study describing the clinical characteristics and outcomes of PeV encephalitis in infants aged < 90 days. Rates of PeV encephalitis were determined based on the number of PeV encephalitis cases out of all meningoencephalitis multiplex polymerase chain reaction panel (MEP) obtained among infants aged < 90 days per year. Out of 2115 infants evaluated for meningoencephalitis, 32 (1.5%) cases of PeV encephalitis were identified. All cases had an absence of pleocytosis and normal protein and glucose levels on CSF analysis. Half of the cases presented with a symptomatic triad (fever, rash, and fussiness). More than one-third of cases (39%) presented with a sepsis-like syndrome, 13% presented with seizures, and 25% were admitted to the pediatric intensive care unit (PICU). MRI of the brain was obtained in four of the cases presented with seizure, all of which demonstrated characteristic radiological findings of the periventricular white matter with frontoparietal predominance and involving the corpus callosum, thalami, and internal and external capsules. Rates of PeV encephalitis varied from year to year, with the highest rates in 2018 and 2022. PeV was the second most detected pathogen in MEP in both 2018 and 2022, and the fifth most detected pathogen in all positive MEP during the study period 2017-2022.

CONCLUSION

PeV can cause encephalitis and sepsis-like syndrome in infants, and it should be considered even with normal CSF parameters. Prospective studies are needed to better understand PeV epidemiology and to monitor outbreaks.

WHAT IS KNOWN

• PeV is a frequent cause of encephalitis and clinical sepsis in infants in the first 90 days. • Normal CSF parameters in PeV encephalitis and diagnostic importance of MEP to avoid unnecessary prolonged antibiotics and hospitalization.. • Centers for Disease Control and Prevention (CDC) issued a Health Advisory alert in Summer 2022 of uptick PeV encephalitis cases in the USA likely secondary of COVID-19 mitigation measures relaxation, but no comparison with previous years..

WHAT IS NEW

• Knowledge of radiological MRI brain characteristics in PeV encephalitis can be a clue diagnosis. • Knowledge of the biennial seasonality pattern in PeV infection. • PeV was the second most detected pathogen in BIOFIRE ME panel in both 2018 and 2022 in our cohort sample.

Novel Human Parechovirus 3 Diversity, Recombination, and Clinical Impact Across 7 Years: An Australian Story

BACKGROUND

A novel human parechovirus 3 Australian recombinant (HPeV3-AR) strain emerged in 2013 and coincided with biennial outbreaks of sepsis-like illnesses in infants. We evaluated the molecular evolution of the HPeV3-AR strain and its association with severe HPeV infections.

METHODS

HPeV3-positive samples collected from hospitalized infants aged 5-252 days in 2 Australian states (2013-2020) and from a community-based birth cohort (2010-2014) were sequenced. Coding regions were used to conduct phylogenetic and evolutionary analyses. A recombinant-specific polymerase chain reaction was designed and utilized to screen all clinical and community HPeV3-positive samples.

RESULTS

Complete coding regions of 54 cases were obtained, which showed the HPeV3-AR strain progressively evolving, particularly in the 3' end of the nonstructural genes. The HPeV3-AR strain was not detected in the community birth cohort until the initial outbreak in late 2013. High-throughput screening showed that most (>75%) hospitalized HPeV3 cases involved the AR strain in the first 3 clinical outbreaks, with declining prevalence in the 2019-2020 season. The AR strain was not statistically associated with increased clinical severity among hospitalized infants.

CONCLUSIONS

HPeV3-AR was the dominant strain during the study period. Increased hospital admissions may have been from a temporary fitness advantage and/or increased virulence.

Human Platelet Lysate Induces Antiviral Responses against Parechovirus A3

Human platelet lysate (hPL) contains abundant growth factors for inducing human cell proliferation and may be a suitable alternative to fetal bovine serum (FBS) as a culture medium supplement. However, the application of hPL in virological research remains blank. Parechovirus type-A3 (PeV-A3) belongs to Picornaviridae, which causes meningoencephalitis in infants and young children. To understand the suitability of hPL-cultured cells for PeV-A3 infection, the infection of PeV-A3 in both FBS- and hPL-cultured glioblastoma (GBM) cells were compared. Results showed reduced PeV-A3 infection in hPL-cultured cells compared with FBS-maintained cells. Mechanistic analysis revealed hPL stimulating type I interferon (IFN) antiviral pathway, through which phospho-signal transducer and activator of transcription 1 (STAT1), STAT2, interferon regulatory factor 3 (IRF3) were activated and antiviral genes, such as IFN-α, IFN-β, and Myxovirus resistance protein 1 (MxA), were also detected. In addition, an enhanced PeV-A3 replication was detected in the hPL-cultured GBM cells treated with STAT-1 inhibitor (fludarabine) and STAT1 shRNA. These results in vitro suggested an unexpected effect of hPL-activated type I IFN pathway response to restrict virus replication and that hPL may be a potential antiviral bioreagent.

Clinical profile of children with parechovirus meningitis in Singapore

Human parechovirus (HPeV) is one of the most common causes of aseptic meningitis in children worldwide. This study aims to review the epidemiology, clinical presentation, and cerebrospinal fluid (CSF) findings in HPeV meningitis and compare these with Enterovirus (EV) meningitis. This is a retrospective study of children aged ≤ 1 year admitted for HPeV meningitis between November 2015 and July 2017, with positive CSF HPeV PCR and negative blood and CSF bacterial cultures. The clinical findings were compared with a historical cohort of children with EV meningitis admitted between July 2008 and July 2011. There were 71 children with HPeV meningitis, aged between 2 and 127 days, with the majority (96%) being ≤ 90 days old. The most common symptoms reported were poor feeding (42%), tachycardia out of proportion to fever (27%), and lethargy (20%). Only 2 patients (3%) had CSF pleocytosis. Cerebral spinal fluid white blood cell counts ranged from 0 to 28 cells/mm³, with a median of 3 cells/mm³ [interquartile range (IQR) 1-6 cells/mm³]. When compared to our historical cohort of EV meningitis ≤ 90 days old, children with HPeV meningitis ≤ 90 days old were less likely to have CSF pleocytosis (OR 0.008, 95% CI 0.001-0.057). HPeV and EV meningitis are known to cause sepsis-like illness in infants < 90 days old. This study further supports this, with the requirement for fluid bolus therapy for tachycardia or poor perfusion noted to be higher in children with HPeV meningitis ≤ 90 days old (OR 6.3, 95% CI 2.7-14.2).

Infectious exanthemas in childhood

Most childhood exanthemas are harmless. However, recognizing serious diseases with life-threatening complications at an early stage is important for the timely initiation of adequate therapy. This requires knowledge of the specific patterns of the exanthema, obtained from the medical history and the clinic, including the patient's general condition and physical examination. In unclear cases, additional diagnostic measures are undertaken, such as blood tests and smears (cutaneous, mucocutaneous). Viruses are the most common cause of childhood exanthemas. New variants of infectious agents, improved diagnostics and stays in tropical and subtropical countries have expanded the spectrum of infectious exanthemas.

Maternal parechovirus A (PeV-A) shedding, serostatus, and the risk of central nervous system PeV-A infections in infants

BACKGROUND

Parechovirus A (PeV-A) has emerged as a leading cause of infant central nervous system (CNS) infections. Risk factors associated with infant acquisition of PeV-A are not well understood.

METHODS

We conducted prospective PeV-A/enterovirus (EV) CNS infection surveillance, enrolling 461 hospitalized infants <90 days old who underwent sepsis evaluations and lumbar puncture during 2011-2012. Infants were grouped by RT-PCR detection of PeV-A, EV, or neither virus (Neg) in CSF. We collected demographic/clinical data and tested specimens from all infants. For 427 mothers, we collected demographic/clinical data and evaluated PeV-A3 and EV shedding, and PeV-A3 neutralizing antibody for 147 mothers.

RESULTS

PeV-A was detected in 40 infants (8.7%), 4 in 2011 and 36 in 2012. EV was detected in 35 infants (7.6%), 16 in 2011, and 19 in 2012. PeV-A infected infants presented with irritability, abdominal discomfort, fever, and tachycardia, plus both lymphopenia and absence of CSF pleocytosis which help differentiate PeV-A from EV CNS infection. PeV-A was detected in 9/427 maternal throat swabs; eight of their infants also had PeV-A CNS infection. Infants whose mothers had PeV-A3-positive throat swabs were more likely to be PeV-A3-positive than infants whose mothers had negative throat swabs (relative risk [RR], 13.4 [95% CI, 8.6 - 20.7]). Maternal PeV-A3 seropositivity decreased with increasing maternal age. Mothers of PeV-A-positive infants had lower median PeV-A3 neutralizing titers and were more likely seronegative.

CONCLUSIONS

Maternal viral shedding, serostatus and neutralization titers appear to be important factors in infant PeV-A3 CNS infections.

HPeV3-associated acute encephalitis/encephalopathy among Japanese infants

OBJECTIVE

The current study aimed to identify and compare the clinical characteristics of human parechovirus type 3 (HPeV3)-associated acute encephalitis/encephalopathy (HPeV3E/E) between infants with abnormal brain magnetic resonance imaging (MRI) findings (typical, or MRI-positive HPeV3E/E) and those with MRI-negative findings (MRI-negative HPeV3E/E).

METHODS

This is a retrospective study on patients with HPeV3 infection, and a two-step questionnaire survey performed on 837 hospitals in Japan between 2014 and 2016.

RESULTS

We identified 240 infants with HPeV3 infection, of which 34 had been clinically-diagnosed HPeV3E/E (cHPeV3E/E). However, detailed clinical data were provided by 32 of the 34 patients. Among these 32, 23 had undergone MRI and were categorized into two groups, MRI-positive (n = 17) and -negative (n = 6). There were no significant intergroup differences in clinical lab results or symptoms, except for gastrointestinal symptoms that were only present in the MRI-negative patients. The MRI-positive group showed white matter involvement on brain MRI during the acute phase, and 8 patients presented with lesions on follow-up MRI. Furthermore, 4 (50%) of the 8 patients had neurological sequelae.

CONCLUSION

Clinical characteristics of cHPeV3E/E patients with and without lesions on brain MRI showed no significant differences. Therefore, considering the difficulty in distinguishing febrile infants with cHPeV3E/E from those with a sepsis-like illness, during an HPeV3 infection epidemic, it is imperative to frequently perform brain MRI in febrile infants presenting with severe disease for the early diagnosis of HPeV3E/E presenting with brain lesions.

Innate Immune Responses in Serum and Cerebrospinal Fluid From Neonates and Infants Infected With Parechovirus-A3 or Enteroviruses

BACKGROUND

Parechovirus (PeV)-A3 and enteroviruses (EV) are the most common viruses causing sepsis and meningoencephalitis in neonates and young infants. Clinical manifestations of PeV-A3 infection are more severe than those of EV infection, and no pleocytosis with a positive polymerase chain reaction (PCR) result for PeV-A3 in cerebrospinal fluid (CSF) are characteristic findings. We hypothesized that innate immune responses to PeV-A3 and EV are distinct in serum and CSF.

METHODS

We evaluated 22 cytokines/chemokines in serum and CSF from PeV-A3- or EV-infected patients younger than 4 months in Niigata, Japan, from 2015 through 2018. Infection was diagnosed with real-time PCR followed by sequencing. Febrile neonates and infants with sepsis-like syndrome who had negative bacterial culture and viral PCR for both PeV-A and EV were also included (non-PeV-A/EV patients).

RESULTS

Among 192 febrile patients, we evaluated 16 PeV-A3-infected, 15 EV-infected, and 8 non-PeV-A/EV patients. Serum pro-/anti-inflammatory cytokine/chemokine levels were higher in PeV-A3-infected patients than in EV-infected patients (P < .02). Although most cytokine/chemokine were elevated in CSF from EV-infected patients, levels were low or undetectable in PeV-A3-infected and non-PeV-A/EV patients (P < .001).

CONCLUSIONS

Distinct cytokine/chemokine patterns in serum and CSF may explain the different clinical manifestations of PeV-A3-infected and EV-infected neonates and young infants.

Year-Round, Routine Testing of Multiple Body Site Specimens for Human Parechovirus in Young Febrile Infants

OBJECTIVES

To test our hypothesis that routine year-round testing of specimens from multiple body sites and genotyping of detected virus would describe seasonal changes, increase diagnostic yield, and provide a better definition of clinical manifestations of human parechovirus (PeV-A) infections in young febrile infants.

STUDY DESIGN

PeV-A reverse-transcriptase polymerase chain reaction (RT-PCR) analysis was incorporated in routine evaluation of infants aged ≤60 days hospitalized at Nationwide Children's Hospital for fever and/or suspected sepsis-like syndrome beginning in July 2013. We reviewed electronic medical records of infants who tested positive for PeV-A between July 2013 and September 2016. Genotyping was performed with specific type 3 RT-PCR and sequencing.

RESULTS

Of 1475 infants evaluated, 130 (9%) tested positive for PeV-A in 1 or more sites: 100 (77%) in blood, 84 (65%) in a nonsterile site, and 53 (41%) in cerebrospinal fluid (CSF). Five infants (4%) were CSF-only positive, 31 (24%) were blood-only positive, and 20 (15%) were nonsterile site-only positive. PeV-A3 was the most common type (85%) and the only type detected in CSF. Although the majority (79%) of infections were diagnosed between July and December, PeV-A was detected year-round. The median age at detection was 29 days. Fever (96%), fussiness (75%), and lymphopenia (56%) were common. Among infants with PeV-A-positive CSF, 77% had no CSF pleocytosis. The median duration of hospitalization was 41 hours. Four infants had bacterial coinfections diagnosed within 24 hours of admission; 40 infants had viral coinfections.

CONCLUSIONS

Although most frequent in summer and fall, PeV-A infections were encountered in every calendar month within the 3-year period of study. More than one-half of patients had PeV-A detected at more than 1 body site. Coinfections were common. PeV-A3 was the most common type identified and the only type detected in the CSF.

Clinical Signs, Prevention and Treatment of Viral Infections in Infants

Certain infectious diseases are common in infants than any other age groups and are associated with morbidities in childhood and adulthood, and even mortality in severe cases. Environment, epidemic and maternal immunity are the main causes of these infections. Early diagnosis using molecular methods and treatment is therefore important to prevent future complications. Vaccines are recommended during infancy and childhood to prevent these infections. This review highlights some of the most commonly reported viral infections in children, their clinical signs, prevention and treatment.

Mittens and Booties Syndrome: A Unique Manifestation of Human Parechovirus Infection in Infants

We describe the first 2 cases from the United States, of human parechovirus infection in infants manifesting a distinct rash of the hands and feet. We propose the term "Mittens and Booties Syndrome" and provide a review of the literature of all published cases.

Persistence of High Neutralizing Antibody Titers After Neonatal and Early Infantile Infection with Parechovirus-A3

This 3-year follow-up study evaluated neutralizing antibody titers (NATs) against parechovirus-A3 (PeV-A3) in neonates and young infants who developed PeV-A3 infection. All children had low NATs at disease onset and high NATs after infection during infancy. At age 3 years, all 16 patients tested had high NATs (≥1:512) against PeV-A3 indicating that specific PeV-A3 NATs persist into childhood.

First reported case of Human Parechovirus encephalitis in an adult patient complicated by Refractory Status Epilepticus

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Human Parechovirus (HPeV) infections are common amongst young children. However, data in adult cases are lacking.

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We report a unique case of HPeV meningoencephalitis in an adult complicated by Refractory Status Epilepticus (RSE).

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This case expands the epidemiological knowledge of HPeV and when to test for it in adults.

Human Parechovirus (HPeV) infections are common amongst children, particularly neonates. However, data in adult cases are lacking. We report a unique case of HPeV meningoencephalitis in an adult complicated by Refractory Status Epilepticus (RSE).

A Case Series of Parechovirus Encephalopathy: Apnea and Autonomic Dysregulation in Critically Ill Infants

This article aims to describe a rare cause of severe encephalitis in 2 cases of infants with signs of intracranial hypertension and severe autonomic dysregulation. The authors conclude that human parechoviruses are becoming a more recognized cause of encephalitis because of the increasing use of rapid detection methods. With early recognition of this clinical entity, improved care can be administered.

Impact of Cerebrospinal Fluid Multiplex Assay on Diagnosis and Outcomes of Central Nervous System Infections in Children: A Before and After Cohort Study

BACKGROUND

This study evaluated the performance of cerebrospinal fluid multiplex assay in the diagnosis of pediatric central nervous system (CNS) infection, and assessed for the effect on clinical management.

METHODS

A 15-month prospective cohort of pediatric patients with confirmed CNS infection was compared with a 15-month retrospective cohort from the Top End region of the Northern Territory, Australia. The study characterized all the CNS infections over the 30-month period and compared the time to organism identification and antibiotic management before and after the introduction of the multiplex assay.

RESULTS

Thirty-six cases of pediatric CNS infection were diagnosed before the introduction of the multiplex assay, and 29 afterwards. Multiplex assay was performed on 26/29 (90%) of the cerebrospinal fluid isolates from children with confirmed CNS infections in the prospective cohort. Enterovirus was the most common causative organism identified in 14 children, followed by human parechovirus in 4 children. The multiplex assay performed with 93.8% sensitivity and 90.0% specificity when compared with microbiologic culture or reference laboratory results. The median time to organism identification reduced from 6.0 to 2.0 days (P value <0.001), the median duration of antibiotic therapy from 3.0 to 2.0 days (P value <0.001) and median hospitalization reduced from 5.0 to 3.0 days (P value 0.016) after introduction of the multiplex assay.

CONCLUSIONS

The multiplex assay is a useful adjunct diagnostic tool enabling prompt organism identification and reducing antibiotic treatment and hospitalization duration. The assay would be of most value to hospitals that do not have access to an onsite molecular laboratory.

Retrospective Evaluation of Infants Aged 1 to 60 Days with Residual Cerebrospinal Fluid (CSF) Tested Using the FilmArray Meningitis/Encephalitis (ME) Panel

In pediatric practice it is common for infants under 2 months of age to undergo evaluation for sepsis when they are ill, often including lumbar puncture to assess for central nervous system (CNS) infection. The FilmArray Meningitis/Encephalitis (ME) panel is a newly approved test for rapid identification of CNS pathogens. Our objective was to study the epidemiology of CNS infection in young infants and the potential impact of rapid multiplex PCR on their care. A performance evaluation of the FilmArray ME panel was conducted from February 2014 to September 2014 at 11 sites. FilmArray ME panel results were compared to reference standards but not shared with providers. In our study, medical records for infants (aged 1 to 60 days) enrolled at three sites were reviewed for clinical, laboratory, and outcome data. A total of 145 infants were reviewed. The median age was 25 days. Most of the infants were hospitalized (134/145 [92%]) and received antibiotics (123/145 [85%]), and almost half (71/145 [49%]) received acyclovir. One infant had a bacterial pathogen, likely false positive, identified by the FilmArray ME panel. Thirty-six infants (25%) had a viral pathogen detected, including 21 enteroviruses. All infants with enteroviral meningitis detected by the FilmArray ME panel and conventional PCR were hospitalized, but 20% were discharged in less than 24 h when conventional PCR results became available. The FilmArray ME panel may play a role in the evaluation of young infants for CNS infection. Results may be used to guide management, possibly resulting in a decreased length of stay and less antimicrobial exposure for infants with low-risk viral infection detected.

Analytical validation of viral CNS Flow Chip kit for detection of acute meningitis and encephalitis

A new molecular assay (Viral CNS Flow Chip kit, Master Diagnóstica, Spain) has been developed for the detection of eight viruses causing acute meningitis and encephalitis, i.e. herpes simplex viruses 1-2, varicella zoster virus, human enterovirus, human parechovirus, Toscana virus, human cytomegalovirus and Epstein Barr virus. The new assay is a multiplex one-step RT-PCR followed by automatic flow-through hybridization, colorimetric detection and image analysis. The limit of detection was 50 copies/reaction, and 10 copies/reaction for human enterovirus and the other seven viruses, respectively. The analytical validation was performed with nucleic acids extracted from 268 cerebrospinal fluid samples and the results were compared with routine molecular assays. An excellent coefficient of agreement was observed between V-CNS and routine assays [kappa index: 0.948 (95%CI: 0.928-0.968)]. The overall sensitivity and specificity was 95.9% (95%CI: 91.2-98.3%) and 99.9% (95%CI: 99.6-100%), respectively. Viral CNS Flow Chip kit is an efficient multiplex platform for the detection of the main viruses involved in acute meningitis and encephalitis. The inclusion of a TOSV genome target may improve the laboratory diagnosis of viral neurological infections in endemic areas.

Severe Parechovirus 3 Infections in Young Infants-Kansas and Missouri, 2014

BACKGROUND

Infection with parechovirus type 3 (PeV3) can cause severe neurologic and sepsis-like illness in young infants; clinical and epidemiologic descriptions have been limited. We aimed to characterize PeV3 illness and explore risk factors for acquisition in a cluster of neonatal cases at Children's Mercy Hospital in Kansas City, Missouri.

METHODS

Cerebrospinal fluid specimens were obtained from infants aged <180 days who were hospitalized with sepsis-like illness or meningitis between June 1 and November 1, 2014. PeV-positive specimens were sequenced at the Centers for Disease Control and Prevention. We reviewed the medical and birth charts of the infants and performed face-to-face parent interviews. We analyzed characteristics according to infant age and intensive care admission status.

RESULTS

We identified 35 cases of PeV infection in infants aged 5 to 56 days. Seven infants required intensive care (median age, 11 days vs 27 days among those who did not require intensive care; P = .0044). Six of these 7 infants had neurologic manifestations consistent with seizures, and all 6 of them were treated with acyclovir but subsequently tested negative for herpes simplex virus. Virus sequences formed 2 lineages, both of which were associated with severe illness. Half of the infants were reported to have household contacts who were ill during the week before onset. Infants aged ≤7 days at onset were more likely to have been delivered at the same hospital.

CONCLUSIONS

PeV3 can cause severe neurologic illness in neonates, and younger infants are more likely to require intensive care. PeV3 should be considered along with herpes simplex virus and other pathogens when evaluating young infants with sepsis-like illness or meningitis. More widespread testing for PeV3 would enable us to gain a better understanding of the clinical scope and circulation of this virus.

Neonatal nonpolio enterovirus and parechovirus infections

Nonpolio enteroviruses and parechoviruses are frequent causes of neonatal infection. Clinical manifestations of infection range from asymptomatic infection to mild infection without sequelae to septic shock with muiltiorgan failure. Neonates with clinically apparent infection typically have mothers and/or other contacts with recent symptoms consistent with a viral illness. Severe neonatal infection with nonpolio enterovirus or parechovirus cannot be differentiated clinically from serious bacterial infection. The preferred method for diagnosing neonatal nonpolio enterovirus or parechovirus infection is PCR as it is rapid, sensitive, specific, and commercially available for the detection of virus from various clinical specimens. Investigational agents such as the capsid inhibitors pleconaril and pocapavir show promise for treatment of neonatal enterovirus infections, and other investigational agents are being developed. This review focuses on the epidemiology, diagnosis, and treatment of neonatal nonpolio enterovirus and parechovirus infections.

Encephalitis in US Children

Encephalitis is an uncommon but severe disease characterized by neurologic dysfunction with central nervous system inflammation. Children with encephalitis should receive supportive care and empiric therapies for common and treatable causes while prioritizing diagnostic evaluation for common, treatable, and high-risk conditions. Even with an extensive diagnostic workup, an infectious cause is identified in less than half of cases, suggesting a role for postinfectious or noninfectious processes.

Clinical features and seasonality of parechovirus infection in an Asian subtropical city, Hong Kong

BACKGROUND

The epidemiology of human parechovirus (HPeV) in Asia remains obscure. We elucidated the prevalence, seasonality, type distribution and clinical presentation of HPeV among children in Hong Kong.

METHODS

A 24-month prospective study to detect HPeV in children ≤36 months hospitalized for acute viral illnesses.

RESULTS

2.3% of the 3911 children examined had HPeV infection, with most (87.5%) concentrated in September-January (autumn-winter). 81.3% were HPeV1 and 12.5% were HPeV4, while HPeV3 was rare (2.5%). HPeV was a probable cause of the disease in 47.7% (42/88), mostly self-limiting including acute gastroenteritis, upper respiratory tract infection and maculopapular rash. A neonate developed severe sepsis-like illness with HPeV3 as the only pathogen detected. A high proportion (60.0%) of children coinfected with HPeV and other respiratory virus(es) had acute bronchiolitis or pneumonia. Six children with HPeV coinfections developed convulsion / pallid attack. Most rash illnesses exhibited a generalized maculopapular pattern involving the trunk and limbs, and were more likely associated with HPeV4 compared to other syndrome groups (36.4% vs. 3.1%, p = 0.011).

CONCLUSIONS

In Hong Kong, HPeV exhibits a clear seasonality (autumn-winter) and was found in a small proportion (2.3%) of young children (≤36 months) admitted with features of acute viral illnesses. The clinical presentation ranged from mild gastroenteritis, upper respiratory tract infection and febrile rash to convulsion and severe sepsis-like illness. HPeV3, which is reported to associate with more severe disease in neonates, is rare in Hong Kong. HPeV coinfection might associate with convulsion and aggravate other respiratory tract infections.

The Viruses of the Gut Microbiota

The gut virome is the viral component of the gut microbiome. Knowledge regarding its composition, interindividual and temporal variability is increasing, and the significance of its impact on human health, both in homeostasis and disease is being recognized. Here we review the recent advances in this field, and the questions that arise in the context of the rapidly increasing information regarding its composition and function. With the extending collection of human data, the power of next generation sequencing, and functional studies, the factors that influence the composition of the gut virome and its impact on human health will be further refined in the coming years.

Extreme Hyperferritinemia in Dizygotic Twins With Human Parechovirus-3 Infection

Human parechovirus-3 has been associated with severe clinical manifestations in infants, such as sepsis-like illness and meningoencephalitis. Nevertheless, the vast majority of patients have a favorable outcome. We report the occurrence of this infection in dizygotic infants with extreme hyperferritinemia and a transient impairment of natural killer cell cytotoxicity.

Human parechovirus and enterovirus initiate distinct CNS innate immune responses: Pathogenic and diagnostic implications

BACKGROUND

Human parechovirus (HPeV) and enterovirus (EV) cause a range of human diseases including serious CNS infections. Little is known regarding the immune response to HPeV meningitis compared to EV meningitis or how the immune response to HPeV reflects its pathogenesis.

OBJECTIVE

To characterize the innate immune response to HPeV CNS infection in order to increase our understanding of HPeV pathogenesis and possibly help identify HPeV in the clinical setting.

STUDY DESIGN

CSF samples from 13 patients with HPeV meningitis, 7 patients with EV meningitis, and 11 patients negative for CNS infections were analyzed for chemokines/cytokines using multiplex ELISA assays.

RESULTS

CSF levels of the majority of cytokines/chemokines analyzed were significantly higher in patients with EV meningitis (EV group) compared to patients with HPeV meningitis (HPeV group) and controls. In the HPeV group, a small number of cytokine/chemokine levels were higher than controls; however, these levels were either significantly lower or not significantly different compared to the EV group. IL-6 levels were lower in HPeV than in both EV and controls.

CONCLUSIONS

The immune response to HPeV CNS infection differs from that of EV. Distinct patterns of cytokine/chemokine expression in HPeV infections suggest HPeV-mediated modulation of the immune response. HPeV disrupts the interferon cascade and seems to interfere with early inflammatory signaling. Although HPeV elicits a predominantly muted immune reaction, a partial, general infectious-type cytokine/chemokine response does occur. Beyond providing insight into HPeV pathogenesis, the identified cytokine/chemokine profile may aid in early detection of HPeV infection.

Genome analysis revealed novel genotypes and recombination of the human parechoviruses prevalent in children in Eastern China

BACKGROUND

Human parechovirus (HPeV) is a genus of virus in the family Picornaviridae, having two species A and B. HPeVs are common infectious agents, usually causing mild diarrhea and respiratory disease in young children.

RESULTS

Here, we collected and sequenced the near complete genome sequences of 17 novel HPeVs from children with diarrhea in eastern China, which showed significant nucleotide sequence divergence. Phylogenetic analysis based on the complete genomes of these HPeV strains revealed that they belonged to seven different genotypes (including three putative novel genotypes), suggesting that HPeVs showed genotype diversity in this area. Recombination analysis indicated that one of the HPeVs, belonging to HPeV-1 with strain name 146Chzj02, was a recombinant generated by inter-genotype recombination among three HPeV strains belonging to three different genotypes, respectively.

CONCLUSION

Our data revealed the property of the genotype diversity of HPeVs prevalent in children with diarrhea in eastern China, which will be helpful in the future study of the viral evolution of HPeVs and the identification and typing of HPeVs in the clinical laboratory.