High prevalence of developmental concern amongst infants at 12 months following hospitalised parechovirus infection

Neurodevelopmental Outcomes Following Childhood Viral Meningitis in Canterbury New Zealand

BACKGROUND

Most childhood meningitis is viral in countries with widespread conjugate vaccine use. This study assessed clinical features and neurodevelopmental outcomes in preschool children following enteroviral and parechoviral meningitis.

METHODS

Children 18-42 months of age in Canterbury, New Zealand were included, who had enterovirus (EV) or parechovirus (HPEV) meningitis from 2015 to 2021. Comprehensive neurodevelopmental assessments were completed by a psychologist using the Bayley Scale for Infant Development-3 (BSID-3). Mean composite and scaled scores and proportion below the cutoff were assessed in each domain. Clinical data was analyzed.

RESULTS

There were 79 children 18-42 months old with previous EV or HPEV meningitis. BSID assessments were completed for 33 children (55% male), median age 32 months, from 2019 to 2022 including 23 with EV and 10 HPEV meningitis. At diagnosis, 32 (97%) received intravenous/intramuscular antibiotics, and 6 received a fluid bolus. Parents reported developmental speech concerns in 6 children, and delayed motor milestones in 1 child. There was no reported sensorineural hearing loss. BSID mean composite scores were in the expected range for cognition 102 (confidence interval: 98-106), language 96 (93-100) and motor 102 (98-106) domains. Overall, 12/33 (36%) children had below expected scores in 1 developmental domain, including scores 1-2 SD below the normative mean for cognition (2/33; 6%), receptive language (6/33; 18%), expressive language (5/33; 15%) and gross motor (6/33; 18%). There were no differences between scores in EV and HPEV meningitis.

CONCLUSION

Following viral meningitis, more than a third of preschool children had a mild developmental delay with comprehensive neurodevelopmental assessment, suggesting targeted follow-up should be considered.

The evolutionary phylodynamics of human parechovirus A type 3 reveal multiple recombination events in South Korea

Human parechovirus A (HPeV-A) is a causative agent of respiratory and gastrointestinal illnesses, acute flaccid paralysis encephalitis, meningitis, and neonatal sepsis. To clarify the characteristics of HPeV-A infection in children, 391 fecal specimens were collected from January 2014 to October 2015 from patients with acute gastroenteritis in Seoul, South Korea. Of these, 221/391 (56.5%) HPeV-A positive samples were found in children less than 2 years old. Three HPeV-A genotypes HPeV-A1 (117/221; 52.94%), HPeV-A3 (100/221; 45.25%), and HPeV-A6 (4/221; 1.81%) were detected, among which HPeV-A3 was predominant with the highest recorded value of 58.6% in 2015. Moreover, recombination events in the Korean HPeV-A3 strains were detected. Phylogenetic analysis revealed that the capsid-encoding regions and noncapsid gene 2A of the four Korean HPeV-A3 strains are closely related to the HPeV-A3 strains isolated in Canada in 2007 (Can82853-01), Japan in 2008 (A308/99), and Taiwan in 2011 (TW-03067-2011) while noncapsid genes P2 (2B-2C) and P3 (3A-3D) are closely related to those of HPeV-A1 strains BNI-788St (Germany in 2008) and TW-71594-2010 (Taiwan in 2010). This first report on the whole-genome analysis of HPeV-A3 in Korea provides insight into the evolving status and pathogenesis of HPeVs in children.

Early life parechovirus infection neuropsychological outcomes at 8 years: a cohort study

Human parechovirus (HPeV) is a leading cause of Central Nervous System (CNS) infection in infancy. Despite this, little is known regarding the long-term neuropsychological impacts from HPeV infection. The aim of the present study was to explore the long-term neuropsychological impacts eight-year post-HPeV infection contracted during infancy. This study also aimed to investigate the differential impacts of HPeV itself compared to the effects of secondary meningitis (n = 23) or encephalitis (n = 3) associated with HPeV infection. Thirty-nine HPeV children participated in the study. Children completed performance-based measures of neuropsychological and language functioning (the Wechsler Abbreviated Scale of Intelligence, the Clinical Evaluation of Language Fundamentals - Fourth Edition, and the Test of Everyday Attention for Children). Parents completed questionnaire-based measures of emotional, behavioral, and pragmatic language functioning (the Behaviour Rating Inventory of Executive Functioning, the Child Behavior Checklist, and the Social Communication Questionnaire). Results revealed that, overall, children with HPeV were significantly more impaired on measures of selective, sustained, and divided attention compared to normative test populations. The current study incidentally found at least double the prevalence of Attention-Deficit/Hyperactivity Disorder (ADHD) in the HPeV sample than what is typical in the normal population, suggesting that HPeV infection during infancy may be a risk factor for the later development of ADHD. Additionally, the presence of secondary meningitis or encephalitis did not relate to poorer neuropsychological outcomes in the current sample. The findings of this study have important implications regarding clinical management for children following HPeV infection in infancy.

Human parechovirus meningitis in children: state of the art

Human Parechovirus is a common cause of infection occurring especially during the first years of life. It may present with a broad spectrum of manifestations, ranging from a pauci-symptomatic infection to a sepsis-like or central nervous system disease. Aim of this study is to explore the knowledge on Parechovirus meningitis. According to the purpose of the study, a systematic review of the literature focusing on reports on central nervous system. Parechovirus infection of children was performed following PRISMA criteria. Out of the search, 304 papers were identified and 81 records were included in the revision dealing with epidemiology, clinical manifestations, laboratory findings, imaging, therapy and outcome. Parechovirus meningitis incidence may vary all over the world and outbreaks may occur. Fever is the most common symptom, followed by other non-specific signs and symptoms including irritability, poor feeding, skin rash or seizures. Although several reports describe favourable short-term neurodevelopmental outcomes at discharge after Parechovirus central nervous system infection, a specific follow up and the awareness on the risk of sequelae should be underlined in relation to the reported negative outcome. Evidence seems to suggest a correlation between magnetic imaging resonance alteration and a poor outcome.

Disruption of seasonal enterovirus and parechovirus detections in the CSF and plasma of children during the COVID-19 pandemic

BACKGROUND

Enteroviruses (EV) and parechovirus (PeV) are a common cause of CNS infection in children. Both viruses demonstrate consistent seasonal patterns, with detections mainly in the summer-fall months. While research has shown COVID-19 pandemic-related disruption of traditional seasonality of respiratory pathogens, the pandemic's impact on non-respiratory pathogens is less understood. The aim of this study was to quantify the EV/PeV seasonal variations during pre-COVID years compared to variations observed during the COVID pandemic.

METHODS

Patients with EV/PeV testing of CSF/plasma between January 2012 through September 2022 were identified. Restricted cubic spline methods were used to model the detections. Poisson models were utilized to model pre-COVID (2012-2019) EV/PeV detections. The expected seasonal trends from these models were then compared to the observed EV/PeV detections during the COVID pandemic (2020-2022).

RESULTS

A total of 5199 patients were included. The annual pre-pandemic proportion of EV detections ranged between 7.5%-20.3%. PeV exhibited a biennial pattern with peak proportions between 8.0%-16.3%. EV/PeV detections during the COVID pandemic period, especially during 2020 and 2021, were considerably lower than would have been expected based on pre-pandemic modeling. However, PeV detections from January through September 2022 nearly reached the pre-pandemic modeled expectation, including instances of exceeded expectations.

CONCLUSIONS

A significant disruption in expected seasonal EV/PeV detections was observed during the early phases of the COVID-19 pandemic. However, testing that occurred during summer-fall of 2022, when social mitigation initiatives were relaxed, showed a rapid increase in detections. Additional data are needed to further understand which public health initiatives are effective at decreasing EV/PeV transmission.

Parechovirus infection in infants: Evidence-based parental counselling for paediatricians

AIM

Human parechovirus (HPeV) is an increasingly recognised cause of severe illness and central nervous system infection in infants. Medium- to long-term neurodevelopmental outcomes post-HPeV infection remain unknown. This study aims to assess neurodevelopmental outcomes for children hospitalised as infants with HPeV infection in their second and third years of life.

METHODS

This prospective cohort study followed children hospitalised with HPeV in Brisbane, Queensland during the 2017/2018 outbreak. Serial application of Ages and Stages Questionnaire (ASQ) was used to assess developmental progress in the second and third years of life. Data from clinical follow-up, audiology and neuroradiology were included.

RESULTS

In the second year of life, 63% (n = 29) of children showed some or significant concerns for developmental delay. This had largely been ameliorated by the third year of life when only 30% (n = 14) reported developmental concerns. Prematurity and apnoeas were associated with developmental concerns at 27-36 months of age. Communication was the most common domain of concern.

CONCLUSIONS

The majority of infants hospitalised with HPeV infection in 2017-2018 showed normalisation of developmental progress by 27-36 months of age. Further investigation into more subtle neurological impairments in later childhood is required. These results can help guide clinicians in counselling parents during the acute illness and in planning appropriate follow-up.

Monoclonal antibody against VP0 recognizes a broad range of human parechoviruses

Parechoviruses (PeVs) are common viruses that cause mild gastrointestinal or respiratory symptoms to severe central nervous system infections. In infants, parechovirus infection is one of the leading causes of life-threatening viral disease. High-quality antibodies with broad binding specificities are essential to improve accurate parechovirus diagnosis in diagnostic laboratories. Such antibodies have potential in the development of rapid antigen detection assay against PeVs. In the present study, VP4 and VP2 genes from human parechovirus A1 (PeV-A1) were cloned and VP0 fusion protein produced to develop monoclonal antibodies against PeVs. Two pan-parechovirus antibodies, one IgG and one IgM isotype, were isolated. The properties of IgG1/κ monoclonal (designated as Mab-PAR-1) was studied further. Mab-PAR-1 was shown to be functional in western blot against denatured recombinant protein and viral particles. In immunofluorescence assay, the antibody tested positive for nineteen PeV-A1 isolates while showing no cross-reactivity to fourteen entero- and rhinovirus types. In addition, Mab-PAR-1 showed positive reactivity against five other cultivable parechovirus types 2-6. A unique Mab-PAR-1 epitope located in the junction of the three capsid proteins VP0, VP1, and VP3 was identified using a peptide library screen. This study demonstrates that PeV-A1-VP0 protein is functional antigen for developing monoclonal antibody for diagnosis of broad range of parechovirus infections.

Childhood Outcomes Following Parechovirus Infections in a US Young Infant Cohort

BACKGROUND

Parechovirus A type 3 (PeV-A3) is associated with central nervous system infection in young infants. There are limited data regarding long-term outcomes, mostly reported from Australia and European populations. The objective of this study was to assess frequency of neurodevelopmental impairment (NDI) following PeV-A3 infection in our US cohort.

METHODS

Infants hospitalized during the 2014 outbreak with laboratory-confirmed PeV-A3 infection were evaluated with medical history, neurologic examination, parental completion of Ages and Stages Questionnaire and developmental assessment using Bayley Scales of Infant and Toddler Development, Third Edition cognitive, motor and language quotients. Determination of NDI was based on published criteria. Relationship of severity of PeV disease to outcome measures was determined using Fisher exact, χ2 and Mann-Whitney U test as appropriate.

RESULTS

Nineteen children, term gestation, were evaluated at ~3 years of age; PeV-A3 illness was uncomplicated for 6 (32%), complex, non-neurologic for 9 (47%) and encephalitis/seizures for 4 (21%). No differences were noted in mean Bayley Scales of Infant and Toddler Development, Third Edition quotients between infants by clinical presentation. Quotients for all were within 1 SD of population norms. Two (11%) children had mild NDI; 1 with mild cerebral palsy. Ages and Stages Questionnaire results included 11% at referral level and 37% suspect concern. Parents of 6 (32%) noted behavior concerns. These findings were unrelated to severity of the PeV-A3 illness.

CONCLUSIONS

Parent concerns were identified frequently following infant PeV-A3 disease. Eleven percent had neurodevelopmental impairment at 3 years of age. Severity at presentation did not correlate with adverse childhood outcomes. Longitudinal developmental monitoring following infantile PeV-A3 disease is warranted.

Parechovirus A Infections in Healthy Australian Children During the First 2 Years of Life: A Community-based Longitudinal Birth Cohort Study

Background

Hospital-based studies identify parechovirus (PeV), primarily PeV-A3, as an important cause of severe infections in young children. However, few community-based studies have been published and the true PeV infection burden is unknown. We investigated PeV epidemiology in healthy children participating in a community-based, longitudinal birth cohort study.

Methods

Australian children (n = 158) enrolled in the Observational Research in Childhood Infectious Diseases (ORChID) study were followed from birth until their second birthday. Weekly stool and nasal swabs and daily symptom diaries were collected. Swabs were tested for PeV by reverse-transcription polymerase chain reaction and genotypes determined by subgenomic sequencing. Incidence rate, infection characteristics, clinical associations, and virus codetections were investigated.

Results

PeV was detected in 1423 of 11 124 (12.8%) and 17 of 8100 (0.2%) stool and nasal swabs, respectively. Major genotypes among the 306 infection episodes identified were PeV-A1 (47.9%), PeV-A6 (20.1%), and PeV-A3 (18.3%). The incidence rate was 144 episodes (95% confidence interval, 128–160) per 100 child-years. First infections appeared at a median age of 8 (interquartile range, 6.0–11.7) months. Annual seasonal peaks changing from PeV-A1 to PeV-A3 were observed. Infection was positively associated with age ≥6 months, summer season, nonexclusive breastfeeding at age <3 months, and formal childcare attendance before age 12 months. Sole PeV infections were either asymptomatic (38.4%) or mild (32.7%), while codetection with other viruses in stool swabs was common (64.4%).

Conclusions

In contrast with hospital-based studies, this study showed that diverse and dynamically changing PeV genotypes circulate in the community causing mild or subclinical infections in children.

Parechovirus can cause severe illnesses in children. However, studies focus mainly on hospitalized populations. True disease burden in the community remains largely unknown. From our community-based cohort, we found diverse parechovirus genotypes in the community, causing mild or subclinical infections in children.

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.

Positive Impact of Routine Testing for Enterovirus and Parechovirus on Length of Hospitalization and Antimicrobial Use among Inpatients ≤6 Months of Age

Enterovirus (EV) and parechovirus (PeV) are leading viral causes of central nervous system (CNS) infection among hospitalized neonates and young infants, yet testing for PeV is not routinely performed. The goal of our study was to determine how EV and PeV CSF RT-PCR testing impacted the duration of antibiotic use and the length of hospitalization (LOS) in children ≤6 months old with suspected CNS infection. This retrospective cohort study at Children's Mercy Kansas City evaluated data from patients ≤6 months old for whom routine CSF EV and PeV reverse transcription-PCR (RT-PCR) testing was performed during January 2011 to December 2018. Electronic data were abstracted from the electronic medical record, including demographics, systemic antimicrobial use, imaging data, herpes simplex virus (HSV) testing, and overall hospital charges. Among 1,926 patients, 345 (17.9%) were RT-PCR positive for EV and 172 (8.9%) were positive for PeV. A significantly shorter LOS was observed for patients with EV (51.6 h; P < 0.001) and PeV (66.3 h; P = 0.048) compared to patients that tested negative for both viruses (74.1 h). Discontinuation of empirical antibiotic therapy following test result availability occurred more frequently for PeV patients (57.8%; P = 0.03) and EV patients (65.4%; P < 0.001) than RT-PCR-negative patients (48.5%). Routine EV/PeV RT-PCR testing of cerebrospinal fluid (CSF) samples in children impacted care of hospitalized neonates and young infants. Rapid and prompt diagnosis has the potential to reduce antibiotic usage, length of stay, and patient charges.

Human parechovirus are emerging pathogens with broad spectrum of clinical syndromes in adults

Parechoviruses are emerging pathogens of humans often affecting the pediatric age group, with a growing line of evidence implicating them as agents of a broad spectrum of clinical syndromes in adults. However, because many clinicians are not familiar with the manifestation of the infections, they are not included in the list of diagnostic pathogens. Furthermore, due to the indistinguishable feature of the infection compared with other common pathogens, a large number of cases are likely to go unchecked. Some may develop asymptomatic infection and recover without overt clinical disease. In this manuscript, we reviewed available literature on parechovirus infection in adult and summarized information relating to epidemiology, clinical manifestation, laboratory diagnosis, and therapeutics. The information provided should help in early case detection and support an evidence-based clinical decision.

Neurological and neurodevelopmental outcomes after human parechovirus CNS infection in neonates and young children: a systematic review and meta-analysis

BACKGROUND

Human parechoviruses are a major cause of CNS infection in neonates and young children. They have been implicated in neurological sequelae and neurodevelopmental delay. However, the magnitude of this effect has not been systematically reviewed or assessed with meta-analyses. We investigated short-term, medium-term, and long-term neurological sequelae and neurodevelopmental delay in neonates and young children after parechovirus-CNS-infection.

METHODS

In this systematic review and meta-analyses of studies, we searched PubMed, Embase, and PsycInfo, from the inception of the database until March 18, 2019, for reviews, systematic reviews, cohort studies, case series, and case control studies reporting on neurological or neurodevelopmental outcomes of children 3 months or younger with parechovirus infection of the CNS. Studies that were published after Dec 31, 2007, assessed children younger than 16 years, detailed parechoviruses infection of the CNS (confirmed by PCR), and followed up on neurological and neurodevelopmental outcomes were included. Studies published before Dec 31, 2007, were excluded. The predefined primary outcomes were the proportions of children with neurological sequelae, impairment in auditory or visual functions, or gross motor function delay. The proportion of children in whom neurological or neurodevelopmental outcomes were reported was pooled in meta-analyses. For each outcome variable we calculated the pooled proportion with 95% CI. The proportion of children in whom neurological or neurodevelopmental outcomes were reported was extracted by one author and checked by another. Two authors independently assessed the methodological quality of the studies.

FINDINGS

20 studies were eligible for quantitative synthesis. The meta-analyses showed an increasing proportion of children with neurological sequelae over time: 5% during short-term follow-up (pooled proportion 0·05 [95% CI 0·03-0·08], I²=0·00%; p=0·83) increasing to 27% during long-term follow-up (0·27 [0·17-0·40], I²=52·74%; p=0·026). The proportion of children with suspected neurodevelopmental delay was 9% or more during long-term follow-up. High heterogeneity and methodological issues in the included studies mean that the results should be interpreted with caution.

INTERPRETATION

This systematic review suggests the importance of long follow-up, preferably up to preschool or school age (5-6 years), of children with parechovirus infection of the CNS. Although not clinically severe, we found an increasing proportion of neonates and young children with CNS infection had associated neurological sequelae and neurodevelopmental delay over time. We recommend the use of standardised methods to assess neurological and neurodevelopmental functions of these children and to compare results with age-matched reference groups.

FUNDING

No funding was received for this study.

Adapting the Ages and Stages Questionnaire to Identify and Quantify Development Among Children With Evidence of Zika Infection

This article describes novel methods of applying the Ages and Stages Questionnaire-3rd edition (ASQ-3) to assess and quantify developmental delay among children following the 2015-2016 Zika virus outbreak in Brazil. Many of the children with Zika virus infection were expected to have severe developmental delay. However, administering the ASQ-3 to caregivers of these children according to standard protocol would have screened for the overall presence of delay but not the severity of delay. We adopted an amended protocol for administration of the ASQ-3 to quantify the developmental functioning of children severely affected by Zika virus infection in this investigation. Protocols for administering the ASQ-3 among this population were drafted in consultation with developmental measurement experts and are presented here. Specific developmental estimates are discussed, including developmental age equivalents, developmental quotients, and developmental quotient z scores. The calculations of these estimates are presented with examples in the context of the 2015-2016 Zika virus outbreak and associated microcephaly among prenatally infected children from 2 states in northeastern Brazil. Potential applications of these methods for estimating developmental ability among similar pediatric populations are discussed.

Early Life Parechovirus Infection Neurodevelopmental Outcomes at 3 Years: A Cohort Study

OBJECTIVE

To investigate the long-term developmental and behavioral outcomes in an established cohort of children hospitalized as infants with human parechovirus (HPeV) infection and sepsis-like illness.

STUDY DESIGN

The HPeV cohort was composed of children 3 years of age after HPeV infection and hospitalization in early infancy that occurred during a well-documented HPeV genotype 3 outbreak in Australia. We assessed neurodevelopmental and behavioral outcomes using the Bayley Scales of Infant and Toddler Development-III and the Child Behavior Checklist. We compared their outcomes with a subsample of healthy control infants drawn from the independently sampled Triple B Pregnancy Cohort Study.

RESULTS

Fifty children, with a mean age of 41 months, were followed for 3 years after hospital admission with HPeV infection. There were 47 children whose original illness was fever without source or sepsis-like illness and 3 who had encephalitis. All children in the HPeV cohort showed age-specific development within the population normal range on the Bayley Scales of Infant and Toddler Development-III. There was no difference in developmental attainment compared with 107 healthy control infants after adjusting for measured confounders. The HPeV cohort showed higher average scores on the Child Behavior Checklist and a higher frequency of clinical range scores compared with healthy controls.

CONCLUSIONS

Although HPeV sepsis-like illness did not result in neurodevelopmental delay at 3 years of age, it was associated with increased behavioral problems compared with healthy controls. The behavioral problems reached a clinical threshold in a minority of children. Results inform clinical management and planning for children after severe HPeV infection in infancy.

Parechovirus A Pathogenesis and the Enigma of Genotype A-3

Parechovirus A is a species in the Parechovirus genus within the Picornaviridae family that can cause severe disease in children. Relatively little is known on Parechovirus A epidemiology and pathogenesis. This review aims to explore the Parechovirus A literature and highlight the differences between Parechovirus A genotypes from a pathogenesis standpoint. In particular, the curious case of Parechovirus-A3 and the genotype-specific disease association will be discussed. Finally, a brief outlook on Parechovirus A research is provided.

Outcomes beyond hospital discharge in infants and children with viral meningitis: A systematic review

Viruses are the commonest cause of childhood meningitis, but outcomes beyond hospital discharge are poorly described. We undertook a systematic literature review of long-term outcomes following paediatric viral meningitis. A search was carried out using MEDLINE, Embase, and Cochrane Review for studies from 1 January 1990 to 31 December 2018. Studies were included where specific outcome measures were available beyond hospital discharge for children <16 years old with viral meningitis. In total, 3588 papers were identified of which 14 were eligible for inclusion. Four studies reported outcomes in children with nonenterovirus 71 meningitis. A US study of 16 cases demonstrated subtle language difficulties at 3-year follow-up in infants in contrast to an Australian study, which revealed no impairment in language. A Fijian study showed that two out of eight cases had sensorineural hearing loss compared with none in a UK cohort of 668 infants. Three studies evaluated outcomes of enterovirus 71 meningitis in China and Taiwan, two showed cases recovered without sequelae, while one demonstrated an increased risk of attention deficit hyperactivity disorder. Two studies including 141 cases of human parechovirus revealed no evidence of neurodevelopmental sequelae. Conversely, an Australian study demonstrated neurodevelopmental sequelae in 11 out of 77 infants with parechovirus meningitis. Most studies identified in this review demonstrated a high proportion of good clinical outcomes following viral meningitis. However, the data are limited, so robustly conducted neurodevelopmental studies are warranted to inform the evidence-based management of viral meningitis beyond hospital discharge.

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.

Evolutionary analysis of human parechovirus type 3 and clinical outcomes of infection during the 2017-18 Australian epidemic

Human parechovirus type 3 (HPeV3) can cause severe sepsis-like illness in young infants and may be associated with long term neurodevelopmental delay later in childhood. We investigated the molecular epidemiology of HPeV infection in thirty three infants requiring hospitalization before, during and after the peak of the 2017/18 HPeV epidemic wave in Australia. During the peak of the epidemic, all cases were infected with an HPeV3, while before and after the peak, HPeV1 was the predominant type detected. The predominant HPeV3 was the recombinant HPeV3 also detected in the 2013/14 and 2015/16 Australian epidemics. Sepsis-like or meningitis-like symptoms were only reported in cases infected with the recombinant HPeV3. Phylogenetic analysis of the recombinant HPeV3 revealed that the virus continued to evolve, also between the Australian outbreaks, thus indicating continued circulation, despite not being detected and reported in Australia or elsewhere in between epidemic waves. The recombinant HPeV3 continued to show a remarkable stability in its capsid amino acid sequence, further strengthening our previous argument for development of a vaccine or immunotherapeutics to reduce the severity of HPeV3 outbreaks due to this virus.

Parechovirus: an important emerging infection in young infants

Epidemics of human parechovirus (HPeV) causing disease in young children have occurred every 2 years in Australia since 2013. HPeV genotype 3 caused the epidemic from late 2017 to early 2018. Most HPeV infections cause no or mild symptoms including gastroenteritis or influenza-like illness. Characteristically, young infants present with fever, irritability and on occasions a diffuse rash ("red, hot and angry" babies). Severe disease can manifest as meningoencephalitis, seizures or sepsis-like presentations (including septic shock), or less common presentations including signs of surgical abdomen. Testing for HPeV by specific molecular tests is indicated in children younger than 6 months of age with characteristic presentations without another confirmed diagnosis including febrile illnesses with other suggestive features (eg, rash, seizures), sepsis syndromes (including shock), and suspected meningoencephalitis (which may be detected by magnetic resonance imaging only). There are no effective antiviral therapies. Treatment is primarily supportive, including management of complications. Some infants with severe HPeV infection may have adverse neurodevelopment. Follow-up by a paediatrician is recommended.

Neurodevelopment medium-term outcome after parechovirus infection

AIM

Human parechoviruses (HPeV) are responsible for fever without a source (FWS), sepsis-like illness and encephalitis in neonates and children under 3 months of age. Short-term outcome is generally good, but there is great concern about medium and long- term outcome of infants after HPeV infection. The aim of this study is to assess the medium-term outcome in infants following HPeV infection without encephalitis.

METHODS

Patients who suffered HPeV infection involving cerebrospinal fluid were evaluated twice using Ages and Stages Questionnaire-3 (ASQ-3). The first evaluation was conducted at least one year after the infection and the second one year later.

RESULTS

Sixteen patients were evaluated in the first assessment, and three of them presented mild alterations in motor function domains. Moreover, hypotonia was observed in the neurologic exam in one case, and hemiparesis in another case. In the second assessment fifteen patients were included, and only the patient with hemiparesis continued presenting gross motor disfunction, with complete recovery of the remaining patients.

INTERPRETATION

We have observed a good medium-term prognosis in infants after HPeV infections, with improvement of mild motor alterations after at-home intervention. Infants who suffer HPeV infection without encephalitis seem to have a better prognosis than those with encephalitis.

Human parechovirus meningitis and gross-motor neurodevelopment in young children

This multicenter prospective cohort study describes the impact of human parechovirus meningitis on gross-motor neurodevelopment of young children. Gross-motor function was measured using Alberta Infant Motor Scale. Of a total of 38 eligible children < 10 months of age at onset, nine cases had clinical evidence of meningitis and polymerase chain reaction positive for human parechovirus in cerebrospinal fluid; 11 had no meningitis and polymerase chain reaction positive for human parechovirus in nasopharyngeal aspirate, blood, urine, or feces; and in 18, no pathogen was identified (reference group).The children with human parechovirus meningitis showed more frequent albeit not statistically significant suspect gross-motor function delay (mean Z-score (standard deviation) - 1.69 (1.05)) than children with human parechovirus infection-elsewhere (- 1.38 (1.51)). The reference group did not fall in the range of suspect gross-motor function delay (- 0.96 (1.07)). Adjustment for age at onset and maternal education did not alter the results.Conclusion: Six months after infection, children with human parechovirus meningitis showed more frequent albeit not statistically significant suspect gross-motor function delay compared to the population norm and other two groups. Longitudinal studies in larger samples and longer follow-up periods are needed to confirm the impact and persistence of human parechovirus meningitis on neurodevelopment in young children. What is Known: • Human parechovirus is progressively becoming a major viral cause of meningitis in children. • There is keen interest in the development of affected infants with human parechovirus meningitis. What is New: • This study describes prospectively gross-motor functional delay in children with both clinical evidence of meningitis and polymerase chain reaction positive for human parechovirus in cerebrospinal fluid. • It shows the importance of screening young children for developmental delay in order to refer those with delay for early intervention to maximize their developmental potential.

Infant identical triplets' presentation of human parechovirus Type 3

Introduction

Human parechovirus (HPeV) infections appear common across age groups, and transmission is likely fecal-oral and through respiratory secretions. Cyclical and seasonal patterns have been described; however, HPeV has likely been previously underdiagnosed due to lack of commercially available diagnostic testing.

Presentation of Case

We present identical triplets contracting HPeV Type 3.

Discussion

The clinical presentation, similar to echoviruses, is broad and includes asymptomatic shedding, severe pulmonary and neurologic disease, and disseminated intravascular coagulation. Neonates and young infants are particularly susceptible. In neonates, distinctive MRI brain findings have been described that, when combined with clinical presentation, suggest HPeV. Infection clusters have been described, and neonates with older siblings may be a risk factor.

Conclusion

This case suggests that HPeV has been under-recognized in the United States, and HPeV Type 3 prevalence is likely underestimated. The case highlights variation in presentation, including lack of fever and rash, which were previously documented as common HPeV symptoms.

Parechovirus A Detection by a Comprehensive Approach in a Clinical Laboratory

Parechovirus A (Human parechovirus, HPeV) causes symptoms ranging from severe neonatal infection to mild gastrointestinal and respiratory disease. Use of molecular approaches with RT-PCR and genotyping has improved the detection rate of HPeV. Conventional methods, such as viral culture and immunofluorescence assay, together with molecular methods facilitate comprehensive viral diagnosis. To establish the HPeV immunofluorescence assay, an antibody against HPeV capsid protein VP0 was generated by using antigenic epitope prediction data. The specificity of the anti-HPeV VP0 antibody was demonstrated on immunofluorescence assay, showing that this antibody was specific for HPeV but not enteroviruses. A total of 74 HPeV isolates, 7 non–polio-enteroviruses and 12 HPeV negative cell culture supernatant were used for evaluating the efficiency of the anti-HPeV VP0 antibody. The sensitivity of HPeV detection by the anti-HPeV VP0 antibody was consistent with 5′untranslated region (UTR) RT-PCR analysis. This study established comprehensive methods for HPeV detection that include viral culture and observation of cytopathic effect, immunofluorescence assay, RT-PCR and genotyping. The methods were incorporated into our routine clinical practice for viral diagnosis. In conclusion, this study established a protocol for enterovirus and HPeV virus identification that combines conventional and molecular methods and would be beneficial for HPeV diagnosis.