Infectious factors in myocarditis: a comprehensive review of common and rare pathogens

BACKGROUND

Myocarditis is a significant health threat today, with infectious agents being the most common cause. Accurate diagnosis of the etiology of infectious myocarditis is crucial for effective treatment.

MAIN BODY

Infectious myocarditis can be caused by viruses, prokaryotes, parasites, and fungi. Viral infections are typically the primary cause. However, some rare opportunistic pathogens can also damage heart muscle cells in patients with immunodeficiencies, neoplasms and those who have undergone heart surgery.

CONCLUSIONS

This article reviews research on common and rare pathogens of infectious myocarditis, emphasizing the complexity of its etiology, with the aim of helping clinicians make an accurate diagnosis of infectious myocarditis.

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.

Clinical Spectrum and Epidemiology of Human Parechovirus Infections in Infants: A Retrospective Study in the Western Part of Sweden

Background

Human parechovirus (HPeV) infections can cause sepsis and meningoencephalitis in infants. To improve our knowledge of the consequences of HPeV infections in young children, the incidence, clinical spectrum, and short-term outcome among infants infected with HPeV were investigated retrospectively.

Methods

The presence of HPeV RNA was investigated by polymerase chain reaction in cerebrospinal fluid from 327 children aged 0 to 12 months sampled between 2014 and 2017. Eighty-one were infected with HPeV and included in the study. These infants were divided into 3 groups based on clinical assessment: HPeV was the presumed cause of disease (n = 35); HPeV could have contributed to or been considered the cause of disease (n = 24); and HPeV was not considered the cause of disease (n = 22).

Results

Infection with HPeV type 3 was common in all groups (n = 54), and most children were younger than 3 months (n = 63). The children in the first group (HPeV as presumed cause) had meningoencephalitis (n = 20), viral sepsis (n = 9), or non-severe viral infection (n = 6). The youngest were more prone to develop meningoencephalitis, while the slightly older children had symptoms of viral sepsis or nonsevere viral infection (P < .05). Eleven had symptom onset within 2 days after birth. Two infants diagnosed with sudden infant death syndrome were HPeV infected when tested postmortem.

Conclusions

HPeV infections were identified in 25% of children with suspected central nervous system infection. The clinical presentation of those infected with HPeV varied with age. HPeV infections may be associated with sudden infant death syndrome, although this is not well studied. The results suggest that HPeV infections may be underdiagnosed in young infants.

Enterovirus and parechovirus meningoencephalitis in infants: A ten-year prospective observational study in a neonatal intensive care unit

BACKGROUND

Non-polio enteroviruses (EV) and human parechoviruses (HPeV) are known etiological agents of meningoencephalitis in neonates. However, reports of neuroradiological findings and neurodevelopmental outcomes in this population are scarce.

OBJECTIVES

to describe clinical characteristics, neuroradiological findings and, in a subset of patients, neurodevelopmental outcomes in a cohort of infants with EV or HPeV meningoencephalitis within 60 days of life.

STUDY DESIGN

clinical/laboratory data, neuroradiological findings (cranial ultrasound, cUS, brain magnetic resonance imaging, MRI), and neurodevelopmental outcomes assessed by Ages and Stages Questionnaires - third edition were prospectively collected.

RESULTS

overall, 32 infants with EV (21, 67.8 %) or HPeV (11, 28.2 %) meningoencephalitis were enrolled. Infants with HPeV (73 %: type 3 HPeV) presented more frequently with seizures (18.2 % vs. 0, p value=0.03), lymphopenia (1120 vs. 2170 cells/mm3, p = 0.02), focal anomalies at electroencephalography (EEG) (63.6 vs. 23.8 %, p = 0.03), and pathological findings at MRI (72.7 % vs. 15.8 %, p value=0.004) compared to those affected by EV. cUS was not significantly altered in any of the enrolled infants. All infants with EV meningoencephalitis evaluated at 12-24 months and at 30-48 months were normal. Two out of the 7 infants with HPeV meningoencephalitis showed some concerns in gross motor (1/7, 14.3 %) or in problem solving (1/7, 14.3 %) function at 30-48 months of age.

CONCLUSIONS

In our cohort, neonates infected by HPeV had more severe clinical manifestations, more alterations at brain MRI, and some signs of long-term neurodevelopmental delay. Our data highlight the heterogeneity of manifestations in infants with EV or HPeV meningoencephalitis, and the need for long-term follow-up of those infected by HPeV in the neonatal period.

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.

The Burden of Human Parechoviruses Among Children in Oman: A retrospective study

Objectives

This study aimed to evaluate the burden, clinical and laboratory features and outcomes of human parechoviruses (HPeVs) infection among children in Oman.

Methods

This retrospective study included children (aged <18 years) with molecularly proven HPeV infection who were managed at Sultan Qaboos University Hospital, Muscat, Oman, between January 2017 and December 2019. Data were obtained from the patients' medical records and analysed to describe their demographics, clinical and laboratory features, management and outcomes.

Results

HPeV was detected in 61 patients, 44 (72%) of whom were males. The median age of these patients was nine months (interquartile range [IQR]: 6-15 months). HPeV was detected throughout the year without any significant peaks. Majority of the patients (n = 51, 84%) had co-infection with other viruses. Forty-eight (79%) children with HPeV infection required hospitalisation, and their median length of hospital stay was five days (IQR: 3-8 days). Ex-prematurity (n = 10, 16%) was the commonest comorbidity among this group. Fever (n = 41, 67%) and cough (n = 41, 67%) were the commonest presenting symptoms among the children. Two-thirds of the HPeV-infected children in this cohort were managed for lower respiratory tract infection; none was managed for meningitis. Gastroenteritis was not common in this cohort; only eight children had diarrhoea. All children made a full recovery.

Conclusion

HPeVs infection does not show a clear seasonality in Oman. Most of the children were aged <2 years and had a viral co-infection. The outcomes of HPeV infection were favourable, with no mortalities, but a thorough follow-up for neurological outcomes was lacking.

Myeloid-associated differentiation marker is an essential host factor for human parechovirus PeV-A3 entry

Human parechovirus (PeV-A) is an RNA virus that belongs to the family Picornaviridae and it is currently classified into 19 genotypes. PeV-As usually cause mild illness in children and adults. Among the genotypes, PeV-A3 can cause severe diseases in neonates and young infants, resulting in neurological sequelae and death. In this study, we identify the human myeloid-associated differentiation marker (MYADM) as an essential host factor for the entry of six PeV-As (PeV-A1 to PeV-A6), including PeV-A3. The infection of six PeV-As (PeV-A1 to PeV-A6) to human cells is abolished by knocking out the expression of MYADM. Hamster BHK-21 cells are resistant to PeV-A infection, but the expression of human MYADM in BHK-21 confers PeV-A infection and viral production. Furthermore, VP0 capsid protein of PeV-A3 interacts with one extracellular domain of human MYADM on the cell membrane of BHK-21. The identification of MYADM as an essential entry factor for PeV-As infection is expected to advance our understanding of the pathogenesis of PeV-As.

Human parechovirus meningoencephalitis

Human parechovirus-3 (HPeV-3) infection is one of the differential diagnoses of neonatal meningoencephalitis. A 13-day-old full-term female neonate presented with a seizure. Brain MRI showed classic imaging findings of the meningoencephalitis which was confirmed on cerebrospinal fluid analysis.

Contribution

The HPeV-3 is an emerging pathogen for neonatal meningoencephalitis. The case in this study is unique with classic imaging findings, which are not routinely encountered in day-to-day practice. This case raises reader awareness.

Surgery for intractable epilepsy after severe encephalopathy with reversible splenial lesion and new onset hippocampal lesion associated with parechovirus

We describe a case of severe encephalopathy with reversible splenial lesion associated with parechovirus, followed by intractable temporal lobe epilepsy (TLE), which was improved by epilepsy surgery. A 3-year-old girl was admitted because of fever, consciousness disturbance and generalized tonic clonic seizure. Her seizure lasted for four hours. Fluid-attenuated inversion recovery (FLAIR) showed a hyperintensity in the splenium of the corpus callosum. Electroencephalogram (EEG) demonstarated continuous diffuse epileptic activity represented by synchronous and rhythmic high-amplitude spikes and waves, which led to the diagnosis of status epilepticus. Her consciousness was improved with fosphenytoin, midazolam and methylprednisolone pulse after 3 days. Seven days later, FLAIR hyperintensity in the splenium of the corpus callosum was disappeared; however, a hyperintensity in the right hippocampus was detected. Since the stool examination was positive for parechovirus, her final diagnosis was reversible splenial lesion syndrome (RESLES) associated with parechovirus. At age 8, she experienced epigastric sensation and consciousness disturbance once a week. Based on the scalp EEG and radiological findings, she was diagnosed with intractable right TLE. We performed a right selective amygdalohippocampectomy and anterior temporal disconnection at 10 years of age. One year and 3 months after surgery, she was seizure free. To our knowledge, this is the first report of severe febrile epilepticus status. with RESLES associated with parechovirus, followed by intractable TLE, which was resolved by epilepsy surgery.

Incidence of Childhood Meningoencephalitis in Children With a Suspected Meningoencephalitis in the Netherlands

Supplemental Digital Content is available in the text.

Development of a real-time RT-PCR assay for the detection of pan-human parechoviruses

Background

Parechoviruses (PeV-As), which constitute a new genus within the family Picornaviridae, have been associated with numerous localized outbreaks of serious diseases, such as coryza, pneumonia, maculopapular exanthem, and conjunctivitis. However, to the best of our knowledge, only a few laboratories worldwide conduct tests for the identification of this group of viruses. Therefore, in this study, we aimed to develop and validate a real-time RT-PCR assay for the identification of PeV-As.

Methods

To design and validate a real-time PCR primer–probe targeting the 5′-UTR region of PeV-As, the 5′-UTR sequences of PeV-As available in GenBank were aligned using the MUSCLE algorithm in MEGA v7.0. Thereafter, the highly conserved 5′-UTR region was selected, and its primer–probe sequence was designed using Primer Premier v5.0. This primer–probe sequence was then evaluated for specificity, sensitivity, and repeatability, and for its validation, it was tested using fecal samples from 728 healthy children living in Beijing (China).

Results

The PeV-A real-time RT-PCR assay detected only the RNA-positive standards of PeV-A genotypes (1–8, 14, 17, and 18), whereas 72 serotypes of non-PeV-A EV viruses were undetected. In addition, the VP1 region of these 11 PeV-A genotypes that tested positive were amplified using the primers designed in this study. Typing results indicated that eight, one, and two strains of the 11 were PeV-A1, PeV-A4, and PeV-A6, respectively. We also determined and presented the genetic characterization and phylogenetic analyses results corresponding to these 11 VP1 region sequences. Furthermore, real-time RT-PCR assay showed good sensitivity with LOD of 10² copies/μL. Positive results in eight parallel experiments at each concentration gradient from 10⁷ copies/μL to 10² copies/μL, indicating good repeatability.

Conclusion

Our findings suggested that the real-time RT-PCR assay developed in this study can be applied for routine PeV-A identification. We detected PeV-A1, 4 and 6 genotypes in the 728 faecal samples using this method. Additionally, we believe that our results will serve as a foundation for further studies on PeV-As and facilitate the expansion of the gene sequence information available in GenBank.

Parent-administered Neurodevelopmental Follow up in Children After Picornavirus CNS Infections

BACKGROUND

Data on the neurodevelopment of children who experienced central nervous system (CNS) infections with enteroviruses (EV) or parechoviruses (hPeV) is scarce and mostly limited to follow up of short-term outcomes.

METHODS

Parents of children who presented between 2014 and 2019, underwent a lumbar puncture and whose cerebrospinal fluid was polymerase chain reaction positive for EV or hPeV, were asked to complete a care-giver-administered neurodevelopmental assessment tool (The Ages and Stages Instrument [ASQ3]). Clinical data of the infective episode were collected from patient notes.

RESULTS

Of 101 children, 43 (10 hPeV+, 33 EV+) submitted ASQ3 results. Median age at assessment was 38.9 months (interquartile range, 15.4-54.8), the follow-up interval 3 years (median 37 months; interquartile range, 13.9-53.1). Age, inflammatory markers, and cerebrospinal fluid pleocytosis during the infective event were not associated with ASQ3 scores. In 23 children (17 EV+, 6 hPeV+), no neurodevelopmental concerns were reported. Two more had preexisting developmental delay and were excluded. Of the remaining, 18/41 (43.9%) reported ASQ3 scores indicating need for monitoring or professional review in at least 1 category, not differing by pathogen (EV 14/31, 45.2%; hPeV 4/10, 40%; P = 0.71). Seven children will require formal review, scoring ≥2 SD below the mean in at least 1 category (6/31 EV+, 1/10 hPeV+, P = 0.7), 3 scored ≥2 SD below the mean in more than 1 area.

CONCLUSIONS

Parent-administered developmental assessment of children with a history of early picornavirus infection of the CNS identified a subgroup that requires formal neurodevelopmental review. Wider application of community-based developmental screening will complement our understanding of the impact of CNS infections in early childhood.

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.

Rapid syndromic molecular testing and human parechovirus infection in children: A report of three cases in Argentina

Human parechovirus (HPeV) is one of the members of the family Picornaviridae that has been associated with fever of unknown origin, gastroenteritis, clinical sepsis, meningitis, or encephalitis in very young infants. HPeV detection is not routinely performed in most clinical microbiology laboratories in Argentina and, therefore, its real prevalence is unknown. We here report three cases of HPeV CNS infection that presented to our hospital with different clinical features after the implementation of a multiplex PCR meningitis/encephalitis panel. Molecular diagnostic techniques could help improve patient care and understand the real prevalence of this infection in Argentina.

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.

Severity of parechovirus infections in infants under 3 months of age and comparison with enterovirus infections: A French retrospective study

While enteroviruses (EV) are a well-recognized cause of aseptic meningitis in children, human parechoviruses (HPeV), especially genotype 3, have been increasingly reported as a frequent cause of sepsis-like illness and meningitis among young infants. The aim of this study was to describe the epidemiological, clinical, and laboratory characteristics of HPeV infections in infants and to compare them with those of well-known EV infections. This monocentric retrospective study was carried out at the pediatric unit of Nantes University Hospital from January 2015 to August 2018. All patients under 18 years of age with diagnosis codes referring to fever, for whom viral infection was suspected and cerebrospinal fluid (CSF) specimens were collected, were included. All CSF specimens were screened by duplex real-time polymerase chain reaction (PCR) assay that allows for the simultaneous detection of EV and HPeV in clinical samples. During the study period, 1373 CSF specimens from patients under 18 were included. A total of 312 CSF samples were positive for HPeV (n=34) or EV (n=278). Among the 34 HPeV-positive patients, 97% (33/34) were under 3 months of age, whereas the rate was 54% (149/278) for EV-positive patients (P<0.001); thus, patients under 3 months of age were defined as the study population for the rest of this work. A review of the medical records was carried out for the positive cases. In this population, the HPeV detection rate was 5.6% versus 25.3% (P<0.001) for EV. All but one of the HPeV samples available for genotyping were HPeV-3. No seasonality was observed for HPeV infections. Length of hospital stay tended to be longer for children infected with HPeV compared with those infected by EV (3 days vs. 2 days, P=0.05). Clinicians reported more severe illness presentations among HPeV-infected infants, with more frequent administration of fluid bolus (P<0.02). Regarding laboratory characteristics, a significant lack of cellular reaction in the CSF (P=0.004) as well as lower C-reactive protein (CRP) levels (P=0.006) and neutrophil counts (P<0.001) were noted for HPeV infections compared with EV infections. Our results confirm the early onset of HPeV infections (more than 95% of patients aged under 3 months). The clinical presentation and laboratory characteristics of the two infections was similar. However, some higher clinical severity criteria and a lack of CSF pleocytosis were regularly observed in patients with HPeV infections. Considering the significant proportion (5.6%; 95% CI, 3.7-7.5) of all CSF samples in our series, HPeV detection should be systematically included in the microbiological diagnosis of febrile children under 3 months of age.

Proposal for the Recognition of a New Disease Concept from Japan: Parechovirus A3-Associated Myalgia

Parechovirus A3 (PeVA3) was first reported in 2004 and has been recognized as a causative agent of mild and severe infectious diseases in children. We first reported an outbreak of PeVA3-associated myalgia (PeVA3-M) in Yamagata, Japan, in 2008. We have repeatedly observed PeVA3-M cases in 2011, 2014, and 2016, and identified the first child case in 2014. Reports of PeVA3-M have increased since 2014, indicating that the recognition of PeVA3-M has spread across Japan. The findings showed that PeVA3-M commonly occurs among adults aged 30-40 years, particularly in males. Elevation of creatinine phosphokinase, C-reactive protein, and myoglobin, as well as magnetic resonance imaging findings, suggest inflammation of the muscles and/or fascia of the four limbs. Patients recover within 1-2 weeks without any sequelae. A longitudinal molecular epidemiological study in Yamagata revealed that PeVA3 strains cause a variety of diseases, ranging from mild to severe, including PeVA3-M, in subjects ranging from neonates to adults, irrespective of their genetic cluster. As PeVA3-M has not yet been reported abroad, more widespread recognition of PeVA3-M as an emerging disease is important. We hope this review will help clinicians and researchers in understanding PeVA3-M and therefore advance related research in Japan as well as around the world.

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.

Development of Monoclonal Antibodies and Antigen-Capture ELISA for Human Parechovirus Type 3

Human parechovirus type 3 (HPeV3) is an etiologic agent of respiratory diseases, meningitis, and sepsis-like illness in both infants and adults. Monoclonal antibodies (mAbs) can be a promising diagnostic tool for antigenic diseases such as virus infection, as they offer a high specificity toward a specific viral antigen. However, to date, there is no specific mAb available for the diagnosis of HPeV3 infection. In this study, we developed and characterized mAbs specific for HPeV3 capsid protein VP0. We used cell-free, wheat germ-synthesized viral VP0 protein for immunizing BALB/c mice to generate hybridomas. From the resultant hybridoma clones, we selected nine clones producing mAbs reactive to the HPeV3-VP0 antigen, based on enzyme-linked immunosorbent assay (ELISA). Epitope mapping showed that these mAbs recognized three distinct domains in HPeV3 VP0. Six mAbs recognized HPeV3 specifically and the other three mAbs showed cross-reactivity with other HPeVs. Using the HPeV3-specific mAbs, we then developed an ELISA for viral antigen detection that could be reliably used for laboratory diagnosis of HPeV3. This ELISA system exhibited no cross-reactivity with other related viruses. Our newly developed mAbs would, thus, provide a useful set of tools for future research and ensure HPeV3-specific diagnosis.

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.

Association Between Neutralizing Antibody Titers against Parechovirus A3 in Maternal and Cord Blood Pairs and Perinatal Factors

BACKGROUND

Parechovirus A3 (PeV-A3) is a pathogen that causes severe infectious diseases such as sepsis and meningoencephalitis in neonates and young infants. In this study, we aimed to measure the neutralizing antibody titer (NAT) against PeV-A3 in paired maternal and cord blood samples and to clarify the serum epidemiology of PeV-A3 and the association between the NAT and perinatal factors.

METHODS

NATs against PeV-A3 were measured in 1033 mothers (maternal and cord blood pairs; total of 2066 samples) who delivered their infant in Fukushima Prefecture between December 2013 and June 2014. RD-18S cells were used to measure NATs against PeV-A3. The association between NATs against PeV-A3 in maternal and cord blood and perinatal factors was determined using multivariate logistic regression analysis.

RESULTS

The median gestational age of the infants was 39 weeks 4 days (interquartile range, 38 weeks 4 days to 40 weeks 3 days). The NATs against PeV-A3 in maternal blood and in cord blood were almost the same. The proportion of samples assigned to the low-titer group (NAT ≤ 1:16) was approximately 70%, and the proportion of samples assigned to the high-titer group tended to increase with gestational age. The high-titer rate and geometric mean titers decreased with increased maternal age.

CONCLUSIONS

Cord blood indicates that neonates born at a lower gestational age and older mothers have a low NAT against PeV-A3. Thus, more attention should be paid to the onset of severe PeV-A3 disease in such neonates and young infants.

Epidemic and Inter-epidemic Burden of Pediatric Human Parechovirus Infection in New South Wales, Australia, 2017-2018

BACKGROUND

Human parechovirus (HPeV) typically infects young children, and although infection is often asymptomatic, some types (eg, HPeV3) are associated with severe clinical manifestations, including central nervous system infection or sepsis-like syndrome, particularly affecting young infants. The third documented national epidemic of HPeV occurred in Australia in 2017-2018.

METHODS

Four public laboratories that perform almost all of the HPeV PCR testing in New South Wales provided data regarding HPeV tests performed from July 1, 2017 to June 30, 2018. Limited demographic and clinical data were obtained from electronic medical records for laboratory test-positive cases that presented to each of the 3 pediatric hospitals in New South Wales.

RESULTS

Five hundred eighty-one HPeV-positive samples obtained from 395 cases were included in the analysis. The peak of the outbreak occurred in late November 2017 (approximately 35 new cases each week), with the main HPeV epidemic occurring between the spring and summer months of September 2017 to January 2018; although this seasonality was observed primarily in infants less than 12 months of age. Among the 388 pediatric cases, almost half were younger than 2 months (188; 47%) and only 10 were children older than 2 years. The annualized estimated incidence of laboratory confirmed HPeV infection in children was approximately 142.4 cases per 100,000 children younger than 5 years in New South Wales during the epidemic season.

CONCLUSIONS

The large burden of HPeV infection and disease identified in young infants in this and previous Australian studies highlight the need for more comprehensive national surveillance of HPeV infections and improved prevention strategies.

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.

Epidemic Myalgia Associated with Human Parechovirus Type 3 Infection

A 42-year-old man was hospitalized due to a fever, orchiodynia, and extremely severe myalgia predominantly in the extremities, which made it difficult for him to stand or walk. He had a history of contact with his son who had acute upper respiratory infection. Based on the characteristic clinical symptoms and detection of the partial sequence of human parechovirus type 3 (HPeV3) in throat swabs as well as stool and serum samples, he was diagnosed with epidemic myalgia associated with HPeV3 infection. Because HPeV3 infection is widespread among children in Japan, HPeV3-associated myalgia should be considered when adult patients manifest such distinguishing clinical characteristics.

Novel scoring system for differentiating parechovirus-A3 and enterovirus infection in neonates and young infants

BACKGROUND

Parechovirus-A3 (PeV-A3) and the enteroviruses (EVs) are the most common viral pathogens responsible for sepsis and meningoencephalitis in neonates and young infants; however, differences in the clinical presentations of two infections are not well described.

OBJECTIVES

To describe the clinical presentations of PeV-A3- and EVs-related diseases and develop a novel scoring system to differentiate two diseases.

STUDY DESIGN

This prospective study used real-time PCR and genetic sequencing to evaluate viral etiologies of febrile neonates and infants <4 months with suspected sepsis or meningoencephalitis in Niigata area, Japan, in 2014-2016. The clinical manifestations of PeV-A3- and EVs-infected patients were compared, and a novel scoring system was developed after identifying the most distinguishable clinical findings, followed by the external cohort validation.

RESULTS

In 210 patients evaluated, we identified 56 PeV-A3-infected (27%) and 43 EVs-infected (20%) patients. The following clinical manifestations were significant in PeV-A3-infected patients, as compared with EVs-infected patients; a higher body temperature (38.9°C vs. 38.5°C, P < .01) and heart rate (181/min vs. 168/min, P = .01), cold extremities (72% vs. 34%, P < .01) and skin mottling (65% vs. 23%, P < .01), lower white blood cell count (5,200/μL vs. 8,900/μL, P < .01) and incidence of cerebrospinal fluid (CSF) pleocytosis (2% vs. 63%, P < .01). Using some of these significant findings, the scoring system successfully distinguished the diseases (accuracy: 86% and 83% for the derivative and external validation cohorts, respectively).

CONCLUSIONS

We found significant clinical manifestations in PeV-A3-infected patients compared to EVs-infected patients. The scoring system may be helpful to distinguish two infections, especially at onset of outbreak.

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.

An Emerging Human Parechovirus Type 5 Causing Sepsis-Like Illness in Infants in Australia

Human parechovirus (HPeV), particularly type 3 (HPeV3), is an important cause of sepsis-/meningitis-like illness in young infants. Laboratory records identified a total of ten HPeV-positive cases in Southeastern Australia between January and July 2019. The HPeV present in these cases were typed by Sanger sequencing of the partial viral capsid protein 1 (VP1) region and selected cases were further characterised by additional Sanger or Ion Torrent near-full length virus sequencing. In seven of the ten cases, an HPeV type 5 (HPeV5) was identified, and in the remaining three cases, an HPeV type 1 was identified. The HPeV5-positive cases were infants under the age of 3 months admitted to hospital with fever, rash, lethargy and/or sepsis-like clinical signs. Near full-length virus sequencing revealed that the HPeV5 was most likely a recombinant virus, with structural genes most similar to an HPeV5 from Belarus in 2018, and a polymerase gene most similar to an HPeV3 from Australia in 2013/14. While HPeV5 is not typically associated with severe clinical signs, the HPeV5 identified here may have been able to cause more severe disease in young infants through the acquisition of genes from a more virulent HPeV.

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.

Human Parechovirus Meningoencephalitis: Neuroimaging in the Era of Polymerase Chain Reaction-Based Testing

Human parechovirus infection is an increasingly recognized cause of neonatal meningoencephalitis. We describe characteristic clinical features and brain MR imaging abnormalities of human parechovirus meningoencephalitis in 6 infants. When corroborated by increasingly available polymerase chain reaction-based testing of the CSF, the distinctive MR imaging appearance may yield a specific diagnosis that obviates costly and time-consuming further clinical evaluation. In our study, infants with human parechovirus presented in the first 35 days of life with seizures, irritability, and sepsis. MR imaging consistently demonstrated low diffusivity within the thalami, corpus callosum, and subcortical white matter with a frontoparietal predominance. T1 and T2 shortening connoting white matter injury along the deep medullary veins suggests venous ischemia as an alternative potential pathogenetic mechanism to direct neuroaxonal injury.

Paediatric intensive care admissions during the 2015-2016 Queensland human parechovirus outbreak

AIM

The human parechovirus (HPeV) has emerged as a pathogen causing sepsis-like presentations in young infants, but there is a lack of data on HPeV presentations requiring intensive care support. We aimed to characterise the clinical presentation, disease severity, management and outcome of a population-based cohort of children with microbiologically confirmed HPeV infection requiring admission to paediatric intensive care units (PICUs) in Queensland, Australia during a recent outbreak.

METHODS

This was a multicentre retrospective study of children admitted to PICU between 1 January 2015 and 31 December 2016 with confirmed HPeV infection.

RESULTS

Thirty infants (median age 20 days) with HPeV genotype 3 were admitted to PICU, representing 16% of all children with HPeV admitted to hospital and 6.4% of non-elective PICU admissions in children <1 year of age. Children requiring PICU admission were younger than children admitted to hospital (P = 0.001). Apnoea, haemodynamic instability with tachycardia and seizures represented the main reasons for PICU admission. Eleven children (37%) required mechanical ventilation for a median duration of 62 h, 22 (73%) received fluid boluses and 7 (23%) were treated with vasoactive agents for a median duration of 53 h. Median length of stay was 2.62 days. A total of 24 children (80%) fulfilled sepsis criteria, 14 (47%) severe sepsis and 7 (23%) septic shock criteria. Eight (27%) had abnormal brain magnetic resonance imaging. No patient died.

CONCLUSIONS

We confirm that HPeV infection is an important cause of sepsis-like syndrome in infants with substantial associated morbidity. Optimal management and long-term outcomes require further investigation.

TIPICO IX: report of the 9th interactive infectious disease workshop on infectious diseases and vaccines

The Ninth Interactive Infectious Disease workshop TIPICO was held on November 22–23, 2018, in Santiago de Compostela, Spain. This 2-day academic experience addressed current and topical issues in the field of infectious diseases and vaccination. Summary findings of the meeting include: cervical cancer elimination will be possible in the future, thanks to the implementation of global vaccination action plans in combination with appropriate screening interventions. The introduction of appropriate immunization programs is key to maintain the success of current effective vaccines such as those against meningococcal disease or rotavirus infection. Additionally, reduced dose schedules might improve the efficiency of some vaccines (i.e., PCV13). New vaccines to improve current preventive alternatives are under development (e.g., against tuberculosis or influenza virus), while others to protect against infectious diseases with no current available vaccines (e.g., enterovirus, parechovirus and flaviviruses) need to be developed. Vaccinomics will be fundamental in this process, while infectomics will allow the application of precision medicine. Further research is also required to understand the impact of heterologous vaccine effects. Finally, vaccination requires education at all levels (individuals, community, healthcare professionals) to ensure its success by helping to overcome major barriers such as vaccine hesitancy and false contraindications.

Enterovirus and parechovirus meningitis in infants younger than 90 days old in the UK and Republic of Ireland: a British Paediatric Surveillance Unit study

OBJECTIVES

This study aimed to prospectively collect detailed clinical information for all enterovirus (EV) and human parechovirus (HPeV) meningitis cases in infants aged <90 days in the UK and Ireland.

PARTICIPANTS, DESIGN AND SETTING

Prospective, active national surveillance during July 2014 to July 2015 through the British Paediatric Surveillance Unit. Reporting paediatricians completed questionnaires requesting information on clinical presentation, investigations, management and outcomes at hospital discharge and after 12 months.

MAIN OUTCOME MEASURES

To describe the clinical burden of EV and HPeV meningitis in infants aged <90 days.

RESULTS

During the 13-month surveillance period, 703 cases (668 EV, incidence0.79/1,000 live- births; 35 HPeV, 0.04/1,000 live-births) were identified. The most common clinical presentations were fever (EV: 570/668(85%); HPeV: 28/35(80%)), irritability (EV: 441/668(66%); HPeV: 23/35(66%)) and reduced feeding (EV: 363/668(54%); HPeV 23/35(66%)). Features of circulatory shock were present in 27% (182/668) of EV and 43% (15/35) of HPeV cases. Overall, 11% (76/668) of EV and 23% (8/35) of HPeV cases required intensive care support. Nearly all cases (678/703, 96%) were confirmed by cerebrospinal fluid (CSF) PCR, with 52% (309/600) having normal CSF white cell count for age. Two infants with EV meningitis died (2/668, 0.3%) and four survivors (4/666, 0.6%) had long-term complications at 12 months' follow-up. Infants with HPeV meningitis survived without sequelae. Overall 189 infants had a formal hearing test and none had sensorineural hearing loss.

CONCLUSION

The incidence of laboratory-confirmed EV/HPeV meningitis in young infants is more than twice that for bacterial meningitis. Less than 1% will develop severe neurological complications or die of their infection. Further studies are required to formally assess long-term neurodevelopmental sequelae.

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.

A 2.8-Angstrom-Resolution Cryo-Electron Microscopy Structure of Human Parechovirus 3 in Complex with Fab from a Neutralizing Antibody

Human parechovirus 3 (HPeV3) infection is associated with sepsis characterized by significant immune activation and subsequent tissue damage in neonates. Strategies to limit infection have been unsuccessful due to inadequate molecular diagnostic tools for early detection and the lack of a vaccine or specific antiviral therapy. Toward the latter, we present a 2.8-Å-resolution structure of HPeV3 in complex with fragments from a neutralizing human monoclonal antibody, AT12-015, using cryo-electron microscopy (cryo-EM) and image reconstruction. Modeling revealed that the epitope extends across neighboring asymmetric units with contributions from capsid proteins VP0, VP1, and VP3. Antibody decoration was found to block binding of HPeV3 to cultured cells. Additionally, at high resolution, it was possible to model a stretch of RNA inside the virion and, from this, identify the key features that drive and stabilize protein-RNA association during assembly.IMPORTANCE Human parechovirus 3 (HPeV3) is receiving increasing attention as a prevalent cause of sepsis-like symptoms in neonates, for which, despite the severity of disease, there are no effective treatments available. Structural and molecular insights into virus neutralization are urgently needed, especially as clinical cases are on the rise. Toward this goal, we present the first structure of HPeV3 in complex with fragments from a neutralizing monoclonal antibody. At high resolution, it was possible to precisely define the epitope that, when targeted, prevents virions from binding to cells. Such an atomic-level description is useful for understanding host-pathogen interactions and viral pathogenesis mechanisms and for finding potential cures for infection and disease.

High frequency and diversity of parechovirus A in a cohort of Malawian children

Parechoviruses (PeVs) are highly prevalent viruses worldwide. Over the last decades, several studies have been published on PeV epidemiology in Europe, Asia and North America, while information on other continents is lacking. The aim of this study was to describe PeV circulation in a cohort of children in Malawi, Africa. A total of 749 stool samples obtained from Malawian children aged 6 to 60 months were tested for the presence of PeV by real-time PCR. We performed typing by phylogenetic and Basic Local Alignment Search Tool (BLAST) analysis. PeV was found in 57% of stool samples. Age was significantly associated with PeV positivity (p = 0.01). Typing by phylogenetic analysis resulted in 15 different types, while BLAST typing resulted in 14 different types and several indeterminate strains. In total, six strains showed inconsistencies in typing between the two methods. One strain, P02-4058, remained untypable by all methods, but appeared to belong to the recently reclassified PeV-A19 genotype. PeV-A1, -A2 and -A3 were the most prevalent types (26.8%, 13.8% and 9.8%, respectively). Both the prevalence and genetic diversity found in our study were remarkably high. Our data provide an important contribution to the scarce data available on PeV epidemiology in Africa.

Human Parechovirus 3 in Infants: Expanding Our Knowledge of Adverse Outcomes

BACKGROUND

Human parechovirus particularly genotype 3 (HPeV3) is an emerging infection affecting predominantly young infants. The potential for neurologic sequelae in a vulnerable subset is increasingly apparent. A review of 2 epidemics of human parechovirus (HpeV) infection in 2013 and in 2015 in Queensland, Australia, was undertaken, with an emphasis on identifying adverse neurodevelopmental outcome.

METHODS

All hospitalized cases with laboratory-confirmed HPeV infection between October 2013 June 2016 were identified. Clinical, demographic, laboratory and imaging data were collected and correlated with reported developmental outcome.

RESULTS

Laboratory-confirmed HPeV infections were identified in 202 patients across 25 hospitals; 86.6% (n = 175) were younger than 3 months 16.3% (n = 33) received intensive care admission. Of 142 cerebrospinal fluid samples which were HPeV polymerase chain reaction positive, all 89 isolates successfully genotyped were HPeV3. Clinical information was available for 145 children; 53.1% (n = 77) had follow-up from a pediatrician, of whom 14% (n = 11) had neurodevelopmental sequelae, ranging from hypotonia and gross motor delay to spastic quadriplegic cerebral palsy and cortical visual impairment. Of 15 children with initially abnormal brain magnetic resonance imaging, 47% (n = 7) had neurodevelopmental concerns, the remainder had normal development at follow-up between 6 and 15 months of age.

CONCLUSIONS

This is the largest cohort of HPeV3 cases with clinical data and pediatrician-assessed neurodevelopmental follow-up to date. Developmental concerns were identified in 11 children at early follow-up. Abnormal magnetic resonance imaging during acute infection did not specifically predict poor neurodevelopmental in short-term follow-up. Continued follow-up of infants and further imaging correlation is needed to explore predictors of long-term morbidity.

Progress in human picornavirus research: New findings from the AIROPico consortium

Several research groups in Europe are active on different aspects of human picornavirus research. The AIROPico (Academia-Industry R&D Opportunities for Picornaviruses) consortium combined the disciplines of pathogenesis, diagnostics and therapy development in order to fill the gaps in our understanding of how picornaviruses cause human disease and how to combat them. AIROPico was the first EU consortium dedicated to human picornavirus research and development, and has largely accelerated and improved R&D on picornavirus biology, diagnostics and therapy. In this article, we present the progress on pathogenesis, diagnostics and treatment strategy developments for human picornaviruses resulting from the structured, translational research approach of the AIROPico consortium. We here summarize new insights in protection against infection by maternal or cross-protective antibodies, the visualisation of interactions between virus and neutralizing antibodies by cryoEM structural imaging, and the outcomes from a picornavirus-infected human 3D organoid. Progress in molecular detection and a fast typing assay for rhinovirus species are presented, as well as the identification of new compounds potentially interesting as therapeutic compounds.

Increased detection of human parechovirus infection in infants in England during 2016: epidemiology and clinical characteristics

BACKGROUND

Human parechovirus (HPeV), like enteroviruses, usually causes mild self-limiting respiratory and gastrointestinal symptoms. In infants, HPeV can occasionally cause serious illnesses, including sepsis-like syndrome and encephalitis. In summer 2016, Public Health England (PHE) received increasing reports of severe HPeV infections nationally. We, therefore, reviewed all infants with confirmed HPeV across England during 2016.

METHODS

HPeV cases in infants aged <12 months reported to PHE during 2016 were followed up using a clinical questionnaire. Additional cases identified by clinicians completing the questionnaire were also included.

RESULTS

We identified 106 infants with confirmed HPeV infection during 2016. The disease peaked during early summer. Most infants (98/106, 92%) were aged <90 days, and 43% (46/106) were neonates. Fever was the most commonly reported symptom (92%) and signs of circulatory shock were present in 53%. Eighteen infants (18%) required paediatric intensive care admission. Most infants had normal or low C reactive protein concentrations (<10 mg/dL in 75%, <50 mg/dL in 98%). A lumbar puncture was performed in 98% of cases; 92% (33/36) of neonates and 93% (53/57) of older infants had normal white cell count in the cerebrospinal fluid (CSF). Nearly all reported cases (98%) were confirmed by CSF PCR. All infants survived, but five had ongoing seizures after hospital discharge.

CONCLUSIONS

HPeV is an important cause of febrile illness in infants and can have severe clinical presentations. Early diagnosis may help reduce antimicrobial use, unnecessary investigations and prolonged hospitalisation. While prognosis remains favourable, some infants will develop long-term complications-paediatricians should ensure appropriate follow-up after discharge.

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.

Epidemiology and Immune Pathogenesis of Viral Sepsis

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. Sepsis can be caused by a broad range of pathogens; however, bacterial infections represent the majority of sepsis cases. Up to 42% of sepsis presentations are culture negative, suggesting a non-bacterial cause. Despite this, diagnosis of viral sepsis remains very rare. Almost any virus can cause sepsis in vulnerable patients (e.g., neonates, infants, and other immunosuppressed groups). The prevalence of viral sepsis is not known, nor is there enough information to make an accurate estimate. The initial standard of care for all cases of sepsis, even those that are subsequently proven to be culture negative, is the immediate use of broad-spectrum antibiotics. In the absence of definite diagnostic criteria for viral sepsis, or at least to exclude bacterial sepsis, this inevitably leads to unnecessary antimicrobial use, with associated consequences for antimicrobial resistance, effects on the host microbiome and excess healthcare costs. It is important to understand non-bacterial causes of sepsis so that inappropriate treatment can be minimised, and appropriate treatments can be developed to improve outcomes. In this review, we summarise what is known about viral sepsis, its most common causes, and how the immune responses to severe viral infections can contribute to sepsis. We also discuss strategies to improve our understanding of viral sepsis, and ways we can integrate this new information into effective treatment.

Viral Sepsis in Children

Sepsis in children is typically presumed to be bacterial in origin until proven otherwise, but frequently bacterial cultures ultimately return negative. Although viruses may be important causative agents of culture-negative sepsis worldwide, the incidence, disease burden and mortality of viral-induced sepsis is poorly elucidated. Consideration of viral sepsis is critical as its recognition carries implications on appropriate use of antibacterial agents, infection control measures, and, in some cases, specific, time-sensitive antiviral therapies. This review outlines our current understanding of viral sepsis in children and addresses its epidemiology and pathophysiology, including pathogen-host interaction during active infection. Clinical manifestation, diagnostic testing, and management options unique to viral infections will be outlined.

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.

Human Parechovirus Infection in Children in Taiwan: a Retrospective, Single-Hospital Study

To understand human parechovirus (HPeV) infections in Taiwanese children, we analyzed data for 112 children (age≤10 years) with HPeV infection diagnosed between July 2007 and June 2016 in a medical center in Kaohsiung, southern Taiwan. The patients were infected with HPeV1 (n=94), HPeV3 (n=3), HPeV4 (n=3), HPeV6 (n=1) and non-typeable HPeV (n=11). We compared the clinical implications for children younger than 3 months (n=56) and 3 months and older (n=31), excluding 25 children with concomitant infections. Fever was noted in almost half of the children younger than 3 months but was more frequent in older than in younger children (83.9% vs 46.4%). As compared with older children, children younger than 3 months had a lower incidence of respiratory symptoms (30.1% vs 83.9%), more frequently required intensive care unit admission (28.6% vs 3.2%), and had longer hospital stays (mean 10.95 vs 5.13 days). Importantly, about one-third of the children were suspected to have hospital-acquired or cluster infections in the environment of medical institutions, with a significantly high proportion of 42.9% (24/56) in younger infants. Hospital-acquired infections might play a key role in the spread of HPeV, especially in children younger than 3 months.

Myocarditis Caused by Human Parechovirus in Adult

The infectious etiology of myocarditis often remains unidentified. We report a case of myocarditis associated with human parechovirus (HPeV) infection in an adult. HPeV is an emerging pathogen that can cause serious illness, including myocarditis, in adults. Testing for HPeV should be considered in differential diagnosis of myocarditis.