Parechovirus: an important emerging infection in young infants

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.

Clinical presentation and management of enterovirus and parechovirus infection in children: A single-centre study in regional Australia

OBJECTIVE

This study aims to analyse the clinical presentation caused by enterovirus (EV) and/or human parechovirus (HPeV) infection in children, as well as the management of such cases admitted to a regional hospital in Australia.

METHODS

Retrospective study reviewing medical records.

SETTING

Single hospital in regional Australia.

PARTICIPANTS

All children under 18 years admitted over the 5-year period beginning from 1 January 2017 with confirmed EV and/or HPeV infection. Cases with clinically insignificant EV/HPeV isolation were excluded.

MAIN OUTCOME MEASURES

Data collected included demographic data, signs and symptoms present, specimens of EV/HPeV isolation, co-occurring pathogens, peak C-reactive protein (CRP), antibiotic therapy, discharge diagnosis and follow-up after discharge.

RESULTS

Overall, 27 patients fulfilled the inclusion criteria; 81.5% of the patients were ≤3 months of age with a median of 2 months (interquartile range 1-3); 74.1% were males. The most common clinical features were a fever ≥38°C and irritability/lethargy/high-pitched cry. 29.6% of the patients had co-occurring pathogens detected, and a CRP ≤10 mg/L was observed in 77.8% of cases. All but two children were treated with antibiotics while awaiting polymerase chain reaction results. The most common discharge diagnosis was meningitis. In all, 74.1% of the children attended follow-up appointments.

CONCLUSIONS

EV and HPeV should be considered as a possible aetiology of fever and irritability/lethargy/high-pitched cry in children under 3 months.

Pediatric Respiratory Hospitalizations in the Pre-COVID-19 Era: The Contribution of Viral Pathogens and Comorbidities to Clinical Outcomes, Valencia, Spain

Viral respiratory diseases place a heavy burden on the healthcare system, with children making up a significant portion of related hospitalizations. While comorbidities increase the risk of complications and poor outcomes, many hospitalized children lack clear risk factors. As new vaccines for respiratory viral diseases emerge, this study examined pediatric respiratory hospitalizations, focusing on viral etiology, complication rates, and the impact of comorbidities to guide future policy. Data were analyzed from eight pre-COVID influenza seasons (2011/2012-2018/2019) involving patients under 18 years hospitalized with respiratory complaints across 4-10 hospitals in Valencia, Spain. Respiratory specimens were tested for eight viral targets using multiplex real-time reverse-transcription polymerase chain reaction. Demographics, clinical outcomes, discharge diagnoses, and laboratory results were examined. Among the hospitalized children, 26% had at least one comorbidity. These children had higher rates of pneumonia, asthma exacerbation, and pneumothorax, and were twice as likely to require ICU admission, though mechanical ventilation and length of stay were similar to those without comorbidities. Respiratory syncytial virus (RSV) was the most common virus detected (23.1%), followed by rhinovirus/enterovirus (9.5%) and influenza (7.2%). Viral codetection decreased with age, occurring in 4.6% of cases. Comorbidities increase the risk of complications in pediatric respiratory illnesses, however, healthcare utilization is driven largely by otherwise healthy children. Pediatric viral vaccines could reduce this burden and should be further evaluated.

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.

Urban wastewater-based epidemiology for multi-viral pathogen surveillance in the Valencian region, Spain

Wastewater-based epidemiology (WBE) has lately arised as a promising tool for monitoring and tracking viral pathogens in communities. In this study, we analysed WBE's role as a multi-pathogen surveillance strategy to detect the presence of several viral illness causative agents. Thus, an epidemiological study was conducted from October 2021 to February 2023 to estimate the weekly levels of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), Respiratory Syncytial virus (RSV), and Influenza A virus (IAV) in influent wastewater samples (n = 69). In parallel, a one-year study (October 2021 to October 2022) was performed to assess the presence of pathogenic human enteric viruses. Besides, monitoring of proposed viral fecal contamination indicators crAssphage and Pepper mild mottle virus (PMMoV) was also assessed, along with plaque counting of somatic coliphages. Genetic material of rotavirus (RV), human astrovirus (HAStV), and norovirus genogroup I (GI) and GII was found in almost all samples, while hepatitis A and E viruses (HAV and HEV) only tested positive in 3.77 % and 22.64 % of the samples, respectively. No seasonal patterns were overall found for enteric viruses, although RVs had a peak prevalence in the winter months. All samples tested positive for SARS-CoV-2 RNA, with a mean concentration of 5.43 log genome copies per liter (log GC/L). The tracking of the circulating SARS-CoV-2 variants of concern (VOCs) was performed by both duplex RT-qPCR and next generation sequencing (NGS). Both techniques reliably showed how the dominant VOC transitioned from Delta to Omicron during two weeks in Spain in December 2021. RSV and IAV viruses peaked in winter months with mean concentrations 6.40 and 4.10 log GC/L, respectively. Moreover, the three selected respiratory viruses strongly correlated with reported clinical data when normalised by wastewater physico-chemical parameters and presented weaker correlations when normalising sewage concentration levels with crAssphage or somatic coliphages titers. Finally, predictive models were generated for each respiratory virus, confirming high reliability on WBE data as an early-warning system and communities illness monitoring system. Overall, this study presents WBE as an optimal tool for multi-pathogen tracking reflecting viral circulation and diseases trends within a selected area, its value as a multi-pathogen early-warning tool stands out due to its public health interest.

A Case Series of Infants 60 Days of Age or Younger With Human Parechovirus (PeV) Meningitis From a New York City Pediatric Emergency Department

Human parechovirus is a relatively lesser known virus that has recently spread across the United States, primarily affecting newborns and young infants. A particular strain of parechovirus, PeV-A3, has been found in the cerebrospinal fluid studies of many young patients in the spring and summer of 2022; however, short- and long-term neurologic effects of this virus are often not well known. We present a case series of 4 infants, 60 days of age or younger, found to have human parechovirus meningitis. Our retrospective study found that none of the 4 infants presented with any significant neurological findings, nor did they develop any specific neurologic signs or symptoms during their hospitalizations. Patients should continue to be monitored for long-term neurological and neurodevelopmental sequelae.

Respiratory viral detection in the plasma and cerebrospinal fluid (CSF) of young febrile infants

Background

Respiratory viral infections are common in febrile infants ≤90 days. However, the detection of viruses other than enterovirus in the blood and cerebrospinal fluid (CSF) of young infants is not well defined. We sought to quantify the occurrence of respiratory viruses in the blood and CSF of febrile infants ≤90 days.

Methods

We conducted a nested cohort study examining plasma and CSF samples from febrile infants 15-90 days via rtPCR. The samples were tested for respiratory viruses (respiratory syncytial virus, influenza, enterovirus, parechovirus, adenovirus, bocavirus). Clinical and laboratory data were also collected to determine the presence of serious bacterial infections (SBI).

Results

Twenty-four percent (30 of 126) of infants had plasma/CSF specimens positive for a respiratory virus. Enterovirus and parechovirus were the most commonly detected respiratory viruses. Viral positivity was highest in plasma samples at 25% (27 of 107) compared with CSF samples at 15% (nine of 62). SBIs (specifically urinary tract infections) were less common in infants with a sample positive for a respiratory virus compared to those without a virus detected (3% vs. 26%, p = 0.008).

Conclusions

Our findings support the use of molecular diagnostics to include the identification of parechovirus in addition to enterovirus in febrile infants ≤90 days. Additionally, these data support the utilization of blood specimens to diagnose enterovirus and parechovirus infections in febrile infants ≤90 days.

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.

Occurrence of multiple respiratory viruses in wastewater in Queensland, Australia: Potential for community disease surveillance

The early warning and tracking of COVID-19 prevalence in the community provided by wastewater surveillance has highlighted its potential for much broader viral disease surveillance. In this proof-of-concept study, 46 wastewater samples from four wastewater treatment plants (WWTPs) in Queensland, Australia, were analyzed for the presence and abundance of 13 respiratory viruses, and the results were compared with reported clinical cases. The viruses were concentrated using the adsorption-extraction (AE) method, and extracted nucleic acids were analyzed using qPCR and RT-qPCR. Among the viruses tested, bocavirus (BoV), parechovirus (PeV), rhinovirus A (RhV A) and rhinovirus B (RhV B) were detected in all wastewater samples. All the tested viruses except influenza B virus (IBV) were detected in wastewater sample from at least one WWTP. BoV was detected with the greatest concentration (4.96-7.22 log10 GC/L), followed by Epstein-Barr virus (EBV) (4.08-6.46 log10 GC/L), RhV A (3.95-5.63 log10 GC/L), RhV B (3.74-5.61 log10 GC/L), and PeV (3.17-5.32 log10 GC/L). Influenza viruses and respiratory syncytial virus (RSV) are notifiable conditions in Queensland, allowing the gene copy (GC) concentrations to be compared with reported clinical cases. Significant correlations (ρ = 0.60, p < 0.01 for IAV and ρ = 0.53, p < 0.01 for RSV) were observed when pooled wastewater influenza A virus (IAV) and RSV log10 GC/L concentrations were compared to log10 clinical cases among the four WWTP catchments. The positive predictive value for the presence of IAV and RSV in wastewater was 97 % for both IAV and RSV clinical cases within the four WWTP catchments. The overall accuracy of wastewater analysis for predicting clinical cases of IAV and RSV was 97 and 90 %, respectively. This paper lends credibility to the application of wastewater surveillance to monitor respiratory viruses of various genomic characteristics, with potential uses for increased surveillance capabilities and as a tool in understanding the dynamics of disease circulation in the communities.

Management of neonatal central nervous system viral infections: Knowledge gaps and research priorities

Congenital CMV, enteroviruses, human parechovirus and herpes simplex virus are all common causes of severe central nervous system (CNS) infection in neonates. The introduction of screening (i.e. newborn hearing screening programme), integration of molecular syndromic testing (i.e. multiplex polymerase chain reaction assays) and increase in sexually transmitted infections (i.e. anogenital herpes) have contributed to increases in each of these infections over the last decade. However, therapeutic options are highly limited in part due to the lack of epidemiological data informing trials. This review will describe our current understanding of the clinical burden and epidemiology of these severe neonatal CNS infections, outline the novel antiviral and vaccines in the pipeline and suggest future research studies which could help develop new therapeutics.

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.

Parechovirus A infection and risk of gastroenteritis in children: A systematic review and meta-analysis

Parechovirus A (PeV-A) belongs to the genus Parechovirus in the family Picornaviridae associated with gastroenteritis illness, particularly in children, but prior studies have produced ambiguous results. This study aimed to provide a systematic review of the PeV-A prevalence in paediatric patients with gastroenteritis and the association between PeV-A infection and the risk of gastroenteritis. A systematic search of the literature was conducted in Embase, PubMed, Scopus, and Web of Science, in combination with the reference lists of potentially relevant articles. A random effect-based model was applied to analyse data from included studies. The pooled odds ratio (OR) and 95% confidence interval (CI) were used for assessing the risk between PeV-A and gastroenteritis. A total of 41 studies assessing 21,850 cases and 1746 healthy controls were analysed. The overall prevalence of PeV-A among paediatric patients with gastroenteritis was 10.4% (95% CI: 7.9%-13.2%), while it was estimated at 8.1% (95% CI: 5.1%-11.7%) based on studies only investigating children without gastroenteritis. The pooled OR for all eight case-control studies was 1.079 (95% CI: 0.730-1.597), indicating there was no statistically significant association. PeV-A genotype 1 was the most frequent genotype of PeV-A infection in children with gastroenteritis. The PeV-A prevalence in cases of gastroenteritis is higher than that in children without gastroenteritis. However, the present meta-analysis did not indicate a statistically significant association between PeV-A infection and risk of gastroenteritis. Given the considerable heterogeneity and various sample sizes among the included studies, relevant investigations in the future should be carried out based on a large-scale population.

Human Platelet Lysate Induces Antiviral Responses against Parechovirus A3

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

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.

Development of a multiplex droplet digital PCR assay for detection of enterovirus, parechovirus, herpes simplex virus 1 and 2 simultaneously for diagnosis of viral CNS infections

Background

Enterovirus (EV), parechovirus (HPeV), herpes simplex virus 1 and 2 (HSV1/2) are common viruses leading to viral central nervous system (CNS) infections which are increasingly predominant but exhibit deficiency in definite pathogen diagnosis with gold-standard quantitative PCR method. Previous studies have shown that droplet digital PCR (ddPCR) has great potential in pathogen detection and quantification, especially in low concentration samples.

Methods

Targeting four common viruses of EV, HPeV, HSV1, and HSV2 in cerebrospinal fluid (CSF), we developed a multiplex ddPCR assay using probe ratio-based multiplexing strategy, analyzed the performance, and evaluated it in 97 CSF samples collected from patients with suspected viral CNS infections on a two-channel ddPCR detection system.

Results

The four viruses were clearly distinguished by their corresponding fluorescence amplitude. The limits of detection for EV, HPeV, HSV1, and HSV2 were 5, 10, 5, and 10 copies per reaction, respectively. The dynamic range was at least four orders of magnitude spanning from 2000 to 2 copies per reaction. The results of 97 tested clinical CSF specimens were identical to those deduced from qPCR/qRT-PCR assays using commercial kits.

Conclusion

The multiplex ddPCR assay was demonstrated to be an accurate and robust method which could detect EV, HPeV, HSV1, and HSV2 simultaneously. It provides a useful tool for clinical diagnosis and disease monitoring of viral CNS infections.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12985-022-01798-y.

Characterization of Pathogenesis and Inflammatory Responses to Experimental Parechovirus Encephalitis

Human parechovirus type 3 (PeV-A3) infection has been recognized as an emerging etiologic factor causing severe nerve disease or sepsis in infants and young children. But the neuropathogenic mechanisms of PeV-A3 remain unknown. To understand the pathogenesis of PeV-A3 infection in the neuronal system, PeV-A3-mediated cytopathic effects were analyzed in human glioblastoma cells and neuroblastoma cells. PeV-A3 induced interferons and inflammatory cytokine expression in these neuronal cells. The pronounced cytopathic effects accompanied with activation of death signaling pathways of apoptosis, autophagy, and pyroptosis were detected. A new experimental disease model of parechovirus encephalitis was established. In the disease model, intracranial inoculation with PeV-A3 in C57BL/6 neonatal mice showed body weight loss, hindlimb paralysis, and approximately 20% mortality. PeV-A3 infection in the hippocampus and cortex regions of the neonatal mouse brain was revealed. Mechanistic assay supported the in vitro results, indicating detection of PeV-A3 replication, inflammatory cytokine expression, and death signaling transduction in mouse brain tissues. These in vitro and in vivo studies revealed that the activation of death signaling and inflammation responses is involved in PeV-A3-mediated neurological disorders. The present results might account for some of the PeV-A3-associated clinical manifestations.

Hidden Viral Sequences in Public Sequencing Data and Warning for Future Emerging Diseases

RNA viruses cause numerous emerging diseases, mostly due to transmission from mammalian and avian reservoirs. Large-scale surveillance of RNA viral infections in these animals is a fundamental step for controlling viral infectious diseases. Metagenomic analysis is a powerful method for virus identification with low bias and has contributed substantially to the discovery of novel viruses. Deep-sequencing data have been collected from diverse animals and accumulated in public databases, which can be valuable resources for identifying unknown viral sequences. Here, we screened for infections of 33 RNA viral families in publicly available mammalian and avian sequencing data and found approximately 900 hidden viral infections. We also discovered six nearly complete viral genomes in livestock, wild, and experimental animals: hepatovirus in a goat, hepeviruses in blind mole-rats and a galago, astrovirus in macaque monkeys, parechovirus in a cow, and pegivirus in tree shrews. Some of these viruses were phylogenetically close to human-pathogenic viruses, suggesting the potential risk of causing disease in humans upon infection. Furthermore, infections of five novel viruses were identified in several different individuals, indicating that their infections may have already spread in the natural host population. Our findings demonstrate the reusability of public sequencing data for surveying viral infections and identifying novel viral sequences, presenting a warning about a new threat of viral infectious disease to public health. IMPORTANCE Monitoring the spread of viral infections and identifying novel viruses capable of infecting humans through animal reservoirs are necessary to control emerging viral diseases. Massive amounts of sequencing data collected from various animals are publicly available, and these data may contain sequences originating from a wide variety of viruses. Here, we analyzed more than 46,000 public sequencing data and identified approximately 900 hidden RNA viral infections in mammalian and avian samples. Some viruses discovered in this study were genetically similar to pathogens that cause hepatitis, diarrhea, or encephalitis in humans, suggesting the presence of new threats to public health. Our study demonstrates the effectiveness of reusing public sequencing data to identify known and unknown viral infections, indicating that future continuous monitoring of public sequencing data by metagenomic analyses would help prepare and mitigate future viral pandemics.

Infectious exanthemas in childhood

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

Phylogenetic molecular evolution and recombination analysis of complete genome of human parechovirus in Thailand

Human parechovirus (HPeV), which is a member of the Picornavirus group of viruses, is a pathogen that is reported to be associated with manifestations that include respiratory tract involvement, gastroenteritis, sepsis-like symptom, and central nervous system complication. Until now, nineteen genotypes have been identified. The lack of proofreading property of viral RNA-dependent RNA polymerase (RdRp) together with recombination among the intra- and inter-genotypes of the virus results in high diversity. However, data specific to the molecular evolutionary perspective of the complete genome of HPeV remains limited. This study aimed to analyze the phylogenetic, molecular evolution, and recombination characteristics of the complete genome of HPeV strains isolated in Thailand during 2009–2012. Fifty-eight samples that were previously confirmed to be HPeV positive and then evaluated for genotyping were subjected to complete genome amplification to generate ten overlapping PCR fragments using a set of in-house designed primers. The same position of the viral genome was read in triplicate using direct Sanger sequencing. All samples were classified into the same previously defined genotypes in both whole-genome and VP1 phylogenic tree. However, sample B1091/HPeV14/2011 exhibited discordant grouping between whole-genome and VP1 on the phylogenetic tree. Bootscan analysis revealed that B1091/HPeV14/2011 inherited from two genotypic viruses, including VP1 from HPeV14, and the rest of the genome from HPeV1B. The results of this study provide important insights into the molecular evolution of and recombination in the viral genome of HPeV that will improve and accelerate our ability to develop treatment and prophylactic strategies in the future.

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.

The role of picornavirus infection in epileptogenesis

Picornaviridae are a family of small positive-strand RNA viruses, and transmitted via the respiratory or fecal-oral route. The neurotropic picornaviruses can induce acute or late recurrent seizures following central nervous system infection, by infecting the peripheral nerve, crossing the blood-brain barrier and migrating in the Trojan-horse method. Theiler’s murine encephalomyelitis virus (TMEV), as a member of Picornaviridae family, can cause encephalitis, leading to chronic spontaneous seizures. TMEV-infected C57BL/6 mice have been used as an animal model for exploring the mechanism of epileptogenesis and assessing new antiepileptic drugs. Astrogliosis, neuronal death and microglial recruitment have been detected in the hippocampus following the picornaviruse-induced encephalitis. The macrophages, monocytes, neutrophils, as well as IL-6 and TNF-α released by them, play an important role in the epileptogenesis. In this review, we summarize the clinical characteristics of picornavirus infection, and the immunopathology involved in the TMEV-induced epilepsy.

Causes and Clinical Features of Childhood Encephalitis: A Multicenter, Prospective Cohort Study

BACKGROUND

We aimed to determine the contemporary causes, clinical features, and short-term outcome of encephalitis in Australian children.

METHODS

We prospectively identified children (≤14 years of age) admitted with suspected encephalitis at 5 major pediatric hospitals nationally between May 2013 and December 2016 using the Paediatric Active Enhanced Disease Surveillance (PAEDS) Network. A multidisciplinary expert panel reviewed cases and categorized them using published definitions. Confirmed encephalitis cases were categorized into etiologic subgroups.

RESULTS

From 526 cases of suspected encephalitis, 287 children met criteria for confirmed encephalitis: 57% (95% confidence interval [CI], 52%-63%) had infectious causes, 10% enterovirus, 10% parechovirus, 8% bacterial meningoencephalitis, 6% influenza, 6% herpes simplex virus (HSV), and 6% Mycoplasma pneumoniae; 25% (95% CI, 20%-30%) had immune-mediated encephalitis, 18% acute disseminated encephalomyelitis, and 6% anti-N-methyl-d-aspartate receptor encephalitis; and 17% (95% CI, 13%-21%) had an unknown cause. Infectious encephalitis occurred in younger children (median age, 1.7 years [interquartile range {IQR}, 0.1-6.9]) compared with immune-mediated encephalitis (median age, 7.6 years [IQR, 4.6-12.4]). Varicella zoster virus encephalitis was infrequent following high vaccination coverage since 2007. Thirteen children (5%) died: 11 with infectious causes (2 influenza; 2 human herpesvirus 6; 2 group B Streptococcus; 2 Streptococcus pneumoniae; 1 HSV; 1 parechovirus; 1 enterovirus) and 2 with no cause identified. Twenty-seven percent (95% CI, 21%-31%) of children showed moderate to severe neurological sequelae at discharge.

CONCLUSIONS

Epidemic viral infections predominated as causes of childhood encephalitis in Australia. The leading causes include vaccine-preventable diseases. There were significant differences in age, clinical features, and outcome among leading causes. Mortality or short-term neurological morbidity occurred in one-third of cases.

Molecular detection and phylogenetic analysis of human parechovirus in children with acute gastroenteritis in Iran

Aim: Human parechovirus (HPeV) is one of the major causes of acute gastroenteritis in children. Materials & methods: Stool specimens (n = 250) were collected from children aged ≤3 years during 2018–2019. HPeV RNA was detected by reverse transcription-PCR and genotyping by VP1 gene, Rotavirus (RV) screened by ELISA. Results: HPeV was detected in 12% of the cases. The children under 6-months old (64.2%) were a sensitive group and HPeV was more prevalent during January–February (73.3%). The co-infection of HPeV with RV was 50%. All of the sequenced samples belong to the HPeV-1 genotype. Conclusion: HPeV-1 is one of the major causes of acute viral gastroenteritis in children and the co-infection of RV can be an additional infection in some cases.

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.

Paediatric Active Enhanced Disease Surveillance (PAEDS) 2017 and 2018: Prospective hospital-based surveillance for serious paediatric conditions

Introduction

The Paediatric Active Enhanced Disease Surveillance (PAEDS) network is a hospital-based active surveillance system employing prospective case ascertainment for selected serious childhood conditions, particularly vaccine-preventable diseases and potential adverse events following immunisation (AEFI). This report presents surveillance data for 2017 and 2018.

Methods

Specialist nurses screened hospital admissions, emergency department (ED) records, laboratory and other data on a daily basis in seven paediatric tertiary referral hospitals across Australia to identify children with the conditions under surveillance. In 2017 and 2018 these included acute flaccid paralysis (AFP; a syndrome associated with poliovirus infection), acute childhood encephalitis (ACE), influenza, intussusception (IS; a potential AEFI with rotavirus vaccines), pertussis, varicella-zoster virus infection (varicella and herpes zoster), invasive meningococcal, and invasive Group A streptococcus diseases. An additional social research component was added to evaluate parental attitudes to vaccination.

Results

PAEDS captured 1,580 and 925 cases for 2017 and 2018, respectively, across all conditions under surveillance. Key outcomes of PAEDS included: contribution to national AFP surveillance to reach the World Health Organization reporting targets; identification of a third human parechovirus outbreak among other infectious diseases linked to ACE; demonstration of variable influenza activity between 2017 and 2018, with vaccine effectiveness (VE) analysis demonstrating that the protection offered through vaccination is season-dependent. All IS cases associated with vaccine receipt were reported to the relevant state health department. Varicella and herpes zoster case numbers remained unchanged, with vaccine uptake found to be suboptimal among eligible children under the NIP. Enhanced pertussis surveillance continues to capture controls for VE estimation. Surveillance for invasive meningococcal disease showed predominance for serotype B at 57% over 2 years among 77 cases where serotyping was available, and surveillance for invasive group A streptococcus captured severe disease in children.

Conclusion

PAEDS continues to provide unique policy-relevant data on serious paediatric conditions using hospital-based sentinel surveillance.

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.

Polymerase chain reaction for human parechovirus on blood samples improves detection of clinical infections in infants

Human parechovirus (HPeV) is an emerging pathogen for infants. Improved diagnostics are needed due to the non-specific clinical presentation. Real-time reverse transcription polymerase chain reaction (RT-PCR) on blood samples may be an adjunct to diagnosis. A retrospective cohort of HPeV-affected infants was used to assess sensitivity and specificity of a HPeV RT-PCR on blood and cerebrospinal fluid (CSF). As a secondary analysis, the Ct value of the PCR results was compared to clinical correlates of severity. Between 2017 and 2018 blood samples were obtained from 97 infants of whom 44 had HPeV clinical and laboratory proven infection. Eighty-three concurrent CSF samples were available. Sensitivity was 93.3% [95% CI 82-99] for blood HPeV RT-PCR and 85% [95% CI 73.9-96.1] for CSF HPeV RT-PCR. Blood HPeV RT-PCR Ct values < 25 cycles were associated with age < 28 days and < 3 days of symptoms. No statistical associations were identified between potential clinical markers of severity and Ct value. HPeV RT-PCR on blood is a valuable adjunct to diagnostic testing for acute HPeV-related illness in infants. Results can be expected to be robust until at least day 5 of symptoms, with optimal sampling occurring close to onset of symptoms.

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.

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.

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.