Human Parechovirus Infections Research Articles

Human Parechovirus Meningoencephalitis In an Eight-Day-Old Infant

Human parechovirus (HPeV) infections have been increasing in the United States since May 2022, according to the Centers for Disease Control and Prevention. HPeVs are a member of the Picornaviridae family and share similarities with enteroviruses, though they differ in genomic structure. HPeV commonly affects children, with disease manifestations ranging anywhere from an asymptomatic infection to severe disease. HPeV typically affects the gastrointestinal and respiratory tracts but may rarely also cause severe infection of the central nervous system (CNS), leading to sepsis-like illness, meningitis, and encephalitis. Of the 19 established serotypes of HPeV, serotypesA1 and A3 are most commonly identified in humans. HPeV serotype A3 is of particular importance as it more commonly causes sepsis and CNS infection, especially in children. In the United States between 2014 and 2016, a total of 2758 cases of enteroviruses and parechoviruses were reported to the National Enterovirus Surveillance System. Of those cases, 2.3% were distinguished as HPeVA3. This case details the clinical course of an eight-day-old infant with HPeV meningoencephalitis. The infant initially presented with fever and other nonspecific symptoms, which later progressed to include diffuse erythroderma and seizure activity. Although current management of HPeV meningoencephalitis involves supportive care and close monitoring, determining HPeV as a cause of infection is important due to the long-term sequelae that patients may develop. Potential complications of infection include white matter lesions of the brain, cerebral palsy, developmental delay, and visual impairment. This case was documented to increase awareness of the rising incidence of HPeV infections in children in the United States, as well as to detail the signs and symptoms of HPeV meningoencephalitis in a neonate.

Early Neonatal Presentation and Neuroimaging of Parechovirus Meningoencephalitis in a Preterm Baby: A Case Report.

Neonatal meningoencephalitis caused by human parechovirus infection is being increasingly recognized in recent literature. While most cases are postnatally acquired, intrauterine infection is rare, presents early and has a more severe impact on brain health and development. We discuss here an infant born preterm at 34 weeks gestational age, with neonatal course remarkable for severe encephalopathy presenting on day 2 of life due to human parechovirus meningoencephalitis transmitted in utero. Early magnetic resonance brain imaging detected extensive white matter injury and subsequently evolved into multicystic leukoencephalopathy. Posthospital discharge, infant was noted to have early neurodevelopmental impairment at 4 months corrected age.

Human Enterovirus B Is a Significant Cause of Aseptic Meningitis and Sepsis-Like Illness in Young Infants in Thailand.

Human enterovirus (EV) and Parechovirus (PeV) infections are major causes of sepsis-like illness in infants < 90 days of age. Enterovirus species B (EV-B) was found to be the leading cause of aseptic meningitis in young infants. In Thailand, EV and PeV are not part of the routine screening of blood or cerebrospinal fluid (CSF) of children with suspected aseptic meningitis and sepsis-like illness. Consequently, data on EV and PeV epidemiology are limited. This study tested clinical samples from hospitalized young infants with suspected aseptic meningitis or sepsis-like illness between 2013 and 2022 for EV, PeV, and Herpes simplex virus (HSV). Of 95 specimens, 10 were positive for EV, representing 10.5%. These positive samples included eight CSF and two stool samples. No samples were positive for PeV and HSV. Of these positive cases, EV-B was detected in eight, and EV-A was detected in two cases. The species of EV-B detected include echovirus-18 (E18) (n=2), E21 (n=2), E4(n=1), E5 (n=1), E9 (n=1), and E11 (n=1). Ourreport demonstrates the significant role of EV-B, and less frequently EV-A, in Thai infants with aseptic meningitis and sepsis-like illness.

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

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

Human Parechovirus (HPeV) infections: clinical presentations, patterns, and evolution of neonatal brain injury.

Human Parechovirus (HPeV) infections: clinical presentations, patterns, and evolution of neonatal brain injury.

The Burden of Human Parechoviruses Among Children in Oman

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 &lt;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 &lt;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. Keywords: Children; Parechovirus; Infection; Patient Outcome Assessment; Oman.

1747. Clinical Spectrum of a Large Multi-State U.S. Cohort of Parechovirus Infection in Neonates and Young Infants

Abstract Background Severe manifestations of human parechovirus (HPeV) infection, including meningoencephalitis and sepsis, can occur in neonates and young infants. Death has rarely been reported. Rates of HPeV infection fluctuate from year to year in the community. After the home isolation during the initial COVID-19 era in 2020, waves of respiratory viral outbreaks at unusual times of the year were identified in the pediatric community in 2021 and 2022, including increased number of cases of severe HPeV infection in young infants. This study characterizes the U.S. outbreak of HPeV infections that occurred in newborns and young infants in 2022. Methods A multi-site, retrospective and prospective observational study identified hospitalized infants &amp;lt; =6 months, with a body fluid specimen positive for HPeV. IRB approval of a single protocol was obtained at each site. Data obtained included hospital summary, maternal and birth history, medications, bacterial and viral testing, and radiology results. Analysis included infants with hospitalizations from January 1 through December 31, 2022. Results 13 academic sites were enrolled, which included 8 sites achieving full IRB approval/activation and completed data collection, and 5 sites pending activation [Fig 1A]. Interim analysis shows 112 infants across eleven states hospitalized with HPeV infection with a median hospital duration of 3 days (range 0-178 d), peaking in May 2022 [Fig 1B], with a spectrum of biochemical markers [Table 1]. The median age at hospitalization was 21.5 days of life (IQR 10, 32 d). All but five infants received antibiotics during the admission, and more than half (54%) received acyclovir. Other pathogens were rarely reported [Table 2]. 45 (38%) infants received MRI brain imaging during hospitalization of which 29 were abnormal; 10 reports directly mentioning HPeV in the interpretation. A total of 51 EEGs were completed in 31 infants; 20 infants (18%) had seizures reported. 17 infants required anticonvulsants. Two infants died. Conclusion We report the first multi-site, clinical description of the 2022 U.S. outbreak of HPeV among neonates and young infants. This is the first large series of infants with HPeV to report mortality. Further development of a multi-site U.S. collaboration to improve surveillance for HPeV is needed. Disclosures Laura Filkins, PhD, Avsana Labs: Board Member|Avsana Labs: Stocks/Bonds|Biofire Diagnostics: Grant/Research Support Claudia M. Espinosa, MD, MSc, AstraZeneca: Grant/Research Support|Enanta: Grant/Research Support|Jansen and Jansen: Advisor/Consultant|Kentucky Rural Health Association: Honoraria|Merck: Grant/Research Support|Sanofi: Advisor/Consultant|Sanofi: Grant/Research Support|Sanofi: Honoraria|Sobi: Dinner Joseph A. Bocchini, Jr., MD, Avalere: Advisor/Consultant|Enanta: Site PI on multicenter clinical trials, contract with employer|Moderna: Advisor/Consultant|Novavax: Sub-I on multicenter clinical trials, contract with employer|Pfizer: Advisor/Consultant|Pfizer: Site PI on multicenter clinical trials, contract with employer|Regeneron: Site PI on multicenter clinical trials, contract with employer|Sobi: Advisor/Consultant|Valneva: Advisor/Consultant Roberto P. Santos, MD, MSCS, Eli Lilly (SARS-CoV-2, baricitinid) - Site Open for Enrollment on March 8, 2023: Industry-sponsored clinical trials with research contract awarded to the University of Mississippi Medical Center with RPS as site PI|Eli Lilly (SARS-CoV-2, LY3819253, LY3832479) - study discontinuation on January 3, 2022: Industry-sponsored clinical trials with research contract awarded to the University of Mississippi Medical Center with RPS as site PI|JNJ (RSV, rilematovir) - study discontinuation on March 1, 2022: Industry-sponsored clinical trials with research contract awarded to the University of Mississippi Medical Center with RPS as site PI|MSD (HIV, islatravir, doravirine) - study discontinuation on December 6, 2022: Industry-sponsored clinical trials with research contract awarded to the University of Mississippi Medical Center with RPS as site PI Rangaraj Selvarangan, BVSc, PhD, D(ABMM), FIDSA, FAAM, Abbott: Honoraria|Altona Diagnostics: Grant/Research Support|Baebies Inc: Advisor/Consultant|BioMerieux: Advisor/Consultant|BioMerieux: Grant/Research Support|Bio-Rad: Grant/Research Support|Cepheid: Grant/Research Support|GSK: Advisor/Consultant|Hologic: Grant/Research Support|Lab Simply: Advisor/Consultant|Luminex: Grant/Research Support David W. Kimberlin, MD, Gilead: Grant/Research Support|Gilead: I served as site PI on Gilead's study of remdesivir in pediatric patients. All monies went directly to my university and not to me.

Usefulness of BioFire Filmarray Meningitis/Encephalitis Panel for Diagnosis of Human Parechovirus Infection in Infants and Identification of Local Outbreaks.

Usefulness of BioFire Filmarray Meningitis/Encephalitis Panel for Diagnosis of Human Parechovirus Infection in Infants and Identification of Local Outbreaks.

Human parechovirus infections in children: modern concepts

This article is a review of modern ideas about human parechovirus infection in children. At this time human parechoviruses are a common cause of infectious diseases in childhood with clinical presentation of acute gastroenteritis, upper respiratory tract pathology, fever, and rash. Severe forms damaging the central nervous system or the development of sepsis are possible in newborns and infants and are almost exclusively associated with parechovirus A type 3 (HPeV-A3). The infection is transmitted mainly via food and droplet routes. The main method of infection diagnosis is the detection of viral RNA by real-time PCR in cerebrospinal fluid, blood, and feces. No treatment for the parechovirus infection has been developed so far.

HUMAN PARECHOVIRUS CENTRAL NERVOUS SYSTEM INFECTION IN A YOUNG INFANT COHORT.

In 2022, a surge in cases of pediatric human parechovirus (HPeV) central nervous system infections in young infants was seen at our institution. Despite the dramatic increase in the number of cases seen that year, the clinical features of the illness were similar to prior years. The recent pediatric HPeV surge highlights the need to evaluate treatment options and standardize follow-up to better understand the long-term prognosis of infants with HPeV infection.

Parechovirus neonatal sepsis and meningitis – a (still) poorly recognised agent

Human parechovirus (HPeV), a Picornaviridae virus, is a microorganism associated with respiratory and gastrointestinal infections, in most cases with a benign clinical course. However, some serotypes have been recently associated with a more serious clinical outcome in young children, namely sepsis-like disease and meningitis. In this report, we describe the case of a previously healthy, 11-day-old infant in our Paediatric Emergency Department who presented with high fever, irritability and poor feeding. No other accompanying symptoms, such as respiratory, gastrointestinal or urinary, were shown by the patient. Family history unveiled an 18-month-old sibling with an upper respiratory tract infection. Physical examination was unremarkable. Laboratory testing revealed a normal total white cell count with lymphopenia and a maximum C-reactive protein value of 21.4 mg/L. Cerebrospinal fluid (CSF) analysis showed pleocytosis with high proteinorrachia and normal glycorrhachia. With the clinical suspicion of sepsis, she was hospitalized for clinical surveillance, and empirical antibiotics were administered. Although the bacteriological exams of blood and CSF were negative, RNA of an HPeV was detected in the CSF. She had a favourable clinical course, the cerebral ultrasound was normal, and the clinical follow-up showed adequate psychomotor development until today (18 months old). Recent publications suggested HPeV as one of the major agents of neonatal sepsis and meningitis. Similarly, several other studies reported significant neurological impairments in infants with HPeV infection. In line with these recent findings, we believe this clinical case further supports the need for more extensive research in viral aetiology and in particular of this, not so uncommon, agent in order to avoid unnecessary and potentially harmful interventions in newborns presenting with a sepsis-like clinical picture.

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

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. 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. 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. 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.

The Identification and Genetic Characterization of Parechovirus Infection Among Pediatric Patients With Wide Clinical Spectrum in Chongqing, China.

Human parechoviruses (HPeVs) are important causes of infection in children. However, without a comprehensive and persistent surveillance, the epidemiology and clinical features of HPeV infection remain ambiguous. We performed a hospital-based surveillance study among three groups of pediatric patients with acute respiratory infection (Group 1), acute diarrhea (Group 2), and hand, foot and mouth disease (Group 3) in Chongqing, China, from 2009 to 2015. Among 10,212 tested patients, 707 (6.92%) were positive for HPeV, with the positive rates differing significantly among three groups (Group 1, 3.43%; Group 2, 14.94%; Group 3, 3.55%; P < 0.001). The co-infection with other pathogens was detected in 75.2% (531/707) of HPeV-positive patients. Significant negative interaction between HPeV and Parainfluenza virus (PIV) (P = 0.046, OR = 0.59, 95% CI = 0.34–0.98) and positive interactions between HPeV and Enterovirus (EV) (P = 0.015, OR = 2.28, 95% CI = 1.23–4.73) were identified. Among 707 HPeV-positive patients, 592 (83.73%) were successfully sequenced, and 10 genotypes were identified, with HPeV1 (n = 396), HPeV4 (n = 86), and HPeV3 (n = 46) as the most frequently seen. The proportion of genotypes differed among three groups (P < 0.001), with HPeV1 and HPeV4 overrepresented in Group 2 and HPeV6 overrepresented in Group 3. The spatial patterns of HPeV genotypes disclosed more close clustering of the currently sequenced strains than those from other countries/regions, although they were indeed mixed. Three main genotypes (HPeV1, HPeV3, and HPeV4) had shown distinct seasonal peaks, highlighting a bi-annual cycle of all HpeV and two genotypes (HPeV 1 and HPeV 4) with peaks in odd-numbered years and with peaks in even-numbered years HPeV3. Significantly higher HPeV1 viral loads were associated with severe diarrhea in Group 2 (P = 0.044), while associated with HPeV single infection than HPeV-EV coinfection among HFMD patients (P = 0.001). It’s concluded that HPeV infection was correlated with wide clinical spectrum in pediatric patients with a high variety of genotypes determined. Still no clinical significance can be confirmed, which warranted more molecular surveillance in the future.

Menenjitli Bir Bebekte İnsan Parekovirüs Enfeksiyonu Olgusu

Menenjitli Bir Bebekte İnsan Parekovirüs Enfeksiyonu Olgusu

Menenjitli Bir Bebekte İnsan Parekovirüs Enfeksiyonu Olgusu

Menenjitli Bir Bebekte İnsan Parekovirüs Enfeksiyonu Olgusu

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.

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.

PCR detection rates for serum and cerebrospinal fluid from neonates and young infants infected with human parechovirus 3 and enteroviruses.

Human parechovirus 3 (HPeV-3) and enteroviruses (EV) are commonly detected viruses in febrile neonates and young infants and are usually diagnosed by PCR. However, in this population, data on detection rates for samples from different anatomical sites are limited. To determine PCR detection rates for HPeV-3 and EVs in serum and cerebrospinal fluid (CSF) samples from febrile neonates and young infants. This prospective study identified viruses in serum and CSF samples collected from febrile neonates and young infants (age <4 months) in Niigata, Japan, during 2014-2018. HPeV-3 or EV infection was defined as a positive quantitative real-time PCR result for the virus in serum or CSF. Genotypes were identified by sequence analyses of the viral protein 1 region. Among 216 patients, we identified 56 HPeV-3-infected (26 %) and 48 EV-infected patients (22 %). All (56/56; 100 %) HPeV-3-infected patients had a positive PCR result for serum, and 49/56 (88 %) had a positive result for CSF. In EV-infected patients, 40/48 (83 %) were positive for serum, and 34/48 (71 %) were positive for CSF, and 22/48 (46 %) were positive for serum (n = 14) or CSF (n = 8). If only a CSF sample had been obtained, 7 (12 %) HPeV-3 infections and 14 (29 %) EV infections would have been undiagnosed. Detection rates in serum and CSF differed by genotype in EV-infected patients. Viral RNA detection rates differed between serum and CSF in HPeV-3- and EV-infected neonates/infants. Combined evaluation of serum and CSF samples is important for accurate viral diagnosis in this population.

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

ObjectivesTo test our hypothesis that routine year-round testing of specimens from multiple body sites and genotyping of detected virus would describe seasonal changes, increase diagnostic yield, and provide a better definition of clinical manifestations of human parechovirus (PeV-A) infections in young febrile infants.Study designPeV-A reverse-transcriptase polymerase chain reaction (RT-PCR) analysis was incorporated in routine evaluation of infants aged ≤60 days hospitalized at Nationwide Children's Hospital for fever and/or suspected sepsis-like syndrome beginning in July 2013. We reviewed electronic medical records of infants who tested positive for PeV-A between July 2013 and September 2016. Genotyping was performed with specific type 3 RT-PCR and sequencing.ResultsOf 1475 infants evaluated, 130 (9%) tested positive for PeV-A in 1 or more sites: 100 (77%) in blood, 84 (65%) in a nonsterile site, and 53 (41%) in cerebrospinal fluid (CSF). Five infants (4%) were CSF-only positive, 31 (24%) were blood-only positive, and 20 (15%) were nonsterile site–only positive. PeV-A3 was the most common type (85%) and the only type detected in CSF. Although the majority (79%) of infections were diagnosed between July and December, PeV-A was detected year-round. The median age at detection was 29 days. Fever (96%), fussiness (75%), and lymphopenia (56%) were common. Among infants with PeV-A–positive CSF, 77% had no CSF pleocytosis. The median duration of hospitalization was 41 hours. Four infants had bacterial coinfections diagnosed within 24 hours of admission; 40 infants had viral coinfections.ConclusionsAlthough most frequent in summer and fall, PeV-A infections were encountered in every calendar month within the 3-year period of study. More than one-half of patients had PeV-A detected at more than 1 body site. Coinfections were common. PeV-A3 was the most common type identified and the only type detected in the CSF.

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

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. 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. 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. 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.