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

Diagnosis, management, and outcomes of parechovirus infections in infants: an overview

Parechovirus A (PeV-A) infections have been detected with increasing frequency in US infants under 6 months of age, leading to a Centers for Disease Control and Prevention (CDC) health advisory in July 2022. Clinicians are advised to consider PeV-A laboratory testing of blood and cerebrospinal fluid when infants present with unexplained fever, sepsis-like illness, or neurological issues. Clinical laboratories are encouraged to offer in-house molecular testing for PeV-A to avoid diagnostic delays, unnecessary use of antibiotics, and prolonged hospitalization of infants presenting with sepsis-like illness. While data are evolving on potential neurodevelopmental sequelae after PeV-A infant central nervous system infections, most infected infants return to baseline health for age. This review examines the PeV-A literature with a focus on PeV-A3, including aspects of epidemiology, clinical presentations/management, laboratory diagnostics, genotyping, and post-infectious sequelae related to PeV-A infections in infants.

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.

Human parechovirus meningitis in children: state of the art

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

Update on nonpolio enterovirus and parechovirus infections in neonates and young infants

PURPOSE OF REVIEW

To review the epidemiology, clinical manifestations, and treatment strategies of nonpolio enterovirus and parechovirus (PeV) infections, and identify research gaps.

RECENT FINDINGS

There is currently no approved antiviral agent for enterovirus or PeV infections, although pocapavir may be provided on a compassionate basis. Elucidation of the structure and functional features of enterovirus and PeV may lead to novel therapeutic strategies, including vaccine development.

SUMMARY

Nonpolio human enterovirus and PeV are common childhood infections that are most severe among neonates and young infants. Although most infections are asymptomatic, severe disease resulting in substantial morbidity and mortality occurs worldwide and has been associated with local outbreaks. Long-term sequelae are not well understood but have been reported following neonatal infection of the central nervous system. The lack of antiviral treatment and effective vaccines highlight important knowledge gaps. Active surveillance ultimately may inform preventive strategies.

Detection of Parechovirus and Enterovirus Among Infants Evaluated for Late-onset Sepsis in the Neonatal Intensive Care Unit: The Viral Respiratory Infections in the Neonatal Intensive Care Unit-Parechovirus-Enterovirus Study

In a prospective cohort study of 65 inborn infants who were evaluated for late-onset sepsis at >72 hours of age in 2 academic neonatal intensive care units, none had parechovirus or enterovirus RNA detected by polymerase chain reaction performed on nasopharyngeal specimens during the first or subsequent sepsis evaluations (n = 80).

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.