Nosocomial Outbreak of Parechovirus 3 Infection among Newborns, Austria, 2014

Detection and genetic diversity of parechoviruses in children with acute flaccid paralysis in Cameroon

Human Parechoviruses (HPeVs) have rarely been considered in the virological investigation of Acute Flacid Paralysis (AFP) cases in Africa, where enteric infections are very common. This study investigated the prevalence and genetic diversity of HPeV in 200 children aged ≤ 15 years with AFP in Cameroon from 2018 to 2019. HPeVs were detected in their faecal RNA using 5'-untranslated real-time RT-PCR. Detected HPeVs were typed by phylogenetic comparison with homologous sequences from homotypic reference strains. Overall, HPeV RNA was detected in 11.0% (22/200) of the 200 stool samples tested. Twelve HPeVs were successfully sequenced and reliably assigned to HPeV-A1, A4, A5, A10, A14, A15, A17 and A18 genotypes. Phylogenetic analyses revealed a high genetic variability among the studied HPeVs, as well as between the studied HPeVs and their previously reported counterparts from Cameroon in 2014. These findings suggest that different HPeV genotypes co-circulate in Cameroon without documented epidemics.

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

Background

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

Methods

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

Results

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

Conclusions

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

An outbreak investigation of parechovirus-A3 in a newborn nursery

OBJECTIVE

To investigate parechovirus-A3 (PeV-A3) transmission in a newborn nursery, after encountering 3 neonates with fever and rash.

DESIGN

An observational study.

SETTING

At a newborn nursery at the general hospital in Hyogo, Japan.

PARTICIPANTS

Symptomatic neonates and their family members, and asymptomatic neonates born during the same period.

METHODS

PCR assays for PeV-A and genotyping were used for the investigation of PeV-A3. Preserved umbilical cords were used to identify the route of transmission.

RESULTS

PeV-A3 infection was confirmed in the three symptomatic neonates. The index case had fever and rash, and the 2 neonates treated later became symptomatic and had serum, cerebrospinal fluid, and stool specimens that were positive for PeV-A3 on PCR. The umbilical cord of the index case was positive for PeV-A3 on PCR. The family members of the index case, including the mother, were asymptomatic before delivery. The older sister and cousin of the PeV-A3-infected neonate had positive PCR results. The sequence analysis suggested 2 possible transmission routes: vertical and horizontal transmission in a newborn nursery and/or a family outside the hospital. The incubation period of PeV-A3 infection was estimated to be 1-3 days (maximum, 7 days).

CONCLUSION

Horizontal transmission of PeV-A3 was confirmed in a newborn nursery. Vertical transmission was suggested by the detection of RNA in an umbilical cord sample from the index case. These observations indicate that PeV-A3 can be horizontally transmitted in a newborn nursery and that special caution is required to prevent healthcare-associated transmission of PeV-A3.

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.

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.

Detection of Parechovirus A1 with Monoclonal Antibody against Capsid Protein VP0

Parechovirus A (PeV-A; human parechovirus) causes mild infections and severe diseases such as neonatal sepsis, encephalitis, and cardiomyopathy in young children. Among the 19 types of PeV-A, PeV-A1 is the most common type of infection. We have previously established an immunofluorescence assay for detecting multiple PeV-A types with a polyclonal antibody against the conserved epitope of VP0. Although the polyclonal antibody is useful for PeV-A diagnosis, it could not distinguish the PeV-A genotypes. Thus, the development of a specific monoclonal antibody for identifying the common infection of PeV-A1 would be beneficial in clinical diagnosis practice. In this study, the recombinant full-length PeV-A1 VP0 protein was used in mouse immunization; a total 10 hybridomas were established. After evaluation by immunoblotting and fluorescence assays, six hybridoma clones with monoclonal antibody (mAb) production were confirmed. These mAbs, which specifically recognize viral protein PeV-A1 VP0 without cross-reactivity to PeV-A3, will prove useful in research and PeV-A1 diagnosis.

Epidemiology of Human Parechovirus Type 3 Upsurge in 2 Hospitals, Freiburg, Germany, 2018

In 2018, a cluster of pediatric human parechovirus (HPeV) infections in 2 neighboring German hospitals was detected. Viral protein 1 sequence analysis demonstrated co-circulation of different HPeV-3 sublineages and of HPeV-1 and -5 strains, thereby excluding a nosocomial outbreak. Our findings underline the need for HPeV diagnostics and sequence analysis for outbreak investigations.

Parechovirus A Pathogenesis and the Enigma of Genotype A-3

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

Enterovirus infections in pediatric hematologic/oncologic patients

BACKGROUND

Enteroviruses (EV) are a large group of Picornaviruses associated with respiratory, gastrointestinal, and neurologic symptoms in the immunocompetent host. Little is known about the epidemiologic and clinical impact in pediatric hematologic/oncologic patients.

PROCEDURE

From 2001 through 2017, different clinical specimens were collected from pediatric hematologic/oncologic patients and were tested for enteroviral RNA.

RESULTS

Of 13 004 specimens collected from 761 patients, 38 (0.3%) obtained from 14 patients (1.8%) tested positive for EV RNA. Viral shedding was observed without viremia and vice versa. None of 80 cerebrospinal fluid specimens obtained from 60 patients with neurologic symptoms were positive for EV RNA. None of 14 patients positive for EV RNA showed EV-specific symptoms. In 11/14 patients, EV RNA was found to be negative in the follow-up specimen. The remaining patient with a severe primary immune deficiency showed repeated positive EV RNA results for >5 years.

CONCLUSIONS

In this pediatric hematologic/oncologic cohort, EV infection occurred rarely and without related symptoms. Specimens concurrently obtained from one patient are commonly not in accordance with each other. In the vast majority of patients, EV RNA appears to turn negative in the follow-up specimen. EV infections seem to have a low impact in this patient cohort.

Parechovirus A Detection by a Comprehensive Approach in a Clinical Laboratory

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

Virus detection by transmission electron microscopy: Still useful for diagnosis and a plus for biosafety

Transmission electron microscopy (TEM) is the only imaging technique allowing the direct visualization of viruses, due to its nanometer‐scale resolution. Between the 1960s and 1990s, TEM contributed to the discovery of many types of viruses and served as a diagnostic tool for identifying viruses directly in biological samples, either in suspension or in sections of tissues or mammalian cells grown in vitro in contact with clinical samples. The diagnosis of viral infections improved considerably during the 1990s, with the advent of highly sensitive techniques, such as enzyme‐linked immunosorbent assay (ELISA) and PCR, rendering TEM obsolete for this purpose. However, the last 20 years have demonstrated the utility of this technique in particular situations, due to its “catch‐all” nature, making diagnosis possible through visualization of the virus, without the need of prior assumptions about the infectious agent sought. Thus, in several major outbreaks in which molecular techniques failed to identify the infectious agent, TEM provided the answer. TEM is also still occasionally used in routine diagnosis to characterize infections not diagnosed by molecular assays. It is also used to check the microbiological safety of biological products. Many biopharmaceuticals are produced in animal cells that might contain little‐known, difficult‐to‐detect viruses. In this context, the “catch‐all” properties of TEM make it possible to document the presence of viruses or virus‐like particles in these products.

Healthcare-Associated Viral Infections: Considerations for Nosocomial Transmission and Infection Control

Nosocomial and healthcare-associated viral infections are major contributors to patient morbidity and mortality, prolonged hospitalization, and increased healthcare costs in all pediatric age groups. Healthcare workers are also at risk of acquiring nosocomial viral infections, affecting their own health, as well as facilitating spread of the infection to other patients, their family, and the community. Healthcare-associated viral infections may occur in a variety of healthcare settings, including clinics, emergency centers, urgent care centers, procedure suites, operating rooms, hospital wards, nurseries, and intensive care units. In addition, non-patient care areas, such as the cafeteria, waiting areas, and playrooms may also be a source of viral infections that can spread in the healthcare setting. These infections may be device-related or transmitted via blood products or organ donation and respiratory droplets, through food including human milk, person to person, or via air ducts, fomites, and surfaces. They most commonly involve the respiratory and gastrointestinal tracts; however, all organ systems may potentially be involved. Both DNA and RNA viruses, either common or exotic, may contribute to healthcare-associated viral infections. Advances in molecular viral diagnostics have enabled rapid detection and routine surveillance for viral infections and now allow early identification of viruses. Prompt identification allows timely containment measures to minimize transmission to other patients or healthcare workers and avoids hospital, community, and global outbreaks.

Severe Parechovirus 3 Infections in Young Infants-Kansas and Missouri, 2014

BACKGROUND

Infection with parechovirus type 3 (PeV3) can cause severe neurologic and sepsis-like illness in young infants; clinical and epidemiologic descriptions have been limited. We aimed to characterize PeV3 illness and explore risk factors for acquisition in a cluster of neonatal cases at Children's Mercy Hospital in Kansas City, Missouri.

METHODS

Cerebrospinal fluid specimens were obtained from infants aged <180 days who were hospitalized with sepsis-like illness or meningitis between June 1 and November 1, 2014. PeV-positive specimens were sequenced at the Centers for Disease Control and Prevention. We reviewed the medical and birth charts of the infants and performed face-to-face parent interviews. We analyzed characteristics according to infant age and intensive care admission status.

RESULTS

We identified 35 cases of PeV infection in infants aged 5 to 56 days. Seven infants required intensive care (median age, 11 days vs 27 days among those who did not require intensive care; P = .0044). Six of these 7 infants had neurologic manifestations consistent with seizures, and all 6 of them were treated with acyclovir but subsequently tested negative for herpes simplex virus. Virus sequences formed 2 lineages, both of which were associated with severe illness. Half of the infants were reported to have household contacts who were ill during the week before onset. Infants aged ≤7 days at onset were more likely to have been delivered at the same hospital.

CONCLUSIONS

PeV3 can cause severe neurologic illness in neonates, and younger infants are more likely to require intensive care. PeV3 should be considered along with herpes simplex virus and other pathogens when evaluating young infants with sepsis-like illness or meningitis. More widespread testing for PeV3 would enable us to gain a better understanding of the clinical scope and circulation of this virus.

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

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

Neonatal nonpolio enterovirus and parechovirus infections

Nonpolio enteroviruses and parechoviruses are frequent causes of neonatal infection. Clinical manifestations of infection range from asymptomatic infection to mild infection without sequelae to septic shock with muiltiorgan failure. Neonates with clinically apparent infection typically have mothers and/or other contacts with recent symptoms consistent with a viral illness. Severe neonatal infection with nonpolio enterovirus or parechovirus cannot be differentiated clinically from serious bacterial infection. The preferred method for diagnosing neonatal nonpolio enterovirus or parechovirus infection is PCR as it is rapid, sensitive, specific, and commercially available for the detection of virus from various clinical specimens. Investigational agents such as the capsid inhibitors pleconaril and pocapavir show promise for treatment of neonatal enterovirus infections, and other investigational agents are being developed. This review focuses on the epidemiology, diagnosis, and treatment of neonatal nonpolio enterovirus and parechovirus infections.

Human Parechovirus: an Increasingly Recognized Cause of Sepsis-Like Illness in Young Infants

Human parechovirus (HPeV) is increasingly being recognized as a potentially severe viral infection in neonates and young infants. HPeV belongs to the family Picornaviridae and is currently divided into 19 genotypes. HPeV-1 is the most prevalent genotype and most commonly causes gastrointestinal and respiratory disease. HPeV-3 is clinically the most important genotype due to its association with severe disease in younger infants, which may partly be explained by its distinct virological properties. In young infants, the typical clinical presentation includes fever, severe irritability, and rash, often leading to descriptions of "hot, red, angry babies." Infants with severe central nervous system (CNS) infections are at an increased risk of long-term sequelae. Considering the importance of HPeV as a cause of severe viral infections in young infants, we recommend that molecular diagnostic techniques for early detection be included in the standard practice for the investigation of sepsis-like illnesses and CNS infections in this age group.

Human parechovirus type 3 infection: An emerging infection in neonates and young infants

Human parechoviruses (HPeVs) are RNA viruses that have characteristics similar to those of enteroviruses and usually cause mild respiratory or gastrointestinal symptoms. Human parechovirus type 3 (HPeV3), first reported in 2004, is exceptional because it can provoke sepsis and meningoencephalitis leading to neurological sequelae, and even death, in neonates and young infants. Pediatricians and researchers are increasingly aware that HPeV3 is responsible for serious disease in neonates and young infants. Retrospective studies and several reports of epidemics of HPeV3 infection have provided data on epidemiology, clinical symptoms and signs, laboratory findings, and outcomes. However, the pathogenesis of HPeV3 infection remains unclear, which explains the lack of specific antiviral therapy and effective prevention measures. Maternal antibodies are important in protection against severe HPeV3-related disease, and this may be a clue regarding its pathogenesis. HPeV3 epidemics are likely to continue, and because the clinical manifestations of HPeV3 are severe, determining the pathogenesis of HPeV3 infection and establishing specific antiviral therapies are important goals for future research.