Human parechovius and enterovirus in neonates: Distinct infections with overlapping features

Enterovirus Encephalitis in Newborns: Not-Periventricular Brain Involvement and Vascular Pathogenesis in a Novel Case

Neonatal encephalitis by either enteroviruses (EVs) or parechoviruses (PeVs) is often complicated by hemispheric periventricular white matter lesions. Although showing many similarities, the two types of encephalitis differ in some clinical and laboratory aspects, mostly because PeV encephalitis does not show any change of protein and white cell content in the cerebrospinal fluid, and clinically, the onset of PeV encephalitis is often marked by early seizures accompanying a fever of sepsis-like disease. Instead, no difference exists relative to the white matter lesions, which are constantly described as periventricular, even in rare detailed neuropathological studies. Herein, taking a cue from a neonate with EV encephalitis who showed occipital white matter lesions involving the overlying cortex, but completely sparing the periventricular area, we demonstrate that the brain lesions in EV encephalitis in newborns can be more extended than known. To our knowledge, the not-periventricular involvement of the white matter with EV encephalitis has never been described so far, as well as the potential of EV to injure the cortex. We confirm the pathogenetic role of a vascular mechanism for the tissue injury, but other proposed mechanisms are also discussed. It is noteworthy that the neurological outcome of this newborn remained favorable, and no epileptic seizures occurred in the first few days nor afterward.

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.

Innate Immune Responses in Serum and Cerebrospinal Fluid From Neonates and Infants Infected With Parechovirus-A3 or Enteroviruses

BACKGROUND

Parechovirus (PeV)-A3 and enteroviruses (EV) are the most common viruses causing sepsis and meningoencephalitis in neonates and young infants. Clinical manifestations of PeV-A3 infection are more severe than those of EV infection, and no pleocytosis with a positive polymerase chain reaction (PCR) result for PeV-A3 in cerebrospinal fluid (CSF) are characteristic findings. We hypothesized that innate immune responses to PeV-A3 and EV are distinct in serum and CSF.

METHODS

We evaluated 22 cytokines/chemokines in serum and CSF from PeV-A3- or EV-infected patients younger than 4 months in Niigata, Japan, from 2015 through 2018. Infection was diagnosed with real-time PCR followed by sequencing. Febrile neonates and infants with sepsis-like syndrome who had negative bacterial culture and viral PCR for both PeV-A and EV were also included (non-PeV-A/EV patients).

RESULTS

Among 192 febrile patients, we evaluated 16 PeV-A3-infected, 15 EV-infected, and 8 non-PeV-A/EV patients. Serum pro-/anti-inflammatory cytokine/chemokine levels were higher in PeV-A3-infected patients than in EV-infected patients (P < .02). Although most cytokine/chemokine were elevated in CSF from EV-infected patients, levels were low or undetectable in PeV-A3-infected and non-PeV-A/EV patients (P < .001).

CONCLUSIONS

Distinct cytokine/chemokine patterns in serum and CSF may explain the different clinical manifestations of PeV-A3-infected and EV-infected neonates and young infants.

Contribution of Enteroviruses to Acute Central Nervous System or Systemic Infections in Northern Italy (2015-2017): Is It Time to Establish a National Laboratory-Based Surveillance System?

Background

Enteroviruses (EVs) can cause infections and outbreaks of mild to severe diseases, such as central nervous system (CNS) and systemic infections. The contribution of EVs to acute CNS/systemic infections requiring hospitalization was assessed by analysing data extracted from virology laboratory database.

Methods

Real-life data obtained from two molecular virology laboratories located in Northern Italy were retrieved from databases and analysed retrospectively. The queries used to extract the data were (i) requests for EV-RNA detection in clear cerebrospinal fluid (CSF) specimens collected from hospitalized patients with suspected acute CNS (including aseptic meningitis, encephalitis, and acute flaccid myelitis/paralysis) or systemic infections (sepsis-like illness or fever (≥ 38°C) of unknown origin), (ii) CSF samples collected from January 1st, 2015, to December 31st, 2017.

Results

582 requests of EV-RNA detection in CSF samples collected from as many patients of any age were recorded. EV-RNA was detected in 4.5% of the CSF samples; 92.3% of EV-positive cases were patients < 15 years, 58.3% of whom were < 3 months. EVs circulated all-year-round, and the highest EV-positive rates were observed from May to August. The risk of EV infection and the relative illness ratio value among children < 1 − year − old were significantly higher than those observed for older patients.

Conclusions

EV surveillance should be carried out for all pediatric patients < 15 years and especially children less than 1 year of age with clinically suspected CNS infection/systemic infections. The implementation of a laboratory-based surveillance established for analysing the virological data provided by laboratories that routinely perform EV molecular testing may enable us to determine the impact of EVs that can cause infections requiring hospitalization.

Host Immune Response to Enterovirus and Parechovirus Systemic Infections in Children

Background

Enterovirus (EV) and parechovirus type A3 (PeV-A3) cause infections ranging from asymptomatic to life-threatening. Host immune responses in children, particularly innate responses to PeV-A3, remain largely unknown. The aim of this study was to determine aspects of the cytokine/chemokine responses to EV and PeV-A3 in cerebrospinal fluid (CSF) and plasma obtained from children with systemic/central nervous system infection.

Methods

A total of 74 salvaged CSF samples (27 with EV, 23 with PeV-A3, and 24 with neither EV nor PeV-A3) and 35 paired blood samples (10 with EV, 14 with PeV-A3, and 11 with neither) were studied. Concentrations of cytokines and chemokines were measured using a customized 21-plex MILLIPLEX MAP Human Cytokine/Chemokine Magnetic Bead Panel. Additionally, clinical characteristics data for all the patients were collected from electronic medical records to evaluate the potential association between the immune response and presentations.

Results

We demonstrate that EV and PeV-A3 infections induce different cytokine/chemokine immune responses in children. EV induces more robust responses in CSF with significantly elevated levels of fractalkine, interferon (IFN)-α2, IFN-γ, interleukin (IL)-1Rα, IL-4, IL-8, and tumor necrosis factor α; PeV-A3 induces less robust or absent responses in CSF but robust responses in plasma, with significantly higher concentrations of IFN-α2, IL-15, IL-1Rα, interferon-γ-inducible protein–10, and monocyte chemoattractant protein–1.

Conclusions

High cytokine/chemokine concentrations in the plasma of PeV-A3 patients compared with EV patients could explain higher/more prolonged fever in PeV-A3 patients, whereas relatively low cytokine/chemokine concentrations in PeV-A3 CSF might explain the absence of CSF pleocytosis.

Prevalence and characteristics of human parechovirus and enterovirus infection in febrile infants

BACKGROUND

Human parechovirus (HPeV) and human non-polio enterovirus (EV) are important causes of fever without source (FWS) in young infants. Their prevalence and clinical characteristics are largely unknown in Asian countries. This study was conducted to elucidate the epidemiology and clinical characteristics of HPeV and EV infection in febrile young infants in Japan.

METHODS

During February 2010-August 2015, we obtained 53 stool, 44 throat swab, and 20 cerebrospinal fluid samples from 56 infants (<3 months) with FWS at a single hospital. To each sample, we applied reverse transcription-polymerase chain reaction for HPeV and EV. We compared the clinical characteristics of HPeV and EV patients.

RESULTS

HPeV was detected in 11 and EV in 17 patients. HPeV was detected during July-September. HPeV patients, compared with EV patients, had lower age (32 vs 47 days; P = n.s.), higher prevalence of exclusive breast-feeding (81.8 vs 29.4%; P = 0.024), and lower prevalence of sick contacts (36.4 vs 88.2%; P = 0.010). More HPeV than EV patients met the systemic inflammatory response syndrome criteria (90.9 vs 52.9%; P = 0.049). In the HPeV group, leukopenia, thrombopenia, and elevated deviation enzyme were observed, although the prevalence of abnormal cerebrospinal fluid was significantly lower than in the EV group. HPeV patients had longer hospital stay (7 vs 5 days; P = 0.025).

CONCLUSION

HPeV and EV are important causal viruses of FWS. Characteristic clinical pictures exist in these virus infections, but further research is needed to accumulate more cases to produce a comprehensive picture of these virus infections.

Molecular epidemiology of enterovirus and parechovirus infections according to patient age over a 4-year period in Spain

The epidemiology and clinical association of enterovirus (EV) and parechovirus (HPeV) infections, as well as the type-distribution-according-to-age, were determined during a 4-year study period in Spain. During 2010-2013, a total of 21,832 clinical samples were screened for EV and the detection frequency was 6.5% (1,430). Of the total EV-negative samples, only 1,873 samples from 2011 to 2013 were available for HPeV testing. HPeV was detected in 42 (2%) of them. Positive samples were genotyped using PCR and sequencing. EV infections occurred in all age groups of patients: neonates (17%), children 28 days to 2 years (29%), children 2-14 years (40%), and adults (14%). Thirty-four different EV types were identified. HPeV infections were detected exclusively in infants <8 m (70% neonates, P < 0.05). All but one HPeV were HPeV-3. Differences in type frequency detection were found according to age and clinical manifestation. Coxsackievirus (CV)-B4 (61%), CV-B5 (83%), and HPeV-3 (64%) were more frequent in neonates than in older patients (P < 0.05). Echovirus (E)-3 (60%), E-18 (47%), E-25 (62%), CV-A6 (61%), CV-A16 (72%), and EV-71 (75%) were mainly detected in children 28 days to 2 years (P < 0.05), whereas, E-6 (79%), E-20 (88%), and E-30 (85%) were predominant in children >2 years and adults (P < 0.05). Clinically, meningitis was associated with EV (P < 0.01) whereas, encephalitis was more frequent in HPeV-infected patients. CV-B types were associated with myocarditis (90%; P < 0.05) and EV species A with hand-foot-mouth-disease/atypical exanthema (88%; P < 0.05). J. Med. Virol. 89:435-442, 2017. © 2016 Wiley Periodicals, Inc.

Virological testing of cerebrospinal fluid in children aged less than 14 years with a suspected central nervous system infection: A retrospective study on 304 consecutive children from January 2012 to May 2015

OBJECTIVE

The study aimed to describe the prevalence of HSV DNA, VZV DNA, Enterovirus RNA, Parechovirus RNA, CMV DNA, EBV DNA, adenovirus DNA, HHV-6 DNA, HHV-7 DNA, HHV-8 DNA and Parvovirus B19DNA in children aged less 14 years with a suspected viral infection of the central nervous system in a clinical practice setting.

METHODS

Between January 2012 and May 2015, cerebrospinal fluids from 304 children were tested with an in-house real-time PCR method.

RESULTS

A positive PCR was detected in 64 subjects (21%): the mean number of tests performed in patients who showed a viral infection was 7.5, significantly higher (p = 0.001) with respect to that reported in negative samples (6.4). Enterovirus is the leading virus detected: 12 out of the 37 positive children reported were newborns (85.7% of all the newborns with a positive result). The second most frequently identified virus was HHV-7 (5 positive PCR out of 105 samples tested, 4.8%, if we excluded a child with a concomitant S. pneumoniae isolated), a prevalence significantly higher with respect to VZV (p = 0.02) and to CMV (p = 0.04). HHV-6 was the third most commonly identified aetiology (4.2%). All children were immunocompetent.

SIGNIFICANCE

Only a minority of children had a specific viral aetiology identified: the rate of HHV-7 positivity suggests a routine testing of these viruses within the diagnostic algorithm in immunocompetent paediatric patients. This approach could help to define the clinical role of this herpesvirus.