Respiratory Presentation of Pediatric Patients in the 2014 Enterovirus D68 Outbreak

Global prevalence and case fatality rate of Enterovirus D68 infections, a systematic review and meta-analysis

A substantial amount of epidemiological data has been reported on Enterovirus D68 (EV-D68) infections after the 2014 outbreak. Our goal was to map the case fatality rate (CFR) and prevalence of current and past EV-D68 infections. We conducted a systematic review (PROSPERO, CRD42021229255) with published articles on EV-68 infections in PubMed, Embase, Web of Science and Global Index Medicus up to January 2021. We determined prevalences using a model random effect. Of the 4,329 articles retrieved from the databases, 89 studies that met the inclusion criteria were from 39 different countries with apparently healthy individuals and patients with acute respiratory infections, acute flaccid myelitis and asthma-related diseases. The CFR estimate revealed occasional deaths (7/1353) related to EV-D68 infections in patients with severe acute respiratory infections. Analyses showed that the combined prevalence of current and past EV-D68 infections was 4% (95% CI = 3.1-5.0) and 66.3% (95% CI = 40.0-88.2), respectively. The highest prevalences were in hospital outbreaks, developed countries, children under 5, after 2014, and in patients with acute flaccid myelitis and asthma-related diseases. The present study shows sporadic deaths linked to severe respiratory EV-D68 infections. The study also highlights a low prevalence of current EV-D68 infections as opposed to the existence of EV-D68 antibodies in almost all participants of the included studies. These findings therefore highlight the need to implement and/or strengthen continuous surveillance of EV-D68 infections in hospitals and in the community for the anticipation of the response to future epidemics.

Emergence of divergent enterovirus (EV) D68 sub-clade D1 strains, northern Italy, September to October 2018

Between September and October 2018, an enterovirus D68 (EV-D68) outbreak occurred in patients hospitalised with severe acute respiratory infection in northern Italy; 21 laboratory-confirmed cases were reported. Phylogenetic analysis revealed that 16/20 of the EV-D68 sequences belonged to a divergent group within the sub-clade D1. Since its upsurge, EV-D68 has undergone rapid evolution with the emergence of new viral variants, emphasising the need for molecular surveillance that include outpatients with respiratory illness.

Respiratory presentation of patients infected with enterovirus D68 in Taiwan

BACKGROUND

Enterovirus-D68 (EV-D68) has been endemic in Taiwan for some years with a small number of positive cases. Detailed information about respiratory presentation is lacking. This study characterized the clinical course in children admitted to the medical center and regional hospital in Taichung during 2015.

METHODS

Retrospective chart review of patients with confirmed EV-D68 infection admitted to the medical center and regional hospital in Taichung with respiratory symptoms in the second half of 2015. Past medical history, clinical presentation, management, and course in hospital were collected and analyzed. Simple demographic data and clinical symptoms were also collected from patients confirmed with EV-D68 infection who visited clinics in Taichung.

RESULTS

Six children were included. Two patients had a prior history of asthma or recurrent dyspnea, and one had other preexisting medical comorbidities. One child was admitted to the pediatric intensive care unit. All the patients were cured. Cough, rhinorrhea, tachypnea and fever were the most common clinical symptoms among inpatients, while influenza-like illness (ILI) was prevalent in outpatients.

CONCLUSION

EV-D68 infection resulted in respiratory presentations of asthma-like illness in the hospitalized pediatric population. Patients with a prior history of asthma or recurrent dyspnea appear to be more severely affected.

Prospective enterovirus D68 (EV-D68) surveillance from September 2015 to November 2018 indicates a current wave of activity in Wales

Since 7 June 2018, an enterovirus D-68 (EV-D68) season (the third since 2015) is ongoing in Wales, with 114 confirmed cases thus far. Median age of the 220 cases since 2015 is 2.5 years (2.5 years in intensive care cases), 94% were hospitalised, 17% (n = 38) in intensive care. All had respiratory symptoms; bronchiolitis symptoms were reported in 60 cases, severe respiratory symptoms in 23 and acute flaccid myelitis in two cases.

Genomic analysis of serologically untypable human enteroviruses in Taiwan

BACKGROUND

Human enteroviruses contain over 100 serotypes. We have routinely conducted enterovirus surveillance in northern Taiwan; but about 10% of isolates could not be serotyped using traditional assays. Next-generation sequencing (NGS) is a powerful tool for genome sequencing.

METHODS

In this study, we established an NGS platform to conduct genome sequencing for the serologically untypable enterovirus isolates.

RESULTS

Among 130 serologically untypable isolates, 121 (93%) of them were classified into 29 serotypes using CODEHOP (COnsensus-DEgenerate Hybrid Oligonucleotide Primer)-based RT-PCR to amplify VP1 genes (VP1-CODEHOP). We further selected 52 samples for NGS and identified 59 genome sequences from 51 samples, including 8 samples containing two virus genomes. We also detected 23 genome variants (nucleotide identity < 90% compared with genome sequences in the public domain) which were potential genetic recombination, including 9 inter-serotype recombinants and 14 strains with unknown sources of recombination.

CONCLUSIONS

We successfully integrated VP1-CODEHOP and NGS techniques to conduct genomic analysis of serologically untypable enteroviruses.

Aetiology and risks factors associated with the fatal outcomes of childhood pneumonia among hospitalised children in the Philippines from 2008 to 2016: a case series study

OBJECTIVE

Pneumonia remains the leading cause of hospitalisations and deaths among children aged <5 years. Diverse respiratory pathogens cause acute respiratory infections, including pneumonia. Here, we analysed viral and bacterial pathogens and risk factors associated with death of hospitalised children.

DESIGN

A 9-year case series study.

SETTING

Two secondary-care hospitals, one tertiary-care hospital and one research centre in the Philippines.

PARTICIPANTS

5054 children aged <5 years hospitalised with severe pneumonia.

METHODS

Nasopharyngeal swabs for virus identification, and venous blood samples for bacterial culture were collected. Demographic, clinical data and laboratory findings were collected at admission time. Logistic regression analyses were performed to identify the factors associated with death.

RESULTS

Of the enrolled patients, 57% (2876/5054) were males. The case fatality rate was 4.7% (238/5054), showing a decreasing trend during the study period (p<0.001). 55.0% of the patients who died were either moderately or severely underweight. Viruses were detected in 61.0% of the patients, with respiratory syncytial virus (27.0%) and rhinovirus (23.0%) being the most commonly detected viruses. In children aged 2-59 months, the risk factors significantly associated with death included age of 2-5 months, sensorial changes, severe malnutrition, grunting, central cyanosis, decreased breath sounds, tachypnoea, fever (≥38.5°C), saturation of peripheral oxygen <90%, infiltration, consolidation and pleural effusion on chest radiograph.Among the pathogens, adenovirus type 7, seasonal influenza A (H1N1) and positive blood culture for bacteria were significantly associated with death. Similar patterns were observed between the death cases and the aforementioned factors in children aged <2 months.

CONCLUSION

Malnutrition was the most common factor associated with death and addressing this issue may decrease the case fatality rate. In addition, chest radiographic examination and oxygen saturation measurement should be promoted in all hospitalised patients with pneumonia as well as bacteria detection to identify patients who are at risk of death.

Development of a respiratory disease model for enterovirus D68 in 4-week-old mice for evaluation of antiviral therapies

Enterovirus D68 (EV-D68) is a non-polio enterovirus that affects the respiratory system and can cause serious complications, especially in children and older people with weakened immune systems. As an emerging virus, there are no current antiviral therapies or vaccines available. Our goal was to develop a mouse model of human EV-D68 infection that mimicked the disease observed in humans and could be used for evaluation of experimental therapeutics. This is the first report of a respiratory disease model for EV-D68 infection in mice. We adapted the virus by 30 serial passages in AG129 mice, which are deficient in IFN- α/β and -γ receptors. Despite a lack of weight loss or mortality in mice, lung function measured by plethysmography, showed an increase in enhanced pause (Penh) on days 6 and 7 post-infection. In addition, as virus adapted to mice, virus titer in the lungs increased 50-fold, and the pro-inflammatory cytokines MCP-1 and RANTES increased 15-fold and 2-fold in the lung, respectively. In addition, a time course of mouse-adapted EV-D68 infection was determined in lung, blood, liver, kidney, spleen, leg muscle, spinal cord and brain. Virus in the lung replicated rapidly after intranasal inoculation of adapted virus, 10⁶ CCID₅₀/mL by 4 h and 10^8.3 CCID₅₀/mL by 24 h. Virus then spread to the blood and other tissues, including spinal cord and brain. This mouse model for EV-D68 infection includes enhanced pause (Penh) as an indicator of morbidity, and viremia, virus titers and proinflammatory cytokines in the lung, and lung histopathology as indicators of disease. Our mouse-adapted virus has a similar antiviral profile to the original isolate as well as another respiratory picornavirus, rhinovirus-14. This model will be valuable in evaluating experimental therapies in the future.

Enterovirus D68 - The New Polio?

Enterovirus D68 (EV-D68) has emerged over the recent years, with large outbreaks worldwide. Increased occurrence has coincided with improved clinical awareness and surveillance of non-polio enteroviruses. Studies showing its neurotropic nature and the change in pathogenicity have established EV-D68 as a probable cause of Acute Flaccid Myelitis (AFM). The EV-D68 storyline shows many similarities with poliovirus a century ago, stimulating discussion whether EV-D68 could be ascertaining itself as the "new polio." Increasing awareness amongst clinicians, incorporating proper diagnostics and integrating EV-D68 into accessible surveillance systems in a way that promotes data sharing, will be essential to reveal the burden of disease. This will be a necessary step in preventing EV-D68 from becoming a threat to public health.

Enterovirus D-68 in children presenting for acute care in the hospital setting

BACKGROUND

Severe respiratory disease associated with enterovirus D68 (EV-D68) has been reported in hospitalized pediatric patients. Virologic and clinical characteristics of EV-D68 infections exclusively in patients presenting to a hospital Emergency Department (ED) or urgent care have not been well defined.

METHODS

Mid-nasal swabs from pediatric patients with respiratory symptoms presenting to the ED or urgent care were evaluated using a commercial multiplex PCR platform. Specimens positive for rhinovirus/enterovirus (HRV/EV) were subsequently tested using real-time reverse-transcriptase PCR for EV-D68. The PCR cycle threshold (CT) was used as a viral load proxy. Clinical outcomes were compared between patients with EV-D68 and patients without EV-D68 who tested positive for HRV/EV.

RESULTS

From August to December 2014, 511 swabs from patients with HRV/EV were available. EV-D68 was detected in 170 (33%) HRV/EV-positive samples. In multivariable models adjusted for age and underlying asthma, patients with EV-D68 were more likely to require hospitalization for respiratory reasons (odds ratio (OR): 3.11, CI: 1.85-5.25), require respiratory support (OR: 1.69, CI: 1.09-2.62), have confirmed/probable lower respiratory tract infection (LRTI; OR: 3.78, CI: 2.03-7.04), and require continuous albuterol or steroids (OR: 3.91, CI: 2.22-6.88 and OR: 4.73, CI: 2.65-8.46, respectively). Higher EV-D68 viral load was associated with need for respiratory support and LRTI in multivariate models.

CONCLUSIONS

Among pediatric patients presenting to the ED or urgent care, EV-D68 causes more severe disease than non-EV-D68 HRV/EV independent of underlying asthma. High viral load was associated with worse clinical outcomes. Rapid and quantitative viral testing may help identify and risk stratify patients.

Concurrent Community Transmission of Enterovirus D68 With Human Rhinoviruses and Respiratory Syncytial Virus Among Children in Sendai, Japan

BACKGROUND

In the autumn of 2015, we experienced a surge in the number of pediatric cases of wheeze in our hospital, which was suspected to be caused by enterovirus (EV)-D68 transmission in the community. Thus, we implemented an ad hoc retrospective surveillance for EV-D68.

METHODS

Patients <15 years of age with acute respiratory infection were eligible for inclusion in this study. All enrolled patients underwent virus detection test. Additionally, neutralization tests (NTs) were performed using the stored serum samples of the enrolled patients to compare the antigenicity of the virus isolated in this study with that isolated in 2010 and evaluate the anti-EV-D68 antibody prevalence.

RESULTS

Respiratory syncytial virus (RSV) was the most commonly detected virus (35%), followed by EV-D68 (19%) and non-EV-D68 enteroviruses/human rhinoviruses (14%). Patients with EV-D68 infection had higher median age than those with RSV infection (P < 0.05). Moreover, patients with EV-D68 infection showed a higher expiratory wheeze prevalence than those with non-EV-D68 enterovirus/rhinovirus and RSV infections. The antigenicity of the isolate from the current study was similar to the virus that circulated in 2010. At the early study phase, children in our community did not have high NT titers, but the median log NT titer increased from 1.5 to 5 over time (P < 0.05).

CONCLUSION

This study showed the concurrent circulation of EV-D68 with non-EV-D68 enteroviruses/rhinoviruses and RSV in infants and children in our community and captured the early stage of EV-D68 transmission.