Surveillance of enteroviruses from paediatric patients attended at a tertiary hospital in Catalonia from 2014 to 2017

Changing Epidemiology of Hand, Foot, and Mouth Disease Causative Agents and Contributing Factors

Hand, foot, and mouth disease (HFMD) is a common viral infection primarily affecting children. It causes vesicles on the skin and inside the mouth. Although most cases get better on their own, severe cases can lead to complications such as brain stem encephalitis, meningoencephalitis, acute flaccid paralysis, and pulmonary edema. Hand, foot, and mouth disease is caused by various enteroviruses, with enterovirus A71 (EV-A71) and coxsackievirus A16 being the most common. However, recent studies have shown a shift in the molecular epidemiology of HFMD-causing pathogens, with coxsackievirus A6 and coxsackievirus A10 causing more infections. In addition, extensive recombination events have been identified among enterovirus strains, which may have a role in faster evolution and extinction of dominant enterovirus serotypes. Other strains of enterovirus can also cause severe complications, and there has been an increase in mortality associated with brain stem encephalitis in children under 3 years of age and teenagers. Currently, there are no effective antiviral therapies available to treat enterovirus infections. Vaccines against EV-A71 have been approved and are now used in mainland China. Studying the changing epidemiology of HFMD pathogens and the evolution patterns of its causative agents is crucial in developing effective prevention and control strategies. Increased interest in the molecular epidemiology of HFMD causative agents has led to a better understanding of the critical drivers of HFMD outbreaks, which can inform efforts to prevent and control the disease.

Characteristics of enterovirus infection associated neurologic disease associated in a pediatric population in Spain

INTRODUCTION

Enteroviruses are a type of RNA-strained virus with more than 100 different genotypes. Infection can be asymptomatic, and, if any, symptoms can range from mild to severe. Some patients can develop neurological involvement, such as aseptic meningitis, encephalitis, or even cardiorespiratory failure. However, in children, the risk factors for developing severe neurological involvement are not well understood. The aim of this retrospective study was to analyze some characteristics associated with severe neurological involvement in children hospitalized for neurological disease after enterovirus infection.

METHODS

retrospective observational study analyzing clinical, microbiological and radiological data of 174 children hospitalized from 2009 to 2019 in our hospital. Patients were classified according to the World Health Organization case definition for neurological complications in hand, foot and mouth disease.

RESULTS

Our findings showed that, in children between 6 months old and 2 years of age, the appearance of neurological symptoms within the first 12h from infection onset-especially if associated with skin rash-was a significant risk factor for severe neurological involvement. Detection of enterovirus in cerebrospinal fluid was more likely in patients with aseptic meningitis. By contrast, other biological samples (e.g., feces or nasopharyngeal fluids) were necessary to detect enterovirus in patients with encephalitis. The genotype most commonly associated with the most severe neurological conditions was EV-A71. E-30 was mostly associated with aseptic meningitis.

CONCLUSIONS

Awareness of the risk factors associated with worse neurological outcomes could help clinicians to better manage these patients to avoid unnecessary admissions and/or ancillary tests.

Enterovirus D68 in Hospitalized Children, Barcelona, Spain, 2014-2021

To determine molecular epidemiology and clinical features of enterovirus D68 (EV-D68) infections, we reviewed EV-D68–associated respiratory cases at a hospital in Barcelona, Spain, during 2014–2021. Respiratory samples were collected from hospitalized patients or outpatients with symptoms of acute respiratory tract infection or suggestive of enterovirus infection. Enterovirus detection was performed by real-time multiplex reverse transcription PCR and characterization by phylogenetic analysis of the partial viral protein 1 coding region sequences. From 184 patients with EV-D68 infection, circulating subclades were B3 (80%), D1 (17%), B2 (1%), and A (<1%); clade proportions shifted over time. EV-D68 was detected mostly in children (86%) and biennially (2016, 2018, 2021). In patients <16 years of age, the most common sign/symptom was lower respiratory tract infection, for which 11.8% required pediatric intensive care unit admission and 2.3% required invasive mechanical ventilation; neurologic complications developed in 1. The potential neurotropism indicates that enterovirus surveillance should be mandatory.

Inborn errors of TLR3- or MDA5-dependent type I IFN immunity in children with enterovirus rhombencephalitis

Enterovirus (EV) infection rarely results in life-threatening infection of the central nervous system. We report two unrelated children with EV30 and EV71 rhombencephalitis. One patient carries compound heterozygous TLR3 variants (loss-of-function F322fs2* and hypomorphic D280N), and the other is homozygous for an IFIH1 variant (loss-of-function c.1641+1G>C). Their fibroblasts respond poorly to extracellular (TLR3) or intracellular (MDA5) poly(I:C) stimulation. The baseline (TLR3) and EV-responsive (MDA5) levels of IFN-β in the patients’ fibroblasts are low. EV growth is enhanced at early and late time points of infection in TLR3- and MDA5-deficient fibroblasts, respectively. Treatment with exogenous IFN-α2b before infection renders both cell lines resistant to EV30 and EV71, whereas post-infection treatment with IFN-α2b rescues viral susceptibility fully only in MDA5-deficient fibroblasts. Finally, the poly(I:C) and viral phenotypes of fibroblasts are rescued by the expression of WT TLR3 or MDA5. Human TLR3 and MDA5 are critical for cell-intrinsic immunity to EV, via the control of baseline and virus-induced type I IFN production, respectively.

Outbreak of Enterovirus Infection with Neurological Presentations in a Pediatric Population in Northern Spain: A Clinical Observational Study

OBJECTIVE

The study aimed to describe the cases of neurological disease related to the outbreak of enterovirus (EV) in three regions in Northern Spain during 2016.

MATERIALS AND METHODS

Multicenter retrospective observational study. Clinical, radiological, and microbiological data were analyzed from patients younger than 15 years with confirmed EV-associated neurological disease admitted to 10 hospitals of Asturias, Cantabria, and Castile and Leon between January 1 and December 31, 2016.

RESULTS

Fifty-five patients were included. Median age was 24 months (interquartile range = 18.5 months). Fifteen patients were classified as aseptic meningitis (27.3%). In total, 37 cases presented brainstem encephalitis (67.3%), 25 of them due to EV-A71 with excellent prognosis (84.6% asymptomatic 2 months following the onset). Three cases of acute flaccid myelitis (5.5%) by EV-D68 were reported and presented persistent paresis 2 months following the onset. Microbiological diagnosis by reverse transcriptase polymerase chain reaction was performed in all cases, finding EV in cerebrospinal fluid in meningitis, but not in brainstem encephalitis and acute flaccid myelitis, where EV was found in respiratory or rectal samples. Step therapy was administrated with intravenous immunoglobulin (IVIG; 32.7%), methylprednisolone (10%), and plasmapheresis (3.6%). Four patients received fluoxetine (7.3%). Twenty patients needed to be admitted to pediatric intensive care unit (36.4%).

CONCLUSION

Clinical, microbiological, and radiological diagnosis is essential in outbreaks of EV neurological disease, taking into account that it can be difficult to identify EV-A71 and EV-D68 in CSF, requiring throat or rectal samples. There is not specific treatment to these conditions and the efficacy and understanding of the mechanism of action of immune-modulatory treatment (IVIG, corticosteroids, and plasmapheresis) is limited.

Enteroviruses in Respiratory Samples from Paediatric Patients of a Tertiary Care Hospital in Germany

Enteroviruses are associated with various diseases accompanied by rare but severe complications. In recent years, outbreaks of enterovirus D68 and enterovirus A71 associated with severe respiratory infections and neurological complications have been reported worldwide. Since information on molecular epidemiology in respiratory samples is still limited, the genetic diversity of enteroviruses was retrospectively analysed over a 4-year period (2013-2016) in respiratory samples from paediatric patients. Partial viral major capsid protein gene (VP1) sequences were determined for genotyping. Enteroviruses were detected in 255 (6.1%) of 4187 specimens. Phylogenetic analyses of 233 (91.4%) strains revealed 25 different genotypes distributed to Enterovirus A (39.1%), Enterovirus B (34.3%), and Enterovirus D (26.6%). The most frequently detected genotypes were enterovirus D68 (26.6%), coxsackievirus A6 (15.9%), and enterovirus A71 (7.3%). Enterovirus D68 detections were associated with lower respiratory tract infections and increased oxygen demand. Meningitis/encephalitis and other neurological symptoms were related to enterovirus A71, while coxsackievirus A6 was associated with upper respiratory diseases. Prematurity turned out as a potential risk factor for increased oxygen demand during enterovirus infections. The detailed analysis of epidemiological and clinical data contributes to the non-polio enterovirus surveillance in Europe and showed high and rapidly changing genetic diversity of circulating enteroviruses, including different enterovirus D68 variants.

Reinforced poliovirus and enterovirus surveillance in Romania, 2015-2016

Due to the risk of poliovirus importation from Ukraine in 2015, a combined surveillance program monitoring the circulation of enteroviruses (EVs) in healthy children from at-risk areas and in the environment was conducted in Romania. Virological testing of stool samples collected from 155 healthy children aged from two months to six years and of 186 sewage water samples collected from different areas was performed. A total of 58 (37.42%) stool samples and 50 (26.88%) sewage water samples were positive for non-polio EVs, but no poliovirus was detected. A high level of circulation of echovirus (E) types 6 and 7 and coxsackievirus (CV) type B5 was observed.

Characterisation of the sewage virome: comparison of NGS tools and occurrence of significant pathogens

NGS techniques are excellent tools to monitor and identify viral pathogens circulating among the population with some limitations that need to be overcome, especially in complex matrices. Sewage contains a high amount of other microorganisms that could interfere when trying to sequence viruses for which random PCR amplifications are needed before NGS. The selection of appropriate NGS tools is important for reliable identification of viral diversity among the population. We have compared different NGS methodologies (Untargeted Viral Metagenomics, Target Enrichment Sequencing and Amplicon Deep Sequencing) for the detection and characterisation of viruses in urban sewage, focusing on three important human pathogens: papillomaviruses, adenoviruses and enteroviruses. A full picture of excreted viruses was obtained by applying Untargeted Viral Metagenomics, which detected members of four different vertebrate viral families in addition to bacteriophages, plant viruses and viruses infecting other hosts. Target Enrichment Sequencing, using specific vertebrate viral probes, allowed the detection of up to eight families containing human viruses, with high variety of types within the families and with a high genome coverage. By applying Amplicon Deep Sequencing, the diversity of enteroviruses, adenoviruses and papillomaviruses observed was higher than when applying the other two strategies and this technique allowed the subtyping of an enterovirus A71 C1 strain related to a brainstem encephalitis outbreak occurring at the same time in the sampling area. From the data obtained, we concluded that the different strategies studied provided different levels of analysis: TES is the best strategy to obtain a broad picture of human viruses present in complex samples such as sewage. Other NGS strategies are useful for studying the virome of complex samples when also targeting viruses infecting plants, bacteria, invertebrates or fungi (Untargeted Viral Metagenomics) or when observing the variety within a sole viral family is the objective of the study (Amplicon Deep Sequencing).

Human Coronaviruses and Other Respiratory Viruses: Underestimated Opportunistic Pathogens of the Central Nervous System?

Respiratory viruses infect the human upper respiratory tract, mostly causing mild diseases. However, in vulnerable populations, such as newborns, infants, the elderly and immune-compromised individuals, these opportunistic pathogens can also affect the lower respiratory tract, causing a more severe disease (e.g., pneumonia). Respiratory viruses can also exacerbate asthma and lead to various types of respiratory distress syndromes. Furthermore, as they can adapt fast and cross the species barrier, some of these pathogens, like influenza A and SARS-CoV, have occasionally caused epidemics or pandemics, and were associated with more serious clinical diseases and even mortality. For a few decades now, data reported in the scientific literature has also demonstrated that several respiratory viruses have neuroinvasive capacities, since they can spread from the respiratory tract to the central nervous system (CNS). Viruses infecting human CNS cells could then cause different types of encephalopathy, including encephalitis, and long-term neurological diseases. Like other well-recognized neuroinvasive human viruses, respiratory viruses may damage the CNS as a result of misdirected host immune responses that could be associated with autoimmunity in susceptible individuals (virus-induced neuro-immunopathology) and/or viral replication, which directly causes damage to CNS cells (virus-induced neuropathology). The etiological agent of several neurological disorders remains unidentified. Opportunistic human respiratory pathogens could be associated with the triggering or the exacerbation of these disorders whose etiology remains poorly understood. Herein, we present a global portrait of some of the most prevalent or emerging human respiratory viruses that have been associated with possible pathogenic processes in CNS infection, with a special emphasis on human coronaviruses.

The high genetic similarity between rhinoviruses and enteroviruses remains as a pitfall for molecular diagnostic tools: A three-year overview

BACKGROUND

Enteroviruses (EVs) and rhinoviruses (RVs) belong to the Enterovirus genus within the Picornaviridae family, and show genetic similarities. These viruses are related to mild diseases, but EVs infections can sometimes lead to more severe complications. Current diagnostic molecular techniques should discriminate between the four EV and the three RV species that infect humans. The aim was to revise the EV and RV PCR-confirmed specimens by sequencing for genetic characterisation.

MATERIAL AND METHODS

Respiratory tract specimens were collected from patients with suspicion of respiratory infection. Respiratory viruses' laboratory-confirmation was performed by commercial multiplex real-time RT-PCR assays. Genetic characterisation of all EV and in a selection of RV was performed based on the phylogenetic analyses of partial VP1 and VP4/2 sequences, respectively.

RESULTS

From 19,957 tested specimens, 309 (1.5%) were EV-positive, 2546 (12%) were RV-positive, and 233 (1%) were EV/RV co-detections. The phylogenetic analyses revealed that: among single EV detections, 177/309 (57%) were characterised as EV, 2/309 (1%) as RV, and 130/309 (42%) could not be typed; among single 1771 RV detections (Ct < 35), 1651/1771 (93%) were characterised as RV, 3/1771 (0.3%) as EV and 117/1771 (6.7%) could not be typed. Among EV/RV co-detections, 62/233 (27%) were characterised as EV, 130/233 (56%) as RV and 41/233 (18%) could not be typed.

CONCLUSIONS

A diagnostic method well considered for routine laboratory-confirmation of respiratory viruses should discriminate EV and RV targets. RVs are usually associated with mild respiratory disease, but the potential relatedness of EVs to neurological complications makes their monitoring mandatory. Therefore, an accurate detection and differentiation should be required in commercial diagnostic solutions.