Search Results (42)

Enterovirus D68 (EV-D68) is a non-polio enterovirus that can cause a polio-like paralysis condition, acute flaccid myelitis (AFM). EV-D68-associated AFM cases waned in the US after 2018, and the reasons for this are unknown. It has recently been demonstrated that EV-D68 containing point mutations in viral structural proteins VP1 and VP3 resulted in decreased paralysis in different neonatal mouse models. However, phenotypes of these mutations in a human multicellular central nervous system (CNS) model are unknown. We hypothesize that mutations in VP1 and VP3 will similarly direct neurotropism in human spinal cord organoids (hSCOs). To investigate this, we recreated viruses with mutations in VP3 (I88V) or VP1 (L1I/N2D/T98A/E283K or L1P/V148A/K282R) and infected hSCOs. We found that VP3 I88V and VP1 L1I/N2D/T98A/E283K resulted in decreased titer and viral protein staining, consistent with attenuated neurovirulence in previously published murine models. We also found through immunofluorescence that VP1 L1P/V148/K282R mutations altered cellular tropism, primarily infecting glial cells rather than neuronal cells. When these mutations were combined, their effects on neurotropism were not additive. Sequence analysis of recently circulating EV-D68 strains reveals that VP3 I88 and VP1 E283 have remained the dominant amino acid residues since 2014, whereas VP1 sites 1, 2, and 98 have higher population diversity, indicating that these residues may be contributing to newly reduced neurovirulence after 2018. Full article

In this review, we examine the occurrence of two independent, single recombination events which occurred between human enteroviruses (Picornaviridae, Enterovirus, Enterovirus betacoxsackie). These recombination events contributed to the emergence of two viruses which adapted to pigs. These viruses have caused epizootics of swine vesicular disease (SVD) for many years. As was shown previously, the classical SVD virus (SVDV-1) originated from human coxsackievirus B5. The strain T75 (SVDV-2) emerged from human coxsackievirus B4 in the Tambov region of Russia, where it circulated from 1975 to 1977. A high percentage of similarity between both types of the SVD virus was found in the 3D protein coding region (88%). In our previous work, analysis of the VP1 gene dates the appearance of the SVDV-2 precursor to between 1954 and 1975. In this work, the origin of the genome region encoding non-structural proteins was analyzed and is believed to be a result of multiple recombination events between human enteroviruses (hypothetically, E1, E9, E11 and coxsackievirus A9). The recombination breakpoint between the region of structural CVB4 proteins and non-structural T75 proteins is located in region 2A. This mini-review also represents the historical research of SVDV-1 and SVDV-2 strains (O72(USS/6/72) and T75, respectively) isolated in the former Soviet Union. Full article

Background/Objectives: Since 2023, a significant increase in measles cases has been reported worldwide, and Italy has been among the most affected European countries. In this context, the integration of laboratory and epidemiological data enables timely case classification and helps distinguish between imported and indigenous cases, supporting disease control. However, most studies address only selected aspects of surveillance. Therefore, this study aimed to provide an integrated analysis of virological and epidemiological surveillance activities conducted between November 2023 and December 2025 by the Regional Reference Laboratory in the Emilia-Romagna Region (ERR). Methods: A total of 806 clinical samples (269 urine, 267 oral fluids—saliva or oropharyngeal swabs—and 270 sera) from 291 suspected measles cases were tested by molecular and/or serological methods, and MV genotyping was performed. Samples from discarded cases were also analysed for parvovirus B19 (B19V), human herpesvirus 6 (HHV-6), enterovirus (EV), and varicella zoster virus (VZV), chikungunya virus (CHIKV) and dengue virus (DENV). Results: Of 291 suspected cases, 176 (60.5%) were confirmed. Median age was 33 years, with 46% in the 15–39 year group. Vaccination status was available for 165: 90.3% were unvaccinated, 5.4% had one dose, and 4.2% had two doses. Notably, over half of confirmed cases occurred in areas with vaccine-hesitant communities. MV strain characterisation was performed in 99.4% of MV-RNA positive cases, with 84.3% genotype D8 and 15.6% genotype B3; 83% of strains were of indigenous origin, suggesting an ongoing endemic circulation. Clinical data showed complications in 19.3%, mainly pneumonia and diarrhoea. Additionally, differential diagnosis enabled the identification of the etiological agent in 37.5% of measles/rubella discarded cases, and 37.6% (29/77) tested positive for B19V. Conclusions: The study results highlight that effective measles surveillance must be supported by integrating timely virological diagnosis, molecular and epidemiological investigations, and differential diagnosis, to achieve the WHO goals of eliminating measles transmission. Full article

This study constructed a bioinformatics prediction algorithm for human enterovirus uncoating receptors based on amino acid sequences and physicochemical properties. Based on the availability of uncoating receptor information and three-dimensional (3D) structural data, human enterovirus serotypes were classified into training, validation, and prediction datasets. Using amino acid sequences of receptor-binding sites and their physicochemical properties as model features, a prediction model was constructed using the Naive Bayes algorithm and bioinformatic network analysis method. The results showed that both the training and validation datasets achieved a prediction accuracy of 100%. Among the 56 serotypes in the prediction dataset, the vast majority utilized seven known types of uncoating receptors (e.g., SCARB2, CAR, and ICAM-1), while a minority of serotypes may share the same novel, unknown receptor. This study indicates that uncoating receptors can be accurately predicted based on the amino acid sequences and physicochemical properties of human enteroviruses. Furthermore, the three-dimensional structural features at receptor-binding sites can be reflected through corresponding amino acid sequences and their physicochemical properties. This study facilitates a more in-depth investigations of enterovirus pathogenic mechanisms and provides important insights for the development of vaccines and antiviral drugs. Full article

This study explored the distribution and genetic characteristics of respiratory pathogens in outpatients with acute respiratory infections (ARIs) in Yangon, Myanmar, during the 2023 rainy season. Among 267 patients who tested negative for influenza, RSV, and SARS-CoV-2 using rapid diagnostic tests, 84.6% were positive for at least one pathogen according to a multiplex polymerase chain reaction (PCR) assay, the BioFire^® FilmArray^® Respiratory Panel 2.1. The most common viruses detected were rhinovirus/enterovirus (RV/EV) at 37.8%, respiratory syncytial virus (RSV) at 22.4%, and human metapneumovirus (hMPV) at 10.0%. These pathogens co-circulated mainly from July to September, with RV/EV consistently predominant. Symptom comparison among RV/EV-, RSV-, and hMPV-infected patients showed similar clinical features, though fever was more common in hMPV cases. Among RV/EV-positive patients, 59.3% had single infections, while 40.7% experienced co-infections, especially with RSV and adenovirus. Genotyping identified 28 types from five species, primarily RV-A and RV-C, which were genetically diverse. One EV-D68 case was also found, emphasizing its potential risk. This study underscores the genetic diversity and clinical impact of RV/EV and stresses the importance of ongoing molecular surveillance in Myanmar’s post-COVID-19 context to inform effective public health responses. Full article

Enterovirus 68 (EV-D68) is a non-enveloped virus with a positive-sense single-stranded RNA genome that causes respiratory diseases and acute flaccid myelitis, posing significant threats to human health. However, an effective vaccine remains undeveloped. SIRT1, a nicotinamide adenine dinucleotide (NAD+)-dependent enzyme, plays a key role in cellular metabolism, but its interaction with NAD+ during viral infections is not well understood. In this study, through a metabolomics analysis, we demonstrate that EV-D68 infection influences cellular metabolism. Additionally, we show that NAD+ inhibits EV-D68 infection both in vivo and in vitro. EV-D68 reduces cellular NAD+ levels by regulating the expression of enzymes involved in NAD+ consumption and synthesis. Moreover, the infection increases the expression of sirtuin 1 (SIRT1), which inhibits EV-D68 replication in turn. Mechanistically, SIRT1 suppresses EV-D68 5′UTR-mediated translation, and the antiviral effect of SIRT1 on EV-D68 replication is enhanced by NAD+. Collectively, our findings highlight the critical role of NAD+ metabolism in EV-D68 infection and reveal the antiviral potential of SIRT1, providing valuable insights for the development of antiviral strategies. Full article

Enteroviruses have been a historical concern since the identification of polioviruses in humans. Wild polioviruses have almost been eliminated, while multiple species of non-polio enteroviruses and their variants co-circulate annually. To date, at least 116 types have been found in humans and are grouped into the species Enterovirus A–D and Rhinovirus A–C. However, there are few available antiviral drugs, especially with a universal pharmaceutical effect. Here, we demonstrate that peptide P25 from EV-D68 has broad antiviral activity against EV A–D enteroviruses in vitro. P25, derived from the HI loop and β-I sheet of VP1, operates through a conserved hydrophilic motif -R---K-K--K- and the hydrophobic F near the N-terminus. It could prevent viral infection of EV-A71 by competing for the heparan sulfate (HS) receptor, binding and stabilizing virions by suppressing the release of the viral genome. P25 also inhibited the generation of infectious viral particles by reducing viral protein synthesis. The molecular docking revealed that P25 might bind to the pocket opening area, a potential target for broad-spectrum antivirals. Our findings implicate the multiple antiviral effects of peptide P25, including blocking viral binding to the HS receptor, impeding viral genome release, and reducing progeny particles, which could be a novel universal anti-enterovirus drug candidate. Full article

Some respiratory viruses, such as Human Rhinovirus, SARS-CoV-2, and Enterovirus D-68 (EV-D68), share the feature of hijacking host lipids in order to generate specialised replication organelles (ROs) with unique lipid compositions to enable viral replication. We have recently uncovered a novel non-canonical function of the stimulator of interferon genes (STING) pathway, as a critical factor in the formation of ROs in response to HRV infection. The STING pathway is the main DNA virus sensing system of the innate immune system controlling the type I IFN machinery. Although it is well-characterised as part of the DNA sensor machinery, the STING function in RNA viral infections is largely unexplored. In the current study, we investigated whether other RO-forming RNA viruses, such as EV-D68 and SARS-CoV-2, can also utilise STING for their replication. Using genetic and pharmacological inhibition, we demonstrate that STING is hijacked by these viruses and is utilised as part of the viral replication machinery. STING also co-localises with glycolytic enzymes needed to fuel the energy for replication. The inhibition of STING leads to the modulation of glucose metabolism in EV-D68-infected cells, suggesting that it might also manipulate immunometabolism. Therefore, for RO-generating RNA viruses, STING seems to have non-canonical functions in membrane lipid re-modelling, and the formation of replication vesicles, as well as immunometabolism. Full article

Coxsackievirus A24 (CV-A24) is a human enterovirus that causes acute flaccid paralysis. However, a Coxsackievirus A24 variant (CV-A24v) is the most common cause of eye infections. The causes of these variable pathogenicity and tissue tropism remain unclear. To elucidate the phylodynamics of CV-A24 and CV-A24v, we analyzed a dataset of 66 strains using Bayesian phylodynamic approach, along with detailed sequence variation and epistatic analyses. Six CV-A24 strains available in GenBank and 60 CV-A24v strains, including 11 Taiwanese strains, were included in this study. The results revealed striking differences between CV-A24 and CV-A24v exhibiting long terminal branches in the phylogenetic tree, respectively. CV-A24v presented distinct ladder-like clustering, indicating immune escape mechanisms. Notably, 10 genetic recombination events in the 3D regions were identified. Furthermore, 11 missense mutation signatures were detected to differentiate CV-A24 and CV-A24v; among these mutations, the F810Y substitution may significantly affect the secondary structure of the GH loop of VP1 and subsequently affect the epitopes of the capsid proteins. In conclusion, this study provides critical insights into the evolutionary dynamics and epidemiological characteristics of CV-A24 and CV-A24v, and highlights the differences in viral evolution and tissue tropism. Full article

Enterovirus-D68 (EV-D68) is a reemerging virus that has been associated with numerous outbreaks in children in the past 10 years. Most assays examining viral infection kinetics have relied on the use of quantitative RT-PCR (qRT-PCR) assays as an assay of choice. Though valuable, there are inherent limitations that introduce variability, thereby reducing its value when comparing results across the field. Unlike the qRT-PCR assay that uses a standard curve to determine the copy number of viral RNA, the droplet digital PCR assay (ddPCR) directly quantifies the absolute number of copies within a given sample, which in turn makes the assay highly sensitive and accurate. Here, we have developed an EV-D68-specific ddPCR assay that effectively quantifies EV-D68 RNA copies in both cells and supernatants within a dynamic range of 6.7 × 10⁻³ copies/μL to 1.2 × 10⁴ copies/μL of the sample. The assay was highly specific for a broad range of EV-D68 isolates (Fermon, US/MO/14-18947, US/MO/14-18949, US/KY/14-18953, USA/2018-23088, USA/2020-23336 and EV-D68-infected human nasal turbinate samples from the 2022 outbreak) without cross-reactivity to other viruses such as Enterovirus-A71 (EV-A71), Human Parechovirus (HPeV)-1 and -2, Coxsackievirus (CV)-B1, Human Coronavirus (HCoV)-NL63, SARS-CoV-2, Influenza-A and B, Rhinovirus, and Respiratory Syncytial Virus (RSV)-A2, which are known to cause infection in children. The assay was able to readily quantify EV-D68 in infected cells and supernatants along with nasal turbinate samples collected from children during the 2022 outbreak. Our results suggest that the assay can be readily translated to accurately quantify viral loads in tissues and body fluids such as plasma and lung or nasal aspirates. Full article

The open-source drug library, namely, MMV Pandemic Response Box, contains 153 antiviral agents, a chemically and pharmacologically diverse mixture of early-stage, emerging anti-infective scaffolds, and mature compounds currently undergoing clinical development. Hence, the Pandemic Response Box might contain compounds that bind and interfere with target molecules or cellular pathways that are conserved or shared among the closely related viruses with enterovirus A71 (EV-A71). This study aimed to screen antiviral agents included in the Pandemic Response Box for repurposing to anti-EV-A71 activity and investigate the inhibitory effects of the compounds on viral replication. The compounds’ cytotoxicity and ability to rescue infected cells were determined by % cell survival using an SRB assay. The hit compounds were verified for anti-EV-A71 activity by virus reduction assays for viral RNA copy numbers, viral protein synthesis, and mature particle production using qRT-PCR, Western blot analysis, and CCID₅₀ assay, respectively. It was found that some of the hit compounds could reduce EV-A71 genome replication and protein synthesis. D-D7 (2-pyridone-containing human rhinovirus 3C protease inhibitor) exhibited the highest anti-EV-A71 activity. Even though D-D7 has been originally indicated as a polyprotein processing inhibitor of human rhinovirus 3C protease, it could be repurposed as an anti-EV-A71 agent. Full article

Enteroviruses are among the most common viruses pathogenic to humans. They are associated with various forms of disease, ranging from mild respiratory illness to severe neurological diseases. In recent years, an increasing number of isolated cases of children developing meningitis or encephalitis as a result of enterovirus infection have been reported, as well as discrete enterovirus D68 outbreaks in North America in 2014 and 2016. We developed an assay to rapidly genotype enteroviruses by sequencing a region within the VP1 gene using nanopore Flongles. We retrospectively analyzed enterovirus-/rhinovirus-positive clinical samples from the Zurich, Switzerland area mainly collected during two seasons in 2019/2020 and 2021/2022. Respiratory, cerebrospinal fluid, and stool samples were analyzed. Whole-genome sequencing was performed on samples with ambiguous genotyping results and enterovirus D68-positive samples. Out of 255 isolates, a total of 95 different genotypes were found. A difference in the prevalence of enterovirus and rhinovirus infections was observed for both sample type and age group. In particular, children aged 0–4 years showed a higher frequency of enterovirus infections. Comparing the respiratory seasons, a higher prevalence was found, especially for enterovirus A and rhinovirus A after the SARS-CoV-2 pandemic. The enterovirus genotyping workflow provides a rapid diagnostic tool for individual analysis and continuous enterovirus surveillance. Full article

Acute respiratory viruses (ARVs) are the leading cause of diseases in humans worldwide. High-risk individuals, including children and the elderly, could potentially develop severe illnesses that could result in hospitalization or death in the worst case. The most common ARVs are the Human respiratory syncytial virus, Human Metapneumovirus, Human Parainfluenza Virus, rhinovirus, coronaviruses (including SARS and MERS CoV), adenoviruses, Human Bocavirus, enterovirus (-D68 and 71), and influenza viruses. The olfactory deficits due to ARV infection are a common symptom among patients. This review provides an overview of the role of SARS-CoV-2 and other common ARVs in the development of human olfactory pathophysiology. We highlight the critical need to understand the signaling underlying the olfactory dysfunction and the development of therapeutics for this wide-ranging category of AVRs to restore the altered or loss of smell in affected patients. Full article

In 2014, enterovirus D68 (EV-D68), previously associated primarily with mild respiratory illness, caused a large outbreak of severe respiratory illness and, in rare instances, paralysis. We compared the viral binding and replication of eight recent EV-D68 clinical isolates collected both before and during the 2014 outbreak and the prototype Fermon strain from 1962 in cultured HeLa cells and differentiated human primary bronchial epithelial cells (BEC) to understand the possible reasons for the change in virus pathogenicity. We selected pairs of closely related isolates from the same phylogenetic clade that were associated with severe vs. asymptomatic infections. We found no significant differences in binding or replication in HeLa cell cultures between the recent clinical isolates. However, in HeLa cells, Fermon had significantly greater binding (2–3 logs) and virus progeny yields (2–4 logs) but a similar level of replication (1.5–2 log increase in viral RNA from 2 h to 24 h post infection) compared to recent isolates. In differentiated BECs, Fermon and the recent EV-D68 isolates had similar levels of binding; however, the recent isolates produced 1.5–2-log higher virus progeny yields than Fermon due to increased replication. Interestingly, no significant differences in replication were identified between the pairs of genetically close recent EV-D68 clinical isolates despite the observed differences in associated disease severity. We then utilized RNA-seq to define the transcriptional responses in BECs infected with four recent EV-D68 isolates, representing major phylogenetic clades, and the Fermon strain. All the tested clinical isolates induced similar responses in BECs; however, numerous upregulated genes in antiviral and pro-inflammatory response pathways were identified when comparing the response to clinical isolates versus Fermon. These results indicate that the recent emergence in severe EV-D68 cases could be explained by an increased replication efficiency and enhanced inflammatory response induced by newly emerged clinical isolates; however, host factors are likely the main determinants of illness severity. Full article

Echovirus 3 (E3), a serotype of human enterovirus B (HEV-B), causes severe diseases in infants. Here, we determined the structures of E3 with a monoclonal antibody (MAb) 6D10 by cryo-EM to comprehensively understand the specificities and the immunological characteristic of this serotype. The solved cryo-EM structures of the F-, A-, and E-particles of E3 bound with 6D10 revealed the structural features of the virus–antibody interface. Importantly, the structures of E-particles bound with 6D10 revealed for the first time the nature of the C-terminus of VP1 for HEV-Bs at the structural level. The highly immunogenic nature of this region in the E-particles provides new strategies for vaccine development for HEV-Bs. Full article