Detection of Enterovirus D68 in Wastewater Samples from the UK between July and November 2021

Infection with enterovirus D68 (EV-D68) has been linked with severe neurological disease such as acute flaccid myelitis (AFM) in recent years. However, active surveillance for EV-D68 is lacking, which makes full assessment of this association difficult. Although a high number of EV-D68 infections were expected in 2020 based on the EV-D68′s known biannual circulation patterns, no apparent increase in EV-D68 detections or AFM cases was observed during 2020. We describe an upsurge of EV-D68 detections in wastewater samples from the United Kingdom between July and November 2021 mirroring the recently reported rise in EV-D68 detections in clinical samples from various European countries. We provide the first publicly available 2021 EV-D68 sequences showing co-circulation of EV-D68 strains from genetic clade D and sub-clade B3 as in previous years. Our results show the value of environmental surveillance (ES) for the early detection of circulating and clinically relevant human viruses. The use of a next-generation sequencing (NGS) approach helped us to estimate the prevalence of EV-D68 viruses among EV strains from other EV serotypes and to detect EV-D68 minor variants. The utility of ES at reducing gaps in virus surveillance for EV-D68 and the possible impact of nonpharmaceutical interventions introduced to control the COVID-19 pandemic on EV-D68 transmission dynamics are discussed.

Strain dependent structural effects and in vivo efficacy of enterovirus-D68 inhibitors

Acute flaccid myelitis (AFM) leads to loss of limb control in young children and is likely due to Enterovirus-D68 (EV-D68), for which there is no current treatment. We have developed a lead isoxazole-3-carboxamide analog of pleconaril (11526092) which displayed potent inhibition of the pleconaril-resistant CVB3-Woodruff (IC50 6-20 nM), EV-D68 (IC50 58 nM), and other enteroviruses. A mouse respiratory model of EV-D68 infection, in which pleconaril is inactive, showed decreased viremia of 3 log units as well as statistically significant 1 log reduction in lung titer reduction at day 5 after treatment with 11526092. A cryo-electron microscopy (cryo-EM) structure of EV-D68 in complex with 11526092 suggests that the increased potency may be due to additional hydrophobic interactions. Cryo-EM structures of 11526092 and pleconaril demonstrate destabilization of EV-D68 (MO strain) compared to the previously described stabilization of EV-D68 (Fermon strain) with pleconaril, illustrating clear strain dependent mechanisms of this molecule. 11526092 represents a more potent inhibitor in vitro with in vivo efficacy providing a potential future treatment for EV-D68 and AFM, suggesting an improvement over pleconaril for further optimization.

An Overview of Acute Flaccid Myelitis

: Acute Flaccid Myelitis is defined by the presence of Acute Flaccid Paralysis (AFP) and a spinal cord lesion on magnetic resonance imaging that is primarily limited to the grey matter. AFM is a difficult situation to deal with when you have a neurologic illness. According to the Centers for Disease Control and Prevention (CDC), a large number of cases were discovered in the United States in 2014, with 90% of cases occurring in children. Although the exact cause of AFM is unknown, mounting evidence suggests a link between AFM and enterovirus D68 (EV-D68). In 2014, an outbreak of AFM was discovered in the United States. The condition was initially linked to polioviruses; however, it was later found that the viruses were caused by non-polioviruses Enteroviruses D-68 (EV-D68). The number of cases has increased since 2014, and the disease has been declared pandemic in the United States. The sudden onset of muscle weakness, usually in an arm or leg, as well as pain throughout the body, the patient's facial expression changing to one of weakness, and shortness of breath, ingesting, and speaking are all common symptoms in patients suffering from neurologic disease. This article includes graphic and histograms representations of reported AFM incidents and criteria for causality, epidemiology, various diagnostic approaches, signs and symptoms, and various investigational guidelines. It also includes key statements about recent AFM disease clinical findings.

Transcriptomic Profiling Reveals a Role for TREM-1 Activation in Enterovirus D68 Infection-Induced Proinflammatory Responses

Increasing cases related to the pathogenicity of Enterovirus D68 (EV-D68) have made it a growing worldwide public health concern, especially due to increased severe respiratory illness and acute flaccid myelitis (AFM) in children. There are currently no vaccines or medicines to prevent or treat EV-D68 infections. Herein, we performed genome-wide transcriptional profiling of EV-D68-infected human rhabdomyosarcoma (RD) cells to investigate host-pathogen interplay. RNA sequencing and subsequent experiments revealed that EV-D68 infection induced a profound transcriptional dysregulation of host genes, causing significantly elevated inflammatory responses and altered antiviral immune responses. In particular, triggering receptor expressed on myeloid cells 1 (TREM-1) is involved in highly activated TREM-1 signaling processes, acting as an important mediator in EV-D68 infection, and it is related to upregulation of interleukin 8 (IL-8), IL-6, IL-12p70, IL-1β, and tumor necrosis factor alpha (TNF-α). Further results demonstrated that NF-κB p65 was essential for EV-D68-induced TREM-1 upregulation. Moreover, inhibition of the TREM1 signaling pathway by the specific inhibitor LP17 dampened activation of the p38 mitogen-activated protein kinase (MAPK) signaling cascade, suggesting that TREM-1 mainly transmits activation signals to phosphorylate p38 MAPK. Interestingly, treatment with LP17 to inhibit TREM-1 inhibited viral replication and infection. These findings imply the pathogenic mechanisms of EV-D68 and provide critical insight into therapeutic intervention in enterovirus diseases.