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Non-polio enteroviruses represent one of the most pervasive yet underappreciated groups of human pathogens. Belonging to the genus Enterovirus within the family Picornaviridae, these small, non-enveloped, positive-sense single-stranded RNA viruses encompass more than a hundred serotypes traditionally grouped into coxsackieviruses A and B, echoviruses, and newer enterovirus species A to D. Although polio once dominated public perception of the genus, global vaccination has pushed paralytic poliomyelitis to the brink of eradication, shifting attention to the non-polio members that continue to circulate widely. Most infections are asymptomatic or cause self-limited fever, rash, or gastroenteritis, but a meaningful minority precipitate severe and sometimes lifelong disease. The past decade has revived scientific and clinical interest in these viruses, driven by re-emerging neurovirulent strains, strengthened links to chronic non-communicable disease, and surprising therapeutic repurposing as anticancer agents. This review surveys four fronts where non-polio enteroviruses are reshaping medicine: viral myocarditis, acute flaccid myelitis, type 1 diabetes, and oncolytic virotherapy.
Figure 1. Main receptors for human enteroviruses.
(Source: Peters CE, et al. 2021)
Among the non-polio enteroviruses, group B coxsackieviruses (CVB1-CVB6) are the best-established viral cause of myocarditis, an inflammatory disease of the heart muscle that can progress to dilated cardiomyopathy, heart failure, and sudden death. The prototypical laboratory and clinical model is CVB3, which enters cardiomyocytes through the coxsackievirus-adenovirus receptor and triggers cascades of innate and adaptive immunity. The disease unfolds in recognizable stages: an early innate phase in the first week dominated by viral replication and pattern-recognition receptor activation, followed by a T-lymphocyte-mediated phase around days 7-14 in which both viral clearance and collateral cardiac damage peak, and in a subset of patients a chronic phase in which persistent viral or immunological insult drives remodeling. This staging helps explain why acute myocarditis often resolves spontaneously while a minority decline into chronic cardiomyopathy. Emerging work highlights regulatory layers that modulate outcome, including long noncoding RNAs such as MEG3, which acts as a competitive endogenous RNA sponging miR-21 and, through the P38-MAPK axis, restrains CVB3 replication and attenuates cardiac injury. Beyond direct cardiomyocyte infection, the dialogue between the heart, the gut microbiota, and systemic immunity is increasingly viewed as a determinant of severity, suggesting that intestinal immune modulation could become an adjunctive strategy. The therapeutic landscape remains limited, with supportive care and careful immunomodulation dominating, yet the clearer dissection of stage-specific mechanisms is opening avenues for timing-controlled interventions. Clinically, myocarditis remains a diagnosis of exclusion that relies on a combination of cardiac biomarkers, electrocardiography, echocardiography, cardiac magnetic resonance imaging, and occasionally endomyocardial biopsy; the overlap with other cardiomyopathies complicates early recognition. In the chronic phase, management shifts toward heart-failure therapy and, in selected cases, mechanical support, but the viral contribution to ongoing injury is difficult to eradicate once persistent infection is established. This gap between acute control and durable cure is precisely what stage-aware immunomodulation and host-directed therapies aim to close.
While coxsackieviruses have long been linked to cardiac and pancreatic disease, enterovirus D68 (EV-D68) has surged into public health prominence as a re-emerging respiratory and neuroinvasive pathogen. First isolated in 1962, EV-D68 remained obscure for decades before large outbreaks began in 2014, recurring in a striking biennial pattern (2014, 2016, 2018, and again in 2022) and concentrating in children under sixteen. The virus causes wheezing and hypoxia reminiscent of asthma exacerbations, but its most feared complication is acute flaccid myelitis (AFM), a polio-like syndrome in which lower motor neurons of the spinal cord gray matter are damaged, producing sudden asymmetric limb weakness, areflexia, and in severe cases respiratory failure. Pathological and molecular studies have localized EV-D68 RNA and antigen to anterior horn motor neurons, and comparative sequencing of outbreak isolates indicates that substitutions in the capsid proteins VP1 and VP3 - together with modest contributions from the 5' untranslated region - underlie the acquired neurotropism. The absence of a licensed antiviral or vaccine leaves clinicians with only supportive care and rehabilitation; many children regain partial strength but permanent deficits are common. Encouragingly, preclinical work has identified candidate interventions, including small-molecule inhibitors of the highly conserved 2A protease and humanized monoclonal antibodies that halt paralysis even when administered after neurological symptoms begin. These advances underscore EV-D68 as a priority for both surveillance and therapeutic development. From a public-health standpoint, EV-D68 is easy to underestimate. Its biennial surges coincide with seasonal respiratory virus circulation, and because specific testing is not routinely performed, true incidence is almost certainly underascertained. Distinguishing EV-D68-associated AFM from other causes of acute flaccid paralysis - including poliovirus, other neurotropic enteroviruses, and non-infectious myelopathies - demands coordinated surveillance that pairs clinical neurology with virological typing of respiratory and cerebrospinal fluid specimens. Several countries have begun folding EV-D68 into their polio-eradication surveillance infrastructure, a pragmatic model for catching emerging neurovirulent clades early.
Perhaps the most tantalizing non-polio enterovirus story concerns type 1 diabetes, a chronic autoimmune destruction of pancreatic beta cells. Enteroviruses - especially species B coxsackieviruses - have been suspected triggers for decades, but only recently has molecular epidemiology furnished compelling quantitative support. A 2023 meta-analysis of sixty controlled studies encompassing over twelve thousand participants found that molecular detection of enteroviral RNA or protein was strongly associated with both islet autoimmunity and clinical type 1 diabetes, with the odds of detection in new-onset disease exceeding sixteen-fold relative to controls. Biological plausibility is high: beta cells express the coxsackievirus-adenovirus receptor and decay-accelerating factor that mediate viral entry, and several non-mutually exclusive mechanisms could convert infection into autoimmunity - direct virus-induced beta-cell lysis, bystander T-cell damage, and molecular mimicry in which antiviral T cells cross-react with beta-cell antigens such as GAD65. Persistent infection may further perpetuate inflammation and HLA class I overexpression in islets. The translational payoff is significant: if diabetogenic enteroviruses are causal, then vaccines against coxsackievirus B could prevent or delay type 1 diabetes, and candidate vaccines are already entering clinical trials. Distinguishing correlation from causation in humans remains the key unresolved question, but the convergence of prospective cohorts, pancreatic histopathology, and modern sequencing has made enterovirus suppression a credible public-health intervention. The preventive implication is now being tested directly. Candidate coxsackievirus B vaccines designed to elicit broadly neutralizing antibodies against multiple serotypes have advanced into early clinical evaluation, motivated by the hypothesis that removing the viral trigger could delay or avert beta-cell autoimmunity in genetically susceptible children. Interpreting such trials will require large, long-duration cohorts with frequent sampling for autoantibodies and virological markers, but their design marks a turning point: enteroviruses are no longer only studied as agents of acute infection but as modifiable targets for chronic-disease prevention.
In a striking reversal of fortune, the same propensity of enteroviruses to infect and kill human cells has been harnessed as an anticancer strategy. Coxsackievirus A21, a naturally occurring serotype that uses intercellular adhesion molecule 1 as its entry receptor, selectively replicates in and lyses tumor cells with intact type I interferon signaling defects and high receptor expression. Intratumoral administration of coxsackievirus A21 in patients with advanced melanoma has produced durable responses, and combination with immune-checkpoint blockade has amplified efficacy: in a phase 1b trial, the oncolytic agent plus an anti-CTLA-4 antibody yielded objective responses in 30% of treated patients overall and 47% of those without prior anti-PD-1 therapy, with regression of both injected and distant lesions consistent with systemic antitumor immunity. Intravenous formulations have also been explored in lung and urothelial carcinomas, where the virus reached tumor tissue and showed a manageable safety profile. Beyond melanoma, intracavitary coxsackievirus A21 has been investigated in non-muscle-invasive bladder cancer, exploiting superficial tumor exposure and a dense interferon-permissive microenvironment. These efforts illustrate a broader principle: enteroviral oncolysis not only exerts direct cytotoxic effects but also converts immunologically "cold" tumors into "hot" ones by releasing tumor antigens and stimulating innate immunity. Challenges remain in predicting responsiveness, controlling inflammatory toxicity, and engineering delivery, but oncolytic enteroviruses have secured a durable place in the expanding virotherapy pipeline. Translating oncolytic enteroviruses from promising trials to routine care depends on solving two practical problems. The first is patient selection: tumors with intact innate antiviral sensing and high receptor expression are most permissive, suggesting that interferon-signaling status and receptor levels could serve as predictive biomarkers. The second is delivery and safety, since systemic administration risks inflammatory toxicity while intratumoral injection is limited to accessible lesions. Ongoing refinements in formulation, combination sequencing with checkpoint blockade, and monitoring of viral shedding are gradually defining the risk-benefit envelope for each tumor type.
Figure 2. Schematic showing that CD40-stimulated drug-resistant malignant B-cells upregulate ICAM-1 and become more sensitive to direct oncolysis and NK-cell-mediated killing by oncolytic coxsackievirus A21.
(Source: Holmes M, et al. 2023)
References
| Target | Cat. No. | Product Name | Size | Species | Application | Detection Sample | |
| EV | DEIA-XY120 | Enterovirus IgA ELISA Kit | 96T | Human | Quantitative | Serum, EDTA plasma, heparin plasma, citrate plasma | Inquiry |
| DEIA-XY121 | Enterovirus IgG ELISA Kit | 96T | Human | Quantitative | Serum, EDTA plasma, heparin plasma, citrate plasma | Inquiry | |
| DEIA-XY122 | Enterovirus IgM ELISA Kit | 96T | Human | Quantitative | Serum, EDTA plasma, heparin plasma, citrate plasma | Inquiry | |
| DEIA081 | Human enterovirus 71 virus(EV71) antibody (IgM) ELISA kit | 96T | Human | Semi-quantitative | Serum, plasma | Inquiry |
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