Search Results (400)

Background: Varicella-zoster virus (VZV) is a neurotropic alphaherpesvirus capable of causing a broad spectrum of neurologic complications beyond classic dermatomal herpes zoster. Although meningitis and encephalitis are well recognized manifestations of neuroinvasive VZV infection, associated autonomic dysfunction remains comparatively underreported, particularly in immunocompetent individuals. Case Presentation: We describe a 66-year-old immunocompetent man who developed VZV meningoencephalitis associated with sacral dermatomal herpes zoster, urinary retention, and bowel dysmotility. Initial symptoms included fever, severe headache, photophobia, and low back pain, with delayed recognition of the characteristic sacral vesicular eruption. The patient subsequently developed encephalopathy and meningeal signs requiring intensive care unit admission. Cerebrospinal fluid analysis demonstrated lymphocytic pleocytosis and markedly elevated protein concentration, and VZV DNA was detected by polymerase chain reaction testing. During hospitalization, the patient developed severe urinary retention and gastrointestinal dysmotility without evidence of mechanical obstruction, raising concern for concurrent autonomic nervous system involvement. Following intravenous acyclovir therapy and supportive management, the patient experienced gradual neurologic and autonomic recovery. Conclusions: This case highlights the potential for multifocal neuroinvasive VZV disease involving both central and autonomic nervous system structures in immunocompetent hosts. Clinicians should maintain awareness that urinary retention and bowel dysmotility may represent clinically significant autonomic manifestations of VZV reactivation, particularly in the setting of sacral dermatomal involvement. Full article

The diversity and abundance of the brain virome is an active field of investigation. However, how the brain virome relates to the presence of viruses outside of the nervous system remains unclear. The rationale for this study is that analyses across multiple biologically linked compartments within the same individuals provide an important opportunity to evaluate virome discordance and viral burden. To characterize viral prevalence and burden across anatomical compartments, we applied the targeted viral enrichment method ViroFind to matched postmortem brain (n = 66), cerebrospinal fluid (CSF; n = 24), and peripheral samples (spleen, peripheral blood mononuclear cells, and lymph nodes; n = 66) from individuals with and without human immunodeficiency virus (HIV) infection and substance use disorder (SUD) in the National NeuroAIDS Tissue Consortium. We detected nucleic acids from 27 viruses representing 12 taxa. Several viruses, including adenovirus, torque teno virus, Epstein–Barr virus, human herpesvirus 6 and 7, cytomegalovirus, parvovirus, and JC polyomavirus, showed significant inter-compartment differences in prevalence or burden. CSF exhibited lower overall viral diversity than brain or peripheral samples, whereas peripheral samples showed the highest viral burden. CNS viral detection was more likely when the same virus was also detected in the periphery. We also detected HBV and HCV in CNS samples despite them not being classically regarded as neurotropic. Broader virome profiling showed greater peripheral viral burden and diversity in HIV-positive than HIV-negative individuals, whereas SUD was not associated with overall viral burden differences. These findings highlight important cross-compartment differences in viral detection, including occurrence of occult HBV infection within the CNS, and support the value of CNS–periphery comparisons in virome studies. These findings can contribute to improved diagnosis and management of viral infections. Full article

Human Herpesvirus 6 (HHV-6) is a neurotropic virus associated with lifelong latency and stress-induced reactivation. Its role in major depressive disorder (MDD) remains unclear. This study investigated the association between HHV-6 infection and MDD and evaluated interaction effects with psychosocial and clinical factors. A cross-sectional study was conducted among 2403 university students in Thailand, including 52 participants with physician-diagnosed MDD and 2351 healthy controls. HHV-6 DNA was detected by quantitative polymerase chain reaction (qPCR) using saliva. Logistic regression and interaction analyses were performed. HHV-6 DNA was detected in 50.7% of participants. HHV-6 infection was not significantly associated with MDD (OR = 1.335, 95% CI: 0.766–2.328, p = 0.309). Multivariable analysis identified congenital disease, high-fat food consumption, stress, and depressive symptoms as independent predictors of MDD. Significant interaction effects were observed between HHV-6 and several factors. HHV-6 was not independently associated with MDD; however, exploratory interaction analyses identified potential relationships with selected psychosocial and host-related factors that require further validation. Full article

Human herpesvirus-6 consists of a pair of viral species, HHV-6A and HHV-6B, which are neurotropic with the ability to invade, persist, and reactivate within the nervous system. Accumulating evidence links HHV-6 to epilepsy and other neuropathologies, including: multiple sclerosis, chronic fatigue syndrome, and neurodegeneration. Yet, mechanisms by which these viruses induce neurological disorders, including their role in epileptogenesis, remain unknown. It has been demonstrated that HHV-6 exhibits tropism for astrocytes, oligodendrocytes, and neurons. Thus, HHV-6 can perturb cellular homeostasis, neuronal signaling, and immune regulation, astrocytic glutamate clearance, GABAergic inhibition, and cholinergic or monoaminergic neurotransmission yielding network hyperexcitability. It is also reported that HHV-6 can activate neuroinflammation through Toll-Like Receptor (TLR), cytokine, and/or NF-$\kappa$B activation, which facilitates neuronal injury and network instability. Indeed, a suite of converging processes suggest a multifactorial nature for HHV-6 related neuropathology. Despite robust experimental and clinical data, definitive causal relationships between HHV-6 and epilepsy (or induction of neurodegeneration) remain elusive. This review discusses evidence for roseolovirus-induced neurological dysfunction and disorders commonly associated with HHV-6A and HHV-6B infections. A preponderance of clinical and experimental evidence suggests that differential tropism for distinct neuronal neurotransmitter chemotypes and glia as well as systemic effects are involved in roseolovirus-mediated neurological disease. Full article

Schmallenberg virus (SBV) has evolved from an emergent Orthobunyavirus identified in Europe in 2011 into an endemic pathogen with complex epidemiological dynamics. This review focuses on three key aspects: pathogenesis and fetal neurotropism, diagnostic limitations within the Simbu serogroup, and challenges in disease control. SBV pathogenesis is characterized by immune evasion mediated by the NSs protein and a marked tropism for the developing central nervous system, resulting in congenital malformations when infection occurs during critical gestational stages. Similar mechanisms are shared with other Simbu serogroup viruses, contributing to overlapping clinical presentations and complicating differential diagnosis. Diagnostic approaches are constrained by the short duration of viraemia and significant serological cross-reactivity among related viruses. While RT-qPCR is effective for detecting acute infections, its utility is limited for retrospective diagnosis, where fetal tissues and pre-colostral serology are required. Widely used ELISAs lack serogroup specificity, raising concerns about the potential under-recognition of co-circulating or emerging viruses. Despite advances in vaccine development, implementation remains limited, and vector control strategies provide only partial mitigation. SBV therefore represents a valuable model for understanding arbovirus persistence in temperate regions. Addressing current challenges will require improved diagnostic specificity, sustainable vaccination strategies, and integrated surveillance systems. Full article

Lyssaviruses are neurotropic viruses that cause fatal encephalitis, with the rabies virus as the most prominent member. The viral glycoprotein (G) plays a key role in infection and is the main target of adaptive immune responses. This study aimed to comparatively analyze linear B- and CD4⁺ T-cell epitopes in the G protein ectodomain of lyssaviruses from phylogroups I (RABV, EBLV-1, EBLV-2, DUVV, and ABLV) and II (LBV and MOKV) using bioinformatics tools. Protein sequences were obtained from GenBank, processed to isolate ectodomains, aligned for identity analysis, and used to generate consensus sequences. CD4⁺ T-cell epitopes were predicted based on HLA-II binding affinity, while linear B-cell epitopes were identified using physicochemical properties and assessed for N-glycan masking. Amino acid identity ranged from 76.71% to 83.79% in phylogroup I and 82.72% in phylogroup II. Phylogroup I showed a higher density of HLA-II epitopes (0.22) than phylogroup II (0.18). Despite differences in antigenicity distribution, conserved linear B-cell epitopes in both phylogroups overlapped with peptides binding to HLA-II DRB1*15:01 and were not masked by N-glycans. These findings highlight putatively conserved antigenic regions identified through computational analysis and may support future studies focused on the development of improved vaccines and immunoprophylactic strategies against lyssaviruses. Full article

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

Background/Objectives: The envelope (E) protein of orthoflaviviruses contains antigenic sites that are composed of one or more epitopes, which can vary in antigenic specificity, including between viral species, strains, and even substrains. Monoclonal antibodies (mAbs) that bind these epitopes vary in functionality based on their specificity. This makes mAbs useful to study the differences in phenotypes between strains of viruses, such as the wild type (WT) and live attenuated vaccine strains of yellow fever virus (YFV). mAb 2D12 was raised against the 17D-204 YFV vaccine substrain virus (YF VAX^®) by Schlesinger et al. in 1983. However, it only neutralizes Asibi WT virus, not the 17D-204 vaccine substrain virus. Results: We confirmed these results and demonstrated that mAb 2D12 fails to neutralize all 17D vaccine substrains (17D-204, 17DD, and 17D-213), indicating that the minor differences between these virus substrains do not affect the epitope or functionality of mAb 2D12. In addition, mAb 2D12 was found to neutralize WT strain of French viscerotropic virus (FVV), with statistically indistinguishable neutralization from the WT strain Asibi. All but one of the live attenuated French neurotropic vaccine (FNV) derivative viruses had significantly lower neutralization than WT strains Asibi and FVV. FVV, Asibi, 17D, and FNV have many amino acid differences in the membrane (M) and E proteins. It is unclear which of them contributes to this differential neutralization. However, FNV and 17D have common amino acid substitutions from WT FVV and Asibi at positions M-36 and E-331, suggesting that one or both of these residues may contribute to the 2D12 epitope. Conclusions: Overall, mAb 2D12 is a valuable tool to distinguish WT virulent strains of YFV from live attenuated vaccine strains. Full article

Infection by neurotropic alphaviruses such as the Eastern equine encephalitis virus (EEEV) causes extensive inflammation in the central nervous system and tissue damage, including disruption of the blood–brain barrier (BBB). Neuroinflammation and BBB disruption following infection are critical pathological considerations for the development of robust countermeasure strategies. Encephalitic disease resulting from EEEV infection currently lacks FDA-approved therapeutic intervention strategies, thus exposing a major capability gap in the ability to address the global health burden that could result from alphavirus infections. In this manuscript, we present a gravity-flow Neurovascular Unit (gNVU) model of the human BBB that may be used for modeling EEEV-induced neuropathology and evaluating countermeasures. The data generated using this model show that EEEV infection causes a time-dependent disruption of BBB integrity and increases the inflammatory load in a manner that correlates with an increase in the viral load. The data also show that the route of introduction of the pathogen has an impact on the pathology measured, with infection through the brain side eliciting a greater inflammatory outcome than infection through the vascular route. Overall, the included data support the utility of this organ-on-a-chip (OOC) platform of the human BBB in understanding encephalitic disease caused by neurotropic viruses and evaluation of therapeutic intervention strategies. Full article

SARS-CoV-2 infection is associated with not only acute respiratory symptoms but is also characterized by strong neurotropism which may contribute to the development of the multisystem post-COVID syndrome (PASC). Patients frequently report chronic neurocognitive disorders such as brain fog, significant attention deficits and increased susceptibility to epileptiform discharges. The aim of this review is to systematize the knowledge regarding deviations in quantitative electroencephalography (QEEG) recordings in convalescents and to evaluate the utility of this method as an objective biomarker. This work constitutes a comprehensive literature review integrating the latest data on neuroinflammation, blood-brain barrier damage and changes in cortical oscillatory dynamics induced by the infection. The literature analysis indicates that the virus may induce a pathological excitation and inhibition imbalance (E/I imbalance) in neuronal networks. In QEEG studies this manifests as excessive activity of slow bands (Theta, Delta), a deficit of rhythms responsible for attention and sensorimotor integration (SMR) and a pathologically elevated Theta to Beta ratio (TBR). In conclusion, QEEG can serve as an objective and highly sensitive tool supporting the diagnosis and stratification of patients with neurocognitive complications of Long COVID. The integration of precise electrophysiological phenotyping with targeted behavioral neuromodulation (e.g., EEG-Biofeedback) fits into the paradigm of personalized medicine and offers a prospective strategy for mitigating long-term neurological burdens. Full article

Neonatal meningitis-associated Escherichia coli (NMEC) is a formidable pathogen in veterinary medicine. The emergence of atypical, multidrug-resistant (MDR) variants complicates disease control. An Escherichia coli (E. coli) strain was isolated from the brain tissue of a deceased calf with acute meningitis. Comprehensive characterizations were performed, including whole-genome sequencing (WGS), multi-locus sequence typing (MLST), antimicrobial susceptibility testing (AST), murine pathogenicity assays, and RT-qPCR evaluation of neuroinflammatory cytokines. Results: The isolate (O18ab:H14) was identified as a capsule-deficient NMEC strain belonging to phylogroup A and sequence type ST1434. WGS showed that the genome size of this strain is 5.1 Mb, containing 73 strictly defined antimicrobial resistance genes and 202 virulence factors. These may be involved in the compensatory mechanism for capsule deficiency, and further functional verification is required. Phenotypically, it exhibited a robust MDR profile. In the murine model, the strain demonstrated high lethality, and induced severe multi-organ lesions characteristic of both meningitis and systemic sepsis. While intraperitoneal injection bypasses natural colonization routes, the brain-specific bacterial persistence and neuronal pathology imply neurotropic potential. Furthermore, RT-qPCR confirmed a severe neuroinflammatory response, marked by the significant upregulation of IL-1β, IL-6, and TNF-α in the infected brains. This study characterizes a novel, highly virulent, and MDR capsule-deficient NMEC/SEPEC hybrid strain. The findings emphasize the urgent need for continuous genomic surveillance of atypical E. coli pathotypes in livestock. Full article

Polyamines are small, positively charged molecules essential for fundamental cellular processes, including transcription, translation, and membrane fluidity. In the central nervous system (CNS), these molecules serve as homeostatic gatekeepers by modulating neuroreceptors like NMDA and supporting autophagic clearance. While basal polyamine levels are necessary for proper neuronal differentiation and memory formation, their dysregulation is a hallmark of neurodegenerative pathologies such as Alzheimer’s and Parkinson’s diseases. Neurotropic viruses, including poliovirus, Zika virus, and human cytomegalovirus are significant human pathogens that rely on cellular metabolites for their replication, including polyamines. These pathogens exploit polyamines at multiple stages of their life cycles, relying on them for virion stability, cellular attachment, and the stimulation of viral enzyme activity. Notably, diverse viral families share this dependence, making polyamine biosynthesis a prime target for broad-spectrum antiviral therapies. This review covers the current understanding of polyamine metabolism in virus infection and CNS health and disease, as well as considering antiviral therapies targeting host polyamines to limit neurotropic virus infection. Full article

Bornaviruses are neurotropic, negative-sense RNA viruses with zoonotic potential, notably Borna disease virus 1 (BoDV-1) and variegated squirrel bornavirus 1 (VSBV-1). BoDV-1 is endemic in certain regions of Central Europe and maintained in bicolored white-toothed shrews, but its presence in Croatia has not been investigated. Given Croatia’s diverse biogeography and the prevalence of rodent-borne diseases, this study aimed to investigate the presence of orthobornaviruses in wild canids and mustelids. Brain samples from red foxes (Vulpes vulpes), golden jackals (Canis aureus moreoticus), wolves (Canis lupus), martens (Martes martes) and badgers (Meles meles) were analysed using pan-bornavirus RT-PCR. Despite successful RNA extraction and internal control amplification, bornavirus RNA was not detected in any of the 860 animal samples tested. Although no orthobornavirus RNA was detected, the results still provide valuable information: bornavirus infections appear to be absent or extremely rare in Croatian wild canids and mustelids. By excluding these species as current potential reservoir hosts, this study helps to refine the geographical extent of bornavirus endemicity and emphasises the importance of continuous One Health surveillance in regions with favourable ecological conditions for zoonotic spillover. Full article

Chandipura virus (CHPV) is a neurotropic rhabdovirus associated with recurrent outbreaks of acute encephalitis in children and a high case fatality rate, particularly in India. Despite its public health relevance, the host molecular processes governing CHPV infection and disease progression remain poorly defined. To address this gap, we conducted a time-resolved transcriptomic analysis to characterize host responses to CHPV infection and to explore host-directed therapeutic opportunities. Human HEK293T cells were infected with CHPV, followed by RNA sequencing (RNA-seq) at 6, 12, 18, and 24 h post infection (hpi). Transcriptome profiling revealed a temporally ordered host response. At 6 hpi, CHPV infection was dominated by strong activation of innate immune and inflammatory pathways, including interferon-stimulated genes and cytokine signaling. Antiviral responses persisted at 12 hpi, accompanied by suppression of metabolic and translational processes, indicating a shift in host cellular priorities. By 18 hpi, metabolic reprogramming—particularly involving lipid and sphingolipid metabolism—was observed alongside altered immune signaling, consistent with viral exploitation of host cellular machinery. At 24 hpi, repression of genes involved in chromatin organization, RNA processing, spliceosome assembly, and ribosome biogenesis reflected a global transcriptional shutdown associated with cytopathic effects. Integration of temporal transcriptomic signatures enabled identification of host pathways amenable to pharmacological targeting. Selected host-directed compounds were evaluated in vitro and exhibited antiviral activity against CHPV in a neuronal cell line. Collectively, this study provides the first time-resolved transcriptomic landscape of CHPV infection in human cells and identifies host-targeted strategies relevant for antiviral development. Full article