Interferon regulatory factor 7 modulates virus clearance and immune responses to alphavirus encephalomyelitis.

IMPORTANCE: Viral encephalomyelitis outcome is dependent on host responses to neuronal infection. Interferon (IFN) is an important component of the innate response, and IFN regulatory factor (IRF) 7 is an inducible transcription factor for the synthesis of IFN-α. IRF7-deficient mice develop fatal paralysis after CNS infection with Sindbis virus, while wild-type mice recover. Irf7 -/- mice produce low levels of IFN-α but high levels of IFN-ß with induction of IFN-stimulated genes, so the reason for this difference is not understood. The current study shows that Irf7 -/- mice developed inflammation earlier but failed to clear virus from motor neuron-rich regions of the brainstem and spinal cord. Levels of IFN-γ and virus-specific antibody were comparable, indicating that IRF7 deficiency does not impair expression of these known viral clearance factors. Therefore, IRF7 is either necessary for the neuronal response to currently identified mediators of clearance or enables the production of additional antiviral factor(s) needed for clearance.

Myeloencephalitis as the only presentation of Omicron SARS-CoV-2 infection.

SARS-CoV-2 is now a major global health issue and manifests mainly as a respiratory disorder. Several other complications involving hypercoagulability, cardiovascular system and central nervous system have been described in the literature. Among these atypical presentations, encephalopathy associated with SARS-CoV-2 is a rare entity with heterogenous clinical and radiological findings. The direct presence of SARS-CoV-2 in cerebrospinal fluid (CSF) was rarely found in encephalopathy patients with acute SARS-Cov-2 infection.Here, we report a case of myeloencephalitis with positive real-time PCR for SARS-CoV-2 in CSF in a young woman presenting exclusively with neurological symptoms. Other differential diagnosis were extensively pursued by a comprehensive aetiological workup. To our knowledge, this is the first case report in the Omicron era. In the context of recent global explosion of SARS-Cov-2 infections, clinicians should consider this pathogen among other possible neurotropic agents and be familiar with its radiological and clinical presentations.

Coronavirus-induced autoimmunity.

The pandemic of Coronavirus disease 2019 (COVID-19), caused by a new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spotlighted the link between viral infection and autoimmunity. In this review, we focus on coronavirus-induced autoimmunity based on evidence from experimental animal models, SARS-CoV infection with in vitro studies of molecular mimicry and COVID-19 with several clinical reports of autoimmune manifestations of this disease. Further studies will be needed to better characterize the role of SARS-CoV-2 in the development of autoimmunity.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: The Human Herpesviruses Are Back!

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) or Systemic Exertion Intolerance Disease (SEID) is a chronic multisystem illness of unconfirmed etiology. There are currently no biomarkers and/or signatures available to assist in the diagnosis of the syndrome and while numerous mechanisms have been hypothesized to explain the pathology of ME/CFS, the triggers and/or drivers remain unknown. Initial studies suggested a potential role of the human herpesviruses especially Epstein-Barr virus (EBV) in the disease process but inconsistent and conflicting data led to the erroneous suggestion that these viruses had no role in the syndrome. New studies using more advanced approaches have now demonstrated that specific proteins encoded by EBV could contribute to the immune and neurological abnormalities exhibited by a subgroup of patients with ME/CFS. Elucidating the role of these herpesvirus proteins in ME/CFS may lead to the identification of specific biomarkers and the development of novel therapeutics.

Myelin-specific T cells in animals with Japanese macaque encephalomyelitis.

OBJECTIVE: To determine whether animals with Japanese macaque encephalomyelitis (JME), a spontaneous demyelinating disease similar to multiple sclerosis (MS), harbor myelin-specific T cells in their central nervous system (CNS) and periphery. METHODS: Mononuclear cells (MNCs) from CNS lesions, cervical lymph nodes (LNs) and peripheral blood of Japanese macaques (JMs) with JME, and cervical LN and blood MNCs from healthy controls or animals with non-JME conditions were analyzed for the presence of myelin-specific T cells and changes in interleukin 17 (IL-17) and interferon gamma (IFNγ) expression. RESULTS: Demyelinating JME lesions contained CD4+ T cells and CD8+ T cells specific to myelin oligodendrocyte glycoprotein (MOG), myelin basic protein (MBP), and/or proteolipid protein (PLP). CD8+ T-cell responses were absent in JME peripheral blood, and in age- and sex-matched controls. However, CD4+ Th1 and Th17 responses were detected in JME peripheral blood versus controls. Cervical LN MNCs from eight of nine JME animals had CD3+ T cells specific for MOG, MBP, and PLP that were not detected in controls. Mapping myelin epitopes revealed a heterogeneity in responses among JME animals. Comparison of myelin antigen sequences with those of JM rhadinovirus (JMRV), which is found in JME lesions, identified six viral open reading frames (ORFs) with similarities to myelin antigen sequences. Overlapping peptides to these JMRV ORFs did not induce IFNγ responses. INTERPRETATIONS: JME possesses an immune-mediated component that involves both CD4+ and CD8+ T cells specific for myelin antigens. JME may shed new light on inflammatory demyelinating disease pathogenesis linked to gamma-herpesvirus infection.

Single-Cell RNA Sequencing Reveals the Diversity of the Immunological Landscape following Central Nervous System Infection by a Murine Coronavirus.

Intracranial (i.c.) infection of susceptible C57BL/6 mice with the neurotropic JHM strain of mouse hepatitis virus (JHMV) (a member of the Coronaviridae family) results in acute encephalomyelitis and viral persistence associated with an immune-mediated demyelinating disease. The present study was undertaken to better understand the molecular pathways evoked during innate and adaptive immune responses as well as the chronic demyelinating stage of disease in response to JHMV infection of the central nervous system (CNS). Using single-cell RNA sequencing analysis (scRNAseq) on flow-sorted CD45-positive (CD45+) cells enriched from brains and spinal cords of experimental mice, we demonstrate the heterogeneity of the immune response as determined by the presence of unique molecular signatures and pathways involved in effective antiviral host defense. Furthermore, we identify potential genes involved in contributing to demyelination as well as remyelination being expressed by both microglia and macrophages. Collectively, these findings emphasize the diversity of the immune responses and molecular networks at defined stages following viral infection of the CNS.IMPORTANCE Understanding the immunological mechanisms contributing to both host defense and disease following viral infection of the CNS is of critical importance given the increasing number of viruses that are capable of infecting and replicating within the nervous system. With this in mind, the present study was undertaken to evaluate the molecular signatures of immune cells within the CNS at defined times following infection with a neuroadapted murine coronavirus using scRNAseq. This approach has revealed that the immunological landscape is diverse, with numerous immune cell subsets expressing distinct mRNA expression profiles that are, in part, dictated by the stage of infection. In addition, these findings reveal new insight into cellular pathways contributing to control of viral replication as well as to neurologic disease.

Survival analysis in non-congenital neurological disorders related to dengue, chikungunya and Zika virus infections in Northeast Brazil.

The Northeast of Brazil has experienced a triple epidemic, with the simultaneous circulation of dengue virus (DENV), chikungunya virus (CHIKV) and Zika virus (ZIKV), which may have contributed to the observed increase across this region of atypical forms of disease and deaths. In view of this fact, non-congenital neurological disorders related to arboviruses were compared with other etiologies, mortality and survival rates of patients admitted to referral neurology hospitals in Pernambuco State, Northeast Brazil, from 2015 to 2018. Blood and cerebrospinal fluid samples were collected and tested using molecular and serological assays. The arbovirus-exposed groups were compared with respect to epidemiological, clinical and neurologic characteristics by using the Pearson's chi-square test. For the survival analysis, the Kaplan-Meier and Hazard Ratio (HR) tests were used, with a 95% confidence interval (CI). Encephalitis and encephalomyelitis were more frequent in arboviruses, while myelitis predominated in the neurological disorders of other etiologies. Guillain-Barré Syndrome (GBS) was similarly distributed amongst the groups. Exposure to one of the arboviruses caused a six-fold increase in the risk of death (HR: 6.37; CI: 2.91 - 13.9). Amongst the arbovirus-exposed groups, infection (DENV/CHIKV) increased nine times the risk of death (HR: 9.07; CI: 3.67 - 22.4). The survival curve indicates that have been exposed to some arbovirus decreased the likelihood of survival compared to those with other etiologies (Log-Rank: p<0.001). Within this scenario, neurologic manifestations of DENV, CHIKV and ZIKV have the potential to increase mortality and decrease survival, and concomitant infection (DENV/CHIKV) is an aggravating factor in reducing the likelihood of survival when compared to monoinfections.

Acute RNA Viral Encephalomyelitis and the Role of Antibodies in the Central Nervous System.

Acute RNA viral encephalomyelitis is a serious complication of numerous virus infections. Antibodies in the cerebral spinal fluid (CSF) are correlated to better outcomes, and there is substantive evidence of antibody secreting cells (ASCs) entering the central nervous system (CNS) and contributing to resolution of infection. Here, we review the RNA viruses known to cause acute viral encephalomyelitis with mechanisms of control that require antibody or ASCs. We compile the cytokines, chemokines, and surface receptors associated with ASC recruitment to the CNS after infection and compare known antibody-mediated mechanisms as well as potential noncytolytic mechanisms for virus control. These non-canonical functions of antibodies may be employed in the CNS to protect precious non-renewable neurons. Understanding the immune-specialized zone of the CNS is essential for the development of effective treatments for acute encephalomyelitis caused by RNA viruses.

Neuronal Ablation of Alpha/Beta Interferon (IFN-α/ß) Signaling Exacerbates Central Nervous System Viral Dissemination and Impairs IFN-γ Responsiveness in Microglia/Macrophages.

Alpha/beta interferon (IFN-α/ß) signaling through the IFN-α/ß receptor (IFNAR) is essential to limit virus dissemination throughout the central nervous system (CNS) following many neurotropic virus infections. However, the distinct expression patterns of factors associated with the IFN-α/ß pathway in different CNS resident cell populations implicate complex cooperative pathways in IFN-α/ß induction and responsiveness. Here we show that mice devoid of IFNAR1 signaling in calcium/calmodulin-dependent protein kinase II alpha (CaMKIIα) expressing neurons (CaMKIIcre:IFNARfl/fl mice) infected with a mildly pathogenic neurotropic coronavirus (mouse hepatitis virus A59 strain [MHV-A59]) developed severe encephalomyelitis with hind-limb paralysis and succumbed within 7 days. Increased virus spread in CaMKIIcre:IFNARfl/fl mice compared to IFNARfl/fl mice affected neurons not only in the forebrain but also in the mid-hind brain and spinal cords but excluded the cerebellum. Infection was also increased in glia. The lack of viral control in CaMKIIcre:IFNARfl/fl relative to control mice coincided with sustained Cxcl1 and Ccl2 mRNAs but a decrease in mRNA levels of IFNα/ß pathway genes as well as Il6, Tnf, and Il1ß between days 4 and 6 postinfection (p.i.). T cell accumulation and IFN-γ production, an essential component of virus control, were not altered. However, IFN-γ responsiveness was impaired in microglia/macrophages irrespective of similar pSTAT1 nuclear translocation as in infected controls. The results reveal how perturbation of IFN-α/ß signaling in neurons can worsen disease course and disrupt complex interactions between the IFN-α/ß and IFN-γ pathways in achieving optimal antiviral responses.IMPORTANCE IFN-α/ß induction limits CNS viral spread by establishing an antiviral state, but also promotes blood brain barrier integrity, adaptive immunity, and activation of microglia/macrophages. However, the extent to which glial or neuronal signaling contributes to these diverse IFN-α/ß functions is poorly understood. Using a neurotropic mouse hepatitis virus encephalomyelitis model, this study demonstrated an essential role of IFN-α/ß receptor 1 (IFNAR1) specifically in neurons to control virus spread, regulate IFN-γ signaling, and prevent acute mortality. The results support the notion that effective neuronal IFNAR1 signaling compensates for their low basal expression of genes in the IFN-α/ß pathway compared to glia. The data further highlight the importance of tightly regulated communication between the IFN-α/ß and IFN-γ signaling pathways to optimize antiviral IFN-γ activity.

A novel orally infected hamster model for Coxsackievirus A16 hand-foot-and-mouth disease and encephalomyelitis.

Coxsackievirus A16 (CV-A16) is one of the major causes of mild and self-limiting hand-foot-and-mouth disease (HFMD) in young children, which may occasionally leads to serious neurological complications. In this study, we had developed a novel, consistent, orally infected CV-A16 HFMD hamster model with encephalomyelitis. Four groups of 7-day-old hamsters in a kinetic study were orally infected with mouse-adapted CV-A16 strains and sacrificed at 1-4 days post infection (dpi), respectively. Tissues were studied by light microscopy, immunohistochemistry to detect viral antigens, in situ hybridization to detect viral RNA, and by viral titration. In a separate transmission experiment, orally infected index hamsters were housed together with contact hamsters to investigate oral and fecal viral shedding by virus culture and reverse transcription polymerase chain reaction (RT-PCR). At severe infection/death endpoints, index and contact hamster infection were also histopathologically analyzed. In the kinetic study, infected hamsters developed signs of infection at 4 dpi. Viral antigens/RNA were localized to brainstem (medulla/pons; reticular formation and motor trigeminal nucleus) and spinal cord anterior horn neurons, oral squamous epithelia and epidermis from 3 to 4 dpi. Salivary and lacrimal glands, myocardium, brown adipose tissue, intestinal smooth muscle, and skeletal muscle infection was also demonstrated. Viremia at 1 dpi and increasing viral titers in various tissues were observed from 2 dpi. In the transmission study, all contact hamsters developed disease 3-5 days later than index hamsters, but demonstrated similar histopathological findings at endpoint. Viral culture and RT-PCR positive oral washes and feces confirmed viral shedding. Our hamster model, orally infected by the natural route for human infection, confirmed CV-A16 neurotropism and demonstrated squamous epitheliotropism reminiscent of HFMD, attributes not found in other animal models. It should be useful to investigate neuropathogenesis, model person-to-person transmission, and for testing antiviral drugs and vaccines.

A case of possible atypical demyelinating event of the central nervous system following COVID-19.

After the novel coronavirus disease outbreak first began in Wuhan, China, in December 2019, the viral epidemic has quickly spread across the world, and it is now a major public health concern. Here we present a 21-year-old male with encephalomyelitis following intermittent vomiting and malaise for 4 days. He reported upper respiratory signs and symptoms 2 weeks before this presentation. Two cerebrospinal fluid (CSF) analyses were notable for mononuclear pleocytosis, elevated protein (more than 100 mg/dl), and hypoglycorrhachia. Brain Magnetic Resonance Imaging (MRI) showed bilateral posterior internal capsule lesions extending to the ventral portion of the pons and a marbled splenium hyperintensity pattern. Cervical and thoracic MRI showed longitudinally extensive transverse myelitis (LETM), none of which were enhanced with gadolinium. Both the AQP4 and MOG antibodies were negative. Spiral chest computed tomography (CT) scan confirmed to COVID-19 as did the high IgG level against coronavirus, but the oropharyngeal swabs were negative. Neurological manifestations of COVID-19 have not been adequately studied. Some COVID-19 patients, especially those suffering from a severe disease, are highly likely to have central nervous system (CNS) manifestations. Our case is a post-COVID-19 demyelinating event in the CNS.

Two novel porcine teschovirus strains as the causative agents of encephalomyelitis in the Netherlands.

BACKGROUND: Porcine teschovirus (PTV) circulates among wild and domesticated pig populations without causing clinical disease, however neuroinvasive strains have caused high morbidity and mortality in the past. In recent years, several reports appeared with viral agents as a cause for neurologic signs in weanling and growing pigs among which PTV and new strains of PTV were described. CASE PRESENTATION: On two unrelated pig farms in the Netherlands the weanling pig population showed a staggering gate, which developed progressively to paresis or paralysis of the hind legs with a morbidity up to 5%. After necropsy we diagnosed a non-suppurative encephalomyelitis on both farms, which was most consistent with a viral infection. PTV was detected within the central nervous system by qPCR. From both farms PTV full-length genomes were sequenced, which clustered closely with PTV-3 (98%) or PTV-11 (85%). Other common swine viruses were excluded by qPCR and sequencing of the virus. CONCLUSION: Our results show that new neuroinvasive PTV strains still emerge in pigs in the Netherlands. Further research is needed to investigate the impact of PTV and other viral agents causing encephalomyelitis within wild and domestic pig populations supported by the awareness of veterinarians.

Both ADP-Ribosyl-Binding and Hydrolase Activities of the Alphavirus nsP3 Macrodomain Affect Neurovirulence in Mice.

Macrodomain (MD), a highly conserved protein fold present in a subset of plus-strand RNA viruses, binds to and hydrolyzes ADP-ribose (ADPr) from ADP-ribosylated proteins. ADPr-binding by the alphavirus nonstructural protein 3 (nsP3) MD is necessary for the initiation of virus replication in neural cells, whereas hydrolase activity facilitates replication complex amplification. To determine the importance of these activities for pathogenesis of alphavirus encephalomyelitis, mutations were introduced into the nsP3 MD of Sindbis virus (SINV), and the effects on ADPr binding and hydrolase activities, virus replication, immune responses, and disease were assessed. Elimination of ADPr-binding and hydrolase activities (G32E) severely impaired in vitro replication of SINV in neural cells and in vivo replication in the central nervous systems of 2-week-old mice with reversion to wild type (WT) (G) or selection of a less compromising change (S) during replication. SINVs with decreased binding and hydrolase activities (G32S and G32A) or with hydrolase deficiency combined with better ADPr-binding (Y114A) were less virulent than WT virus. Compared to the WT, the G32S virus replicated less well in both the brain and spinal cord, induced similar innate responses, and caused less severe disease with full recovery of survivors, whereas the Y114A virus replicated well, induced higher expression of interferon-stimulated and NF-κB-induced genes, and was cleared more slowly from the spinal cord with persistent paralysis in survivors. Therefore, MD function was important for neural cell replication both in vitro and in vivo and determined the outcome from alphavirus encephalomyelitis in mice.IMPORTANCE Viral encephalomyelitis is an important cause of long-term disability, as well as acute fatal disease. Identifying viral determinants of outcome helps in assessing disease severity and developing new treatments. Mosquito-borne alphaviruses infect neurons and cause fatal disease in mice. The highly conserved macrodomain of nonstructural protein 3 binds and can remove ADP-ribose (ADPr) from ADP-ribosylated proteins. To determine the importance of these functions for virulence, recombinant mutant viruses were produced. If macrodomain mutations eliminated ADPr-binding or hydrolase activity, viruses did not grow. If the binding and hydrolase activities were impaired, the viruses grew less well than the wild-type virus, induced similar innate responses, and caused less severe disease, and most of the infected mice recovered. If binding was improved, but hydrolase activity was decreased, the virus replicated well and induced greater innate responses than did the WT, but clearance from the nervous system was impaired, and mice remained paralyzed. Therefore, macrodomain function determined the outcome of alphavirus encephalomyelitis.

Interferon-Gamma Modulation of the Local T Cell Response to Alphavirus Encephalomyelitis.

Infection of mice with Sindbis virus (SINV) provides a model for examining the role of the immune response to alphavirus infection of the central nervous system (CNS). Interferon-gamma (IFN-γ) is an important component of this response, and we show that SINV-infected differentiated neurons respond to IFN-γ in vitro by induction of antiviral genes and suppression of virus replication. To determine the in vivo effects of IFN-γ on SINV clearance and T cell responses, C57BL/6 mice lacking IFN-γ or IFN-γ receptor-1 were compared to wild-type (WT) mice after intracranial SINV infection. In WT mice, IFN-γ was first produced in the CNS by natural killer cells and then by CD4+ and CD8+ T cells. Mice with impaired IFN-γ signaling initiated clearance of viral RNA earlier than WT mice associated with CNS entry of more granzyme B-producing CD8+ T cells. However, these mice established fewer CD8+ tissue-resident memory T (TRM) cells and were more likely to experience reactivation of viral RNA synthesis late after infection. Therefore, IFN-γ suppresses the local development of granzyme B-expressing CD8+ T cells and slows viral RNA clearance but promotes CD8+ TRM cell establishment.

Polioencephalomyelitis in Domestic Swine Associated With Porcine Astrovirus Type 3.

In the past decade, different members of the genus Mamastrovirus have been associated with outbreaks of neurologic disease in humans, cattle, sheep, mink, and, most recently, porcine astrovirus 3 (PoAstV3) in swine. We performed a retrospective analysis of 50 cases of porcine neurologic disease of undetermined cause but with microscopic lesions compatible with a viral encephalomyelitis to better understand the role and pathogenesis of PoAstV3 infection. Nucleic acid was extracted from formalin-fixed paraffin-embedded (FFPE) tissue for reverse transcription quantitative polymerase chain reaction (RT-qPCR) testing for PoAstV3. In addition, 3 cases with confirmed PoAstV3-associated disease were assayed by RT-qPCR to investigate PoAstV3 tissue distribution. PoAstV3 was detected in central nervous system (CNS) tissue via RT-qPCR and in situ hybridization in 13 of 50 (26%) FFPE cases assayed. PoAstV3 was rarely detected in any tissues outside the CNS. Positive cases from the retrospective study included pigs in various production categories beginning in 2010, the earliest year samples were available. Based on these results, PoAstV3 appears to be a recurring putative cause of viral encephalomyelitis in swine that is rarely detected outside of the CNS at the time of clinical neurologic disease, unlike other common viral causes of neurologic disease in swine.

Susceptibility of rat immortalized neuronal cell line Rn33B expressing equine major histocompatibility class 1 to equine herpesvirus-1 infection is differentiation dependent.

Equine herpesvirus-1 (EHV-1), which causes encephalomyelitis in horses, shows endotheliotropism in the central nervous system of horses, and generally does not infect neurons. However, little is known about the mechanism underlying the resistance of neuron to EHV-1, due to the lack of convenient cell culture systems. In this study, we examined EHV-1 infection in immortalized Rn33B rat neuronal cells, which differentiate into neurons when cultured under nonpermissive conditions. Because murine cell lines are resistant to EHV-1 infections due to the lack of functional entry receptors for EHV-1, we used an Rn33B-derived cell line that stably expresses the equine MHC class 1 molecule, which acts as EHV-1 entry receptor (Rn33B-A68B2M cells). EHV-1 infected undifferentiated Rn33B-A68B2M cells more efficiently than differentiated cells, resulting in the production of progeny virus in the former but not in the latter. By contrast, both differentiated and undifferentiated cells infected with herpes simplex virus-1 produced infectious viral progeny. While EHV-1 infection induced stronger expression of IFN alpha gene in differentiated cells than in undifferentiated cells, downstream IFN responses, including phosphorylation of STAT1 (signal transducer and activator of transcription 1) and expression of IFN-stimulated genes, were not activated regardless of whether cells were differentiated or not. These results suggest that neuronal differentiation of RN33B-A68B2M cells reduced their susceptibility to EHV-1, which is not due to different IFN responses. This culture system may be useful as an in vitro model for studying neuron-specific resistance to EHV-1, by investigating viral and host factors responsible for the difference in susceptibility between differentiated and undifferentiated cells.

Cerebrospinal Fluid Neopterin in Children With Enterovirus-Related Brainstem Encephalitis.

BACKGROUND: Enterovirus-A71 causes outbreaks of brainstem encephalitis, ranging from self-limited disease to acute flaccid paralysis. The aim of this study was to assess the role of cerebrospinal fluid (CSF) neopterin as a biomarker of disease severity in children with enterovirus-related brainstem encephalitis. METHODS: A descriptive, prospective cohort study was conducted from April 2016 to March 2017 in a tertiary hospital. Pediatric patients with a diagnosis of brainstem encephalitis with or without myelitis due to enterovirus infection were enrolled. The final study group comprised a convenience sample including all patients with sufficient CSF volume for neopterin determination. The major variables considered in estimating the severity were the diagnosis of encephalomyelitis, the presence of lesions and extensive lesions on brain and spinal magnetic resonance imaging (MRI), hospital stay length greater than seven days, and sequelae at day 30. RESULTS: Of 60 patients, CSF neopterin could be measured in 36. Median age was 26 months (interquartile range: 19 to 32). Thirty-three were diagnosed with brainstem encephalitis and three with encephalomyelitis. Enterovirus-A71 was the only identified genotype (25 of 25). CSF neopterin levels were elevated (>61 nmol/L) in 33 of 36 (92%), with a median of 347 nmol/L (interquartile range: 204 to 525). CSF neopterin was useful to distinguish patients with lesions on MRI (area under the receiver operating characteristic curve = 0.76; P = 0.02) and extensive lesions (area under the receiver operating characteristic curve = 0.76; P = 0.04). CONCLUSIONS: This study suggests an association between CSF neopterin levels and the presence of inflammatory lesions on MRI.

Enterovirus A71 Infection and Neurologic Disease, Madrid, Spain, 2016.

We conducted an observational study from January 2016 through January 2017 of patients admitted to a reference pediatric hospital in Madrid, Spain, for neurologic symptoms and enterovirus infection. Among the 30 patients, the most common signs and symptoms were fever, lethargy, myoclonic jerks, and ataxia. Real-time PCR detected enterovirus in the cerebrospinal fluid of 8 patients, nasopharyngeal aspirate in 17, and anal swab samples of 5. The enterovirus was genotyped for 25 of 30 patients; enterovirus A71 was the most common serotype (21/25) and the only serotype detected in patients with brainstem encephalitis or encephalomyelitis. Treatment was intravenous immunoglobulins for 21 patients and corticosteroids for 17. Admission to the pediatric intensive care unit was required for 14 patients. All patients survived. At admission, among patients with the most severe disease, leukocytes were elevated. For children with brainstem encephalitis or encephalomyelitis, clinicians should look for enterovirus and not limit testing to cerebrospinal fluid.

Molecular characterisation of equid alphaherpesvirus 1 strains isolated from aborted fetuses in Poland.

BACKGROUND: Equid alphaherpesvirus 1 (EHV-1) is one of the main infectious causative agents of abortion in mares and can also be associated with stillbirth, neonatal foal death, rhinopneumonitis in young horses and a neurological disorder called equine herpesvirus myeloencephalopathy (EHM). The neuropathogenicity of the virus was shown to be significantly higher in EHV-1 strains that carry a single nucleotide point (SNP) mutation in the ORF30, which encodes a catalytic subunit of viral DNA polymerase (ORF30 D752). Another gene, ORF68 is frequently used for phylogenetic analysis of EHV-1. METHODS: 27 EHV-1 strains isolated from aborted equine fetuses in Poland, collected between 1993 and 2017, were subjected to PCR targeting the open reading frames (ORFs) 30 and 68 of the EHV-1 genome. PCR products obtained were sequenced and SNPs were analyzed and compared to sequences available in GenBank. RESULTS: None of the analyzed sequences belonged to the ORF30 D752neuropathogenic genotype: all EHV-1 belonged to the non-neuropathogenic variant N752. On the basis of ORF68 sequences, the majority of EHV-1 sequences (76.9%) cannot be assigned to any of the known groups; only six sequences (23.1%) clustered within groups II and IV. CONCLUSIONS: EHV-1 strains obtained from abortion cases belong to the non-neuropathogenic genotype. Many EHV-1 ORF68 sequences have similar SNPs to those already described in Poland, but a clear geographical distribution was not observed. A single particular ORF68 sequence type was observed in strains isolated from 2001 onwards.

Nonsuppurative (Aseptic) Meningoencephalomyelitis Associated with Neurovirulent Astrovirus Infections in Humans and Animals.

Astroviruses are thought to be enteric pathogens. Since 2010, a certain group of astroviruses has increasingly been recognized, using up-to-date random amplification and high-throughput next-generation sequencing (NGS) methods, as potential neurovirulent (Ni) pathogens of severe central nervous system (CNS) infections, causing encephalitis, meningoencephalitis, and meningoencephalomyelitis. To date, neurovirulent astrovirus cases or epidemics have been reported for humans and domesticated mammals, including mink, bovines, ovines, and swine. This comprehensive review summarizes the virology, epidemiology, pathology, diagnosis, therapy, and future perspective related to neurovirulent astroviruses in humans and mammals, based on a total of 30 relevant articles available in PubMed (searched by use of the terms "astrovirus/encephalitis" and "astrovirus/meningitis" on 2 March 2018). A paradigm shift should be considered based on the increasing knowledge of the causality-effect association between neurotropic astroviruses and CNS infection, and attention should be drawn to the role of astroviruses in unknown CNS diseases.