Viral Central Nervous System Research Articles

Varicella zoster virus central nervous system infection - a retrospective study from a tertiary center in Greece.

Central nervous system (CNS) infection due to the varicella zoster virus (VZV) can complicate the primary infection or the reactivation, leading to significant mortality and morbidity. This study aimed to describe the clinical, laboratory, and radiological characteristics of patients with confirmed VZV CNS infection in a tertiary hospital in Greece. Data about patients hospitalized from January 2018 to September 2023 with CNS infection by VZV, confirmed by a syndromic polymerase chain reaction in the cerebrospinal fluid (CSF), were retrospectively collected and evaluated. In total, 14 patients were recorded. The median age was 49 years, and 35.7% were male. Headache was present in 71.4%, a rash in 57.1%, and fevers, nausea or vomiting, and disorientation in 35.7%. The CSF showed lymphocytic pleocytosis in all patients. Brain magnetic resonance imaging was performed in 53.8%. Empirical antivirals were given in 69.2%, and intravenous acyclovir was given to all patients after identification of VZV in the CSF. Only 7.1% (1 patient) required intensive care unit admission, and 7.1% (1 patient) died. Patients presenting without a rash may be slightly younger, have a slightly lower Charlson comorbidity index, be more likely to present with photophobia or phonophobia, and have lower serum CRP. Patients presenting with VZV CNS infection have lymphocytic pleocytosis in the CSF and usually have a favorable outcome with antiviral treatment. Those presenting without a rash may have a different overall clinical phenotype from those with a rash; however, this must be evaluated in larger studies in the future.

Early Diagnosis of CNS Virus Infections from Neurological Autoimmune Diseases: A Cross-Sectional Study from China in ER Setting.

It is challenging to differentiate between central nervous system (CNS) virus infections and neurological autoimmune diseases in the emergency department. Considering their different pathogenesis, we assume they differ in neuropsychiatric symptoms and laboratory results. A total of 80 patients were included in this study, 50 with CNS virus infections and 30 with CNS autoimmune diseases, confirmed by a polymerase chain reaction (PCR) of cerebrospinal fluid (CSF). A binary logistic regression model and receiver operating characteristic (ROC) curve were employed to examine the discrimination between the two types of diseases based on neuropsychiatric symptoms and laboratory results. Compared to patients with neurological autoimmune diseases, patients with CNS virus infections had a higher incidence of abnormal behavior (p = 0.026) and abnormal sensation/thought (p = 0.029); higher total (p = 0.005), direct (p = 0.004), and indirect bilirubin (p = 0.004); and increased CSF cell (p = 0.01) and CSF white cell counts (p = 0.01). Patients with disturbance of consciousness and abnormal sensation/thought were 7.79-fold and 5.07-fold more likely to be diagnosed with CNS virus infections (OR = 7.79, p = 0.008; OR = 5.07, p = 0.032). Each unit increase in blood indirect bilirubin concentration and CSF white cell counts increased the risk of developing CNS virus infections by 1.25-fold and 1.01-fold (OR = 1.25, p = 0.016; OR = 1.01, p = 0.011). ROC analysis showed that the area under the curve was 88.0% (p < 0.001). Our study found that patients with CNS viral infections tend to have higher blood indirect bilirubin concentration, CSF leukocyte count, frequency of disorders of consciousness, and abnormal sensation and thought, which may help differentiate them from those with neurological autoimmune diseases.

Post-COVID-19 cognitive impairments (literature review)

Post-COVID-19 condition (PCC) is a condition that occurs in patients with a history of SARS-CoV-2 infection 3 months after the onset of COVID-19 with symptoms that last at least 2 months and are not explained by any other diseases. PCC affects from 17% to 28% of patients and includes a wide range of clinical manifestations, including cognitive dysfunction. Cognitive dysfunctions can be manifested by a wide range of symptoms, such as memory impairment, attention deficit, executive dysfunction, and reduced information processing speed. Risk factors for developing PCC, with or without cognitive impairment, include late adulthood, pre-existing medical conditions, and severity of acute illness. The underlying mechanisms remain unclear, but suspected factors include neuroinflammation, hypoxia, vascular damage and latent reactivation of the virus, this does not exclude the possibility of direct viral central nervous system invasion. The analysis of retrospective cohort studies showed that the risk of cognitive deficits, dementia, psychotic disorders and seizures remained elevated even 2 years after the infection of SARS-CoV-2. It is interesting to note that there were no differences in the risks of neurological and psychiatric outcomes between infections caused by Omicron (B.1.1.529) or Delta (B.1.617.2) variants. Recent researches show that cognitive deficits after infection of SARS-CoV-2 persist for two years after the infection and were the greatest in individuals with more severe SARS-CoV-2 infection [2]. COVID-19 can impair the function of the interoceptive network of the brain selectively, while exteroceptive brain processing remains undamaged [3].

Meningitis a Listeria monocytogenes in a young, immunocompetent male

Listeria Monocytogenes (LM) is a gram-positive intracellular pathogen usually transmitted to humans by ingesting contaminated food. It typically infects immunocompromised individuals, such as pregnant women, newborns, alcoholics, and the elderly. LM is a rare cause of meningitis in immunocompetent, healthy adults. However, its clinical presentation is similar to that of other viral or bacterial central nervous system infections and its course can be rapid and aggressive. Physicians should therefore always consider LM as a possible etiologic agent of meningitis, especially in cases that do not respond to first-line empiric antibiotic therapy. We report a case of Listeria Monocytogenes meningitis in a previously healthy 16-year-old.

RNA Landscapes of Brain and Brain-Derived Extracellular Vesicles in Simian Immunodeficiency Virus Infection and Central Nervous System Pathology.

Brain tissue-derived extracellular vesicles (bdEVs) act locally in the central nervous system (CNS) and may indicate molecular mechanisms in human immunodeficiency virus (HIV) CNS pathology. Using brain homogenate (BH) and bdEVs from a simian immunodeficiency virus (SIV) model of HIV disease, we identified RNA networks in SIV infection and neuroinflammation. Postmortem occipital cortex samples were obtained from uninfected controls and SIV-infected subjects (acute and chronic phases with or without CNS pathology [SIV encephalitis]). bdEVs were separated and characterized per international consensus guidelines. RNAs from bdEVs and BH were sequenced and quantitative polymerase chain reaction (qPCR)-amplified to detect levels of small RNAs (sRNAs, including microRNAs [miRNAs]) and longer RNAs including messenger RNAs (mRNAs) and circular RNAs (circRNAs). Dysregulated RNAs in BH and bdEVs were identified in acute and chronic infection with pathology groups, including mRNAs, miRNAs, and circRNAs. Most dysregulated mRNAs in bdEVs reflected dysregulation in source BH. These mRNAs are disproportionately involved in inflammation and immune responses. Based on target prediction, several circRNAs that were differentially abundant in source tissue might be responsible for specific differences in sRNA levels in bdEVs during SIV infection. RNA profiling of bdEVs and source tissues reveals potential regulatory networks in SIV infection and SIV-related CNS pathology.

Laboratory diagnosis of CNS infections in children due to emerging and re-emerging neurotropic viruses.

Recent decades have witnessed the emergence and re-emergence of numerous medically important viruses that cause central nervous system (CNS) infections in children, e.g., Zika, West Nile, and enterovirus/parechovirus. Children with immature immune defenses and blood-brain barrier are more vulnerable to viral CNS infections and meningitis than adults. Viral invasion into the CNS causes meningitis, encephalitis, brain imaging abnormalities, and long-term neurodevelopmental sequelae. Rapid and accurate detection of neurotropic viral infections is essential for diagnosing CNS diseases and setting up an appropriate patient management plan. The addition of new molecular assays and next-generation sequencing has broadened diagnostic capabilities for identifying infectious meningitis/encephalitis. However, the expansion of test menu has led to new challenges in selecting appropriate tests and making accurate interpretation of test results. There are unmet gaps in development of rapid, sensitive and specific molecular assays for a growing list of emerging and re-emerging neurotropic viruses. Herein we will discuss the advances and challenges in the laboratory diagnosis of viral CNS infections in children. This review not only sheds light on selection and interpretation of a suitable diagnostic test for emerging/re-emerging neurotropic viruses, but also calls for more research on development and clinical utility study of novel molecular assays. IMPACT: Children with immature immune defenses and blood-brain barrier, especially neonates and infants, are more vulnerable to viral central nervous system infections and meningitis than adults. The addition of new molecular assays and next-generation sequencing has broadened diagnostic capabilities for identifying infectious meningitis and encephalitis. There are unmet gaps in the development of rapid, sensitive and specific molecular assays for a growing list of emerging and re-emerging neurotropic viruses.

Cauda equina syndrome in a patient with human immunodeficiency virus and secondary central nervous system lymphoma: a case report

BackgroundSecondary central nervous system lymphoma (SCNSL) is a known complication of immunocompromised patients with most cases involving the brain parenchyma. Reports of cauda equina syndrome (CES) caused by SCNSL are exceedingly scarce as involvement of this anatomical region is extremely uncommon.Case presentationWe report a case of a 46-years-old, African, female patient with human immunodeficiency virus (HIV) who developed CES in the context of SCNSL. There were no blasts present in the peripheral blood smear. We provide a review of the literature, discussion of the clinical evolution of this patient and the radiological/histopathological findings. The patient ultimately responded well to induction chemotherapy and high dose methotrexate.ConclusionThis case report demonstrates that CES, while a rare occurrence in this clinical context, should be considered in at-risk patients especially those presenting with abnormal neurological findings. Prompt recognition may prevent permanent neurological injury and obviate the need for more invasive therapeutic interventions.

Radiological abnormalities in progressive multifocal leukoencephalopathy: Identifying typical and atypical imaging patterns for early diagnosis and differential considerations.

Progressive multifocal leukoencephalopathy (PML) is a rare viral central nervous system (CNS) demyelinating disease primarily associated with a compromised immune system. PML is seen mainly in individuals with human immunodeficiency virus, lymphoproliferative disease, and multiple sclerosis. Patients on immunomodulators, chemotherapy, and solid organ or bone marrow transplants are predisposed to PML. Recognition of various PML-associated typical and atypical imaging abnormalities is critical for early diagnosis and differentiating it from other conditions, especially in high-risk populations. Early PML recognition should expedite efforts at immune-system restoration, allowing for a favorable outcome. This review aims to provide a practical overview of radiological abnormalities in PML patients and address differential considerations.

The Worldwide Prevalence of Herpes Simplex Virus Encephalitis and Meningitis: A Systematic Review and Meta-Analysis.

Given the relatively high frequency of central nervous system infections and considerable mor- tality and morbidity reported to be caused by herpes simplex viruses among the other viral agents, having a clear knowledge about their epidemiological profile seems necessary. This systematic review and meta-analysis aimed to determine the relative frequency and preva- lence of herpes simplex encephalitis and meningitis in patients tested for viral etiologies. A comprehensive systematic review was performed in PubMed, Scopus, and Web of Science databases, searching for studies on the prevalence and relative frequency of herpes sim- plex virus 1 and herpes simplex virus 2 encephalitis and meningitis. Seventy-one studies were included. Overall, the prevalence of herpes simplex virus encephalitis among patients tested was 8% (95% confidence interval, 6%-11%; I2 = 98%) and the prevalence of herpes simplex virus meningitis among aseptic patients tested was 4% (95% confidence interval, 3%-7%; I2 = 95%), and a significant difference was observed by region. The results of our subgroup analysis for herpes simplex virus encephalitis revealed a prevalence of 8% for pediatric patients and ado- lescents and 12% for adults. The results for herpes simplex virus meningitis showed a prevalence of 4% for pediatric patients and adolescents and 9% for adults. We observed significant differ- ences in the frequency of herpes simplex virus 1 and herpes simplex virus 2 detection rates by region. Having high rates of missed cases due to inadequate, highly sensitive paraclinical tests performed on patients with suspected viral central nervous system infection is one of the pos- sible factors. More studies are needed to detect the possible flaws in the process of diagnosis in different regions.

Characteristics of neonatal herpes simplex central nervous system disease in Australia (1997-2020).

Neonatal herpes simplex virus (HSV) central nervous system (CNS) disease can occur in isolation or as part of disseminated infection. We sought to describe neonatal HSV CNS disease in Australia over 24 years. Neonates (≤28 days) with confirmed HSV infection, reported prospectively to the Australian Paediatric Surveillance Unit (1997-2020), were evaluated for HSV CNS disease (laboratory confirmation with clinical evidence of encephalitis, e.g., lethargy, seizures, focal signs; and/or abnormalities on neuroimaging or electroencephalogram), and compared with neonates without CNS disease. CNS-restricted disease was compared with CNS-disseminated disease. Of 195 neonates with HSV disease; 87 (45%) had CNS disease (1.29 cases/100,000 live births per year, 95% CI: 1·04-1·59). Neonates with CNS disease were significantly more likely to be male than neonates without CNS disease (60% versus 39%, OR=2·32, 95% CI 1·29-4·18). Of the neonates with CNS disease, those with CNS-restricted disease (52/87, 60%) presented later than neonates with CNS-disseminated disease (35/87, 40%), (mean 12 versus 6 days). Twenty (23%) neonates with CNS disease died, the majority with CNS-disseminated disease (n=19). Most neonates received aciclovir therapy (94·3%), however five neonates with unrecognised CNS disseminated disease (diagnosed at autopsy) had not been treated. Survivors of CNS disease were significantly more likely to have adverse neurological sequelae, compared with those without CNS disease (30% versus 4%, OR: 9·60, 95% CI: 2·6-35·0). Male neonates have a higher burden of HSV CNS disease. Despite the use of antiviral agents, morbidity following neonatal HSV CNS disease remains high. Evaluation of adjunctive therapies to improve outcomes is needed.

Tick-borne encephalitis epidemiology and surveillance in Poland, and comparison with selected European countries before and during the COVID-19 pandemic, 2008 to 2020.

BackgroundTick-borne encephalitis (TBE) is the most common viral central nervous system (CNS) infection in Poland. Previous research suggests that its incidence was underestimated in the pre-pandemic period. The COVID-19 pandemic caused a considerable burden on surveillance systems, which could further impact reporting.AimWe aimed to assess the completeness of reporting of TBE in the years 2008 to 2020 and explore the potential impact of the COVID-19 pandemic on reporting to the epidemiological surveillance system, compared with hospitalisations for TBEV and other viral neuro-infections.MethodsWe compared the Polish epidemiology of TBE and other viral infections of the CNS from national surveillance reports with data on hospitalisations from 2008 to 2020 and data from selected European countries.ResultsBetween 2008 and 2020, 3,016 TBE cases were reported to surveillance compared with 3,620 hospitalisations. There was an increasing trend in hospitalisations, while surveillance data demonstrated the opposite, with the largest discrepancy observed in the first pandemic year (354 hospitalisations vs 159 cases reported to surveillance). Serological testing for TBE was used more in the known endemic region of north-eastern Poland and less in non-endemic areas. Other European countries reported higher TBE case numbers and an increase during the COVID-19 pandemic, whereas Poland observed an opposite trend.ConclusionThe sensitivity of TBE surveillance in Poland requires improvement. There are considerable regional differences. Regions that test for TBE intensively report most cases. Policymakers should be made aware of the value of quality epidemiological data for planning prophylactic measures in risk areas.

Epidemiology and diagnosis of viral and bacterial central nervous system infections in Sri Lanka: A Narrative review

Bacterial central nervous system (CNS) infections are life-threatening diseases with high mortality and long-term neurological sequels, while viral CNS infections are mild and self-limited. In Sri Lanka, 1000-1500 and 150-250 patients with meningitis and encephalitis respectively are reported annually to the Epidemiology Unit. Haemophilus influenzae, Group B Streptococcus, Streptococcus pneumoniae, Escherichia coli, Mycobacterium tuberculosis, Neisseria meningitidis, Group D Streptococcus, Leptospira borgpetersenii serovar Tarasssovi, Listeria monocytogenes, Streptococcus bovis biotype 2, enterovirus, Herpes Simplex Virus type 1 and type 2, Varicella zoster virus and cytomegalovirus have been reported up to 2022 in patients with meningitis while dengue virus, Japanese encephalitis virus, Varicella zoster virus, West Nile virus, Human Bocavirus Type 1, 2 and 3, human adenovirus type 41, Echovirus type 9 and 25, Herpes Simplex Virus type 1 and Mycoplasma pneumoniae have been reported in patients with encephalitis and meningoencephalitis. However less than 10% of cases have a definitive aetiological diagnosis with conventional bacterial culture methods routinely used to diagnose bacterial CNS infections, while molecular assays are used only for selected common viral pathogens in government hospitals in Sri Lanka. Use of antibiotics prior to cerebrospinal fluid collection, delay in sample collection, and low volume of samples have been identified as factors for low sensitivity of test results. Scientists, microbiologists and virologists are responsible for developing new test methods to identify current and previously unidentified causative microorganisms to extend the spectrum of neurotropic organisms in Sri Lanka to enhance the aetiological diagnosis.

Epidemiology and Disease Burden of Hospitalized Children With Viral Central Nervous System Infections in China, 2016 to 2020

BackgroundViral central nervous system (CNS) infections seriously threaten the life and health of children, with a high mortality and severe sequelae in China and globally. Surveillance of viral CNS infections in children is important, especially in hospitalized children, to facilitate disease evaluation. MethodsIn this study, we collected the data on the discharged Face Sheet of Medical Records from database from 2016 to 2020 and analyzed the epidemiologic characteristics and disease burden of hospitalized children (≤18 years old) with viral CNS infections in China. We classified the discharge diagnosis of viral CNS infection as viral encephalitis (VE), viral meningitis (VM), viral meningoencephalitis (VME), viral encephalomyelitis (VEM), and viral meningomyelitis (VMM). ResultsA total of 42,641 cases of viral CNS infections were included in the database, consisting of 39,279 cases with VE (92.47%), 2011 cases with VM (4.73%), 1189 cases with VME (2.80%), 118 cases with VEM (0.28%), and 44 cases with VMM (0.10%). The number of hospitalized patients with viral CNS infections accounted for 0.74% (42,641 of 5,790,910) of all hospitalized cases. The onset of viral CNS infections presented seasonal characteristic, with peaks in June to July and December to January. Seizures are the most frequent complication of this disorder. Median length of stay and inpatient expenditures for patients with viral CNS infections were 9 days and 1144.36 USD. Causative viruses were identified in 4.33% (1848 of 42,641) of patients. ConclusionsThis study will help understand the clinical epidemiology and disease burden of hospitalized children with viral CNS infections in China.

Epstein-Barr virus central nervous system involvement in Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis.

Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis (EBV-HLH) is a common subtype of secondary HLH. EBV plays an important part in the course. EBV can cause central nervous system (CNS) infections, and there are few clinical studies on EBV-CNS infection in EBV-HLH patients. All patients who were diagnosed as EBV-HLH and underwent cerebrospinal fluid testing admitted to our center from January 2018 to December 2019 were retrospectively analyzed. Summarized the clinical data, evaluated treatment efficacy after intrathecal injection, and investigated the correlation between EBV-CNS infection with prognosis in EBV-HLH patients. Of 37 of 57 (64.9%) EBV-HLH patients has EBV-CNS infection. The survival of EBV-HLH patients without EBV-CNS infection was significantly better than that in EBV-CNS infection patients (P = 0.018). There were no statistically significant differences in sCD25, ferritin, ALT, AST, LDH, TB, WBC, Hb, and PLT counts between two groups (all P-values > 0.05). Higher EBV-DNA load in peripheral blood was correlated with EBV-CNS infection (P < 0.001). EBV-CNS infection is an independent risk factor affecting the survival of patients (P = 0.004). The CSF cell load of patients with and without EBV-CNS infection groups was significantly different (P = 0.024). Intrathecal injection with methotrexate combined with dexamethasone can effectively decrease CSF EBV-DNA load (P = 0.017) and CSF cell load (P = 0.025). EBV-CNS infection is an independent risk factor affecting prognosis in EBV-HLH patients. Therefore, EBV-CNS infection should cause concern for EBV-HLH patients. Cerebrospinal fluid testing is necessary for all patients. Methotrexate combined with dexamethasone intrathecal injection can be an effective treatment for EBV-CNS infection.

Viral Infection

Viral central nervous system(CNS)infections due to direct viral infection in the CNS include encephalitis/myelitis and meningitis. Acute encephalopathy is a CNS disorder that is mainly associated with viral respiratory infections. This article outlines herpes encephalitis, poliomyelitis, enterovirus A71 brainstem encephalitis/myelitis, and enterovirus D68 paralytic myelitis as acute encephalitis/myelitis, enteroviral meningitis and mumps meningitis as acute viral meningitis, and influenza encephalopathy and HHV-6 encephalopathy as acute encephalopathy.

Immature Brain Cortical Neurons Have Low Transcriptional Competence to Activate Antiviral Defences and Control RNA Virus Infections

Virus infections of the central nervous system (CNS) cause important diseases of humans and animals. As in other tissues, innate antiviral responses mediated by type I interferons (IFNs) are crucially important in controlling CNS virus infections. The maturity of neuronal populations is an established critical factor determining the outcome of CNS virus infection. Using primary cultures of mouse cortical neurons, we investigated the relationships between neuronal maturation, type I IFN responses, and the outcome of Semliki Forest virus infection. The virus replicated better, infected more cells, and produced higher titres of infectious viruses in immature neurons. Complete transcriptome analysis demonstrated that resting immature neurons have low transcriptional competence to mount antiviral responses. They had no detectable transcription of the genes Ddx58 and Ifih1, which encode key RNA virus cytoplasmic sensors RIG-I and MDA5, and very low expression of genes encoding key regulators of associated signalling pathways. Upon infection, immature neurons failed to mount an antiviral response as evidenced by their failure to produce chemokines, IFNs, and other cytokines. Treatment of immature neurons with exogenous IFNβ prior to infection resulted in antiviral responses and lower levels of virus replication and infectious virus production. In contrast, resting mature neurons generated a robust antiviral response. This was augmented by pretreatment with IFNβ. Infection of mature neurons derived from IFNAR−/− mice did not make an antiviral response and replicated virus to high levels.

HDI Highlighter, The First Intelligent Tool to Screen the Literature on Herb-Drug Interactions.

Herbal food supplements are commonly used and can be an important part of patient self-care. Like all other bio-active and therapeutic products, they have a benefit/risk balance. These products are not without adverse effects and potentially interact with other therapies. Educating patients and providing information for health professionals about the risk of herb-drug interactions is key. One of the purposes of the biomedical literature is to inform prescribers. Scientific literature accessible on databases such as PubMed is dense and careful reading is time consuming. We propose a reading aid tool named "HDI highlighter" to help readers to find key information in clinical studies and case reports describing herb-drug interactions. It uses natural language processing algorithms (artificial intelligence) with a pharmaceutical focus. Semantic relation extraction for herb-drug interactions from the biomedical literature are overexpressed using keywords. We have tested it to review 120 published articles over the last 10 years. In these articles, we have shown that case reports often involved long-term or semi-long-term treatments such as cancer or human immunodeficiency virus therapies, antiepileptic drugs, or central nervous system drugs. Similarly, these classes of drugs are more extensively targeted by clinical studies. Herb-drug interactions described in case reports are identified in medicinal, recreational, and alimentary uses. They also usually lack a rigorous description of the herb(s) involved. Typically, clinical studies provide a complete description of protocols and dosages, with a few exceptions explained by patients' needs. Clinical studies on herbs are nevertheless conducted on a limited number of patients. All these limitations make the interpretation of herb-drug interactions complicated, but the HDI highlighter provides a quick overview of the herb-drug interaction literature.

Opioid-Use, COVID-19 Infection, and Their Neurological Implications.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an imminent threat to human health and public safety. ACE2 and transmembrane serine protease 2 proteins on host cells provide the viral entry point to SARS-CoV-2. Although SARS-CoV-2 mainly infects the respiratory system, there have been reports of viral neurotropism and central nervous system injury as indicated by plasma biomarkers, including neurofilament light chain protein and glial fibrillary acidic protein. Even with a small proportion of infections leading to neurological manifestation, the overall number remains high. Common neurological manifestations of SARS-CoV-2 infection include anosmia, ageusia, encephalopathy, and stroke, which are not restricted to only the most severe infection cases. Opioids and opioid antagonists bind to the ACE2 receptor and thereby have been hypothesized to have therapeutic potential in treating COVID-19. However, in the case of other neurotropic viral infections such as human immunodeficiency virus (HIV), opioid use has been established to exacerbate HIV-mediated central nervous system pathogenesis. An analysis of electronic health record data from more than 73 million patients shows that people with Substance Use Disorders are at higher risk of contracting COVID-19 and suffer worse consequences then non-users. Our in-vivo and in-vitro unpublished studies show that morphine treatment causes increased expression of ACE2 in murine lung and brain tissue as early as 24 h post treatment. At the same time, we also observed morphine and lipopolysaccharides treatment lead to a synergistic increase in ACE2 expression in the microglial cell line, SIM-A9. This data suggests that opioid treatment may potentially increase neurotropism of SARS-CoV-2 infection. We have previously shown that opioids induce gut microbial dysbiosis. Similarly, gut microbiome alterations have been reported with SARS-CoV-2 infection and may play a role in predicting COVID-19 disease severity. However, there are no studies thus far linking opioid-mediated dysbiosis with the severity of neuron-specific COVID-19 infection.

Z-DNA binding protein 1 mediates necroptotic and apoptotic cell death pathways in murine astrocytes following herpes simplex virus-1 infection

BackgroundThe mechanisms by which glia respond to viral central nervous system (CNS) pathogens are now becoming apparent with the demonstration that microglia and astrocytes express an array of pattern recognition receptors that include intracellular RNA and DNA sensors. We have previously demonstrated that glia express Z-DNA binding protein 1 (ZBP1) and showed that this cytosolic nucleic acid sensor contributes to the inflammatory/neurotoxic responses of these cells to herpes simplex virus-1 (HSV-1). However, the relative contribution made by ZBP1- to HSV-1-mediated cell death in glia has not been determined.MethodsWe have investigated the relative contribution made by ZBP1- to HSV-1-mediated cell death in primary astrocytes derived from mice genetically deficient in this sensor. We have used capture ELISAs and immunoblot analysis to assess inflammatory cytokine production and ZBP1 and phosphorylated mixed lineage kinase domain-like protein (MLKL) expression levels, respectively, following HSV-1 challenge. Furthermore, we have used a commercially available cell viability assay to determine the proportion and rate of cell death in cells following infection with laboratory and neuroinvasive clinical strains of HSV-1, and pharmacological inhibitors of necroptotic and apoptotic pathway components to assess the relative role of each.ResultsWe show that the loss of ZBP1 in astrocytes results in an increase in the number of viral particles released following HSV-1 infection. Importantly, we have confirmed that HSV-1 induces necroptosis in astrocytes and have established the ability of ZBP1 to mediate this cell death pathway. Interestingly, while ZBP1 is best known for its role in necroptotic signaling, our findings indicate that this sensor can also contribute to virally induced apoptosis in these glia.ConclusionsOur findings indicate that ZBP1 serves as a restriction factor for HSV-1 infection and is associated with the induction of both necroptotic and apoptotic cell death pathways in primary murine astrocytes. While it remains to be seen whether ZBP1-mediated activation of cell death in astrocytes contributes significantly to host protection or, rather, exacerbates HSV-1 encephalitis pathology, the identification of such a role in resident CNS cells may represent a novel target for therapeutic intervention to reduce HSV encephalitis-associated morbidity and mortality.

Development of a multiplex droplet digital PCR assay for detection of enterovirus, parechovirus, herpes simplex virus 1 and 2 simultaneously for diagnosis of viral CNS infections

BackgroundEnterovirus (EV), parechovirus (HPeV), herpes simplex virus 1 and 2 (HSV1/2) are common viruses leading to viral central nervous system (CNS) infections which are increasingly predominant but exhibit deficiency in definite pathogen diagnosis with gold-standard quantitative PCR method. Previous studies have shown that droplet digital PCR (ddPCR) has great potential in pathogen detection and quantification, especially in low concentration samples.MethodsTargeting four common viruses of EV, HPeV, HSV1, and HSV2 in cerebrospinal fluid (CSF), we developed a multiplex ddPCR assay using probe ratio-based multiplexing strategy, analyzed the performance, and evaluated it in 97 CSF samples collected from patients with suspected viral CNS infections on a two-channel ddPCR detection system.ResultsThe four viruses were clearly distinguished by their corresponding fluorescence amplitude. The limits of detection for EV, HPeV, HSV1, and HSV2 were 5, 10, 5, and 10 copies per reaction, respectively. The dynamic range was at least four orders of magnitude spanning from 2000 to 2 copies per reaction. The results of 97 tested clinical CSF specimens were identical to those deduced from qPCR/qRT-PCR assays using commercial kits.ConclusionThe multiplex ddPCR assay was demonstrated to be an accurate and robust method which could detect EV, HPeV, HSV1, and HSV2 simultaneously. It provides a useful tool for clinical diagnosis and disease monitoring of viral CNS infections.