Neuropsychological Impact of West Nile Virus Infection: An Extensive Neuropsychiatric Assessment of 49 Cases in Canada

Rehabilitation approaches in West Nile Virus survivors: a systematic review

INTRODUCTION

Periodic increases in West Nile virus (WNV) infections have been documented. Proper rehabilitative management is essential for these patients, who may experience limitations in daily activities even after the resolution of the acute infection. Since there are currently no globally accepted guidelines, our aim is to conduct a best-evidence synthesis on rehabilitative management for patients with neuroinvasive WNV.

EVIDENCE ACQUISITION

We screened the literature with two independent researchers conducting searches on PubMed, Embase, SCOPUS, and Google Scholar databases for WNV-related studies in the field of rehabilitation. Suitable studies were identified and selected through a rigorous process. The review includes original research articles published up to August 15, 2023.

EVIDENCE SYNTHESIS

Despite the potential for bias in the studies, the literature suggests that a comprehensive and interdisciplinary rehabilitation program, which includes physical therapy with neuromotor and respiratory interventions, occupational therapy, neurocognitive interventions, and speech therapy for dysphagia and communication issues, can lead to functional improvement in WNV patients. This program should be tailored to address each patient's specific challenges, and the duration of the rehabilitation program may vary depending on the individual patient's needs.

CONCLUSIONS

Even if additional research with larger cohorts and higher evidence levels is needed for a comprehensive understanding of WNV patient rehabilitation, an early and comprehensive rehabilitation approach addressing respiratory, neuromuscular, and cognitive aspects appears effective for WNV patient recovery.

CRISPR-Cas system to discover host-virus interactions in Flaviviridae

The Flaviviridae virus family members cause severe human diseases and are responsible for considerable mortality and morbidity worldwide. Therefore, researchers have conducted genetic screens to enhance insight into viral dependency and develop potential anti-viral strategies to treat and prevent these infections. The host factors identified by the clustered regularly interspaced short palindromic repeats (CRISPR) system can be potential targets for drug development. Meanwhile, CRISPR technology can be efficiently used to treat viral diseases as it targets both DNA and RNA. This paper discusses the host factors related to the life cycle of viruses of this family that were recently discovered using the CRISPR system. It also explores the role of immune factors and recent advances in gene editing in treating flavivirus-related diseases. The ever-increasing advancements of this technology may promise new therapeutic approaches with unique capabilities, surpassing the traditional methods of drug production and treatment.

Temporal tracking of microglial and monocyte single-cell transcriptomics in lethal flavivirus infection

As the resident parenchymal myeloid population in the central nervous system (CNS), microglia are strategically positioned to respond to neurotropic virus invasion and have been implicated in promoting both disease resolution and progression in the acute and post-infectious phase of virus encephalitis. In a mouse model of West Nile virus encephalitis (WNE), infection of the CNS results in recruitment of large numbers of peripheral immune cells into the brain, the majority being nitric oxide (NO)-producing Ly6C^hi inflammatory monocyte-derived cells (MCs). In this model, these cells enhance immunopathology and mortality. However, the contribution of microglia to this response is currently undefined. Here we used a combination of experimental tools, including single-cell RNA sequencing (scRNA-seq), microglia and MC depletion reagents, high-dimensional spectral cytometry and computational algorithms to dissect the differential contribution of microglia and MCs to the anti-viral immune response in severe neuroinflammation seen in WNE. Intriguingly, analysis of scRNA-seq data revealed 6 unique microglia and 3 unique MC clusters that were predominantly timepoint-specific, demonstrating substantial transcriptional adaptation with disease progression over the course of WNE. While microglia and MC adopted unique gene expression profiles, gene ontology enrichment analysis, coupled with microglia and MC depletion studies, demonstrated a role for both of these cells in the trafficking of peripheral immune cells into the CNS, T cell responses and viral clearance. Over the course of infection, microglia transitioned from a homeostatic to an anti-viral and then into an immune cell-recruiting phenotype. Conversely, MC adopted antigen-presenting, immune cell-recruiting and NO-producing phenotypes, which all had anti-viral function. Overall, this study defines for the first time the single-cell transcriptomic responses of microglia and MCs over the course of WNE, demonstrating both protective and pathological roles of these cells that could potentially be targeted for differential therapeutic intervention to dampen immune-mediated pathology, while maintaining viral clearance functions.

Vector competence of three species of mosquitoes to Ingwavuma virus (Manzanilla orthobunyavirus), a new bunyavirus found circulating in India

Ingwavuma virus (INGV), a mosquito-borne arbovirus reported from Africa and Southeast Asia has been found circulating in India as evidenced by virus isolation and antibody prevalence. INGV is now classified as Manzanilla orthobunyavirus belonging to family Peribunyaviridae. The virus is maintained in nature in a pig-mosquito-bird cycle. Human infection has been confirmed by virus isolation and detection of neutralizing antibodies. A study was initiated to determine the vector competence of Aedes aegypti, Culex quinquefasciatus, and Cx tritaeniorhynchus mosquitoes to INGV due to their high prevalence in India. Mosquitoes were oral fed on viraemic mice and INGV dissemination to legs, wings, salivary glands (saliva) was studied alongwith virus growth kinetics. The three mosquitoes replicated INGV with maximum titers of 3.7, 3.7 and 4.7log10TCID50/ml respectively and maintained the virus till 16th day post infection. However, vector competence and horizontal transmission to infant mouse was demonstrated only by Cx quinquefasciatus mosquitoes. Vertical or trans-ovarial transmission of INGV could not be demonstrated in the mosquito during the study. Though no major outbreak involving humans has been reported yet, the potential of the virus to replicate in different species of mosquitoes and vertebrates including humans pose a threat to public health should there be a change in its genome.

West Nile Disease Symptoms and Comorbidities: A Systematic Review and Analysis of Cases

West Nile virus (WNV) is a mosquito-borne flavivirus that has emerged as a major cause of viral encephalitis and meningitis, rarely leading to death. Several risk factors have been discussed in the past concerning the severity of the disease, while few reports have focused on precipitating conditions that determine of WNV-related death. Studies on cohorts of patients suffering of West Nile disease (WND) usually encompass low numbers of deceased patients as a result of the rarity of the event. In this systematic review and critical analysis of 428 published case studies and case series, we sought to evaluate and highlight critical parameters of WND-related death. We summarized the symptoms, comorbidities, and treatment strategies related to WND in all published cases of patients that included clinical features. Symptoms such as altered mental status and renal problems presented increased incidence among deceased patients, while these patients presented increased cerebrospinal fluid (CSF) glucose. Our analysis also highlights underestimated comorbidities such as pulmonary disease to act as precipitating conditions in WND, as they were significantly increased amongst deceased patients. CSF glucose and the role of pulmonary diseases need to be revaluated either retrospectively or prospectively in WND patient cohorts, as they may be linked to increased mortality risk.

Unexplained post-acute infection syndromes

SARS-CoV-2 is not unique in its ability to cause post-acute sequelae; certain acute infections have long been associated with an unexplained chronic disability in a minority of patients. These post-acute infection syndromes (PAISs) represent a substantial healthcare burden, but there is a lack of understanding of the underlying mechanisms, representing a significant blind spot in the field of medicine. The relatively similar symptom profiles of individual PAISs, irrespective of the infectious agent, as well as the overlap of clinical features with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), suggest the potential involvement of a common etiopathogenesis. In this Review, we summarize what is known about unexplained PAISs, provide context for post-acute sequelae of SARS-CoV-2 infection (PASC), and delineate the need for basic biomedical research into the underlying mechanisms behind this group of enigmatic chronic illnesses.

Microglia and monocytes in inflammatory CNS disease: integrating phenotype and function

In neurological diseases, the actions of microglia, the resident myeloid cells of the CNS parenchyma, may diverge from, or intersect with, those of recruited monocytes to drive immune-mediated pathology. However, defining the precise roles of each cell type has historically been impeded by the lack of discriminating markers and experimental systems capable of accurately identifying them. Our ability to distinguish microglia from monocytes in neuroinflammation has advanced with single-cell technologies, new markers and drugs that identify and deplete them, respectively. Nevertheless, the focus of individual studies on particular cell types, diseases or experimental approaches has limited our ability to connect phenotype and function more widely and across diverse CNS pathologies. Here, we critically review, tabulate and integrate the disease-specific functions and immune profiles of microglia and monocytes to provide a comprehensive atlas of myeloid responses in viral encephalitis, demyelination, neurodegeneration and ischemic injury. In emphasizing the differential roles of microglia and monocytes in the severe neuroinflammatory disease of viral encephalitis, we connect inflammatory pathways common to equally incapacitating diseases with less severe inflammation. We examine these findings in the context of human studies and highlight the benefits and inherent limitations of animal models that may impede or facilitate clinical translation. This enables us to highlight common and contrasting, non-redundant and often opposing roles of microglia and monocytes in disease that could be targeted therapeutically.

Cognitive decline following acute viral infections: literature review and projections for post-COVID-19

Recently, much attention has been drawn to the importance of the impact of infectious disease on human cognition. Several theories have been proposed, to explain the cognitive decline following an infection as well as to understand better the pathogenesis of human dementia, especially Alzheimer's disease. This article aims to review the state of the art regarding the knowledge about the impact of acute viral infections on human cognition, laying a foundation to explore the possible cognitive decline followed coronavirus disease 2019 (COVID-19). To reach this goal, we conducted a narrative review systematizing six acute viral infections as well as the current knowledge about COVID-19 and its impact on human cognition. Recent findings suggest probable short- and long-term COVID-19 impacts in cognition, even in asymptomatic individuals, which could be accounted for by direct and indirect pathways to brain dysfunction. Understanding this scenario might help clinicians and health leaders to deal better with a wave of neuropsychiatric issues that may arise following COVID-19 pandemic as well as with other acute viral infections, to alleviate the cognitive sequelae of these infections around the world.

Decreased antiviral immune response within the central nervous system of aged mice is associated with increased lethality of West Nile virus encephalitis

West Nile virus (WNV) is an emerging pathogen that causes disease syndromes ranging from a mild flu‐like illness to encephalitis. While the incidence of WNV infection is fairly uniform across age groups, the risk of lethal encephalitis increases with advanced age. Prior studies have demonstrated age‐related, functional immune deficits that limit systemic antiviral immunity and increase mortality; however, the effect of age on antiviral immune responses specifically within the central nervous system (CNS) is unknown. Here, we show that aged mice exhibit increased peripheral organ and CNS tissue viral burden, the latter of which is associated with alterations in activation of both myeloid and lymphoid cells compared with similarly infected younger animals. Aged mice exhibit lower MHCII expression by microglia, and higher levels of PD1 and lower levels of IFNγ expression by WNV‐specific CD8⁺ T cells in the CNS and CD8⁺CD45⁺ cells. These data indicate that the aged CNS exhibits limited local reactivation of T cells during viral encephalitis, which may lead to reduced virologic control at this site.

Clinical and Serological Findings of Madariaga and Venezuelan Equine Encephalitis Viral Infections: A Follow-up Study 5 Years After an Outbreak in Panama

BACKGROUND

Human cases of Madariaga virus (MADV) infection were first detected during an outbreak in 2010 in eastern Panama, where Venezuelan equine encephalitis virus (VEEV) also circulates. Little is known about the long-term consequences of either alphavirus infection.

METHODS

A follow-up study of the 2010 outbreak was undertaken in 2015. An additional survey was carried out 2 weeks after a separate 2017 alphavirus outbreak in a neighboring population in eastern Panama. Serological studies and statistical analyses were undertaken in both populations.

RESULTS

Among the originally alphavirus-seronegative participants (n = 35 of 65), seroconversion was observed at a rate of 14.3% (95% CI, 4.8%-30.3%) for MADV and 8.6% (95% CI, 1.8%-23.1%) for VEEV over 5 years. Among the originally MADV-seropositive participants (n = 14 of 65), VEEV seroconversion occurred in 35.7% (95% CI, 12.8%-64.9%). In the VEEV-seropositive participants (n = 16 of 65), MADV seroconversion occurred in 6.3% (95% CI, 0.2%-30.2%). MADV seroreversion was observed in 14.3% (95% CI, 1.8%-42.8%) of those who were originally seropositive in 2010. VEEV seroconversion in the baseline MADV-seropositive participants was significantly higher than in alphavirus-negative participants. In the population sampled in 2017, MADV and VEEV seroprevalence was 13.2% and 16.8%, respectively. Memory loss, insomnia, irritability, and seizures were reported significantly more frequently in alphavirus-seropositive participants than in seronegative participants.

CONCLUSIONS

High rates of seroconversion to MADV and VEEV over 5 years suggest frequent circulation of both viruses in Panama. Enhanced susceptibility to VEEV infection may be conferred by MADV infection. We provide evidence of persistent neurologic symptoms up to 5 years following MADV and VEEV exposure.

Neurocognitive impacts of arbovirus infections

Arthropod-borne viruses or arbovirus, are most commonly associated with acute infections, resulting on various symptoms ranging from mild fever to more severe disorders such as hemorrhagic fever. Moreover, some arboviral infections can be associated with important neuroinflammation that can trigger neurological disorders including encephalitis, paralysis, ophthalmological impairments, or developmental defects, which in some cases, can lead to long-term defects of the central nervous system (CNS). This is well illustrated in Zika virus-associated congenital brain malformations but also in West Nile virus-induced synaptic dysfunctions that can last well beyond infection and lead to cognitive deficits. Here, we summarize clinical and mechanistic data reporting on cognitive disturbances triggered by arboviral infections, which may highlight growing public health issues spanning the five continents.

Long-term, West Nile virus-induced neurological changes: A comparison of patients and rodent models

West Nile virus (WNV) is a mosquito-borne virus that can cause severe neurological disease in those infected. Those surviving infection often present with long-lasting neurological changes that can severely impede their lives. The most common reported symptoms are depression, memory loss, and motor dysfunction. These sequelae can persist for the rest of the patients’ lives. The pathogenesis behind these changes is still being determined. Here, we summarize current findings in human cases and rodent models, and discuss how these findings indicate that WNV induces a state in the brain similar neurodegenerative diseases. Rodent models have shown that infection leads to persistent virus and inflammation. Initial infection in the hippocampus leads to neuronal dysfunction, synapse elimination, and astrocytosis, all of which contribute to memory loss, mimicking findings in neurodegenerative diseases such as Alzheimer’s disease (AD) and Parkinson’s disease (PD). WNV infection acts on pathways, such as ubiquitin-signaled protein degradation, and induces the production of molecules, including IL-1β, IFN-γ, and α-synuclein, that are associated with neurodegenerative diseases. These findings indicate that WNV induces neurological damage through similar mechanisms as neurodegenerative diseases, and that pursuing research into the similarities will help advance our understanding of the pathogenesis of WNV-induced neurological sequelae.

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In patients with and without diagnosed WNND, there are long-lasting neurological sequelae that can mimic neurodegenerative diseases.

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Some rodent models of WNV reproduce some of these changes with mechanisms similar to neurodegenerative diseases.

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There is significant overlap between WNV and ND pathogenesis and this has been understudied.

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Further research needs to be done to determine accuracy of animal models compared to human patients.

West Nile Virus-Induced Neurologic Sequelae-Relationship to Neurodegenerative Cascades and Dementias

Purpose of Review

West Nile virus (WNV) emerged from Central Africa in the 1990s and is now endemic throughout much of the world. Twenty years after its introduction in the USA, it is becoming apparent that neurological impairments can persist for years following infection. Here, we review the epidemiological data in support of such long-term deficits and discuss possible mechanisms that drive these persistent manifestations.

Recent Findings

Focusing on the recently discovered antimicrobial roles of amyloid and alpha-synuclein, we connect WNV late pathology to overlapping features encountered in neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. We also summarize new research on microglial activation and engulfment of neural synapses seen in recovered WNV as well as in neurodegenerative diseases, and discuss how loss of integrity of the blood-brain barrier (BBB) may exacerbate this process.

Summary

Neuroinvasive viral infections such as WNV may be linked epidemiologically and mechanistically to neurodegeneration. This may open doors to therapeutic options for hitherto untreatable infectious sequelae; additionally, it may also shed light on the possible infectious etiologies of age-progressive neurodegenerative dementias.

Differential In Vitro Infection of Neural Cells by Astroviruses

Encephalitis remains a diagnostic conundrum in humans as over 50% of cases are managed without the identification of an etiology. Astroviruses have been detected from the central nervous system of mammals in association with disease, suggesting that this family of RNA viruses could be responsible for cases of some neurological diseases that are currently without an ascribed etiology. However, there are significant barriers to understanding astrovirus infection as the capacity of these viruses to replicate in nervous system cells in vitro has not been determined. We describe primary and immortalized cultured cells of the nervous system that support infection by astroviruses. These results further corroborate the role of astroviruses in causing neurological diseases and will serve as an essential model to interrogate the neuropathogenesis of astrovirus infection.

Recent advances in unbiased pathogen discovery have implicated astroviruses as pathogens of the central nervous system (CNS) of mammals, including humans. However, the capacity of astroviruses to be cultured in CNS-derived cells in vitro has not been reported to date. Both astrovirus VA1/HMO-C (VA1; mamastrovirus 9) and classic human astrovirus 4 (HAstV4; mamastrovirus 1) have been previously detected from cases of human encephalitis. We tested the ability of primary human neurons, primary human astrocytes, and other immortalized human nervous system cell lines (SK-N-SH, U87 MG, and SW-1088) to support infection and replication of these two astrovirus genotypes. Primary astrocytes and SK-N-SH cells supported the full viral life cycle of VA1 with a >100-fold increase in viral RNA levels during a multistep growth curve, detection of viral capsid, and a >100-fold increase in viral titer. Primary astrocytes were permissive with respect to HAstV4 infection and replication but did not yield infectious virus, suggesting abortive infection. Similarly, abortive infection of VA1 was observed in SW-1088 and U87 MG cells. Elevated expression of the chemokine CXCL10 was detected in VA1-infected primary astrocytes and SK-N-SH cells, suggesting that VA1 infection can induce a proinflammatory host response. These findings establish an in vitro cell culture model that is essential for investigation of the basic biology of astroviruses and their neuropathogenic potential.

Neuroinflammation During RNA Viral Infections

Neurotropic RNA viruses continue to emerge and are increasingly linked to diseases of the central nervous system (CNS) despite viral clearance. Indeed, the overall mortality of viral encephalitis in immunocompetent individuals is low, suggesting efficient mechanisms of virologic control within the CNS. Both immune and neural cells participate in this process, which requires extensive innate immune signaling between resident and infiltrating cells, including microglia and monocytes, that regulate the effector functions of antiviral T and B cells as they gain access to CNS compartments. While these interactions promote viral clearance via mainly neuroprotective mechanisms, they may also promote neuropathology and, in some cases, induce persistent alterations in CNS physiology and function that manifest as neurologic and psychiatric diseases. This review discusses mechanisms of RNA virus clearance and neurotoxicity during viral encephalitis with a focus on the cytokines essential for immune and neural cell inflammatory responses and interactions. Understanding neuroimmune communications in the setting of viral infections is essential for the development of treatments that augment neuroprotective processes while limiting ongoing immunopathological processes that cause ongoing CNS disease.

Viruses have multiple paths to central nervous system pathology

PURPOSE OF REVIEW

Although viral infections of the central nervous system (CNS) are known to acutely cause pathology in the form of cytokine-mediated neural tissue damage and inflammation, the pathophysiology of neurologic sequelae after viral clearance is incompletely understood.

RECENT FINDINGS

Alterations in microglial and glial biology in response to initial infiltration of immune cells that persist within the CNS have recently been shown to promote neuronal dysfunction and cognitive deficits in animal models of viral encephalitis.

SUMMARY

The current review summarizes the current knowledge on the possible role of innate immune signaling during acute infections as triggers of neurologic sequelae that persist, and may even worsen, after clearance of viral infections within the CNS.

CSF1R antagonism limits local restimulation of antiviral CD8+ T cells during viral encephalitis

BACKGROUND

Microglia are resident macrophages of the central nervous system (CNS) locally maintained through colony-stimulating factor 1 receptor (CSF1R) signaling. Microglial depletion via CSF1R inactivation improves cognition in mouse models of neuroinflammation, but limits virologic control in the CNS of mouse models of neurotropic infections by unknown mechanisms. We hypothesize that CSF1R plays a critical role in myeloid cell responses that restrict viral replication and locally restimulate recruited antiviral T cells within the CNS.

METHODS

The impact of CSF1R signaling during West Nile virus infection was assessed in vivo using a mouse model of neurotropic infection. Pharmacological inactivation of CSF1R was achieved using PLX5622 prior to infection with virulent or attenuated strains of West Nile virus (WNV), an emerging neuropathogen. The subsequent effect of CSF1R antagonism on virologic control was assessed by measuring mortality and viral titers in the CNS and peripheral organs. Immune responses were assessed by flow cytometric-based phenotypic analyses of both peripheral and CNS immune cells.

RESULTS

Mice treated with CSF1R antagonist prior to infection exhibited higher susceptibility to lethal WNV infection and lack of virologic control in both the CNS and periphery. CSFR1 antagonism reduced B7 co-stimulatory signals on peripheral and CNS antigen-presenting cells (APCs) by depleting CNS cellular sources, which limited local reactivation of CNS-infiltrating virus-specific T cells and reduced viral clearance.

CONCLUSIONS

Our results demonstrate the impact of CSF1R antagonism on APC activation in the CNS and periphery and the importance of microglia in orchestrating the CNS immune response following neurotropic viral infection. These data will be an important consideration when assessing the benefit of CSF1R antagonism, which has been investigated as a therapeutic for neurodegenerative conditions, in which neuroinflammation is a contributing factor.

Approach to Children with Aggressive Behavior for General Pediatricians and Hospitalists: Part 1-Epidemiology and Etiology

Children and adolescents are increasingly presenting to the hospital and emergency department with aggressive behavior and psychiatric emergencies. The rise in pediatric mental health problems, coupled with a lack of much needed resources, necessitates that pediatricians safely diagnose and treat patients presenting with aggressive behavior. In this article, we discuss the broad differential diagnosis that should be considered when initially evaluating a patient presenting with aggression or altered mental status; underlying causes include predisposing factors, comorbid conditions, and acute organic causes involving almost every organ system. Emergency and hospital physicians should tailor their examination and testing individually based on the patient's history and presentation. [Pediatr Ann. 2018;47(10):e402-e407.].

Does intra-individual neurocognitive variability relate to neuroinvasive disease and quality of life in West Nile Virus?

West Nile Virus (WNV) can be a neuroinvasive pathogen that may produce persistent mild-to-moderate neurocognitive impairments in some infected persons. Intra-individual variability (IIV) is an index of a person's performance across a neuropsychological test or battery, which is an indicator of neurocognitive control and integrity of prefrontal systems. The present study examined possible associations of IIV to neurological health and well-being in WNV infection. Participants included 84 adults with a range of clinical WNV disease (31 West Nile Encephalitis, 16 West Nile Meningitis, 37 West Nile Fever) who completed the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). IIV was operationalized as covariance of variation (CoV), or the intra-individual standard deviation across 5 age-adjusted RBANS standard scores divided by the mean of standard scores. Participants were assessed for health-related quality of life (QoL) using the RAND 36-item short form health survey (SF-36). Analyses revealed that the West Nile Encephalitis group had higher neurocognitive CoV compared to the West Nile Fever group, and this difference was associated with a medium effect size (Cohen's d = .52). Mixed linear models controlling for estimated IQ, activities of daily living, depression, neuroinvasive disease groups, and fatigue showed that higher RBANS CoV was associated with lower physical, but not mental health QoL. In persons with WNV infection, there is a modest association between elevations in IIV and encephalitis, and even subtle disruptions in neuropsychological functioning show relationships with important self-reported functioning as measured by physical health quality of life. Future studies should examine whether IIV predicts long-term health outcomes (e.g., mortality) in individuals infected with WNV.

Recent advances in understanding West Nile virus host immunity and viral pathogenesis

West Nile virus (WNV), a mosquito-borne flavivirus, has been a significant public health concern in the United States for nearly two decades. The virus has been linked to acute viral encephalitis, neurological sequelae, and chronic kidney diseases. Neither antiviral drugs nor vaccines are currently available for humans. In vitro cell culture and experimental animal models have been used to study WNV infection in humans. In this review, we will focus on recent findings and provide new insights into WNV host immunity and viral pathogenesis.

Emerging Viral Infections in Sub-Saharan Africa and the Developing Nervous System: A Mini Review

The global public health concern is heightened over the increasing number of emerging viruses, i.e., newly discovered or previously known that have expanded into new geographical zones. These viruses challenge the health-care systems in sub-Saharan Africa (SSA) countries from which several of them have originated and been transmitted by insects worldwide. Some of these viruses are neuroinvasive, but have been relatively neglected by neuroscientists. They may provide experiments by nature to give a time window for exposure to a new virus within sizeable, previously non-infected human populations, which, for instance, enables studies on potential long-term or late-onset effects on the developing nervous system. Here, we briefly summarize studies on the developing brain by West Nile, Zika, and Chikungunya viruses, which are mosquito-borne and have spread worldwide out of SSA. They can all be neuroinvasive, but their effects vary from malformations caused by prenatal infections to cognitive disturbances following perinatal or later infections. We also highlight Ebola virus, which can leave surviving children with psychiatric disturbances and cause persistent infections in the non-human primate brain. Greater awareness within the neuroscience community is needed to emphasize the menace evoked by these emerging viruses to the developing brain. In particular, frontline neuroscience research should include neuropediatric follow-up studies in the field on long-term or late-onset cognitive and behavior disturbances or neuropsychiatric disorders. Studies on pathogenetic mechanisms for viral-induced perturbations of brain maturation should be extended to the vulnerable periods when neurocircuit formations are at peaks during infancy and early childhood.

Modulation of Lipid Droplet Metabolism-A Potential Target for Therapeutic Intervention in Flaviviridae Infections

Lipid droplets (LDs) are endoplasmic reticulum (ER)-related dynamic organelles that store and regulate fatty acids and neutral lipids. They play a central role in cellular energy storage, lipid metabolism and cellular homeostasis. It has become evident that viruses have co-evolved in order to exploit host lipid metabolic pathways. This is especially characteristic of the Flaviviridae family, including hepatitis C virus (HCV) and several flaviviruses. Devoid of an appropriate lipid biosynthetic machinery of their own, these single-strand positive-sense RNA viruses can induce dramatic changes in host metabolic pathways to establish a favorable environment for viral multiplication and acquire essential components to facilitate their assembly and traffic. Here we have reviewed the current knowledge on the intracellular life cycle of those from the Flaviviridae family, with particular emphasis on HCV and dengue virus (DENV), and their association with the biosynthesis and metabolism of LDs, with the aim to identify potential antiviral targets for development of novel therapeutic interventions.

Health-related quality of life in persons with West Nile virus infection: a longitudinal cohort study

Background

West Nile virus (WNV) infections are predominantly asymptomatic, although almost 1% become neuroinvasive and debilitating. We describe the impact of neuroinvasive and non-neuroinvasive disease on patient health-related quality of life (HRQoL).

Methods

Short Form 36 questionnaire data came from a Canadian WNV cohort (Loeb 2008) of 154 patients followed for up to three years. We generated health utilities using the SF-6D. We calculated mean utility scores throughout follow-up and examined predictors using a linear mixed-effects model. We summarized HRQoL post-acute infection as: (i) long-term utility (mean of scores one year onward); (ii) area under the curve (AUC) one year onward. We examined predictors using beta regression. We used multiple imputation for sensitivity analysis.

Results

Mean utility scores improved from 0.59 (95% CI: 0.38, 0.93) at baseline to 0.77 (0.53, 1) at six months, before plateauing for the remaining two years. Mean long-term utility was 0.81 (0.78, 0.85) and mean AUC was 0.80 (0.76, 0.84). Patients with neuroinvasive disease had consistently worse scores than their non-neuroinvasive counterparts, with the gap nearly closed after six months. After adjusting for confounding, neuroinvasive disease was not a significant predictor of HRQoL either throughout follow-up or post-acute infection. Rather, number of comorbidities and baseline utility scores were. Sensitivity analysis showed similar findings.

Conclusions

Patients with WNV infection reported low HRQoL during acute illness, but improved rapidly by six months, regardless of neuroinvasive disease status. This is the first study reporting health utilities for WNV infection.

Electronic supplementary material

The online version of this article (10.1186/s12955-017-0787-5) contains supplementary material, which is available to authorized users.