West Nile Virus infection triggering autoimmune encephalitis: Pathophysiological and therapeutic implications

Autoimmune Diseases Following Environmental Disasters: A Narrative Review of the Literature

Environmental disasters are extreme environmental processes such as earthquakes, volcanic eruptions, landslides, tsunamis, floods, cyclones, storms, wildfires and droughts that are the consequences of the climate crisis due to human intervention in the environment. Their effects on human health have alarmed the global scientific community. Among them, autoimmune diseases, a heterogeneous group of disorders, have increased dramatically in many parts of the world, likely as a result of changes in our exposure to environmental factors. However, only a limited number of studies have attempted to discover and analyze the complex association between environmental disasters and autoimmune diseases. This narrative review has therefore tried to fill this gap. First of all, the activation pathways of autoimmunity after environmental disasters have been analyzed. It has also been shown that wildfires, earthquakes, desert dust storms and volcanic eruptions may damage human health and induce autoimmune responses to inhaled PM2.5, mainly through oxidative stress pathways, increased pro-inflammatory cytokines and epithelial barrier damage. In addition, it has been shown that heat stress, in addition to increasing pro-inflammatory cytokines, may also disrupt the intestinal barrier, thereby increasing its permeability to toxins and pathogens or inducing epigenetic changes. In addition, toxic volcanic elements may accelerate the progressive destruction of myelin, which may potentially trigger multiple sclerosis. The complex and diverse mechanisms by which vector-borne, water-, food-, and rodent-borne diseases that often follow environmental diseases may also trigger autoimmune responses have also been described. In addition, the association between post-disaster stress and the onset or worsening of autoimmune disease has been demonstrated. Given all of the above, the rapid restoration of post-disaster health services to mitigate the flare-up of autoimmune conditions is critical.

Unique Magnetic Resonance Imaging Findings in Opsoclonus-Myoclonus Syndrome Secondary to the West Nile Virus

Opsoclonus-Myoclonus syndrome is a rare neurological disorder that presents with oculomotor dysfunction and is associated with immunological triggers such as an infection. We present a patient with Opsoclonus-Myoclonus syndrome secondary to a West Nile virus (WNV) infection and focus on a unique series of magnetic resonance imaging findings. The following is a case report based on experience taking care of the patient as a member of the primary team in the hospital, chart review, and imaging findings obtained and reported through the department of radiology. A 61-year-old male presented with fatigue, ataxia, dysarthria, and fever after a recent cabin visit in the summer. The initial workup ruled out meningitis and stroke. The patient's condition deteriorated despite empiric treatment. Repeat magnetic resonance imaging (MRI) revealed patchy fluid-attenuated inversion recovery (FLAIR) hyperintensities in the cerebellar hemispheres. Further evaluation confirmed West Nile virus infection through positive immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies. This case underscores the importance of neuroimaging in evaluating encephalopathy, especially in the presence of multiple comorbidities. These findings contribute to the broader knowledge of West Nile virus encephalitis.

Do we protect ourselves against West Nile Virus? A systematic review on knowledge, attitudes, and practices and their determinants

BACKGROUND

West Nile virus (WNV) is a mosquito-borne flavivirus. In humans, 80% of infections are asymptomatic, while approximately 20% experience influenza-like symptoms. Fewer than 1% develop the neuroinvasive form which can lead to encephalitis, meningitis, acute flaccid paralysis, and even death. The global spread of the virus to areas where it was not previously present has become a growing concern. Since the 2000 s, there have been numerous outbreaks affecting local and travelling populations worldwide. Given the lack of a vaccine, preventative measures are primarily focused on surveillance, vector control, and the use of personal protective behaviours (PPBs). The importance of PPBs is central to public health recommendations. However, translating these messages into coherent action by the public can prove challenging, as the uptake of such measures is inevitably influenced by socio-economic factors, awareness, knowledge, and risk perception.

METHODS

A PRISMA-based systematic research was conducted on EMBASE, PubMed/MEDLINE, and Web of Science databases. PROSPERO registration number CRD42023459714. Quality of studies included in the final stage was evaluated using the Critical Appraisal Checklist for Cross-Sectional Study (CEBMa).

RESULTS

2963 articles were screened, and 17 studies were included in the final round. Out of these, six were deemed of high quality, ten were of medium quality, and one was of low quality. In almost all studies considered, both awareness and knowledge of WNV transmission were above 90%, while concern about WNV ranged from 50% to 80%. Concern about the safety of repellents, either with or without DEET, ranged from 27% to 70%. The percentage of people actually using repellents ranged from 30% to 75%, with the lowest usage reported among individuals over 60 years old (29%) and pregnant women (33%), and the highest among students aged 9-11 (75%). Concern for West Nile Virus (WNV) was consistently linked to an increase in taking preventative measures, including the use of repellents, by two to four times across studies. The school-based intervention was effective in increasing the practice of removing standing water (AOR=4.6; 2.7-8.0) and wearing long clothing (AOR=2.4; 95%CI: 1.3-4.3), but did not have a significant impact on the use of repellents.

CONCLUSIONS

The present systematic review provides an overview of the knowledge, attitudes, and practices (KAP) of WNV and their determinants. While concern about West Nile Virus (WNV) and its effects can be a significant motivator, it is important to promote evidence-based personal protective behaviours (PPBs) to counter unwarranted fears. For example, the use of repellents among the most vulnerable age groups. Given the geographical expansion of WNV, it is necessary to target the entire population preventively, including those who are difficult to reach and areas not yet endemic. The findings of this investigation could have significant implications for public health and support well-informed and effective communication strategies and interventions.

Re-examination of the risk of autoimmune diseases after dengue virus infection: A population-based cohort study

Previous studies suggested that dengue was associated with an increased risk of several autoimmune diseases. However, this association still needs to be explored due to the limitations of these studies. A population-based cohort study was conducted using national health databases in Taiwan and included 63,814 newly diagnosed, laboratory-confirmed dengue patients between 2002 and 2015 and 1:4 controls (n = 255,256) matched by age, sex, area of residence and symptom onset time. Multivariate Cox proportional hazard regression models were used to investigate the risk of autoimmune diseases after dengue infection. Dengue patients had a slightly higher risk of overall autoimmune diseases than non-dengue controls (aHR 1.16; P = 0.0002). Stratified analyses by specific autoimmune diseases showed that only autoimmune encephalomyelitis remained statistically significant after Bonferroni correction for multiple testing (aHR 2.72; P < 0.0001). Sixteen (0.025%) dengue patients and no (0%) controls developed autoimmune encephalomyelitis in the first month of follow-up (HR >9999, P < 0.0001), but the risk between groups was not significantly different thereafter. Contrary to previous studies, our findings showed that dengue was associated with an increased short-term risk of a rare complication, autoimmune encephalomyelitis, but not associated with other autoimmune diseases.

An HIV patient with West Nile encephalitis and Amphiphysin antibodies - More on "West Nile infection triggering autoimmune encephalitis: Pathophysiological and therapeutic implications" by Moutsopoulos et al

We have encountered a patient with HIV who developed rapid worsening altered mental status positive for both acute West Nile encephalitis and amphiphysin antibodies. Upon literature review, we read Dr. Moutsopoulos's paper from your journal with great interest (Karagianni et al., 2019 [1]). While an autoimmune encephalitis following West Nile encephalitis is not novel, there are several interesting features in a patient we have encountered. Firstly, amphiphysin antibodies coexisting with West Nile encephalitis has not been described before. Second, the fact that the clinical course is monophasic, not biphasic, may lead to the suggestion that autoimmune encephalitis triggered by, or coexisting with, West Nile encephalitis may be grossly underrecognized. Third, our patient was HIV positive, but not grossly immunocompromised, which may have played a factor in the autoimmune status.

Case report: Varicella-zoster virus infection triggering progressive encephalomyelitis with rigidity and myoclonus

Progressive encephalomyelitis with rigidity and myoclonus (PERM) is a rare neurological disease of unknown etiology, and most patients with PERM are positive for anti-glycine receptor (GlyR) antibody. In this case study, we report a clinical case of a varicella-zoster virus-infected patient who developed anti-GlyR antibody-positive PERM. He initially suffered from herpes zoster and gradually developed symptoms of impaired brainstem functions including hoarse voice and dysphagia, accompanied by paroxysmal sympathetic hyperactivity. The patient also suffered from severe spasms, which were easily triggered by external stimuli. Glycine receptor antibodies were then found to be positive in serum and cerebrospinal fluid, and the diagnosis of PERM was confirmed. Methylprednisolone and gamma globulin treatments were given, and spasms were improved after treatment. Unfortunately, the patient's family insisted on automatic discharge and the patient passed away several days later.

Nervous System Manifestations of Arboviral Infections

Purpose of Review

Complex environmental factors and human intervention influence the spread of arthropod vectors and the cycle of transmission of arboviruses. The spectrum of clinical manifestations is diverse, ranging from serious presentations like viral hemorrhagic fever (e.g., dengue, yellow fever, rift valley fever) or shock syndromes (e.g., dengue virus) to organ-specific illness like meningoencephalitis.

Recent Findings

A spectrum of clinical neurologic syndromes with potential acute devastating consequences or long-term sequelae may result from some arboviral infections.

Summary

In this review, we describe some of the most frequent and emerging neuro-invasive arboviral infections, spectrum of neurologic disorders including encephalitis, meningitis, myelitis or poliomyelitis, acute demyelinating encephalomyelitis, Guillain-Barré syndrome, and ocular syndromes.

West Nile virus: another emerging arboviral risk for travelers?

Purpose of Review

West Nile virus (WNV) is an arbovirus transmitted by mosquitos of the genus Culex. Manifestations of WNV infection range from asymptomatic to devastating neuroinvasive disease leading to flaccid paralysis and death. This review examines WNV epidemiology and ecology, with an emphasis on travel-associated infection.

Recent Findings

WNV is widespread, including North America and Europe, where its range has expanded in the past decade. Rising temperatures in temperate regions are predicted to lead to an increased abundance of Culex mosquitoes and an increase in their ability to transmit WNV. Although the epidemiologic patterns of WNV appear variable, its geographic distribution most certainly will continue to increase. Travelers are at risk for WNV infection and its complications. Literature review identified 39 cases of documented travel-related WNV disease, the majority of which resulted in adverse outcomes, such as neuroinvasive disease, prolonged recovery period, or death.

Summary

The prediction of WNV risk is challenging due to the complex interactions of vector, pathogen, host, and environment. Travelers planning to visit endemic areas should be advised regarding WNV risk and mosquito bite prevention. Evaluation of ill travelers with compatible symptoms should consider the diagnosis of WNV for those visiting in endemic areas as well as for those returning from destinations with known WNV circulation.

Autoimmune rheumatic diseases: One or many diseases?

Until the etiopathogenic factor(s) of autoimmune and autoinflammatory rheumatic disorders will be identified, their classification into entities will continue. However, their similar clinical manifestations, overlapping syndromes, evolution from one entity into another, as well as common autoantibody responses, suggest that autoimmune and autoinflammatory disorders may constitute distinct pathophysiologic processes on the basis of a different genetic background. Prognosis and effective therapeutic regimens are mostly based on the clinico-pathologic severity of the involved tissues or organs and not on the disease label.

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Autoimmune rheumatic diseases (ARDs) can evolve from one into another disease.

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Different ARDs can appear in the same individual.

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Common humoral auto-reactivities appear in different ARDs.

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Therapy is based on the severity of ARDs expression.

Acute neurologic emerging flaviviruses

The COVID-19 pandemic has shed light on the challenges we face as a global society in preventing and containing emerging and re-emerging pathogens. Multiple intersecting factors, including environmental changes, host immunological factors, and pathogen dynamics, are intimately connected to the emergence and re-emergence of communicable diseases. There is a large and expanding list of communicable diseases that can cause neurological damage, either through direct or indirect routes. Novel pathogens of neurotropic potential have been identified through advanced diagnostic techniques, including metagenomic next-generation sequencing, but there are also known pathogens which have expanded their geographic distribution to infect non-immune individuals. Factors including population growth, climate change, the increase in animal and human interface, and an increase in international travel and trade are contributing to the expansion of emerging and re-emerging pathogens. Challenges exist around antimicrobial misuse giving rise to antimicrobial-resistant infectious neurotropic organisms and increased susceptibility to infection related to the expanded use of immunomodulatory treatments. In this article, we will review key concepts around emerging and re-emerging pathogens and discuss factors associated with neurotropism and neuroinvasion. We highlight several neurotropic pathogens of interest, including West Nile virus (WNV), Zika Virus, Japanese Encephalitis Virus (JEV), and Tick-Borne Encephalitis Virus (TBEV). We emphasize neuroinfectious diseases which impact the central nervous system (CNS) and focus on flaviviruses, a group of vector-borne pathogens that have expanded globally in recent years and have proven capable of widespread outbreak.

The Causes and Long-Term Consequences of Viral Encephalitis

Reports regarding brain inflammation, known as encephalitis, have shown an increasing frequency during the past years. Encephalitis is a relevant concern to public health due to its high morbidity and mortality. Infectious or autoimmune diseases are the most common cause of encephalitis. The clinical symptoms of this pathology can vary depending on the brain zone affected, with mild ones such as fever, headache, confusion, and stiff neck, or severe ones, such as seizures, weakness, hallucinations, and coma, among others. Encephalitis can affect individuals of all ages, but it is frequently observed in pediatric and elderly populations, and the most common causes are viral infections. Several viral agents have been described to induce encephalitis, such as arboviruses, rhabdoviruses, enteroviruses, herpesviruses, retroviruses, orthomyxoviruses, orthopneumovirus, and coronaviruses, among others. Once a neurotropic virus reaches the brain parenchyma, the resident cells such as neurons, astrocytes, and microglia, can be infected, promoting the secretion of pro-inflammatory molecules and the subsequent immune cell infiltration that leads to brain damage. After resolving the viral infection, the local immune response can remain active, contributing to long-term neuropsychiatric disorders, neurocognitive impairment, and degenerative diseases. In this article, we will discuss how viruses can reach the brain, the impact of viral encephalitis on brain function, and we will focus especially on the neurocognitive sequelae reported even after viral clearance.

Invited Review: The spectrum of neuropathology in COVID-19

There is increasing evidence that patients with Coronavirus disease 19 (COVID-19) present with neurological and psychiatric symptoms. Anosmia, hypogeusia, headache, nausea and altered consciousness are commonly described, although there are emerging clinical reports of more serious and specific conditions such as acute cerebrovascular accident, encephalitis and demyelinating disease. Whether these presentations are directly due to viral invasion of the central nervous system (CNS) or caused by indirect mechanisms has yet to be established. Neuropathological examination of brain tissue at autopsy will be essential to establish the neuro-invasive potential of the SARS-CoV-2 virus but, to date, there have been few detailed studies. The pathological changes in the brain probably represent a combination of direct cytopathic effects mediated by SARS-CoV-2 replication or indirect effects due to respiratory failure, injurious cytokine reaction, reduced immune response and cerebrovascular accidents induced by viral infection. Further large-scale molecular and cellular investigations are warranted to clarify the neuropathological correlates of the neurological and psychiatric features seen clinically in COVID-19. In this review, we summarize the current reports of neuropathological examination in COVID-19 patients, in addition to our own experience, and discuss their contribution to the understanding of CNS involvement in this disease.

Search for Viral Infections in Cerebrospinal Fluid From Patients With Autoimmune Encephalitis

Background

It has been reported that virus-mediated brain tissue damage can lead to autoimmune encephalitis (AE) characterized by the presence of antibodies against neuronal surface antigens. In the study, we investigate the presence of viruses in cerebrospinal fluid (CSF) from patients with AE using reverse transcription polymerase chain reaction (RT-PCR)/PCR and shotgun metagenomics.

Methods

CSF samples collected from 200 patients with encephalitis were tested for the presence of antibodies against antiglutamate receptor (NMDAR), contactin-associated protein 2 (CASPR2), glutamate receptors (type AMPA1/2), leucine-rich glioma-inactivated protein 1 (LGI1), dipeptidyl aminopeptidase-like protein 6 (DPPX), and GABA B receptor, and those found positive were further analyzed with real-time RT-PCR/PCR for common viral neuroinfections and shotgun DNA- and RNA-based metagenomics.

Results

Autoantibodies against neuronal cells were detected in CSF from 8 individuals (4% of all encephalitis patients): 7 (3.5%) had anti-NMDAR and 1 (0.5%) had anti-GABA B. RT-PCR/PCR identified human herpes virus type 1 (HSV-1; 300 copies/mL) and the representative of Enterovirus genus (550 copies/mL) in 1 patient each. Torque teno virus (TTV) was found in another patient using metagenomic analysis, and its presence was confirmed by specific PCR.

Conclusions

We detected the presence of HSV, TTV, and Enterovirus genus in CSF samples from 3 out of 8 AE patients. These findings support the concept of viral involvement in the pathogenesis of this disease.

Post-infectious neurological disorders

A multitude of environmental factors can result in breakdown of immune tolerance in susceptible hosts. Infectious pathogens are among the most important environmental triggers in the pathogenesis of autoimmunity. Certain autoimmune disorders have a strong association with specific infections. Several neurological autoimmune disorders are thought to occur through post-infectious mechanisms. In this review, we discuss the proposed mechanisms underlying pathogen-induced autoimmunity, and highlight the clinical presentation and treatment of several post-infectious autoimmune neurological disorders. We also highlight post-infectious neurological disorders in the setting of recent outbreaks.

Does SARS-CoV-2 Trigger Stress-InducedAutoimmunity by Molecular Mimicry? A Hypothesis

Viruses can generate molecular mimicry phenomena within their hosts. Why should severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) not be considered one of these? Information in this short review suggests that it might be so and, thus, encourages research aiming at testing this possibility. We propose, as a working hypothesis, that the virus induces antibodies and that some of them crossreact with host’s antigens, thus eliciting autoimmune phenomena with devasting consequences in various tissues and organs. If confirmed, by in vitro and in vivo tests, this could drive researchers to find effective treatments against the virus.

Involvement of the Nervous System in SARS-CoV-2 Infection

As a severe and highly contagious infectious disease, coronavirus disease 2019 (COVID-19) has caused a global pandemic. Several case reports have demonstrated that the respiratory system is the main target in patients with COVID-19, but the disease is not limited to the respiratory system. Case analysis indicated that the nervous system can be invaded by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and that 36.4% of COVID-19 patients had neurological symptoms. Importantly, the involvement of the CNS may be associated with poor prognosis and disease worsening. Here, we discussed the symptoms and evidence of nervous system involvement (directly and indirectly) caused by SARS-CoV-2 infection and possible mechanisms. CNS symptoms could be a potential indicator of poor prognosis; therefore, the prevention and treatment of CNS symptoms are also crucial for the recovery of COVID-19 patients.

Current Understanding of West Nile Virus Clinical Manifestations, Immune Responses, Neuroinvasion, and Immunotherapeutic Implications

West Nile virus (WNV) is the most common mosquito-borne virus in North America. WNV-associated neuroinvasive disease affects all ages, although elderly and immunocompromised individuals are particularly at risk. WNV neuroinvasive disease has killed over 2300 Americans since WNV entered into the United States in the New York City outbreak of 1999. Despite 20 years of intensive laboratory and clinical research, there are still no approved vaccines or antivirals available for human use. However, rapid progress has been made in both understanding the pathogenesis of WNV and treatment in clinical practices. This review summarizes our current understanding of WNV infection in terms of human clinical manifestations, host immune responses, neuroinvasion, and therapeutic interventions.