Determinants of neurological syndromes caused by varicella zoster virus (VZV)

A holistic exploration of the optimal control strategies on an enhanced mathematical model for the co-infection of HIV/AIDS and varicella-zoster

Because of its high contagiousness and correlation with HIV/AIDS complaints, the virus that causes varicella-zoster virus and its interactions have major consequences for a considerable portion of people worldwide. The primary aim of this work is to suggest and examine optimal control methods for managing the transmission dynamics of HIV/AIDS and Varicella-Zoster co-infection, using an integer model approach. The mathematical analyses of the proposed integer order model places particular emphases on the boundedness and non-negativity of the model solutions, scrutinizing equilibrium points, determining the models basic reproduction ratios (the models basic reproduction numbers) through the next-generation matrix operator method, and assessing the model equilibrium points existences and stabilities in local approach by considering the local stability conditions of Routh and Hurwitz. Additionally, it incorporates an optimal control framework to enhance our understanding of the dynamics involved in the spreading of HIV/AIDS and Varicella-Zoster co-infection within a considered population. This entails determining preventative measures that can be deliberately put into place to lessen the effects of these co-infections. The solutions of the HIV/AIDS and Varicella-Zoster co-infection model converges to the co-infection endemic equilibrium point whenever the associated basic reproduction number is greater than unity, as verified by numerical simulation results. Including optimal management gives the research an innovative viewpoint and helps identify tactical ways to mitigate the negative effects of this co-infection on the public health. The results highlight how crucial it is to address these complex structures in order to protect and improve public health outcomes. Implementing the proposed protection measures and treatment measures simultaneously has most effective result to minimize and eliminate the HIV/AIDS and Varicella-Zoster co-infection disease throughout the population.

Varicella zoster virus-induced autophagy in human neuronal and hematopoietic cells exerts antiviral activity

Autophagy is a degradational pathway with pivotal roles in cellular homeostasis and survival, including protection of neurons in the central nervous system (CNS). The significance of autophagy as antiviral defense mechanism is recognized and some viruses hijack and modulate this process to their advantage in certain cell types. Here, we present data demonstrating that the human neurotropic herpesvirus varicella zoster virus (VZV) induces autophagy in human SH-SY5Y neuronal cells, in which the pathway exerts antiviral activity. Productively VZV-infected SH-SY5Y cells showed increased LC3-I-LC3-II conversion as well as co-localization of the viral glycoprotein E and the autophagy receptor p62. The activation of autophagy was dependent on a functional viral genome. Interestingly, inducers of autophagy reduced viral transcription, whereas inhibition of autophagy increased viral transcript expression. Finally, the genotype of patients with severe ocular and brain VZV infection were analyzed to identify potential autophagy-associated inborn errors of immunity. Two patients expressing genetic variants in the autophagy genes ULK1 and MAP1LC3B2, respectively, were identified. Notably, cells of both patients showed reduced autophagy, alongside enhanced viral replication and death of VZV-infected cells. In conclusion, these results demonstrate a neuro-protective role for autophagy in the context of VZV infection and suggest that failure to mount an autophagy response is a potential predisposing factor for development of severe VZV disease.

Acyclovir treatment of varicella-zoster virus meningeal infections and acute kidney injury: a multicentre case series study

BACKGROUND

Systematic treatment with intravenous acyclovir is usually given when varicella zoster virus (VZV) DNA is isolated in cerebrospinal fluid (CSF), indicating central nervous system (CNS) involvement. Our study aimed to describe therapeutic management and acute kidney injury (AKI) occurrence during acyclovir treatment of VZV infection with CNS involvement.

METHODS

Multicentre, retrospective study including all patients from 2010 to 2022 with VZV DNA in CSF. Patient management and outcomes were compared according to clinical presentation and indications for intravenous acyclovir: i) definite (encephalitis, myelitis or stroke, peripheral nervous system (PNS) with ≥ 2 roots, herpes zoster ≥ 3 dermatomes, immunosuppression), ii) questionable (1 or 2 dermatomes) or iii) no indication (other situations).

RESULTS

154 patients were included (median age 66 (interquartile range 43-77), 87 (56%) males); 60 (39%) had encephalitis, myelitis or stroke, 35 (23%) had PNS involvement, 37 (24%) had isolated meningitis, 14 (9%) had isolated cutaneous presentation, and 8 (5%) had other presentations. Overall, 128 (83%) received intravenous acyclovir for more than 72 h. AKI occurred in 57 (37%) patients. Finally, 42 (27%) and 25 (16%) patients had respectively no or a questionable indication for intravenous acyclovir, while 29 (69%) and 23 (92%) of them received it for more than 72 h, with AKI in 13 (35%) and 13 (52%) patients, respectively. In-hospital mortality was 12% (n = 18), and no deaths were reported in isolated meningitis.

CONCLUSIONS

Intravenous acyclovir is widely prescribed when VZV DNA is isolated in CSF, regardless of the clinical presentation, with a high rate of AKI. Further studies are needed to better define the value of intravenous acyclovir in isolated VZV meningitis.

Hospitalizations of patients with herpes zoster in Poland during 2012-2021: A population-based study

INTRODUCTION

The varicella-zoster virus (VZV) is an infectious agent that causes both chickenpox and herpes zoster/shingles (HZ). This infection can take various clinical forms, result in permanent complications, and be a marker of immunosuppression, e.g. in the course of a neoplastic disease. The aim of this study is to analyze epidemiological trends in hospitalization and hospital mortality rate among HZ patients in Poland (2012-2021).

METHODS

Our study is a population-based, retrospective analysis of hospital discharge records of patients with HZ. Data were obtained from the National Institute of Public Health in Poland, and they covered the period from 2012 to 2021. All hospitalization records with primary or secondary ICD-10 B02 code diagnosis were included in the study.

RESULTS

We analyzed the total number of 23,432 hospital discharge records of HZ patients in 2012-2021. The study group consisted of 22,169 (94.6 %) hospitalization records of first-time diagnosis of HZ in hospitalized patients: 9,309 males (42 %) and 12,860 females (58 %). In this group, 70.3 % were patients over 60 years old. The mean and median age was 64 and 69 years, respectively. The mean annual first-time hospitalization rate for HZ was estimated to be 5.8 per 100,000 person-years (95 % CI: 4.8-6.7 per 100,000 person-years). The hospitalization rate for HZ was similar during 2012-2019. There was a significant decrease in hospitalizations in 2020-2021 in comparison with the previous years (R2 = 0.42, p < 0.05). Women showed a higher hospitalization rate than men (p < 0.001). Urban residents had a higher hospitalization rate than rural residents (p < 0.001). In the analyzed period, 246 deaths were recorded (1.1 % of all hospitalized HZ patients) -119 males and 127 females.

CONCLUSIONS

The HZ-related number of hospitalizations and mortality in Poland are relatively low, but HZ is still a significant health problem. Risk factors include female gender, older age and residence in urban areas.

Whole exome sequencing of patients with varicella-zoster virus and herpes simplex virus induced acute retinal necrosis reveals rare disease-associated genetic variants

Purpose

Herpes simplex virus (HSV) and varicella-zoster virus (VZV) are neurotropic human alphaherpesviruses endemic worldwide. Upon primary infection, both viruses establish lifelong latency in neurons and reactivate intermittently to cause a variety of mild to severe diseases. Acute retinal necrosis (ARN) is a rare, sight-threatening eye disease induced by ocular VZV or HSV infection. The virus and host factors involved in ARN pathogenesis remain incompletely described. We hypothesize an underlying genetic defect in at least part of ARN cases.

Methods

We collected blood from 17 patients with HSV-or VZV-induced ARN, isolated DNA and performed Whole Exome Sequencing by Illumina followed by analysis in Varseq with criteria of CADD score > 15 and frequency in GnomAD < 0.1% combined with biological filters. Gene modifications relative to healthy control genomes were filtered according to high quality and read-depth, low frequency, high deleteriousness predictions and biological relevance.

Results

We identified a total of 50 potentially disease-causing genetic variants, including missense, frameshift and splice site variants and on in-frame deletion in 16 of the 17 patients. The vast majority of these genes are involved in innate immunity, followed by adaptive immunity, autophagy, and apoptosis; in several instances variants within a given gene or pathway was identified in several patients.

Discussion

We propose that the identified variants may contribute to insufficient viral control and increased necrosis ocular disease presentation in the patients and serve as a knowledge base and starting point for the development of improved diagnostic, prophylactic, and therapeutic applications.

Clinical features of varicella-zoster virus caused neurological diseases detected by metagenomic next-generation sequencing

Clinical presentation of central nervous system (CNS) infections caused by varicella-zoster virus (VZV) is highly sophisticated, making identification challenging. We retrospectively reported 18 cases of VZV neurologic disease confirmed by metagenomic next-generation sequencing (mNGS). The detection rate of mNGS was higher than that of PCR assay (100 vs 66.7%, p < 0.05) and serum IgM antibody (100 vs 68.8%, p < 0.05) measurement. Of the 18 cases, five patients were diagnosed with acute meningitis, three with acute meningitis combined with facial neuritis, three with acute meningitis combined with polycranial neuritis, and the remaining seven with various clinical diagnoses. Typical clinical symptoms included headache (15), fever (9), and rash (11). Cranial or spinal MRI showed abnormalities in 12 patients, and 17 patients had obvious neurological symptoms. The predominant genotype of VZV in this study was genotype J (100%, 10/10). All patients were treated with acyclovir/penciclovir and dexamethasone, 16 recovered and 2 died. Our study highlights the good performance of mNGS in diagnosing CNS infection caused by VZV. It could provide additional diagnostic evidence in patients with diverse clinical spectrum and variable manifestations.

Herpesvirus-Associated Encephalitis: an Update

Purpose of Review

Recent Findings

Summary

A Possible Case of Varicella Zoster Virus (VZV) Meningoencephalitis in an Immunocompetent Host

The herpes zoster infection occurs in the United States, particularly targeting those who are immunocompromised, and can present with many manifestations including encephalitis. Instances of varicella zoster virus (VZV) encephalitis in immunocompetent patients have been rarely reported, but such diagnoses are becoming more frequent as detection of VZV has improved with the adoption of molecular diagnostic panels such as the BioFire Film Array meningitis panel (Salt Lake City, USA). Here, we present an interesting case of acute meningoencephalitis in an immunocompetent adult female without dermatomal neuralgia or cutaneous lesions attributable to VZV. Given many inconsistencies between the patient’s presentation and the positive polymerase chain reaction (PCR) result for VZV, we suspected our patient was infected with an undetected organism while possibly simultaneously shedding previously acquired VZV. As molecular diagnostic panels are increasingly used and have greatly improved detection of rarer etiologies of disease, we encourage clinicians to interpret results with caution.

Atypical anti-NMDA receptor encephalitis associated with varicella zoster virus infection

The triggering effect of herpes simplex virus infection on the development of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is now well established. However, there are very few reports that has linked a varicella zoster virus (VZV) reactivation with anti-NMDAR encephalitis. In this report, we describe a case of a 57-year-old man presented with atypical clinical presentation of anti-NMDAR encephalitis with gait ataxia, complete ophtalmoplegia, and abolished reflexes followed by drowsiness and confusion. Initial diagnosis of Bickerstaff's brainstem encephalitis was suspected. Few days later, the patient developed herpes zoster in a localized right T1-T2 dermatome. Cerebrospinal fluid (CSF) polymerase chain reaction (PCR) for VZV was negative. CSF anti-NMDA antibodies were proved positive. A diagnosis of anti-NMDAR encephalitis with concomitant VZV skin reactivation was retained. Favorable outcome with combined antiviral treatment and immunomodulatory therapy was observed. Concomitant VZV reactivation with autoimmune encephalitis is possible. Prognosis and therapeutic options in this rare condition remain to be clarified.

Bilateral Ptosis, Zosteriform Rash and Flaccid Bladder in a 10-Year-old boy

We present a case report of a 10-year-old completely immunized boy presenting with a 2-week history of bilateral eyelid drooping, fatigue followed by bladder and bowel paralysis. This was followed by the appearance of a vesicular painful and itchy rash which directed further diagnosis and treatment as it was consistent with a varicella reactivation rash. This case is a very important addition to the current body of literature on varicella-related neurological complications. It outlines that varicella reactivation can present in completely vaccinated, immunocompetent young children as a neurological syndrome affecting the autonomic nervous system primarily and the rash can occur a few weeks later after presentation of the neurological symptoms.

Viral Proteins with PxxP and PY Motifs May Play a Role in Multiple Sclerosis

Multiple sclerosis (MS) is a debilitating disease that arises from immune system attacks to the protective myelin sheath that covers nerve fibers and ensures optimal communication between brain and body. Although the cause of MS is unknown, a number of factors, which include viruses, have been identified as increasing the risk of displaying MS symptoms. Specifically, the ubiquitous and highly prevalent Epstein–Barr virus, human herpesvirus 6, cytomegalovirus, varicella–zoster virus, and other viruses have been identified as potential triggering agents. In this review, we examine the specific role of proline-rich proteins encoded by these viruses and their potential role in MS at a molecular level.

Varicella Zoster Virus Neuronal Latency and Reactivation Modeled in Vitro

Latency and reactivation in neurons are critical aspects of VZV pathogenesis that have historically been difficult to investigate. Viral genomes are retained in many human ganglia after the primary infection, varicella; and about one-third of the naturally infected VZV seropositive population reactivates latent virus, which most often clinically manifests as herpes zoster (HZ or Shingles). HZ is frequently complicated by acute and chronic debilitating pain for which there remains a need for more effective treatment options. Understanding of the latent state is likely to be essential in the design of strategies to reduce reactivation. Experimentally addressing VZV latency has been difficult because of the strict human species specificity of VZV and the fact that until recently, experimental reactivation had not been achieved. We do not yet know the neuron subtypes that harbor latent genomes, whether all can potentially reactivate, what the drivers of VZV reactivation are, and how immunity interplays with the latent state to control reactivation. However, recent advances have enabled a picture of VZV latency to start to emerge. The first is the ability to detect the latent viral genome and its expression in human ganglionic tissues with extraordinary sensitivity. The second, the subject of this chapter, is the development of in vitro human neuron systems permitting the modeling of latent states that can be experimentally reactivated. This review will summarize recent advances of in vitro models of neuronal VZV latency and reactivation, the limitations of the current systems, and discuss outstanding questions and future directions regarding these processes using these and yet to be developed models. Results obtained from the in vitro models to date will also be discussed in light of the recent data gleaned from studies of VZV latency and gene expression learned from human cadaver ganglia, especially the discovery of VZV latency transcripts that seem to parallel the long-studied latency-associated transcripts of other neurotropic alphaherpesviruses.

Nanoparticles and nanoformulated drugs as promising delivery system in treatment of microbial-induced CNS infection: a systematic review of literature

Central nervous system (CNS) infection is a global health problem with high rate of mortality and associated morbidities. Viruses, bacteria, fungi, and protozoa parasites are the main cause of CNS infection. Various medications are currently used for treatment of brain infections, but most of them do not have enough efficiency because the majority of conventional drugs cannot pass the blood-brain barrier (BBB) to combat the pathogens. Nanotechnology has provided promising approaches to solve this issue, since nanoparticles (NPs) can facilitate the drugs entrance through the BBB. Herein, we systematically reviewed all available literature to provide evidences for practicality of NPs in treatment of CNS infection. A systematic literature search was performed on January 29, 2021, in Web of Science, PubMed, Scopus, Science Direct, Embase, Ovid, and Google Scholar using "CNS infections" and "NPs/nanoformulation" including all their equivalent terms as keyword. Due to lack of human studies, no strict inclusion criteria were defined, and all relevant documents were included. After several steps of article selection, a total of 29 documents were collected and used for data synthesis. The results showed that drug-loaded NPs is fairly safe and can be a promising approach in developing anti-infective agents for treatment of CNS infection, since nanoformulated drugs could act up to tenfold more efficient that drug alone. Findings of this review indicate the importance of NPs and nanoformulation of drugs to enhance the efficiency of treatment and warrant the safety of treatment in human studies; however, clinical trials are required to confirm such efficiency and safety in clinical practice.

The Role of Autophagy in Varicella Zoster Virus Infection

Autophagy is an evolutionary conserved cellular process serving to degrade cytosolic organelles or foreign material to maintain cellular homeostasis. Autophagy has also emerged as an important process involved in complex interactions with viral pathogens during infection. It has become apparent that autophagy may have either proviral or antiviral roles, depending on the cellular context and the specific virus. While evidence supports an antiviral role of autophagy during certain herpesvirus infections, numerous examples illustrate how herpesviruses may also evade autophagy pathways or even utilize this process to their own advantage. Here, we review the literature on varicella zoster virus (VZV) and autophagy and describe the mechanisms by which VZV may stimulate autophagy pathways and utilize these to promote cell survival or to support viral egress from cells. We also discuss recent evidence supporting an overall antiviral role of autophagy, particularly in relation to viral infection in neurons. Collectively, these studies suggest complex and sometimes opposing effects of autophagy in the context of VZV infection. Much remains to be understood concerning these virus–host interactions and the impact of autophagy on infections caused by VZV.

Genetic variants and immune responses in a cohort of patients with varicella zoster virus encephalitis

BACKGROUND

Infection with varicella zoster virus (VZV) may involve different central nervous system (CNS) manifestations, including meningitis, encephalitis, and vasculitis. In cases where otherwise healthy individuals are affected, an inborn error of immunity may underlie increased susceptibility or severity of infection.

METHODS

We collected a cohort of 17 adults who experienced VZV encephalitis and performed whole exome sequencing. Patient PBMCs were infected with VZV and innate antiviral interferon and cytokine responses as well as viral replication was evaluated. Data were analyzed by Mann Whitney U test.

RESULTS

We identified a total of 21 different potentially disease-causing variants in a total of 13 of the 17 patients included. These gene variants were within two major functional clusters: i) innate viral sensors and immune pathways and ii) autophagy pathways. Antiviral interferon (IFN) and cytokine responses were abnormal in the majority of patients, whereas viral replication was increased in only 2/17.

CONCLUSION

This study identifies a list of variants of pathogenic potential, which may serve as a platform for generating hypotheses for future studies addressing genetic and immunological factors associated with susceptibility to VZV encephalitis. Collectively, these data suggest that disturbances in innate sensing and autophagy pathways may predispose to VZV encephalitis.

Varicella-Zoster Virus Infection of Neurons Derived from Neural Stem Cells

Varicella-Zoster virus (VZV) is a human herpesvirus that causes varicella (chickenpox) as a primary infection, and, following a variable period of ganglionic latency in neurons, it reactivates to cause herpes zoster (shingles). An analysis of VZV infection in cultures of neural cells, in particular when these have been obtained from induced pluripotent stem cells (iPSCs) or neural stem cells consisting of highly purified neuronal cultures, has revealed much data that may be of neurobiological significance. Early studies of VZV infection of mature cultured neural cells were mainly descriptive, but more recent studies in homogeneous neural stem cell cultures have used both neuronal cell markers and advanced molecular technology. Two general findings from such studies have been that (a) VZV infection of neurons is less severe, based on several criteria, than that observed in human fibroblasts, and (b) VZV infection of neurons does not lead to apoptosis in these cells in contrast to apoptosis observed in fibroblastic cells. Insights gained from such studies in human neural stem cells suggest that a less severe initial lytic infection in neurons, which are resistant to apoptosis, is likely to facilitate a pathological pathway to a latent state of the virus in human ganglia.

Varicella zoster virus infection in neurological patients in Bulgaria

The clinical manifestations of neurological complications associated with varicella zoster virus (VZV) are non-specific and indistinguishable from those of other viral infections. Therefore, the definite diagnosis requires evidence of VZV infection in cerebrospinal fluid (CSF). The aim of this study was to determine the frequency of VZV DNA detection in CSF of patients with neurological diseases in order to obtain information concerning involvement of VZV infection in neuropathology in the country. This study is a retrospective survey of test results obtained from January 2015 to October 2019. During this period, 411 CSF specimens were tested for the presence of VZV DNA by nested PCR. Fisher's exact test was used to test for statistically significant difference in the frequency of VZV DNA positivity of CSF specimens from different groups. Of all 411 tested CSF samples, 11.2% were positive for VZV DNA. The highest VZV prevalence was detected in CFS from patients with meningitis-18.2%, followed by patients with cranial neuritis (15.4%), encephalitis (12.2%), Guillain-Barré syndrome (11.1%), myelitis (10%), and with other neurological syndromes (8.2%). The difference of VZV prevalence in CSF of patients according to the gender and age was not statistically significant. Our results indicated that VZV is a frequent causative agent of neurological diseases, suggesting an important role of VZV infection for neuropathology in the country. Therefore, efforts for wider application of VZV identification in CSF to facilitate faster onset of antiviral treatment and further strategies concerning varicella zoster virus vaccines in the country are needed.

Imaging manifestations on sequential magnetic resonance imaging in pharyngolaryngeal involvement by varicella zoster virus

Clarifying temporal changes in magnetic resonance imaging (MRI) offers a good chance to understand the pathology of neural lesions; however, such information is scarce in varicella zoster virus (VZV) neuropathies for the glossopharyngeal and vagus nerves. Here, we present the changes in sequential MR images of such a pathology over a period of 12 months from symptom onset.A 27-year-old woman with difficulty in swallowing and hoarseness due to a palatal palsy and arytenoid fixation on the left presented 2 days after onset. MRI revealed a lesion which largely filled the left jugular foramen on T2-weighted images (T2-WI) with high diffusion-weighted imaging (DWI) signals, which has never been previously described, on the 3rd day after onset. The DWI signals were highest on day 3, then deteriorated over 2 months until the signal was only detectable at the intracranial level, but not in the jugular foramen. The glossopharyngeal nerve had returned to normal by 2 months.The time course of the glossopharyngeal and vagus nerve swelling detected on T2-WI suggests that nerve swelling reduces over several months, even though the paralytic symptoms persist. Furthermore, the high DWI signal suggests that nerve swelling was caused by edematous swelling of the nerve fibers, rather than fiber disruption with water displacement in the extracellular space. These findings may provide good clues to speculate on the dynamically changing pathology of VZV neuropathies of the glossopharyngeal and vagus nerves.

Characteristics and long-term prognosis of Danish patients with varicella zoster virus detected in the cerebrospinal fluid, compared with the background population

BACKGROUND

Risk factors for and long-term outcomes following detection of varicella zoster virus (VZV) DNA in the cerebrospinal fluid (CSF) are unknown.

METHODS

We performed a nationwide population-based cohort study of all Danish residents who had VZV DNA detected in the CSF by polymerase chain reaction (PCR) between 1 January 1997 and 1 March 2016 (VZV cohort; n = 517) and an age- and sex- matched comparison cohort from the general Danish population (n = 9823). We examined potential risk factors and mortality, neurologic morbidity, psychiatric morbidity, redemption of medicine prescribed for the nervous system and social outcomes.

RESULTS

Prior hospital admission, redemption of immunosuppressive medicine, comorbidity and immunosuppressive conditions were associated with detection of VZV DNA in the CSF. Mortality was increased in the VZV cohort, especially during the first year of observation and among patients with encephalitis. Patients in the VZV cohort had an increased risk of dementia and epilepsy. The redemption of antiepileptics and antidepressants was increased in the VZV cohort.

CONCLUSIONS

Immunosuppression and comorbidity are associated with increased risk of detection of VZV DNA in the CSF and the condition is associated with increased mortality and neurological morbidity.

An overview of viral infections of the nervous system in the immunosuppressed

Several viruses have the capacity to cause serious infections of the nervous system in patients who are immunosuppressed. Individuals may be immunosuppressed because of primary inherited immunodeficiency, secondary immunodeficiency due to particular diseases such as malignancy, administration of immunosuppressant drugs or organ or bone marrow transplantation. The viruses capable of such opportunistic infection of the nervous system include herpes simplex virus (HSV), Varicella-Zoster virus (VZV), Cytomegalovirus (CMV), Epstein -Barr virus (EBV), Human Herpes virus type 6 (HHV-6), JC virus (JCV), enterovirus, measles virus and Covid-19. In most cases it seems likely that immunological defence mechanisms in the immunosuppressed are deficient which creates a suitable environment for certain viruses to become opportunistic in the nervous and other systems. Further research is required both to understand these opportunistic mechanisms in more detail and also to determine how many virus infections are modified by specific inborn errors of immunological responses.