Zoster sine herpete: virologic verification by detection of anti-VZV IgG antibody in CSF

Immune changes and their relationship with prognosis in patients with varicella-zoster virus encephalitis/meningitis

OBJECTIVES

This study aimed to investigate the immune changes in patients with varicella-zoster virus (VZV) encephalitis/meningitis and explored their relationships with prognosis.

METHODS

A total of 129 patients with herpes zoster (HZ), 32 patients with VZV encephalitis/meningitis and 31 non-HZ and non-VZV people as healthy controls were included into the present study. The numbers of peripheral T lymphocytes and the serum levels of complements 3 (C3), complements 4 (C4) and immunoglobulin A (IgA), immunoglobulin G (IgG), and immunoglobulin M (IgM) were detected and compared among groups. In 32 patients with VZV encephalitis/meningitis, the immune related variables were compared between the favorable and the unfavorable prognosis group and their relationships with prognosis were further evaluated.

RESULTS

There were marked differences in the peripheral CD3+, CD4+ and CD8+ cells and CD4+/CD8+ ratio in the three groups (P<0.05). As compared with HZ and control groups, the peripheral CD3+ and CD4+ cells were reduced dramatically in patients with VZV encephalitis/meningitis (P<0.05). In 32 patients with VZV encephalitis/meningitis, the absolute CD3+ and CD4+ cells in patients with favorable prognosis were significantly higher than in patients with unfavorable prognosis (P<0.05), and they were positively related to the prognosis of these patients (r=0.3852, P=0.0295; r=0.3719, P=0.0361).

CONCLUSION

These immune changes were compromised in VZV encephalitis/meningitis. The peripheral CD3+ and CD4+ levels may be employed to predict prognosis.

Acute unilateral vestibulopathy/vestibular neuritis: Diagnostic criteria

This paper describes the diagnostic criteria for Acute Unilateral Vestibulopathy (AUVP), a synonym for vestibular neuritis, as defined by the Committee for the Classification of Vestibular Disorders of the Bárány Society. AUVP manifests as an acute vestibular syndrome due to an acute unilateral loss of peripheral vestibular function without evidence for acute central or acute audiological symptoms or signs. This implies that the diagnosis of AUVP is based on the patient history, bedside examination, and, if necessary, laboratory evaluation. The leading symptom is an acute or rarely subacute onset of spinning or non-spinning vertigo with unsteadiness, nausea/vomiting and/or oscillopsia. A leading clinical sign is a spontaneous peripheral vestibular nystagmus, which is direction-fixed and enhanced by removal of visual fixation with a trajectory appropriate to the semicircular canal afferents involved (generally horizontal-torsional). The diagnostic criteria were classified by the committee for four categories: 1. "Acute Unilateral Vestibulopathy", 2. "Acute Unilateral Vestibulopathy in Evolution", 3. "Probable Acute Unilateral Vestibulopathy" and 4. "History of Acute Unilateral Vestibulopathy". The specific diagnostic criteria for these are as follows:"Acute Unilateral Vestibulopathy": A) Acute or subacute onset of sustained spinning or non-spinning vertigo (i.e., an acute vestibular syndrome) of moderate to severe intensity with symptoms lasting for at least 24 hours. B) Spontaneous peripheral vestibular nystagmus with a trajectory appropriate to the semicircular canal afferents involved, generally horizontal-torsional, direction-fixed, and enhanced by removal of visual fixation. C) Unambiguous evidence of reduced VOR function on the side opposite the direction of the fast phase of the spontaneous nystagmus. D) No evidence for acute central neurological, otological or audiological symptoms. E) No acute central neurological signs, namely no central ocular motor or central vestibular signs, in particular no pronounced skew deviation, no gaze-evoked nystagmus, and no acute audiologic or otological signs. F) Not better accounted for by another disease or disorder."Acute Unilateral Vestibulopathy in Evolution": A) Acute or subacute onset of sustained spinning or non-spinning vertigo with continuous symptoms for more than 3 hours, but not yet lasting for at least 24 h hours, when patient is seen; B) - F) as above. This category is useful for diagnostic reasons to differentiate from acute central vestibular syndromes, to initiate specific treatments, and for research to include patients in clinical studies."Probable Acute Unilateral Vestibulopathy": Identical to AUVP except that the unilateral VOR deficit is not clearly observed or documented."History of acute unilateral vestibulopathy": A) History of acute or subacute onset of vertigo lasting at least 24 hours and slowly decreasing in intensity. B) No history of simultaneous acute audiological or central neurological symptoms. C) Unambiguous evidence of unilaterally reduced VOR function. D) No history of simultaneous acute central neurological signs, namely no central ocular motor or central vestibular signs and no acute audiological or otological signs. E) Not better accounted for by another disease or disorder. This category allows a diagnosis in patients presenting with a unilateral peripheral vestibular deficit and a history of an acute vestibular syndrome who are examined well after the acute phase.It is important to note that there is no definite test for AUVP. Therefore, its diagnosis requires the exclusion of central lesions as well as a variety of other peripheral vestibular disorders. Finally, this consensus paper will discuss other aspects of AUVP such as etiology, pathophysiology and laboratory examinations if they are directly relevant to the classification criteria.

Neurological complications of varicella zoster virus reactivation: Prognosis, diagnosis, and treatment of 72 patients with positive PCR in the cerebrospinal fluid

BACKGROUND

VZV infection can involve every level of the neurologic system: from the central nervous system (CNS) to the peripheral nervous system (PNS), including aseptic meningitis. Prognosis seems to differ between these neurological involvements. Prognostic factors remain unknown.

METHODS

This is a retrospective multicenter study including all patients with a positive VZV polymerase chain reaction (PCR) in the cerebrospinal fluid (CSF) from eight centers in Paris (France) between 2011 and 2018. Unfavorable outcome was defined as mortality linked to VZV or incomplete recovery. Modified Rankin Scale (mRS) evaluated disability before and after the infection, with the difference designated as Rankin Delta.

RESULTS

Seventy-two patients were included (53% male, median age 51 years, median mRS 0). Immunosuppression was reported in 42%. The clinical spectrum included 26 cases of meningitis, 27 instances of CNS involvement, 16 of PNS involvement, and 3 isolated replications (positive PCR but no criteria for neurological complications from VZV). Antiviral treatment was administered to 69 patients (96%). Sixty-two patients completed follow-up. Death linked to VZV occurred in eight cases. Unfavorable outcome (UO) occurred in 60% and was significantly associated with a higher prior mRS (Odd-ratio (OR) 3.1 [1.4-8.8] p = .012) and the presence of PNS or CNS manifestations (OR 22 [4-181] p = .001, OR 6.2 [1.3-33] p = .03, respectively, compared to meningitis). In the CSF, higher protein level (p < .0001) was also significantly associated with a higher Rankin Delta.

CONCLUSIONS

Neurological complications of VZV with evidence of CSF viral replication are heterogeneous: aseptic meningitis has a good prognosis, whereas presence of CNS and PNS involvement is associated with a higher risk of mortality and of sequelae, respectively.

Zoster sine herpete following BNT162b2 mRNA COVID-19 vaccination in an immunocompetent patient

As a result of the COVID-19 pandemic, mRNA vaccination has become widespread. Recently, it has been suggested that instances of herpes zoster increase following mRNA COVID-19 vaccination. Herein, we describe the first case of zoster sine herpete (ZSH) after mRNA vaccination for COVID-19. A 60-year-old Japanese immunocompetent man presented with fever, fatigue, headache, cervical pain, and lumbar pain, which developed after receiving a second dose of BNT162b2 mRNA COVID-19 vaccination. Whereas most symptoms improved with symptomatic treatment, headache and numbness of the right forehead persisted in areas innervated by the trigeminal and second and third cervical nerves. Based on positive results of an enzyme-linked immunosorbent assay examination for anti-VZV IgM, ZSH was diagnosed, and amitriptyline improved the patient’s symptoms. Diagnosis of ZSH is challenging due to the lack of a characteristic herpes zoster rash. Physicians should be aware that ZSH can develop after mRNA vaccination.

Encephalitis and Brain Abscess

PURPOSE OF REVIEW

This article reviews infections of the brain parenchyma and includes an overview of the epidemiology, pathogenesis, diagnostic approach, and management of infectious encephalitis and brain abscess.

RECENT FINDINGS

The epidemiology of infectious encephalitis and brain abscess has changed in recent years. Vaccination has reduced the incidence of certain viruses associated with encephalitis, while a decrease in fulminant otogenic infections has led to fewer brain abscesses associated with otitis media. However, changes in climate and human population density and distribution have enabled the emergence of newer pathogens and expanded the geographic range of others, and greater adoption of intensive immunosuppressive regimens for autoimmune conditions has increased the risk of opportunistic infections of the brain. The widespread use of early neuroimaging, along with improved diagnostic methodologies for pathogen detection, newer antimicrobial therapies with better brain penetration, and less invasive neurosurgical techniques, has resulted in better outcomes for patients with infectious encephalitis and brain abscess. Novel technologies including metagenomic next-generation sequencing are increasingly being applied to these conditions in an effort to improve diagnosis. Nevertheless, both infectious encephalitis and brain abscess continue to be associated with substantial mortality.

SUMMARY

Infectious encephalitis and brain abscess can present as neurologic emergencies and require rapid assessment, thorough and appropriate diagnostic testing, and early initiation of empiric therapies directed against infectious agents. Close clinical follow-up, proper interpretation of diagnostic results, and appropriate tailoring of therapeutic agents are essential to optimizing outcomes. Diagnosis and management of parenchymal brain infections are complex and often best achieved with a multidisciplinary care team involving neurologists, neurosurgeons, neuroradiologists, infectious disease physicians, and pathologists.

Zoster sine herpete: a review

Zoster sine herpete (ZSH) is one of the atypical clinical manifestations of herpes zoster (HZ), which stems from infection and reactivation of the varicella-zoster virus (VZV) in the cranial nerve, spinal nerve, viscera, or autonomic nerve. Patients with ZSH display variable symptoms, such as neuralgia, however, different from HZ, ZSH show no zoster, which makes clinical diagnosis difficult. ZSH not only causes initial symptoms, such as neuropathic pain in the affected nerve, Bell palsy, and Ramsay Hunt syndrome, but also postherpetic neuralgia and fatal complications such as VZV encephalitis and stroke. The misdiagnosis of ZSH and tardy antiviral treatment may lead to severe ZSH sequelae. We review the publications related to ZSH, especially its diagnosis with VZV DNA and/or anti-VZV immunoglobulin (IgG and IgM). More work about ZSH, especially ZSH epidemiological survey and guidelines for its diagnosis and treatment, are needed because most of the present studies are case reports.

Herpes zoster - typical and atypical presentations

Varicella- zoster virus infection is an intriguing medical entity that involves many medical specialties including infectious diseases, immunology, dermatology, and neurology. It can affect patients from early childhood to old age. Its treatment requires expertise in pain management and psychological support. While varicella is caused by acute viremia, herpes zoster occurs after the dormant viral infection, involving the cranial nerve or sensory root ganglia, is re-activated and spreads orthodromically from the ganglion, via the sensory nerve root, to the innervated target tissue (skin, cornea, auditory canal, etc.). Typically, a single dermatome is involved, although two or three adjacent dermatomes may be affected. The lesions usually do not cross the midline. Herpes zoster can also present with unique or atypical clinical manifestations, such as glioma, zoster sine herpete and bilateral herpes zoster, which can be a challenging diagnosis even for experienced physicians. We discuss the epidemiology, pathophysiology, diagnosis and management of Herpes Zoster, typical and atypical presentations.

Clinical patterns of primary stabbing headache: a single clinic-based prospective study

Background

The clinical features and disease courses of primary stabbing headache (PSH) are diverse. We aimed to identify distinct clinical patterns of PSH.

Methods

We prospectively screened consecutive first-visit patients who presented with stabbing headache at the Samsung Medical Centre Headache Clinic from June 2015 to March 2016. Demographics, headache characteristics, and disease courses were prospectively evaluated. After discerning factors related to the chronicity at the time of presentation, clinical patterns were identified based on the frequency (daily vs. intermittent), clinical course (remitted or not), and total disease duration (<3 or >3 months).

Results

In the 65 patients with PSH included in this study, monophasic (n = 31), intermittent (n = 17), and chronic daily (n = 12) patterns were identified. The median disease durations were 9 days for monophasic PSH, 9 months for chronic daily PSH, and 2 years for intermittent PSH. The features of monophasic PSH were greater severity, single and side-locked locations, more attacks per day, daily occurrence, and good treatment response. Chronic daily PSH was associated with female predominance, longer-lasting stabs, and multiple or migrating locations on bilateral or alternating sides. The characteristics of intermittent PSH included female predominance and sporadic stabs with less intensity.

Conclusions

Our study demonstrated distinct clinical patterns of PSH. In addition to help early recognition of disease, our findings suggest different pathophysiologic mechanisms. Future prospective studies are required to reveal the etiologies of these different PSH patterns and their optimal treatment strategies.

Robust gene expression changes in the ganglia following subclinical reactivation in rhesus macaques infected with simian varicella virus

Varicella zoster virus (VZV) causes varicella during acute infection and establishes latency in the sensory ganglia. Reactivation of VZV results in herpes zoster, a debilitating and painful disease. It is believed that VZV reactivates due to a decline in cell-mediated immunity; however, the roles that CD4 versus CD8 T cells play in the prevention of herpes zoster remain poorly understood. To address this question, we used a well-characterized model of VZV infection where rhesus macaques are intrabronchially infected with the homologous simian varicella virus (SVV). Latently infected rhesus macaques were thymectomized and depleted of either CD4 or CD8 T cells to induce selective senescence of each T cell subset. After T cell depletion, the animals were transferred to a new housing room to induce stress. SVV reactivation (viremia in the absence of rash) was detected in three out of six CD8-depleted and two out of six CD4-depleted animals suggesting that both CD4 and CD8 T cells play a critical role in preventing SVV reactivation. Viral loads in multiple ganglia were higher in reactivated animals compared to non-reactivated animals. In addition, reactivation results in sustained transcriptional changes in the ganglia that enriched to gene ontology and diseases terms associated with neuronal function and inflammation indicative of potential damage as a result of viral reactivation. These studies support the critical role of cellular immunity in preventing varicella virus reactivation and indicate that reactivation results in long-lasting remodeling of the ganglia transcriptome.

The positive duration of varicella zoster immunoglobulin M antibody test in herpes zoster

Laboratory tests for herpes zoster (HZ) are required to confirm varicella zoster virus (VZV) infection, especially when a skin lesion is not typical or apparent. The serological test for VZV IgM antibody is simple and cost-effective; however, the change in the VZV IgM-positive rate over the time course of the disease has not been investigated. Therefore, we conducted an observational study to evaluate the positive rate of VZV IgM results during the time course of HZ and estimate the VZV IgM-positive period.After obtaining serum from patients with typical HZ, the VZV IgM titer was examined using enzyme-linked immunosorbent assay methods. After logarithmic transformation of the VZV IgM titer and the period after the onset of HZ, regression analysis was performed with the 2 transformed variables.A total of 62 patients were included in this study, and VZV IgM antibody was positive only in 23 patients (37%). The estimated antibody-positive period after HZ onset was 3.5 weeks (95% confidence interval 2.8-4.6 weeks).These findings suggest that the serological diagnosis of VZV IgM to confirm HZ is only useful within 3.5 weeks after the onset of symptoms.

Neurological complications of varicella zoster virus reactivation

PURPOSE OF REVIEW

Varicella zoster virus (VZV) reactivation results in zoster, which may be complicated by postherpetic neuralgia, myelitis, meningoencephalitis, and VZV vasculopathy. This review highlights the clinical features, laboratory abnormalities, imaging changes, and optimal treatment of each of those conditions. Because all of these neurological disorders produced by VZV reactivation can occur in the absence of rash, the virological tests proving that VZV caused disease are discussed.

RECENT FINDINGS

After primary infection, VZV becomes latent in ganglionic neurons along the entire neuraxis. With a decline in VZV-specific cell-mediated immunity, VZV reactivates from ganglia and travels anterograde to the skin to cause zoster, which is often complicated by postherpetic neuralgia. VZV can also travel retrograde to produce meningoencephalitis, myelitis, and stroke. When these complications occur without rash, VZV-induced disease can be diagnosed by detection of VZV DNA or anti-VZV antibody in cerebrospinal fluid and treated with intravenous acyclovir.

SUMMARY

Awareness of the expanding spectrum of neurological complications caused by VZV reactivation with and without rash will improve diagnosis and treatment.

Neurologic infections in diabetes mellitus

Even at a time when HIV/AIDS and immunosuppressive therapy have increased the number of individuals living with significant immunocompromise, diabetes mellitus (DM) remains a major comorbid disorder for several rare but potentially lethal infections, including rhino-orbital-cerebral mucormycosis and malignant external otitis. DM is also a commonly associated condition in patients with nontropical pyomyositis, pyogenic spinal infections, Listeria meningitis, and blastomycosis. As West Nile virus spread to and across North America over a decade ago, DM appeared in many series as a risk factor for death or neuroinvasive disease. More recently, in several large international population-based studies, DM was identified as a risk factor for herpes zoster. The relationships among infection, DM, and the nervous system are multidirectional. Viral infections have been implicated in the pathogenesis of type 1 and type 2 DM, while parasitic infections have been hypothesized to protect against autoimmune disorders, including type 1 DM. DM-related neurologic disease can predispose to systemic infection - polyneuropathy is the predominant risk factor for diabetic foot infection. Because prognosis for many neurologic infections depends on timely institution of antimicrobial and sometimes surgical therapy, neurologists caring for diabetic patients should be familiar with the clinical features of the neuroinfectious syndromes associated with DM.

Pathogenesis and current approaches to control of varicella-zoster virus infections

Varicella-zoster virus (VZV) was once thought to be a fairly innocuous pathogen. That view is no longer tenable. The morbidity and mortality due to the primary and secondary diseases that VZV causes, varicella and herpes zoster (HZ), are significant. Fortunately, modern advances, including an available vaccine to prevent varicella, a therapeutic vaccine to diminish the incidence and ameliorate sequelae of HZ, effective antiviral drugs, a better understanding of VZV pathogenesis, and advances in diagnostic virology have made it possible to control VZV in the United States. Occult forms of VZV-induced disease have been recognized, including zoster sine herpete and enteric zoster, which have expanded the field. Future progress should include development of more effective vaccines to prevent HZ and a more complete understanding of the consequences of VZV latency in the enteric nervous system.

The variegate neurological manifestations of varicella zoster virus infection

Varicella zoster virus (VZV) is an exclusively human neurotropic alphaherpesvirus. Primary infection causes varicella (chickenpox), after which the virus becomes latent in ganglionic neurons along the entire neuraxis. With advancing age or immunosuppression, cell-mediated immunity to VZV declines, and the virus reactivates to cause zoster (shingles), dermatomal distribution, pain, and rash. Zoster is often followed by chronic pain (postherpetic neuralgia), cranial nerve palsies, zoster paresis, vasculopathy, meningoencephalitis, and multiple ocular disorders. This review covers clinical, laboratory, and pathological features of neurological complications of VZV reactivation, including diagnostic testing to verify active VZV infection in the nervous system. Additional perspectives are provided by discussions of VZV latency, animal models to study varicella pathogenesis and immunity, and of the value of vaccination of elderly individuals to boost cell-mediated immunity to VZV and prevent VZV reactivation.

Complications of varicella zoster virus reactivation

OPINION STATEMENT

Varicella zoster virus (VZV) is an exclusively human neurotropic alphaherpesvirus. Primary infection causes varicella (chickenpox), after which virus becomes latent in ganglionic neurons along the entire neuraxis. With advancing age or immunosuppression, cell-mediated immunity to VZV declines and virus reactivates to cause zoster (shingles), which can occur anywhere on the body. Skin lesions resolve within 1-2 weeks, while complete cessation of pain usually takes 4-6 weeks. Zoster can be followed by chronic pain (postherpetic neuralgia), cranial nerve palsies, zoster paresis, meningoencephalitis, cerebellitis, myelopathy, multiple ocular disorders and vasculopathy that can mimic giant cell arteritis. All of the neurological and ocular disorders listed above may also develop without rash. Diagnosis of VZV-induced neurological disease may require examination of cerebrospinal fluid (CSF), serum and/ or ocular fluids. In the absence of rash in a patient with neurological disease potentially due to VZV, CSF should be examined for VZV DNA by PCR and for anti-VZV IgG and IgM. Detection of VZV IgG antibody in CSF is superior to detection of VZV DNA in CSF to diagnose vasculopathy, recurrent myelopathy, and brainstem encephalitis. Oral antiviral drugs speed healing of rash and shorten acute pain. Immunocompromised patients require intravenous acyclovir. First-line treatments for post-herpetic neuralgia include tricyclic antidepressants, gabapentin, pregabalin, and topical lidocaine patches. VZV vasculopathy, meningoencephalitis, and myelitis are all treated with intravenous acyclovir.

Varicella zoster vaccines and their implications for development of HSV vaccines

Live attenuated vaccines to prevent varicella and zoster have been available in the US for the past 17 years, with a resultant dramatic decrease in varicella incidence and a predicted future decrease in the incidence of zoster. The pathogenesis and immune responses to varicella zoster virus (VZV) as well as the safety and effectiveness of VZV vaccines are reviewed. The lack of sterilizing immunity provided by VZV vaccines has not prevented them from being safe and effective. Virological and pathological information concerning parallels and differences between VZV and herpes simplex virus (HSV) are highlighted. Although VZV and HSV are distinct pathogens, they appear to have similarities in target organs and immunity that provide an expectation of a high likelihood for the success of vaccination against HSV, and predicted to be similar to that of VZV.

Zoster sine herpete causing facial palsy

OBJECTIVES

The aims of this study were to verify the characteristics of zoster sine herpete (ZSH) causing facial palsy and the effects of different treatments and to confirm the difference from other etiologies.

METHODS

From March 2010 to March 2011, a prospective study was performed on patients with ZSH with facial palsy. Patients were divided into a steroid-treated group and a steroid-antiviral combination group, and then the effects according to regimen of treatment were prospectively analyzed. Last, the difference between the ZSH group and patients diagnosed with Bell palsy and Ramsay Hunt syndrome in the same study period was confirmed retrospectively.

RESULTS

Forty-five patients were diagnosed as having ZSH. Significant improvement was not observed in the ZSH group regardless of the treatment regimen during a 3-week period (P < .05). In patients with ZSH with accompanying typical pain, significant continuous improvement after 6 weeks was observed in patients with combination therapy (P < .05). Compared with patients with Bell palsy and Ramsay Hunt syndrome, there was a significant difference in recovery rate between patients with ZSH (accompanying pain) and those with Bell palsy (89.9%) (P < .05).

CONCLUSION

The initiation of recovery in ZSH started later than that in other peripheral palsies, and slower recovery was shown in patients with ZSH with pain compared with those with Bell palsy. Steroid-antiviral combination therapy was a more effective regimen for treatment compared with steroid-only treatment. To improve the accuracy of ZSH diagnosis, confirming the presence of accompanying typical pain is necessary.

Clinical recognition of varicella zoster virus vasculopathy

INTRODUCTION

It is important to recognize acutely evolving ischemic stroke attributable to reactivation of varicella zoster virus vasculopathy since antiviral agents are effective.

METHODS

Three cases seen by the author over a 2-year period are highlighted.

RESULTS

All patients presented with an evolving arterial or venous ischemia in the background of postherpetic neuralgia proceeding for weeks to months.

CONCLUSION

Chronic neuralgic pain in a dermatomal distribution of an evolving central nervous system vasculopathy is an important clue to its recognition.

Reactivation of type 1 herpes simplex virus and varicella zoster virus in an immunosuppressed patient with acute peripheral facial weakness

We describe a 26-year-old man treated with azathioprine for myasthenia gravis who developed acute left-sided peripheral facial weakness. Brain magnetic resonance imaging (MRI) revealed enhancement in the left geniculate ganglion and in the intracanalicular and tympanic segments of the facial nerve. Analysis of cerebrospinal fluid (CSF) and serum revealed intrathecal synthesis of anti-varicella zoster virus (VZV) IgG antibody. Although previous analyses of saliva, blood mononuclear cells, serum antibodies, middle ear fluid, and auricular and geniculate zone skin scrapings have shown that a small but definite proportion of patients with idiopathic peripheral facial palsy ("Bell's palsy") have the Ramsay Hunt syndrome zoster sine herpete (RHS ZSH), this is the first confirmation of RHS ZSH by intrathecal synthesis of anti-VZV IgG antibody. In addition, herpes simplex virus (HSV)-1 DNA was found in saliva of the patient on 3 consecutive days. Simultaneous reactivation of two alphaherpesviruses (HSV-1 and VZV) in our immunosuppressed patient underscores the need to consider opportunistic infection as a cause of facial weakness.

Review: The neurobiology of varicella zoster virus infection

Varicella zoster virus (VZV) is a neurotropic herpesvirus that infects nearly all humans. Primary infection usually causes chickenpox (varicella), after which virus becomes latent in cranial nerve ganglia, dorsal root ganglia and autonomic ganglia along the entire neuraxis. Although VZV cannot be isolated from human ganglia, nucleic acid hybridization and, later, polymerase chain reaction proved that VZV is latent in ganglia. Declining VZV-specific host immunity decades after primary infection allows virus to reactivate spontaneously, resulting in shingles (zoster) characterized by pain and rash restricted to one to three dermatomes. Multiple other serious neurological and ocular disorders also result from VZV reactivation. This review summarizes the current state of knowledge of the clinical and pathological complications of neurological and ocular disease produced by VZV reactivation, molecular aspects of VZV latency, VZV virology and VZV-specific immunity, the role of apoptosis in VZV-induced cell death and the development of an animal model provided by simian varicella virus infection of monkeys.

Subclinical reactivation of varicella zoster virus in all stages of HIV infection

Analysis of 200 paired serum and cerebrospinal fluid (CSF) samples from 180 HIV-positive individuals, 136 of whom had AIDS, revealed intrathecal synthesis of antibodies specific for varicella zoster virus (VZV) in 28 (16%) individuals, measles virus in 15 (8%), herpes simplex virus-1 (HSV-1) in 1 (0.6%), and HSV-2 in none. Of the 28 subjects with a positive VZV antibody specificity index, only 1 had zoster rash at the time of serum and CSF sampling; of the total 180 HIV-positive subjects, 146 (81%) had no history of zoster. Based on an estimated 33.4 million HIV-positive individuals worldwide, subclinical reactivation of VZV in even less than 16% of HIV-positive people suggests the possibility that millions of people have active VZV infection of the central nervous system. In cases of VZV vasculopathy, myelopathy and even zoster sine herpete, the CSF is often positive for anti-VZV antibody, but negative for VZV DNA. To rule out VZV infection of the nervous system, CSF must be tested for VZV DNA and anti-VZV IgG and IgM antibody.