Detection of varicella-zoster virus DNA in 414 human trigeminal ganglia from cadavers by the polymerase chain reaction: a comparison of the detection rate of varicella-zoster virus and herpes simplex virus type 1

Varicella zoster and fever rash surveillance in Lao People's Democratic Republic

Background

In Lao PDR, the epidemiology of varicella infection is uncertain, since it is not a notifiable disease and VZV outbreaks are rarely reported as fever/rash (F/R) diseases.

Methods

We estimated the seroprevalence of VZV (IgG ELISA) in different age cohorts (9 months to 46 years; N = 3139) and investigated VZV and 6 other viruses in patients during F/R outbreaks and in an ad hoc sentinel site in the context of the national reporting system (IgM ELISA, PCR).

Results

At least 80% of the sampled population had evidence of VZV infection before the age of 15. The largest increase in seroprevalence occurred between the age groups 1 to 5 and 6 to 7 year-olds. A VZV outbreak (clade 2) also occurred in this age group mostly during the first year of primary school (median age 6 years, interquartile range 4.0–7.5). During a dengue outbreak, 6% had varicella. At our F/R sentinel site, 14% of children with viral etiology were laboratory diagnosed as varicella and among others, a sizeable number of measles (N = 12) and rubella cases (N = 25) was detected compared to those reported for the whole country (N = 56 and 45), highlighting nationwide a large challenge of underreporting or misdiagnosis of these notifiable diseases because of lack of diagnostic laboratory capacity.

Conclusion

We recommend strengthening the clinical and laboratory diagnosis of VZV, measles and rubella, the surveillance and reporting of notifiable F/R diseases by retraining of healthcare workers and by setting up sentinel sites and enhancing laboratory capacity.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-3990-7) contains supplementary material, which is available to authorized users.

Post-mortem detection of six human herpesviruses (HSV-1, HSV-2, VZV, EBV, CMV, HHV-6) in trigeminal and facial nerve ganglia by PCR

Background

Among over 100 types of Herpesviridae viruses, eight can infect humans: herpes simplex viruses (HSV-1, HSV-2), varicella zoster virus (VZV), cytomegalovirus (CMV), Epstein-Barr virus (EBV), and human herpesviruses 6, 7, and 8 (HHV-6, HHV-7, HHV-8). After initial infection, the viruses remain latent for the lifetime of the host. The aim of this study was to determine the distribution of six different herpesviruses: HSV-1, HSV-2, VZV, EBV, CMV, and HHV-6 in trigeminal and facial nerve ganglia among a random group of Polish population.

Methods

The studied group consisted of 47 individuals (40 male, seven female); mean age of 47.4 ± 16.5 years) who died of independent causes (suicide, traffic accident, and poisoning, among others). Bilateral trigeminal and facial nerve ganglia of each cadaver were collected during the autopsy. Herpesviruses were detected using multiplex polymerase chain reaction technique.

Results

Herpesviruses were found in trigeminal and/or facial ganglia in 30/47 (63.8%) of cadavers. HHV-6 was the most prevalent of the herpesviruses and was found in nearly half of cadavers (n = 22; 46.8%), followed by HSV-1 (n = 7; 14.9%), VZV (n = 4; 8.5%), EBV (n = 4; 8.5%), HSV-2 (n = 2; 4.3%), and CMV (n = 1; 2.1%). Facial nerve ganglia (n = 23; 48.9%) were more often infected than trigeminal ganglia (n = 13; 27.7%).

Discussion

The results of this study have revealed a common presence of the herpesviruses in trigeminal and facial nerve ganglia among a random group of Polish population. Furthermore, the data also demonstrate simultaneous infection of the ganglia with different herpesviruses. This study has contributed to the knowledge of prevalence and localization of herpesviruses in different structures of the nervous system.

Usefulness of human herpes simplex virus type 1 genotyping for tracing the geographical origins of unidentified cadavers

Aim: We examined the possibility of tracing the origins of cadavers based on the geographic distribution of genotypes of the latent human herpes simplex virus type 1 (HSV-1). Materials & methods: PCR of the V1 region (667 bp) was performed using DNA from human trigeminal ganglia of 107 Japanese cadavers. The phylogenetic analysis was performed using 16 cadavers in Chiba district and 84 reference sequences in the world. Results: The HSV-1 DNA detection rate was 54.2% and it increased with age. This phylogenetic tree showed four large clusters, types I–IV (African, European, Asian and the mixed-type), and two subclusters (Japanese–Korean type and Japanese–Chinese type) in type III. Conclusion: HSV-1 genotype is possible to trace the geographical origin of unidentified cadavers.

Herpes zoster in psoriasis patients treated with tofacitinib

BACKGROUND

Tofacitinib is an oral Janus kinase (JAK) inhibitor. Immunomodulatory therapies can increase the risk for herpes zoster (HZ) in patients with psoriasis.

OBJECTIVE

To evaluate the relationship between tofacitinib use and HZ risk.

METHODS

We used phases 2 and 3 and long-term extension (LTE) data from the tofacitinib development program in psoriasis to calculate HZ incidence rates (IR; events per 100 patient-years); potential HZ risk factors were evaluated using Cox-proportional hazard models.

RESULTS

One hundred thirty (3.6%) patients on tofacitinib (IR 2.55), no patients on placebo, and 2 using etanercept (IR 2.68) developed HZ. Nine patients (7%) were hospitalized, and 8 (6%) had multidermatomal HZ; no encephalitis, visceral involvement, or deaths occurred. In total, 121 (93%) patients on tofacitinib continued or resumed use after HZ. HZ risk factors included Asian descent (hazard ratio [HR] 2.92), using tofacitinib 10 mg twice daily (vs 5 mg twice daily; HR 1.72), prior use of biologics (HR 1.72), and older age (HR 1.30).

LIMITATIONS

Generalizability to other psoriasis populations might be limited. The effect of HZ vaccination was not studied.

CONCLUSION

Tofacitinib is associated with increased HZ risk relative to placebo. Asian race, increasing age, higher dose, and prior biologic exposure are associated with heightened risk.

Maternal Antiviral Immunoglobulin Accumulates in Neural Tissue of Neonates To Prevent HSV Neurological Disease

While antibody responses to neurovirulent pathogens are critical for clearance, the extent to which antibodies access the nervous system to ameliorate infection is poorly understood. In this study on herpes simplex virus 1 (HSV-1), we demonstrate that HSV-specific antibodies are present during HSV-1 latency in the nervous systems of both mice and humans. We show that antibody-secreting cells entered the trigeminal ganglion (TG), a key site of HSV infection, and persisted long after the establishment of latent infection. We also demonstrate the ability of passively administered IgG to enter the TG independently of infection, showing that the naive TG is accessible to antibodies. The translational implication of this finding is that human fetal neural tissue could contain HSV-specific maternally derived antibodies. Exploring this possibility, we observed HSV-specific IgG in HSV DNA-negative human fetal TG, suggesting passive transfer of maternal immunity into the prenatal nervous system. To further investigate the role of maternal antibodies in the neonatal nervous system, we established a murine model to demonstrate that maternal IgG can access and persist in neonatal TG. This maternal antibody not only prevented disseminated infection but also completely protected the neonate from neurological disease and death following HSV challenge. Maternal antibodies therefore have a potent protective role in the neonatal nervous system against HSV infection. These findings strongly support the concept that prevention of prenatal and neonatal neurotropic infections can be achieved through maternal immunization.

Herpes simplex virus 1 is a common infection of the nervous system that causes devastating neonatal disease. Using mouse and human tissue, we discovered that antiviral antibodies accumulate in neural tissue after HSV-1 infection in adults. Similarly, these antibodies pass to the offspring during pregnancy. We found that antiviral maternal antibodies can readily access neural tissue of the fetus and neonate. These maternal antibodies then protect neonatal mice against HSV-1 neurological infection and death. These results underscore the previously unappreciated role of maternal antibodies in protecting fetal and newborn nervous systems against infection. These data suggest that maternal immunization would be efficacious at preventing fetal/neonatal neurological infections.

Granulocytes in Ocular HSV-1 Infection: Opposing Roles of Mast Cells and Neutrophils

PURPOSE

The contributions of mast cells (MCs) to immunologic defense against pathogens in the eye are unknown. We have characterized pericorneal MCs as tissue-resident innate sentinels and determined their impact on the immune response to herpes simplex virus type-1 (HSV-1), a common ocular pathogen.

METHODS

The impact of mast cells on the immune response to HSV-1 infection was investigated using MC-deficient Kit(W-sh) mice. Virus titers, inflammatory cytokine production, eicosanoid profiles, cellular immune responses, and ocular pathology were evaluated and compared with C57BL/6J mice during an acute corneal HSV-1 infection.

RESULTS

Corneas of Kit(W-sh) mice have higher viral titers, increased edema, and greater leukocyte infiltration following HSV-1 infection. Following infection, cytokine profiles were slightly elevated overall in Kit(W-sh) mice. Eicosanoid profiles were remarkably different only when comparing uninfected corneas from both groups. Neutrophils within infected corneas expressed HSV-1 antigen, lytic genes, and served as a disease-causing vector when adoptively transferred into immunocompromised animals. Myeloid-derived suppressor cells did not infiltrate into the cornea or suppress the expansion, recruitment, or cytokine production by CD8+ T cells following acute HSV-1 infection.

CONCLUSIONS

Collectively, these findings provide new insight into host defense in the cornea and the pathogenesis of HSV-1 infection by identifying previously unacknowledged MCs as protective innate sentinels for infection of the ocular surface and reinforcing that neutrophils are detrimental to corneal infection.

The Current State of Vaccine Development for Ocular HSV-1 Infection

HSV-1 continues to be the leading cause of infectious corneal blindness. Clinical trials for vaccines against genital HSV infection have been ongoing for more than three decades. Despite this, no approved vaccine exists, and no formal clinical trials have evaluated the impact of HSV vaccines on eye health. We review here the current state of development for an efficacious HSV-1 vaccine and call for involvement of ophthalmologists and vision researchers.

Varicella-zoster virus and herpes simplex virus 1 can infect and replicate in the same neurons whether co- or superinfected

The two human neurotropic alphaherpesviruses varicella-zoster virus (VZV) and herpes simplex virus type 1 (HSV1) both establish latency in sensory ganglia. Human trigeminal ganglia are known to frequently harbor both viruses, and there is evidence to suggest the presence of both VZV and HSV1 DNA in the same neuron. We ask here whether VZV and HSV1 can exclude themselves and each other and whether they can productively infect the same cells in human neurons and human foreskin fibroblasts (HFF). Simultaneous infection (coinfection) or consecutive infection (superinfection) was assessed using cell-free HSV1 and VZV expressing fluorescent reporter proteins. Automated analysis was carried out to detect singly and dually infected cells. We demonstrate that VZV and HSV1 both display efficient superinfection exclusion (SE) in HFF, with each virus excluding either itself or the other virus. While SE also occurred in neurons, it was with much lower efficiency. Both alphaherpesviruses productively infected the same neurons, whether applied simultaneously or even consecutively, albeit at lower frequencies.

IMPORTANCE

Superinfection exclusion by VZV for itself or the related neurotropic alphaherpesvirus HSV1 has been studied here for the first time. We find that while these viruses display classic SE in fibroblasts, SE is less efficient for both HSV1 and VZV in human neurons. The ability of multiple VZV strains to productively infect the same neurons has important implications in terms of recombination of both wild-type and vaccine strains in patients.

Viable herpes simplex virus type 1 and varicella-zoster virus in the trigeminal ganglia of human cadavers

Human herpes simplex virus type 1 (HSV-1) and varicella-zoster virus (VZV) were isolated in the bilateral trigeminal ganglia of 12 human cadavers with no history of herpes-related symptoms within 1-5 days of death. Sixteen trigeminal ganglia were subjected to explant culture by using Vero cells, but no cytopathogenic effects (CPE) were observed. However, when another eight trigeminal ganglia were placed in a cell strainer and kept from direct contact with Vero cells during culture, CPE were clearly apparent in all cultures. The amount of DNA in the culture supernatants of 16 trigeminal ganglia decreased over time; 12 and 9 of these samples were PCR-positive for HSV-1 and VZV, respectively. In new Vero cells inoculated with supernatants collected 2 days after culture initiation, immunofluorescence staining revealed HSV-1 and VZV in 6 and 5 of 8 trigeminal ganglia, respectively. HSV-1 and VZV DNA was detected in supernatants collected 3 and 7 days after culture initiation and in Vero cells collected after culture completion, but real-time PCR revealed the DNA amounts decreased over time. There was less VZV DNA than HSV-1 DNA. These results demonstrate that infective HSV-1 and VZV can be isolated in culture, and confirm that viable HSV-1 and VZV persist in human trigeminal ganglia for some time after death.

[Genetic susceptibility to herpes simplex encephalitis]

Herpes simplex encephalitis (HSE) is a rare but severe complication of frequent and mostly benign infection with herpes simplex virus (HSV). Although rapid and sensitive diagnosis tools and active antiviral drugs are available, HSE morbidity/mortality levels remain unsatisfactory. Molecular and cellular determinants of HSE are incompletely understood. The rarity and severity of the disease have suggested an increased susceptibility of some subjects to HSV infection. Numerous experimental studies have investigated the respective role of host and viral factors in HSE. The results of these studies have illustrated the major role of the innate immune response, in particular interferons (IFNs), in limiting access of the virus into and/or virus replication in the central nervous system (CNS). In a few children with HSE, specific defects of the immune innate response have been identified, which impair the IFN-α/β and IFN-λ production of fibroblasts and/or neurons infected with HSV and render these cells more permissive to infection. The mutations affect proteins involved in the IFN pathway induced by stimulation of the TLR3 receptor. The patients' susceptibility to infection is restricted to HSV CNS invasion, underlining the major role of TLR3 in CNS protection against viral infection. The incomplete clinical penetrance of these molecular defects suggests that other factors (age, infectious dose) are involved in HSE. Whether pathogenesis of adult HSE is similar has not been investigated.

Immunohistochemical detection of intra-neuronal VZV proteins in snap-frozen human ganglia is confounded by antibodies directed against blood group A1-associated antigens

Varicella-zoster virus (VZV) causes chickenpox, establishes latency in trigeminal (TG) and dorsal root ganglia (DRG), and can lead to herpes zoster upon reactivation. The VZV proteome expressed during latency remains ill-defined, and previous studies have shown discordant data on the spectrum and expression pattern of VZV proteins and transcripts in latently infected human ganglia. Recently, Zerboni and colleagues have provided new insight into this discrepancy (Zerboni et al. in J Virol 86:578-583, 2012). They showed that VZV-specific ascites-derived monoclonal antibody (mAb) preparations contain endogenous antibodies directed against blood group A1 proteins, resulting in false-positive intra-neuronal VZV staining in formalin-fixed human DRG. The aim of the present study was to confirm and extend this phenomenon to snap-frozen TG (n=30) and DRG (n=9) specimens of blood group genotyped donors (n=30). The number of immunohistochemically stained neurons was higher with mAb directed to immediate early protein 62 (IE62) compared with IE63. The IE63 mAb-positive neurons always co-stained for IE62 but not vice versa. The mAb staining was confined to distinct large intra-neuronal vacuoles and restricted to A1(POS) donors. Anti-VZV mAb staining in neurons, but not in VZV-infected cell monolayers, was obliterated after mAb adsorption against blood group A1 erythrocytes. The data presented demonstrate that neuronal VZV protein expression detected by ascites-derived mAb in snap-frozen TG and DRG of blood group A1(POS) donors can be misinterpreted due to the presence of endogenous antibodies directed against blood group A1-associated antigens present in ascites-derived VZV-specific mAb preparations.

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.

A genome-wide comparative evolutionary analysis of herpes simplex virus type 1 and varicella zoster virus

Herpes simplex virus type 1 (HSV-1) and varicella zoster virus (VZV) are closely related viruses causing lifelong infections. They are typically associated with mucocutaneous or skin lesions, but may also cause severe neurological or ophthalmic diseases, possibly due to viral- and/or host-genetic factors. Although these viruses are well characterized, genome-wide evolutionary studies have hitherto only been presented for VZV. Here, we present a genome-wide study on HSV-1. We also compared the evolutionary characteristics of HSV-1 with those for VZV. We demonstrate that, in contrast to VZV for which only a few ancient recombination events have been suggested, all HSV-1 genomes contain mosaic patterns of segments with different evolutionary origins. Thus, recombination seems to occur extremely frequent for HSV-1. We conclude by proposing a timescale for HSV-1 evolution, and by discussing putative underlying mechanisms for why these otherwise biologically similar viruses have such striking evolutionary differences.

Varicella zoster virus latency

Primary infection by varicella zoster virus (VZV) typically results in childhood chickenpox, at which time latency is established in the neurons of the cranial nerve, dorsal root and autonomic ganglia along the entire neuraxis. During latency, the histone-associated virus genome assumes a circular episomal configuration from which transcription is epigenetically regulated. The lack of an animal model in which VZV latency and reactivation can be studied, along with the difficulty in obtaining high-titer cell-free virus, has limited much of our understanding of VZV latency to descriptive studies of ganglia removed at autopsy and analogy to HSV-1, the prototype alphaherpesvirus. However, the lack of miRNA, detectable latency-associated transcript and T-cell surveillance during VZV latency highlight basic differences between the two neurotropic herpesviruses. This article focuses on VZV latency: establishment, maintenance and reactivation. Comparisons are made with HSV-1, with specific attention to differences that make these viruses unique human pathogens.

Varicella-zoster virus human ganglionic latency: a current summary

Varicella-zoster virus (VZV) is a ubiquitous human herpes virus typically acquired in childhood when it causes varicella (chickenpox), following which the virus establishes a latent infection in trigeminal and dorsal root ganglia that lasts for the life of the individual. VZV subsequently reactivates, spontaneously or after specific triggering factors, to cause herpes zoster (shingles), which may be complicated by postherpetic neuralgia and several other neurological complications including vasculopathy. Our understanding of VZV latency lags behind our knowledge of herpes simplex virus type 1 (HSV-1) latency primarily due to the difficulty in propagating the virus to high titers in a cell-free state, and the lack of a suitable small-animal model for studying virus latency and reactivation. It is now established beyond doubt that latent VZV is predominantly located in human ganglionic neurons. Virus gene transcription during latency is epigenetically regulated, and appears to be restricted to expression of at least six genes, with expression of gene 63 being the hallmark of latency. However, viral gene transcription may be more extensive than previously thought. There is also evidence for several VZV genes being expressed at the protein level, including VZV gene 63-encoded protein, but recent evidence suggests that this may not be a common event. The nature and extent of the chronic inflammatory response in latently infected ganglia is also of current interest. There remain several questions concerning the VZV latency process that still need to be resolved unambiguously and it is likely that this will require the use of newly developed molecular technologies, such as GeXPS multiplex polymerase chain reaction (PCR) for virus transcriptional analysis and ChIP-seq to study the epigenetic of latent virus genome ( Liu et al, 2010 , BMC Biol 8: 56).