Distribution of varicella zoster virus and herpes simplex virus in disseminated fatal infections

Acute myelitis with multicranial neuritis caused by Varicella zoster virus: a case report

Background

Varicella zoster virus (VZV) can remain lifelong in the latent state in ganglionic neurons and adrenal glands after the initial infection. However, it can be reactivated anytime and can trigger several severe neurological manifestations such as encephalitis, meningitis, Ramsay-Hunt syndrome, cerebellitis, myelitis, and stroke. In addition, due to the diversity of clinical manifestations, clinical diagnosis of VZV can be difficult, especially in the absence of varicella. Here, we describe the case of a 52-year-old male who presented with symptoms of acute myelitis as well as polycranial neuritis, and was finally diagnosed with VZV infection through metagenomic next-generation sequencing (mNGS).

Case presentation

A 52-year-old male came to our hospital with complaint of headache, fever, weakness of right lower limb, abdominal distension, and hearing loss. T2-weighted MRI revealed a hyperintense lesion in the spinal cord extending from T8 to T11. In addition, enhanced MRI showed small patches and strips hyperintensities in both the spinal cord and meninges. Plain abdominal radiographs and abdominal computed tomography (CT) scan displayed air-fluid levels and incomplete bowel obstruction. Moreover, electrophysiological evaluation of the peripheral neuropathy in the extremities was found to be normal. Finally, by using metagenomic next-generation sequencing (mNGS) we found that the copy number of VZV DNA in cerebrospinal fluid (CSF) was significantly increased and IgG antibody against VZV in CSF was also noted to be positive. Hence, VZV infection was identified in patient’s central neuron system. Finally, after a few days of low dose steroid treatment, the patient's symptoms were found to be significantly improved.

Conclusions

The findings indicate that we should pay proper attention to the various symptoms caused by VZV infection due to the clinical heterogeneity, especially in the absence of cutaneous lesions.

Immunohistochemical diagnosis of human infectious diseases: a review

BACKGROUND

Immunohistochemistry (IHC) using monoclonal and polyclonal antibodies is a useful diagnostic method for detecting pathogen antigens in fixed tissues, complementing the direct diagnosis of infectious diseases by PCR and culture on fresh tissues. It was first implemented in a seminal publication by Albert Coons in 1941.

MAIN BODY

Of 14,198 publications retrieved from the PubMed, Google, Google Scholar and Science Direct databases up to December 2021, 230 were selected for a review of IHC techniques, protocols and results. The methodological evolutions of IHC and its application to the diagnosis of infectious diseases, more specifically lice-borne diseases, sexually transmitted diseases and skin infections, were critically examined. A total of 59 different pathogens have been detected once in 22 different tissues and organs; and yet non-cultured, fastidious and intracellular pathogens accounted for the vast majority of pathogens detected by IHC. Auto-IHC, incorporating patient serum as the primary antibody, applied to diseased heart valves surgically collected from blood culture-negative endocarditis patients, detected unidentified Gram-positive cocci and microorganisms which were subsequently identified as Coxiella burnetii, Bartonella quintana, Bartonella henselae and Tropheryma whipplei. The application of IHC to ancient tissues dated between the ends of the Ptolemaic period to over 70 years ago, have also contributed to paleomicrobiology diagnoses.

CONCLUSION

IHC plays an important role in diagnostic of infectious diseases in tissue samples. Paleo-auto-IHC derived from auto-IHC, is under development for detecting non-identified pathogens from ancient specimens.

Viral Infections in Burn Patients: A State-Of-The-Art Review

Infections that are triggered by the accompanying immunosuppression in patients with burn wounds are very common regardless of age. Among burn patients, the most frequently diagnosed infections include the bacterial ones primarily caused by Pseudomonas aeruginosa or Klebsiella pneumonia, as well as fungal infections with the etiology of Candida spp. or Aspergillus spp. Besides, burn wounds are highly susceptible to viral infections mainly due to the impaired immune responses and defective functions of the immune cells within the wound microenvironment. The most prevalent viruses that invade burn wounds include herpes simplex virus (HSV), cytomegalovirus (CMV), human papilloma virus (HPV), and varicella zoster virus (VZV). Likewise, less prevalent infections such as those caused by the orf virus or Epstein-Barr Virus (EBV) might also occur in immunosuppressed burn patients. Viral infections result in increased morbidity and mortality rates in severely burned patients. Additionally, a positive correlation between the hospitalization duration and the severity of the viral infection has been demonstrated. Viral infections trigger the occurrence of various complications, ranging from mild symptoms to even fatal incidents. Accurate detection of viral infection is of great clinical importance because of the possibility for a quicker introduction of proper treatment therapy and shortening of hospitalization time. The aim of this paper is to provide a comprehensive review of the literature and summarize the findings regarding the most common viral infections in immunosuppressed burn patients.

Unusual presentation of fatal disseminated varicella zoster virus infection in a patient with lupus nephritis: a case report

Background

The risk of life-threatening complications, such as visceral disseminated varicella zoster virus (VZV) infection, is greater in immunosuppressed individuals, such as systemic lupus erythematosus (SLE) patients.

Case presentation

Here, a case is reported of a Caucasian woman diagnosed with lupus nephritis and anti-phospholipid syndrome, who was subjected to mycophenolate mofetil and high-dose steroid remission-induction therapy. Two months later she developed abdominal pain followed by a fatal rapid multi-organ failure. As no typical skin rashes were evident, death was initially attributed to catastrophic anti-phospholipid syndrome. However, autopsy and virological examinations on archival material revealed a disseminated VZV infection.

Conclusions

Overall, this case highlights the importance of having a high clinical suspicion of fatal VZV infections in heavily immunosuppressed SLE patients even when typical signs and symptoms are lacking.

[S2k guideline for the diagnosis and therapy of zoster and post-zoster neuralgia]

Diese Leitlinie richtet sich an Dermatologen, Ophthalmologen, HNO-Ärzte, Pädiater, Neurologen, Virologen sowie Infektiologen, Anästhesisten und Allgemeinmediziner in Klinik und Praxis und dient zur Information für andere medizinische Fachrichtungen, die an der Behandlung des Zoster beteiligt sind. Darüber hinaus soll die Leitlinie Kostenträgern und politischen Entscheidungsträgern zur Orientierung dienen. Die Leitlinie wurde im formellen Konsensusverfahren (S2k) von Dermatologen, Virologen/Infektiologen, Ophthalmologen, HNO-Ärzten, Neurologen, Pädiatern und Anästhesisten/Schmerzmedizinern erstellt.

Die Leitlinie stellt einen Überblick über die klinische und molekulare Diagnostik sowie den Antigennachweis, die Antikörperkultur und Viruskultur dar. Diagnostisch besondere Situationen und komplizierte Verläufe der Erkrankung finden ebenfalls Berücksichtigung. Die antivirale Therapie des Zoster und der Postzosterneuralgie wird im Allgemeinen und für besondere Situationen dargelegt. Detaillierte Angaben zur Schmerzbehandlung finden Erwähnung und sind in einer Übersicht dargestellt. Ebenso werden die lokaltherapeutischen Maßnahmen thematisiert.

Intestinal pseudo-obstruction caused by herpes zoster: Case report and pathophysiology

Herpes zoster (HZ) infection occurs in approximately 10% to 30% of individuals. Visceral neuropathies secondary to HZ can cause cystitis and urinary retention. But colonic pseudo-obstruction can also occur. Peripheral neuropathy may reveal segmental motor paresis of either upper or lower limbs, the abdominal muscles or the diaphragm. We report the case of a 62-year-old male patient who presented with abdominal distention and cutaneous vesicular eruption on the left side of the abdominal wall. Plain X-rays and computed tomography scan showed distended small bowel. A diagnosis of intestinal pseudo-obstruction was made secondary to segmental paresis of the small intestine and visceral neuropathy. Conservative management was successful and the patient was discharged uneventfully. Intestinal pseudo-obstruction ought to be considered when dealing with non-obstructive (adynamic) conditions of the digestive tract associated with HZ infection; since early recognition may help to avoid unnecessary surgery.

Inflammatory and infectious manifestations of immunodeficiency in the gastrointestinal tract

Immune compromise may result from genetic abnormalities, HIV/AIDS, or consequences of therapy for neoplastic and autoimmune diseases. Many immunocompromised patients develop severe gastrointestinal symptoms, particularly diarrhea, accompanied by non-specific or mild endoscopic abnormalities; mucosal biopsy with pathologic interpretation has a major role in the diagnosis and management of these patients. Immunocompromised individuals are at risk for all the diseases that affect those with a healthy immune system, but they are also prone to other illnesses that rarely affect immunocompetent patients. This review discusses the gastrointestinal manifestations of primary and acquired immunodeficiency, chemotherapy-related injury, and infections that show a predilection for immunocompromised patients. Key histologic features and relevant differential diagnoses are emphasized.

Cost-effectiveness of Varicella Vaccination Program in Iran

Background:

Varicella zoster virus is the etiologic agent of primary varicella (chickenpox) during childhood, and varicella vaccination has not been introduced in Iran. The aim of this study is to estimate cost-effectiveness of one- and two-dose Varicella Vaccination Program in Iran.

Methods:

A decision-tree model was conducted to evaluate the cost-effectiveness of the Varicella Vaccination Program in a cohort of 12 months children in Iran. Epidemiologic parameters of varicella were extracted from local and international sources, and cost of disease was estimated based on societal prospective in 2015 US$. Incremental cost per disability-adjusted life years (DALY) averted calculated as final outcome. Sensitivity analysis was also performed for lower and upper estimate of incidence, DALY, and vaccine efficacy.

Results:

Considering the vaccine efficacy of 95%, for the two-dose and 85% for the one-dose vaccination, incremental cost-effectiveness ratio (ICER) per DALYs averted were US$41,531 and US$17,280, respectively. ICER has changed between (US$ 6,177–US$167,047) in lower and upper base estimate of epidemiological burden parameters in sensitivity analysis.

Conclusions:

Varicella vaccination is not cost-effective in Iran in one-dose and two-dose scenario under the assumptions of this study in base case scenario according to the threshold of incremental cost per DALY averted less than three time of GDP per capita in Iran = US$ 14,292. One-dose vaccination program might be cost-effective in upper scenario of epidemiological burden of varicella in sensitivity analysis.

European consensus-based (S2k) Guideline on the Management of Herpes Zoster - guided by the European Dermatology Forum (EDF) in cooperation with the European Academy of Dermatology and Venereology (EADV), Part 1: Diagnosis

Herpes zoster (HZ, shingles) is a frequent medical condition which may severely impact the quality of life of affected patients. Different therapeutic approaches to treat acute HZ are available. The aim of this European project was the elaboration of a consensus-based guideline on the management of patients who present with HZ, considering different patient populations and different localizations. This interdisciplinary guideline aims at an improvement of the outcomes of the acute HZ management concerning disease duration, acute pain and quality of life of the affected patients and at a reduction of the incidence of postherpetic neuralgia and other complications. The guideline development followed a structured and predefined process, considering the quality criteria for guidelines development as suggested by the AGREE II instrument. The steering group was responsible for the planning and the organization of the guideline development process (Division of Evidence based Medicine, dEBM). The expert panel was nominated by virtue of clinical expertise and/or scientific experience and included experts from the fields of dermatology, virology/infectiology, ophthalmology, otolaryngology, neurology and anaesthesiology. Recommendations for clinical practice were formally consented during the consensus conference, explicitly considering different relevant aspects. The guideline was approved by the commissioning societies after an extensive internal and external review process. In this first part of the guideline, diagnostic means have been evaluated. The expert panel formally consented recommendations for the management of patients with (suspected) HZ, referring to the assessment of HZ patients, considering various specific clinical situations. Users of the guideline must carefully check whether the recommendations are appropriate for the context of intended application. In the setting of an international guideline, it is generally important to consider different national approaches and legal circumstances with regard to the regulatory approval, availability and reimbursement of diagnostic and therapeutic interventions.

DOCK8 regulates lymphocyte shape integrity for skin antiviral immunity

Zhang et al. show that DOCK8-deficient T and NK cells develop cell and nuclear shape abnormalities that do not impair chemotaxis but contribute to a form of cell death they term cytothripsis. Cytothripsis of DOCK8-deficient cells prevents the generation of long-lived skin-resident memory CD8 T cells resulting in impaired immune response to skin infection.

DOCK8 mutations result in an inherited combined immunodeficiency characterized by increased susceptibility to skin and other infections. We show that when DOCK8-deficient T and NK cells migrate through confined spaces, they develop cell shape and nuclear deformation abnormalities that do not impair chemotaxis but contribute to a distinct form of catastrophic cell death we term cytothripsis. Such defects arise during lymphocyte migration in collagen-dense tissues when DOCK8, through CDC42 and p21-activated kinase (PAK), is unavailable to coordinate cytoskeletal structures. Cytothripsis of DOCK8-deficient cells prevents the generation of long-lived skin-resident memory CD8 T cells, which in turn impairs control of herpesvirus skin infections. Our results establish that DOCK8-regulated shape integrity of lymphocytes prevents cytothripsis and promotes antiviral immunity in the skin.

Herpes simplex virus lymphadenitis: the elusive doppelganger in immunocompromised patients

Herpes simplex virus has protean manifestations and is an important cause of morbidity in the immunocompromised host. We report a case of recurrent lymphadenopathy and rash in a patient with chronic lymphocytic leukemia. The elusive clinical diagnosis eventually required core biopsy of a lymph node with immunohistochemistry and confirmation by polymerase chain reaction. This case illustrates the challenging clinical and laboratory diagnosis of herpes simplex virus lymphadenitis and the need to maintain a high index of suspicion for infection when treating an immunocompromised patient with unusual and/or persistent symptoms.

Varicella zoster virus infection in inflammatory bowel disease

BACKGROUND

The risk of viral infection is increased in immunosuppressed inflammatory bowel disease (IBD) patients. Varicella zoster virus (VZV) is of particular interest in IBD because of a number of reports of severe, disseminated, and occasionally fatal varicella infection in immunosuppressed IBD patients.

METHODS

We reviewed publications describing VZV infection in IBD patients and combined these data with a review of the current literature relating to both primary and secondary varicella in IBD.

RESULTS

Twenty cases of primary varicella infection and 32 cases of herpes zoster infection have been reported in IBD. Additional cases are reported in clinical trials. The risk of VZV infection is increased with all immunosuppressants used in IBD, but corticosteroids and combination immunosuppression appear to be a particular risk.

CONCLUSIONS

Healthcare providers need to be aware of the various manifestations of primary and secondary VZV infection in immunosuppressed IBD patients. Patients should be screened for VZV immunity and vaccinated prior to commencing immunosuppression.

Varicella-zoster virus infects human embryonic stem cell-derived neurons and neurospheres but not pluripotent embryonic stem cells or early progenitors

Pluripotent human stem cells are a powerful tool for the generation of differentiated cells that can be used for the study of human disease. We recently demonstrated that neurons derived from pluripotent human embryonic stem cells (hESC) can be infected by the highly host-restricted human alphaherpesvirus varicella-zoster virus (VZV), permitting the interaction of VZV with neurons to be readily evaluated in culture. In the present study, we examine whether pluripotent hESC and neural progenitors at intermediate stages of differentiation are permissive for VZV infection. We demonstrate here that VZV infection is blocked in naïve hESC. A block to VZV replication is also seen when a bacterial artificial chromosome (BAC) containing the VZV genome is transfected into hESC. In contrast, related alphaherpesviruses herpes simplex virus 1 (HSV-1) and pseudorabies virus (PrV) productively infect naïve hESC in a cell-free manner, and PrV replicates from a BAC transfected into hESC. Neurons differentiate from hESC via neural progenitor intermediates, as is the case in the embryo. The first in vitro stage at which permissiveness of hESC-derived neural precursors to VZV replication is observed is upon formation of "neurospheres," immediately after detachment from the inductive stromal feeder layer. These findings suggest that hESC may be useful in deciphering the yet enigmatic mechanisms of specificity of VZV infection and replication.

Fatal varicella in an immunocompromised adult associated with a European genotype E2 variant of varicella zoster virus

Varicella zoster virus (VZV) seronegative patients under immunosuppressive therapy are at risk for severe life-threatening varicella. A 25-year-old male patient presented with rash and hepatitis. He had been known to suffer from Crohn's disease and received immunosuppressive treatment with azathioprine. The patient showed dyspnoea, and presented with a generalized rash with vesicular lesions typical for herpesvirus infections. He was started immediately on acyclovir therapy. Varicella infection was determined in this VZV seronegative patient in rash vesicles, blood and tracheal secretions and a high VZV viral load was detected in these specimens. The causative agent was genotyped by sequencing of several genes as a variant of the European genotype E2 containing several unique single nucleotide polymorphisms. Despite all measures, there was progressive septic shock, and the patient died due to multi-organ failure. Immunocompromised adults without varicella history are at high risk to develop life-threatening complications of varicella. Antiviral therapy with acyclovir can only be successful when administered as early as possible on suspicion of varicella infection in this group of patients. The most effective method to prevent severe varicella in immunocompromised patients is active immunization prior to immunosuppressive therapy.

Visceral varicella zoster virus (VZV) after allogeneic hematopoietic stem cell transplant (HSCT) in pediatric patients with chronic graft-versus-host disease (cGVHD)

Reactivation of latent varicella zoster virus is one infectious complication associated with the extensive immunosuppression necessary for hematopoietic stem cell transplant. Most cases are limited to skin and mortality is low. Isolated visceral zoster is rare, presenting with ileus/abdominal pain, hepatitis, and/or hyponatremia. We present 2 cases of visceral varicella zoster virus in adolescents with chronic graft-versus-host disease after hematopoietic stem cell transplant. Both presented with elevated liver enzymes, severe abdominal pain, and hyponatremia but lacked cutaneous involvement. Both received high-dose acyclovir and showed improvement, but eventually expired from hepatic failure. The diagnosis of visceral zoster can be difficult especially without cutaneous manifestations. Vigilance is necessary in patients with chronic graft-versus-host disease, abdominal pain, and/or hepatitis and antiviral therapy should be initiated promptly.

Application of immunohistochemistry to infections

CONTEXT

Pathologists play an important role in the diagnosis or exclusion of infectious diseases. Traditionally, the diagnosis of infectious diseases rely on serologic assays and cultures. Serologic results may be difficult to interpret in the setting of immunosuppression, fresh tissue is not always available for culture, and culture of fastidious pathogens can be difficult and may take weeks or months to yield a result. Although some microorganisms or their cytopathic effects may be readily identifiable on routine and/or histochemical stains, often these changes are not specific or are sparse in the sample evaluated. In these cases, additional immunohistochemical stains are often needed to establish the diagnosis of infection.

OBJECTIVE

To review the current value and limitations of the use of immunohistochemistry in the diagnosis of infectious diseases in formalin-fixed tissue samples.

DATA SOURCES

Literature in Medline and the authors' own experience.

CONCLUSIONS

Immunohistochemistry has proven to be a useful tool in the diagnosis of infectious diseases in tissue samples. Immunohistochemistry is especially useful in the identification of microorganisms that are present in low numbers, stain poorly, are fastidious to grow, are noncultivable, or exhibit an atypical morphology. Finally, it is important to remember that there may be widespread occurrence of common antigens among bacteria and pathogenic fungi and both monoclonal and polyclonal antibodies must be tested for possible cross-reactivity with other organisms.

Occult herpes simplex virus colonization of bullous dermatitides

BACKGROUND

Acantholytic disorders, including pemphigus vulgaris, chronic benign familial pemphigus (Hailey-Hailey disease, superficial pemphigus), Darier disease, and Grover transient acantholytic dermatosis, as well as other vesiculo-bullous disorders, including bullous pemphigoid, epidermolysis bullosa, and atopic dermatitis, are prone to florid infections by herpes simplex virus (HSV)-I and -II, and, more rarely, by varicella-zoster virus (VZV). As these infections are difficult to recognize clinically and histologically, their frequency remains unknown. A possible occult viral colonization has never been documented in these disorders. The manner in which the primary bullous disorders are contaminated by herpesviridae remains unclear.

OBJECTIVE

To retrospectively assess the possible presence of HSV and VZV in a series of biopsies of acantholytic disorders and bullous pemphigoid.

METHOD

The typical alpha-herpesviridae-related cytopathic signs were searched for by conventional microscopy in skin biopsies of patients with bullous pemphigoid (n = 20), pemphigus vulgaris (n = 19), Darier disease (n = 18), chronic benign familial pemphigus (n = 3), and Grover transient acantholytic dermatosis (n = 3). Immunohistochemistry (IHC) targeted specific HSV-I, HSV-II, and VZV antigens. Polymerase chain reaction (PCR) was used for detecting HSV- and VZV-specific DNA sequences.

RESULTS

No cytopathic signs suggestive of HSV or VZV infection were detected. However, IHC revealed HSV antigens in Darier disease (1/18, HSV-I), Grover transient acantholytic dermatosis (1/3, HSV-I), pemphigus vulgaris (1/19, HSV-I), and bullous pemphigoid (2/20, HSV-I and HSV-II). In these IHC-positive cases, PCR amplified specific HSV primers in Darier disease (1/18), pemphigus vulgaris (1/19), and bullous pemphigoid (1/20). VZV antigens and nucleic acids were never identified. The HSV antigens were nearly always restricted to the upper part of the granular layer and thus differed from the usual HSV distribution during cutaneous infection. Negative and positive controls yielded consistently positive and negative results, respectively.

CONCLUSION

This report shows for the first time that clinically and histologically occult HSV colonization may occur in Darier disease, Grover transient acantholytic disease, pemphigus vulgaris, and bullous pemphigoid. Given the frequent use of immunosuppressive treatments for primary bullous disorders, greater awareness of HSV colonization and infection is recommended in these patients.

Acquired intestinal aganglionosis after a lytic infection with varicella-zoster virus

BACKGROUND AND PURPOSE

In this report, we present the first case of an immunologically impaired child surviving a lytic varicella-zoster virus infection affecting the enteric nervous system. In histological findings, myenteric and submucous enteric ganglia were nearly completely absent owing to virus infection.

METHODS

A 3-year-old girl with acute lymphoblastic leukemia and generalized varicella-zoster infection developed an ileus. She underwent multiple laparotomies in which histological sections of the entire small intestine could be obtained.

RESULTS

The histological evaluation of these samples showed a generalized aganglionosis with inflammatory residuals. A more detailed immunohistochemical analysis using neuronal (PGP, enolase), glial (S100), and lymphocytic (LCA) antibodies demonstrated a nearly complete neuronal loss.

CONCLUSION

To our knowledge, this is the first case of a secondary intestinal aganglionosis after varicella-zoster virus infection.

Oral antivirals revisited in the treatment of herpes zoster: what do they accomplish?

Oral antiviral agents currently represent the most important therapeutic keystone in the treatment of herpes zoster. Three oral antiviral agents are available for the treatment of herpes zoster: acyclovir, its derivative valacyclovir, and famciclovir. Meta-analysis of published data has shown that oral acyclovir significantly reduces various herpes zoster-related symptoms as well as the duration, intensity and prevalence of zoster-associated pain (ZAP). However, this drug does not influence postherpetic neuralgia. The newer agents famciclovir and valacyclovir exhibit a better oral bioavailability than acyclovir. These agents have demonstrated similar efficacy to acyclovir with ZAP and they require less frequent administration. When initiated within 72 hours, oral antiviral therapy of herpes zoster is beneficial in selected, elderly immunocompetent patients, reducing the duration and intensity of ZAP and providing more rapid skin lesion healing. Oral antivirals are also of benefit in immunocompromised patients with uncomplicated herpes zoster. However, signs of cutaneous and visceral dissemination should be monitored; if signs occur, intravenous antiviral therapy is indicated.

Atypical recurrent varicella in 4 patients with hemopathies

Relapsing varicella may occur in children with HIV infection and more rarely in younger adults. Our aim was to report unusual clinical, histologic, and virologic aspects of 4 elderly patients with malignant hemopathies who had an unusual form of recurrent varicella develop. Conventional microscopy, immunohistochemistry, and in situ hybridization were applied to smears and skin biopsy specimens. The patients presented a few dozen, scattered, large, papulovesicular lesions with central crusting. No zoster-associated pain or dermatomal distribution of the lesions was noted. Conventional microscopy revealed vascular changes and epidermal alterations typical for alpha-herpes virus infection. The varicella zoster virus major viral envelope glycoproteins gE and gB, and the immediate-early varicella zoster virus IE63 protein and the corresponding genome sequence for gE were detected on Tzanck smears; they were localized in endothelial cells and keratinocytes on skin biopsy specimens. The varicella zoster virus infection in endothelial cells, the vascular involvement, and the widespread distribution of the lesions suggest that the reported eruptions are vascular rather than neural in origin. These findings invalidate the diagnosis of herpes zoster but strongly support the diagnosis of recurrent varicella in an indolent and yet unreported presentation. Furthermore, these eruptions differ from relapsing varicella in children and young adults by the age of the patients, the paucity of clinical lesions, the larger diameter of the lesions and their peculiar clinical aspect, the significantly longer time interval between primary varicella and the recurrence, the prolonged healing time of the lesions, their mild disease course, and the fact that all the lesions are in the same stage of development.

Treatment of mucocutaneous presentations of herpes simplex virus infections

Infections by herpes simplex virus (HSV) types I and II are diverse and quite frequent. After primary infection, the virus establishes a life-long latency in the sensory ganglia and recrudescences may occur at an unpredictable rate. Recurrent labial and genital herpes infections represent the majority of clinical manifestations of HSV infections. Their management is currently well established using evidence-based medicine data. Primary labial herpes is generally not treated with antivirals in otherwise healthy children, although intravenous aciclovir may be offered in severe primary infections, particularly in the immunocompromised patient. The decision whether or not to treat recurrent labial herpes should be evaluated individually and depends on the frequency and severity of relapses, the impairment of the quality of life, and the cost of therapy. Patients with mild disease may benefit from topical therapy, and those with severe and frequent recurrences may be considered for intermittent or long-term oral antiviral therapy. Primary genital herpes is treated with oral or intravenous antivirals, depending on the severity of the infection and associated symptoms. Recurrent genital herpes can be managed with episodic short courses of oral antivirals in patients whose recurrences are moderate to severe and rare, and have a clear prodrome. Patients with >5 episodes/year, severe recurrences or unrecognisable prodromes may be best managed with long-term suppressive antiviral prophylaxis. HSV is also responsible for a variety of other clinical manifestations, including herpetic whitlow, neonatal infection, disseminated and atypical cutaneous infections, traumatic herpes, eczema herpeticum, and HSV-associated erythema multiforme. HSV infection may also represent a complication following cosmetic procedures of the oro-facial region, surgical and dental interventions, sun exposure and burns. Precise treatment guidelines for these HSV infections are not firmly established.

Disseminated herpes simplex virus and varicella zoster virus coinfection in a patient taking thalidomide for relapsed multiple myeloma

Disseminated herpes simplex virus (HSV) and varicella zoster virus (VZV) have been reported individually in immunosuppressed adults. We present a case of coinfection with disseminated HSV and VZV infection in a patient taking thalidomide for relapsed multiple myeloma. This is the first report of opportunistic infection associated with thalidomide.

Visceral zoster as the presenting feature of disseminated herpes zoster

Visceral dissemination of herpes zoster may follow cutaneous dissemination in immunocompromised patients. The skin is not necessarily the only organ affected and may not even be the presenting organ. Immunohistochemical stains available for routine paraffin-embedded tissue biopsy specimens allow for rapid diagnosis of varicella zoster virus. We describe a patient in whom gastric dissemination of herpes zoster was proven by immunohistochemistry. Unexplained hepatitis, pancreatitis, gastritis, or complaints of abdominal pain in immunocompromised patients with herpes zoster should prompt a high degree of suspicion for visceral zoster and immediate treatment with intravenous acyclovir.

Demonstration of varicella-zoster virus infection in the muscularis propria and myenteric plexi of the colon in an HIV-positive patient with herpes zoster and small bowel pseudo-obstruction (Ogilvie's syndrome)

Gastrointestinal symptomatology as a complication of herpes zoster (HZ) is extremely rare, with the majority of reported cases showing only temporal or radiological evidence of GI tract involvement by varicella zoster virus (VZV) infection. We present the first case of documented direct VZV infection in the muscularis propria of the gut presenting as intestinal pseudo-obstruction (Ogilvie's syndrome). The patient was a 34-yr-old HIV+ man who developed small bowel pseudo-obstruction in association with disseminated cutaneous HZ. A partial ileocolectomy specimen demonstrated a focal ulcer in the terminal ileum. Immunohistochemistry against VZV gpI demonstrated diffuse staining of the muscularis propria and myenteric plexi throughout the length of the specimen. Viral particles consistent with Herpesviridae were shown to be present ultrastructurally. We postulate that the viral infection in the neuronal plexi and muscularis propria caused muscle injury leading to pseudo-obstruction.

Rapid genotyping of varicella-zoster virus vaccine and wild-type strains with fluorophore-labeled hybridization probes

We developed a single-tube rapid method for the detection and differentiation of varicella-zoster virus (VZV) vaccine and wild-type strains that combines rapid-cycle PCR with wild-type-specific fluorescent probe melting profiles for product genotyping. A region including the polymorphic site in VZV open reading frame (ORF) 62 was amplified in the presence of two fluorescence-labeled hybridization probes. During the annealing step of the thermal cycling, both probes bound to their complementary sequences in the amplicon, resulting in resonance energy transfer, thus providing real-time fluorescence monitoring of PCR. Continuous acquisition of fluorescence data during a melting curve analysis at the completion of PCR revealed that loss of fluorescence occurred in a strain-specific manner as the detection probe, which was fully complementary to the wild-type VZV ORF 62 region, melted off the template. Use of this method allowed genotyping of samples within minutes after the completion of PCR, eliminating the need for post-PCR sample manipulation. In addition to reducing the time required to produce a result, this method substantially reduces the risk of contamination of the final product as well as the risk of sample tracking errors. The genotypes of 79 VZV-positive samples determined by this fluorescent resonance energy transfer (FRET) method were identical to the genotypes obtained by conventional PCR and restriction fragment length polymorphism analysis. The genotyping of VZV strains by the FRET method is a rapid and reliable method that is suitable for typing and that is also practical for use for the processing of large numbers of specimens.

Herpesvirus infection of the liver

The human herpesviruses can produce a wide variety of disease in the liver (Table 7). The immunocompromised host is particularly susceptible to hepatic manifestations of herpesvirus disease. CMV is the most common opportunistic pathogen in the immunocompromised patient. The clinical presentation of hepatic herpesvirus infection is often nonspecific. A high index of suspicion and rapid progression to liver biopsy to document viral replication (alpha- and betaherpesviruses) or outgrowth of virus-infected cells (gammaherpesviruses) can lead to lifesaving therapeutic interventions.

Chronic verrucous varicella zoster virus skin lesions: clinical, histological, molecular and therapeutic aspects

The outbreak of HIV infection introduced a new phenomenon in varicella zoster virus (VZV) pathology, namely the long-standing wart-like skin lesions that are frequently associated with resistance to thymidine kinase (TK)-dependent antiviral agents. This paper reviews the clinical, histological, and molecular aspects and the therapeutic management of these verrucous lesions. The majority of lesions are characterized by chronically evolving, unique or multiple wart-like cutaneous lesions. The main histopathological features include hyperkeratosis, verruciform acanthosis and VZV-induced cytopathic changes with scant or absent cytolysis of infected keratinocytes. The mechanism that establishes the chronic nature of the lesions appears to be associated with a particular pattern of VZV gene expression exhibiting reduced or nondetectable gE and gB synthesis. Drug resistance to TK-dependent antiviral agents is a result of nonfunctional or deficient viral TK. This necessitates alternative therapeutic management using antiviral agents that target the viral DNA polymerase.

Chronic herpes simplex virus type I glossitis in an immunocompromised man

Herpes simplex virus (HSV) type 1 (HSV-1) infection of the tongue commonly accompanies acute primary herpetic gingivostomatitis. However, recurrent infection of the tongue is exceptional and is restricted to immunocompromised individuals. A 57-year-old man with corticosteroid-dependent chronic obstructive pulmonary disease and sciatica presented with a chronic median glossitis due to HSV-1. The main clinical and histological feature was massive necrosis of the entire mucosa. Immunohistochemistry demonstrated a considerable amount of HSV gB, gC and gD envelope glycoproteins dispersed in the chorion. In contrast, HSV-1 DNA was detected only in a limited number of epithelial cells using in situ hybridization. The extent of necrosis and the pattern of viral DNA and envelope protein distribution represent unique features of median herpetic glossitis, which are not found in more common types of HSV infection.

Current pharmacological approaches to the therapy of varicella zoster virus infections: a guide to treatment

Varicella zoster virus (VZV), a member of the herpesvirus family, is responsible for both primary (varicella, chickenpox) as well as reactivation (zoster, shingles) infections. In immunocompetent patients, the course of varicella is generally benign. For varicella zoster, post-herpetic neuralgia is the most common complication. In immunocompromised patients (particularly those with AIDS), transplant recipients and cancer patients, VZV infections can be life-threatening. For these patients and also for immunocompetent patients at risk such as pregnant women or premature infants, the current treatment of choice is based on either intravenous or oral aciclovir (acyclovir). The low oral bioavailability of aciclovir, as well as the emergence of drug-resistant virus strains, have stimulated efforts towards the development of new compounds for the treatment of individuals with VZV infections. Among these new compounds, penciclovir, its oral prodrug form famciclovir and the oral pro-drug form of aciclovir (valaciclovir), rank among the most promising. As with aciclovir itself, all of these drugs are dependent on the virus-encoded thymidine kinase (TK) for their intracellular activation (phosphorylation), and, upon conversion to their triphosphate form, they act as inhibitors/alternative substrate of the viral DNA polymerase. Therefore, cross-resistance to these drugs may be expected for those virus mutants that are TK-deficient and thus resistant to aciclovir. Other classes of nucleoside analogues dependent for their phosphorylation on the viral TK that have been pursued for the treatment of VZV infections include sorivudine, brivudine, fialuridine, fiacitabine and netivudine. Among oxetanocins, which are partially dependent on viral TK, lobucavir is now under clinical evaluation. Foscarnet, which does not require any previous metabolism to interact with the viral DNA polymerase, is used in the clinic when TK-deficient VZV mutants emerge during aciclovir treatment. TK-deficient mutants are also sensitive to the acyclic nucleoside phosphonates (i.e. [s]-1-[3-hydroxy-2-phosphonylmethoxypropyl]cytosine; HPMPC); these agents do not depend on the virus-encoded TK for their phosphorylation but depend on cellular enzymes for conversion to their diphosphoryl derivatives which then inhibit viral DNA synthesis. Vaccination for VZV has now come of age. It is recommended for healthy children, patients with leukaemia, and patients receiving immunosuppressive therapy or those with chronic diseases. The protection induced by the vaccine seems, to some extent, to include zoster and associated neuralgia. Passive immuniatin based on specific immunoglobulins does not effectively prevent VZV infection and is therefore restricted to high risk individuals (i.e. immunocompromised children and pregnant women).

In situ hybridization and its diagnostic applications in pathology

In situ hybridization (ISH) is a technique by which specific nucleotide sequences are identified in cells or tissue sections. These may be endogenous, bacterial or viral, DNA or RNA. On the basis of research applications, the technique is now being translated into diagnostic practice, mainly in the areas of gene expression, infection and interphase cytogenetics. Diagnostic applications are most often based on short nucleotide sequences (oligomers) labelled with non-isotopic reporter molecules, and sites of binding may be localized by histochemical or immunohistochemical methods. The technique can be applied to routinely fixed and processed tissues; with some targets, it is even possible to obtain hybridization in autopsy material. ISH has been used to detect messenger RNA (mRNA) as a marker of gene expression, where levels of protein storage are low; for example, to confirm an endocrine tumour as the source of excess hormone production. Its application in infectious diseases has to date been mainly in viral infections, such as the typing of human papillomavirus (HPV) or the detection of Epstein-Barr virus by the presence of small nuclear RNAs (EBERs). The expression of mRNAs for histone proteins has been used to detect cells in S phase, and related methods may be applied to detect apoptotic cells. Using probes to chromosome-specific sequences, it is possible to detect aneuploidy, and to document changes in specific chromosomes, which may have prognostic significance in some tumours, such as B-cell chronic lymphatic leukaemia. Using sequence-specific probes, translocations can be identified, such as the t(11;12) of Ewing's sarcoma. This review presents an outline of the technique of in situ hybridization and discusses areas of current and potential diagnostic application.