Molecular diagnosis of visceral herpes zoster

Visceral disseminated varicella zoster virus infection during non-intensive maintenance therapy in a patient with systemic lupus erythematosus

Visceral disseminated varicella zoster virus infection (VD-VZV) is a rare complication in immunocompromised patients. Although systemic lupus erythematosus (SLE) patients have a higher risk of VZV infection, only a few reports describe VD-VZV in SLE. Here, we report a 48-year-old woman with SLE who had received maintenance therapy. She was transferred to the hospital because of severe epigastric pain. There were no significant abnormalities in abdominal computed tomography and upper gastrointestinal endoscopy. On hospital day 4, she developed vesicular eruption on her face and abdomen. VZV antigen was detected in specimens obtained from skin lesions, and treatment with acyclovir was started. VZV DNA in blood turned out to be positive, and the epigastric pain was thought to be caused by VD-VZV. There is a risk of VD-VZV in patients with SLE, even in those receiving non-intensive maintenance therapy.

Visceral disseminated varicella zoster infection: a rare cause of acute abdomen in a patient with well-controlled diabetes mellitus-a case report

BACKGROUND

Visceral disseminated varicella zoster virus (VZV) infections frequently affect immunocompromised patients. Diabetes mellitus has been associated with VZV infection, and most cases of disseminated infection involve patients with poorly controlled blood glucose levels. It initially presents as severe abdominal pain, which is evaluated as an acute abdomen, however, the cause is typically unidentified due to unremarkable computed tomography (CT) findings. We report a case of visceral disseminated VZV infection in a patient with well-controlled diabetes mellitus with fat stranding around the celiac and superior mesenteric artery on CT.

CASE PRESENTATION

A 61-year-old Japanese woman with well-controlled diabetes mellitus presented to the emergency department with severe abdominal pain that gradually worsened. She had stable vital signs and skin rashes, suggestive of varicella. Abdominal CT showed fat stranding around the celiac and superior mesenteric arteries. The patient tested positive for the VZV antigen and was diagnosed with a visceral disseminated VZV infection. Acyclovir was administered, and the patient was discharged on the 14th day.

CONCLUSIONS

Visceral disseminated VZV infection may affect patients with well-controlled diabetes mellitus and causes acute abdomen. Periarterial fat stranding on CT is associated with abdominal pain due to visceral disseminated VZV infection.

A fatal case of severe systemic varicella zoster infection in a patient with chronic use of immunosuppressive agents for cutaneous vasculitis

•

Varicella zoster virus infection can cause severe complication in immunocompromised patients.

•

Early parenteral antiviral therapy is mandatory for preventing severe complication of varicella zoster virus infection.

•

Post exposure prophylaxis varicella zoster immunoglobulin is beneficial for immunocompromised patients.

Acute varicella zoster virus (VZV) infection is a common condition in children, which is considered a mild, self-limited disease with diffuse skin vesicular rash. However, disseminated VZV infection with multiple organ involvement can occur in immunocompromised patients with impaired T cell immunity including solid or hematopoietic stem cell transplant recipients, receiving immunosuppressive therapy, leukemia, lymphoma, and HIV infection. Prompt antiviral therapy is mandatory in those immunocompromised persons. A 52 year-old man receiving chronic immunosuppressive drugs for his underlying leukocytoclastic vasculitis visited emergency department for diffuse skin vesicular rash that developed 4 days after contact with varicella zoster patients at his office. Despite prompt initiation of oral antiviral agents had been prescribed, rapid progression with septic shock, lactate acidosis, and disseminated intravascular coagulopathy occurred. The patient died within 24 h of intensive care unit admission. Varicella zoster infection commonly causes severe complications in adults receiving chronic immunosuppressive therapy. Post exposure prophylaxis varicella zoster immune globulin and early parenteral antiviral agents use after acute varicella virus infection may be mandatory in immunocompromised patients.

Disseminated Varicella zoster infection with abdominal pain and periarterial fat stranding in a patient taking pomalidomide

Background

Disseminated Varicella zoster virus infection (DVI) is a severe infection associated with severe abdominal pain of unknown cause. We report a case in which periarterial (the celiac artery and superior mesenteric artery) fat stranding (PFS) on computed tomography (CT) was the presumed cause of abdominal pain in a patient taking pomalidomide.

Case Presentation

A 62-year-old woman was admitted to our hospital with abdominal pain. Her medical history was multiple myeloma treated with pomalidomide. Computed tomography showed no remarkable findings on admission, but 1 day later, a contrast-enhanced CT showed PFS. A skin eruption appeared on day 4 and we started acyclovir. On day 10, Varicella zoster virus antigen and antibody tests were positive, confirming the diagnosis of DVI. The abdominal pain subsequently improved, together with the PFS, and she was discharged.

Conclusion

When patients present with severe abdominal pain and PFS, DVI and acyclovir must be considered.

Frequency of subclinical herpes zoster in pediatric hematology-oncology patients receiving chemotherapy: A retrospective cohort analysis

Varicella-zoster virus (VZV) reactivation from the enteric nervous system can cause ileus (Ogilvie's syndrome) in adult patients. Since no pediatric cases have been described, we sought to retrospectively analyze VZV reactivation in pediatric hematology-oncology patients to determine whether VZV infection including subclinical VZV reactivation can induce gastrointestinal complications such as Ogilvie's syndrome. Thirty-five patients who received chemotherapy at our institution between September 2013 and June 2018 were included. Serum samples were collected weekly during hospitalization and every 3 months during outpatient maintenance chemotherapy. A real-time polymerase chain reaction assay was used to measure VZV DNA load in serum. The clinical features of patients with VZV infection were retrospectively analyzed. Of 1165 serum samples, 7 (0.6%) were positive for VZV DNA. VZV DNA was detected in 3 of 35 patients. In patient A, VZV DNA was detected during two episodes. The first episode involved varicella-like eruptions caused by the Oka VZV vaccine strain. The second episode involved herpes zoster (HZ) caused by the same strain. Patients B and C had a clinical course that was typical for HZ caused by wild-type VZV. No gastrointestinal symptoms were observed at the time of VZV infection in these three patients. VZV DNA was not detected in any other samples. No pediatric cases with Ogilvie's syndrome caused by VZV reactivation were demonstrated in this cohort. Additionally, no subclinical VZV reactivation was found in this cohort. Further study is needed to elucidate the precise incidence of pediatric Ogilvie's syndrome caused by VZV reactivation.

[Opportunistic infections by human herpes viruses]

Infections in immunosuppressed patients represent a particular challenge in the diagnostics and treatment. They often present with atypical and particularly severe courses, for which rapid diagnostics and treatment are decisive for treatment success. Opportunistic infections with human herpes viruses occur not only more frequently in immunocompromised patients compared to healthy people but also represent a special challenge. In the treatment of immunosuppressed patients, e.g. with human immunodeficiency virus infections and patients with solid organ transplantations, infections with herpes simplex virus, varicella zoster virus, Epstein-Barr virus and cytomegalovirus are particularly important. The symtoms are very variable, ranging from asymptomatic detection of viremia to vital life-threatening organ manifestations. This review article describes the most important clinical presentations of these opportunistic infections. Furthermore, the diagnostic, therapeutic and prophylactic strategies for human herpes viruses are summarized.

Disseminated varicella-zoster virus infection with abdominal pain possibly caused by pirfenidone: A case report

We report a case of chronic hypersensitivity pneumonitis treated with pirfenidone in a 76-year-old woman who complained of acute-onset abdominal pain and rashes. The patient was diagnosed with disseminated varicella-zoster virus (VZV) infection, and pirfenidone was discontinued. Her condition improved in one month. Pirfenidone may induce disseminated VZV infection.

Thoracic and abdominal pain in a 28-year-old woman with a failing kidney transplant

This case report describes a young, immunocompromised patient who presented with thoracic pain. After an extensive workup, she was diagnosed with a varicella zoster virus infection with involvement of the gastric mucosa, pancreas and lungs for which she was treated with acyclovir. Although the viral load decreased significantly, the patient had persistent postherpetic neuralgia and nausea.

Varicella-Zoster Virus and the Enteric Nervous System

Varicella zoster virus (VZV) infects and becomes latent in sensory, enteric, and other autonomic neurons during the viremia of varicella. Reactivation of VZV in neurons that project to the skin causes the rash of zoster; however, reactivation of VZV in enteric neurons can cause a painful gastrointestinal disorder ("enteric zoster") without cutaneous manifestations. Detection of VZV DNA in saliva of patients with gastrointestinal symptoms may suggest enteric zoster. This diagnosis is reinforced by observing a response to antiviral therapy and can be confirmed by detecting VZV gene products in intestinal mucosal biopsies. We developed an in vivo guinea pig model that may be useful in studies of VZV latency and reactivation. VZV-infected lymphocytes are used to induce latent infection in sensory and enteric neurons; evidence suggests that exosomes and stimulator of interferon genes (STING) may, by preventing proliferation play roles in the establishment of neuronal latency.

Herpes Zoster in the Older Adult

Herpes zoster (HZ) is the result of reactivation of latent varicella zoster virus (VZV) and occurs most frequently in older adults. Classically, HZ presents as a unilateral, selflimited, dermatomal rash. Postherpetic neuralgia (PHN) is a common sequela, presenting as severe pain that persists after the rash has resolved. In the elderly, PHN can be debilitating and requires a prompt diagnosis, treatment with antivirals, and adequate pain control. A longer-term pain management strategy is required if PHN occurs. A modestly effective vaccine exists and is recommended for older individuals.

Increased risk of varicella zoster virus infection in inflammatory bowel disease in an Asian population: a nationwide population-based cohort study

PURPOSE

Whether patients with inflammatory bowel disease (IBD) exhibit a high risk of developing varicella zoster virus (VZV) infection in Asian populations remains inconclusive. We investigated the causal relationship between two diseases by analysing the Taiwan National Health Insurance Research Database.

PATIENTS AND METHODS

Based on a universal insurance claims database, we enrolled 7055 IBD patients and 28,220 age- and sex-matched controls. We calculated the hazard ratios (HRs) and 95% confidence intervals (CIs) of the herpes zoster virus (HZV) in the IBD and comparison cohorts, using the Cox proportional hazards regression model.

RESULTS

Patients with IBD exhibited significantly higher risk of the HZV compared with the controls (adjusted HRs, 1.42; 95% CI, 1.27-1.60). Further analysis indicated that male patients (adjusted HRs, 1.61; 95% CI, 1.35-1.92), aged 35-44 (adjusted HRs, 1.47; 95% CI, 1.08-2.01) and aged 65 years and older (adjusted HRs, 1.47; 95% CI, 1.19-1.80), and patients without comorbidities (adjusted HRs, 1.44; 95% CI, 1.26-1.66), exhibited excessive risks of VZV infection. Moreover, our findings show that the overall risk of developing VZV infection increased risk from 1.03 (95% CI, 0.90-1.18) (≤ 2 visits) to 9.76 (95% CI, 7.60-12.5) (> 4 visits), which correlates positively with the frequency of medical visits (trend test p < 0.0001).

CONCLUSION

Patients with IBD, particularly men aged 35-44/65 years and over, and patients without comorbidities, are associated with a long-term risk of VZV infection. The excessive risk of VZV infection should be considered for administering vaccines to IBD patients.

Diagnóstico e manejo do herpes-zóster pelo médico de família e comunidade

O herpesvírus que causa a varicela (catapora) persiste de forma latente no sistema nervoso, podendo se reativar e propagar através das raízes nervosas e se manifestar de forma tardia através de lesões cutâneas dolorosas, condição essa denominada herpes-zóster. O diagnóstico é primariamente clínico, devendo ser feito diagnóstico diferencial com impetigo, dermatite de contato, dermatite herpetiforme e, também, com o próprio herpes simples. Uma vez confirmado o diagnóstico, o tratamento deve ser instituído nas primeiras 72 horas após a erupção das lesões e tem como base a terapia antiviral. Dentre os antivirais, o valaciclovir e o fanciclovir têm eficácia superior quando comparados ao aciclovir. A complicação mais frequente do herpes-zóster é a neuralgia pós-herpética, usualmente manejada com antidepressivos tricíclicos, anticonvulsivantes, lidocaína tópica ou capsaicina. Recentemente foi introduzida no Brasil uma vacina de vírus atenuado para o herpes-zóster, composta pelo mesmo vírus da vacina contra varicela, porém em concentração maior. Entretanto, essa vacina ainda apresenta custo elevado e não está disponível no Sistema Único de Saúde.

Varicella-zoster virus (VZV) infection as a possible cause of Ogilvie's syndrome in an immunocompromised host

We describe an immunodeficient adult with Ogilvie's syndrome preceding a disseminated papulovesicular skin rash in whom varicella-zoster virus infection was demonstrated by PCR assay in cutaneous and colonic biopsy specimens. In view of the significant morbidity and mortality that this condition carries, early and accurate molecular diagnosis and timely treatment are strongly recommended.

Clinical features and risk factors for developing varicella zoster virus dissemination following hematopoietic stem cell transplantation

BACKGROUND

We retrospectively analyzed 80 instances of varicella zoster virus (VZV) disease in 72 patients who underwent allogeneic hematopoietic stem cell transplantation (HSCT) and examined the clinical differences between localized and disseminated disease. Risk factors for developing VZV dissemination were also evaluated.

RESULTS

Of the 80 instances, 54 instances were localized diseases and 26 were disseminated diseases. Patient characteristics did not differ significantly between the 2 groups, except for the first-line therapy and the duration from symptom onset to treatment. In the disseminated group, intravenous acyclovir was used as the first-line therapy more frequently, and more time elapsed before beginning antiviral therapy compared with the localized group. In multivariate analyses, the duration from symptom onset to treatment was identified as an independent risk factor that significantly affected the development of VZV dissemination. Gender, total body irradiation, and chronic graft-versus-host disease, of which the latter 2 factors were reported as risk factors for the development of VZV disease after HSCT, did not affect the development of VZV dissemination.

CONCLUSION

Our results suggest that VZV infection or reactivation may easily progress to viremia with delayed use of antiviral agents and may result in VZV dissemination in immunocompromised patients.

Clinical practice: Herpes zoster

A 65-year-old man presents with a rash of 2 days duration over the right forehead with vesicles and pustules, a few lesions on the right side and tip of the nose, and slight blurring in the right eye. The rash was preceded by tingling in the area and is now associated with aching pain. How should this patient be evaluated and treated?

Application of molecular diagnostic techniques for viral testing

Nucleic acid amplification techniques are commonly used currently to diagnose viral diseases and manage patients with this kind of illnesses. These techniques have had a rapid but unconventional route of development during the last 30 years, with the discovery and introduction of several assays in clinical diagnosis. The increase in the number of commercially available methods has facilitated the use of this technology in the majority of laboratories worldwide. This technology has reduced the use of some other techniques such as viral culture based methods and serological assays in the clinical virology laboratory. Moreover, nucleic acid amplification techniques are now the methods of reference and also the most useful assays for the diagnosis in several diseases. The introduction of these techniques and their automation provides new opportunities for the clinical laboratory to affect patient care. The main objectives in performing nucleic acid tests in this field are to provide timely results useful for high-quality patient care at a reasonable cost, because rapid results are associated with improvements in patients care. The use of amplification techniques such as polymerase chain reaction, real-time polymerase chain reaction or nucleic acid sequence-based amplification for virus detection, genotyping and quantification have some advantages like high sensitivity and reproducibility, as well as a broad dynamic range. This review is an up-to-date of the main nucleic acid techniques and their clinical applications, and special challenges and opportunities that these techniques currently provide for the clinical virology laboratory.

Molecular diagnosis and management of viral infections in hematopoietic stem cell transplant recipients

Viral infections after allogeneic hematopoietic stem cell transplantation (HSCT) are important complications associated with high morbidity and mortality. In this setting, reactivations of persisting latent viral pathogens from donor and/or recipient cells play a central role whereas the sterile environment of transplant units renders new infections less likely. The viruses currently regarded as most relevant in the HSCT setting include particularly the herpes virus family--specifically cytomegalovirus (CMV), Epstein-Barr virus (EBV), and human herpesvirus 6 (HHV-6)--as well as human adenoviruses (AdVs) and the polyoma virus BK (BKV). Timely detection and monitoring of virus copy numbers are prerequisites for successful preemptive treatment approaches. Pre- and post-transplant surveillance by sensitive and quantitative molecular methods has therefore become an essential part of the diagnostic routine. In this review, we discuss diagnostic aspects and the clinical management of the most important viral infections in HSCT recipients, with a focus on pediatric patients.

Varicella zoster virus meningoencephalitis accompanied by rhabdomyolysis without skin eruption

We report a case of a 38-year-old man with a Varicella zoster virus (VZV) reactivation who manifested meningoencephalitis accompanied by rhabdomyolysis without a skin eruption. During the acute phase, VZV DNA was detected in serum and cerebrospinal fluid (CSF) by the polymerase chain reaction (PCR). After 16 days, all symptoms and signs resolved, and follow-up PCR studies revealed negative conversion of VZV in the serum and CSF. We discuss the possible underlying mechanism of VZV reactivation in our patient. This is the first case report of VZV reactivation meningoencephalitis accompanied by rhabdomyolysis without skin eruption demonstrated by viral DNA in the serum and CSF.

Compartmentalization of acyclovir-resistant varicella zoster virus: implications for sampling in molecular diagnostics

BACKGROUND

Acyclovir resistance of varicella zoster virus (VZV) may arise in stem cell transplant (SCT) recipients with VZV disease and is usually a result of mutations in VZV thymidine kinase (TK), which is the target protein of acyclovir. Early detection of such mutations is necessary to enable timely therapy adaptation, for example, to foscarnet. We aimed to investigate whether TK mutations arise over time, and what sample types might be the most useful for this method.

METHODS

Spatially and temporally distinct samples from 3 SCT recipients with VZV disease unresponsive to acyclovir treatment were retrospectively investigated for the presence of TK mutations by polymerase chain reaction and sequence analysis.

RESULTS

In all 3 patients, a mutation in the VZV TK coding region was found resulting in an amino acid substitution. TK mutations were not only temporally but also spatially compartmentalized. In particular, plasma samples frequently showed wild-type TK sequences, whereas cerebrospinal fluid or skin vesicle fluid acquired on the same day contained mutant sequences.

CONCLUSIONS

This study shows the importance of careful sampling for molecular diagnostics of acyclovir resistance in VZV disease. All affected body sites should be sampled and plasma samples may not be representative for the viral mutation status.

Disseminated varicella with multiorgan failure in an immunocompetent adult

A case of fulminant disseminated varicella is reported in a 28-year-old immunocompetent man. He developed hepatitis, severe pneumonia, rhabdomyolysis and disseminated intravascular coagulation, followed by encephalopathy and multiorgan failure despite acyclovir therapy. He spent a total of 3.5 months in intensive care and rehabilitation units. Real-time PCR yielded a rapid diagnosis of varicella-zoster virus (VZV) infection and was used to monitor plasma viral load for 56 days. Plasma viral load peaked at 7.1 log(10)/ml on day 4 after symptom onset, then gradually declined and became undetectable after between 1 and 2 months; viral load in lung fluid followed a similar pattern. The glycoprotein E variant associated with increased VZV virulence was not detected, and the VZV thymidine kinase gene bore no major mutations associated with acyclovir resistance. This case serves as a reminder that varicella can be life-threatening in adults and that vaccination of individuals at risk remains essential.

Management of HSV, VZV and EBV infections in patients with hematological malignancies and after SCT: guidelines from the Second European Conference on Infections in Leukemia

These guidelines on the management of HSV, VZV and EBV infection in patients with hematological malignancies and after SCT were prepared by the European Conference on Infections in Leukemia following a predefined methodology. A PubMed search was conducted using the appropriate key words to identify studies pertinent to management of HSV, VZV and EBV infections. References of relevant articles and abstracts from recent hematology and SCT scientific meetings were also reviewed. Prospective and retrospective studies identified from the data sources were evaluated, and all data deemed relevant were included in this analysis. The clinical and scientific background was described and discussed, and the quality of evidence and level of recommendation were graded according to the Centers for Disease Control criteria.

Triad of severe abdominal pain, inappropriate antidiuretic hormone secretion, and disseminated varicella-zoster virus infection preceding cutaneous manifestations after hematopoietic stem cell transplantation: utility of PCR for early recognition and therapy

A hematopoietic stem cell transplant recipient developed abdominal pain, pneumatosis intestinalis, hepatitis, pancreatitis, and inappropriate antidiuretic hormone secretion. Blood for varicella-zoster virus (VZV) DNA polymerase chain reaction was positive. She was treated with acyclovir and subsequently developed VZV antigen-positive zoster. Detection of VZV DNA in blood may be useful for early diagnosis in immunocompromised hosts who present with zoster without skin lesions.

Herpes simplex and varicella zoster viruses: forgotten but not gone

Herpesvirus infections are common complications of organ transplantation. The most frequent herpesvirus infections are caused by cytomegalovirus (CMV), herpes simplex (HSV) and varicella zoster (VZV). Despite expansion of the therapeutic armamentarium, HSV and VZV continue to cause morbidity and occasional mortality in transplant recipients. Here we review the incidence and risk factors for HSV and VZV disease, their clinical presentation, effects of newer immunosuppressive regimens and prophylaxis for HSV and VZV in solid organ transplant recipients.

Clinical relevance of quantitative varicella-zoster virus (VZV) DNA detection in plasma after stem cell transplantation

Detection of Varicella-Zoster virus (VZV) DNA in plasma can facilitate the early recognition of complicated VZV-infection in immunocompromised hosts. The correlation of VZV-DNA in plasma with clinical presentations of VZV-infection and subsequent aciclovir treatment in allogeneic stem cell transplant (allo-SCT) recipients was studied. In 81 consecutive VZV-IgG positive allo-SCT recipients, VZV-DNA was measured at regular time points (1, 2 and 4 months) following allo-SCT and patient records were screened for VZV-related symptoms and aciclovir treatment. Subsequently, possible VZV-cases were studied in detail for the course of VZV-DNA and treatment effects. During the initial screening, VZV-DNA was detectable in seven patients. The survey of VZV-related symptoms revealed five additional possible VZV-cases. In cases where suitable plasma samples were available (10 out of 12), VZV-DNA was present almost simultaneously with the first clinical manifestations. No evidence of a preceding phase detectable by VZV-DNA only could be observed. Treatment with aciclovir was associated with a prompt reduction of VZV-DNA load. Detection of VZV-DNA in plasma in allo-SCT recipients accurately reflected the clinical presentation of VZV-infection and treatment with aciclovir. VZV-DNA detection in plasma of allo-SCT recipients appears clinically relevant as this may support early recognition and therapeutic management of VZV-infections following allo-SCT.

Retrospective analysis of varicella zoster virus (VZV) copy DNA numbers in plasma of immunocompetent patients with herpes zoster, of immunocompromised patients with disseminated VZV disease, and of asymptomatic solid organ transplant recipients

BACKGROUND

Varicella zoster virus (VZV) causes significant morbidity and mortality in immunocompromised patients. Subclinical reactivation has been described in solid organ recipients and has been associated with graft versus host disease in bone marrow transplantation. Newer studies assessing the prevalence and impact of subclinical VZV reactivation in solid organ transplant (SOT) recipients are lacking.

METHODS AND RESULTS

In a first step we developed a highly sensitive quantitative polymerase chain reaction (qPCR) assay for VZV DNA with a detection limit of < or = 20 copies/mL. Using this assay, we retrospectively analyzed plasma samples of different patient groups for VZV DNA. VZV DNA was found in 10/10 plasma samples of immunocompetent patients with herpes zoster (VZV copy numbers/mL: mean+/-SEM 1710+/-1018), in 1/1 sample of a human immunodeficiency virus-infected patient with primary VZV disease (15,192 copies/mL) and in 4/4 plasma samples of immunocompromised patients with visceral VZV disease (mean of first value 214,214+/-178,572). All 108 plasma samples of asymptomatic SOT recipients off any antiviral therapy, randomly sampled over 1 year, were negative for VZV DNA.

CONCLUSION

Our qPCR assay proved to be highly sensitive (100%) in symptomatic VZV disease. We did not detect subclinical reactivation in asymptomatic SOT recipients during the first post-transplant year. Thus, subclinical VZV reactivation is either a rare event or does not exist. These data need to be confirmed in larger prospective trials.

Chickenpox

PURPOSE OF REVIEW

Varicella-zoster virus (VZV) remains a public health issue around the globe despite the availability of a live attenuated vaccine and several highly active antiviral agents. A program of universal infant vaccination against varicella was introduced in the US almost 10 years ago. Epidemiological data continue to accumulate that will inform decision-making on vaccine use elsewhere. These findings, together with relevant advances in VZV virology, form the substance of this review.

RECENT FINDINGS

Understanding of the pathogenesis of varicella has significantly advanced with the demonstration that the cation-independent mannose 6-phosphate receptor is critical to both entry and egress of enveloped VZV. While our knowledge of intervening events remains sketchy, the future study of VZV will be facilitated by the recent successful cloning of the VZV genome into a bacterial artificial chromosome. Models of latency and reactivation are also being developed, which may help us to understand the epidemiology of herpes zoster in vaccinated populations. Continued evidence of decline in the incidence of varicella, associated hospitalizations and deaths suggests that the vaccine as used in the US is highly effective. However, rates of breakthrough disease are significant and sufficient to sustain outbreaks, even among highly vaccinated populations. This is so despite the generally reduced infectiousness of varicella occurring in vaccinated individuals. There is some evidence of attrition of the immune response over time following immunization in a small proportion of vaccinees.

SUMMARY

Our ability to prevent and treat varicella still outstrips our knowledge of pathogenetic and immune mechanisms. Further clinical advances are likely to arise from growing understanding of VZV biology.

Rapid detection of varicella-zoster virus infection by a loop-mediated isothermal amplification method

The reliability of varicella-zoster virus (VZV) loop-mediated isothermal amplification (LAMP) was evaluated for rapid diagnosis of viral infection. VZV-specific primers only amplified VZV DNA; no LAMP products were observed in reactions performed with other viral DNA templates. The specificity of this method was confirmed by two independent determinations, agarose gel electrophoresis and a turbidity assay. The sensitivity of VZV LAMP, determined by agarose gel electrophoresis, were 500 copies/tube. Detection using the turbidity assay, however, gave a sensitivity of 1,000 copies/tube. After these initial validation studies, reliability of VZV LAMP was evaluated for the detection of viral DNA in clinical specimens. Thirty-two swab samples collected from patients with vesicular skin eruptions were tested for VZV DNA. VZV was confirmed in sample numbers 10-32 by VZV real-time PCR, a previously established technique. VZV LAMP products were detected using turbidity from samples 13 to 32 (sensitivity; 87.0%, specificity; 100%, positive predictive value; 100%, negative predictive value; 75%). Although low levels of VZV DNA could be detected in the three samples exhibiting divergent results (samples numbers 10-12), no VZV LAMP product was detected in these samples, indicating a higher detection limit for this assay. Requirement of a DNA extraction step in the VZV LAMP method was examined in next experiment. The turbidity assay detected a VZV LAMP product in all of the 20 positive swab samples (samples numbers 13-32), regardless of DNA extraction.

Severe acute visceral pain from varicella zoster virus

Varicella zoster virus infection often will not present in the characteristic dermatomal distribution of vesicles in patients who have undergone bone marrow transplantation. We cared for a 51-yr-old man with severe abdominal pain after bone marrow transplantation for non-Hodgkin's lymphoma. The diagnosis of varicella zoster was not entertained until he developed a diffuse vesicular rash several days after the onset of pain. We report this case to alert others who may be consulted regarding pain management options for similar oncology patients.

IMPLICATIONS

We report a patient with lymphoma, prior bone marrow transplant, and acute visceral pain for whom IV opioids in large doses proved inadequate. An interventional pain management technique was considered until characteristic varicella vesicles appeared over the patient's trunk. We report this case to alert others who treat oncology patients that the diagnosis of visceral zoster should be considered when patients who have undergone bone marrow transplantation present with severe visceral pain.