Laboratory Diagnosis of Herpesvirus Infections

Diagnostic Methods and Management Strategies of Herpes Simplex and Herpes Zoster Infections

Herpesviruses are medium-sized double-stranded DNA viruses. Of more than 80 herpesviruses identified, only 9 human herpesviruses have been found to cause infection in humans. These include herpes simplex viruses 1 and 2 (HSV-1 and HSV-2), varicella-zoster virus (VZV), human cyto-megalovirus (HCMV), Epstein-Barr virus (EBV), and human herpesvirus (HHV-6A, HHV-6B, HHV-7, HHV-8). HSV-1, HSV-2, and VZV can be problematic given their characteristic neurotropism which is the ability to invade via fusion of its plasma membrane and reside within neural tissue. HSV and VZV primarily infect mucocutaneous surfaces and remain latent in the dorsal root ganglia for a host's entire life. Reactivation causes either asymptomatic shedding of virus or clinical manifestation of vesicular lesions. The clinical presentation is influenced by the portal of entry, the immune status of the host, and whether the infection is primary or recurrent. Affecting 60% to 95% of adults, herpesvirus-associated infections include gingivostomatitis, orofacial and genital herpes,and primary varicella and herpes zoster. Symptomatology, treatment, and potential complications vary based on primary and recurrent infections as well as the patient's immune status.

Metagenomic Analysis of DNA Viruses with Targeted Sequence Capture of Canine Lobular Orbital Adenomas and Normal Conjunctiva

Our study aims are: (1) to evaluate phenotypically normal canine conjunctival and orbital tissue and tissue from canine lobular orbital adenomas (CLOAs) for the presence of viral genomic material and (2) phylogenetically classify detected DNA viruses to determine if a DNA virus is associated with CLOAs. A total of 31 formalin fixed paraffin embedded CLOA tissue samples, 4 papillomas or sarcoid, and 10 fresh clinically normal conjunctival tissues were included in this study. Genomic DNA was isolated from all samples and sequencing libraries were prepared. The libraries were molecularly indexed and pooled and viral DNA was enriched via targeted sequence capture utilizing ViroCap. The libraries were sequenced on the Illumina HiSeq platform and compared to known viral DNA reference genomes to identify viral DNA. Carnivore parvovirus was identified in 6.4% and 20% of CLOA tissue and normal conjunctival samples, respectively. This study showed that conjunctival tissue from healthy dogs and CLOAs uncommonly harbor DNA viruses, and no DNA virus was associated with these tumors. Further studies are needed to evaluate the etiologic cause of CLOAs.

Viral, bacterial, and fungal infections of the oral mucosa: Types, incidence, predisposing factors, diagnostic algorithms, and management

For millions of years, microbiota residing within us, including those in the oral cavity, coexisted in a harmonious symbiotic fashion that provided a quintessential foundation for human health. It is now clear that disruption of such a healthy relationship leading to microbial dysbiosis causes a wide array of infections, ranging from localized, mild, superficial infections to deep, disseminated life-threatening diseases. With recent advances in research, diagnostics, and improved surveillance we are witnessing an array of emerging and re-emerging oral infections and orofacial manifestations of systemic infections. Orofacial infections may cause significant discomfort to the patients and unnecessary economic burden. Thus, the early recognition of such infections is paramount for holistic patient management, and oral clinicians have a critical role in recognizing, diagnosing, managing, and preventing either new or old orofacial infections. This paper aims to provide an update on current understanding of well-established and emerging viral, bacterial, and fungal infections manifesting in the human oral cavity.

Update on oral herpes virus infections

Oral herpes virus infections (OHVIs) are among the most common mucosal disorders encountered by oral health care providers. These infections can affect individuals at any age, from infants to the elderly, and may cause significant pain and dysfunction. Immunosuppressed patients may be at increased risk for serious and potential life-threatening complications caused by OHVIs. Clinicians may have difficulty in diagnosing these infections because they can mimic other conditions of the oral mucosa. This article provides oral health care providers with clinically relevant information regarding etiopathogenesis, diagnosis, and management of OHVIs.

Diagnostic methods and management strategies of herpes simplex and herpes zoster infections

Herpes infections are extremely prevalent in the adult population. Recognizing early signs and symptoms is essential to provide effective treatment. The immunocompromised population presents treatment challenges requiring prolonged antiviral therapy and more frequent recurrences. Viral culture is often considered the gold standard diagnostic technique; however, polymerase chain reaction (PCR) should be done in tandem with culture especially for varicella zoster virus infections. Antivirals can decrease viral shedding, recurrences of herpes simplex, and hasten healing of herpes zoster. Herpes virus can be a challenging entity to treat with significant morbidity (both physically and psychologically).

Stepwise release of biologically active HMGB1 during HSV-2 infection

BACKGROUND

High mobility group box 1 protein (HMGB1) is a major endogenous danger signal that triggers inflammation and immunity during septic and aseptic stresses. HMGB1 recently emerged as a key soluble factor in the pathogenesis of various infectious diseases, but nothing is known of its behaviour during herpesvirus infection. We therefore investigated the dynamics and biological effects of HMGB1 during HSV-2 infection of epithelial HEC-1 cells.

METHODOLOGY/PRINCIPAL FINDINGS

Despite a transcriptional shutdown of HMGB1 gene expression during infection, the intracellular pool of HMGB1 protein remained unaffected, indicating its remarkable stability. However, the dynamics of HMGB1 was deeply modified in infected cells. Whereas viral multiplication was concomitant with apoptosis and HMGB1 retention on chromatin, a subsequent release of HMGB1 was observed in response to HSV-2 mediated necrosis. Importantly, extracellular HMGB1 was biologically active. Indeed, HMGB1-containing supernatants from HSV-2 infected cells induced the migration of fibroblasts from murine or human origin, and reactivated HIV-1 from latently infected T lymphocytes. These effects were specifically linked to HMGB1 since they were blocked by glycyrrhizin or by a neutralizing anti-HMGB1 antibody, and were mediated through TLR2 and the receptor for Advanced Glycation End-products (RAGE). Finally, we show that genital HSV-2 active infections also promote HMGB1 release in vivo, strengthening the clinical relevance of our experimental data.

CONCLUSIONS

These observations target HMGB1 as an important actor during HSV-2 genital infection, notably in the setting of HSV-HIV co-infection.

Identification and characterization of 20 immunocompetent patients with simultaneous varicella zoster and herpes simplex virus infection

BACKGROUND

It has been shown that varicella zoster virus (VZV) and herpes simplex virus (HSV) can co-localize to the same sensory ganglion. However, only a few case reports on VZV/HSV co-infections exist. Objective To identify and characterize patients with concurrent VZV and HSV infection at the same body site.

SUBJECTS/METHODS

In 1718 patients, the presence of VZV and HSV in suspicious skin lesions was investigated by polymerase chain reaction analysis. Clinical characteristics of co-infected patients were compared with matched control patients infected with either VZV or HSV. The data are discussed in the context of an extensive review of the literature.

RESULTS

Twenty (1.2%) of 1718 patients were infected with both VZV and HSV at the same body site. The mean age was 54 years (range, 2-83). The clinical diagnosis was zoster in 65%, herpes simplex in 20%, varicella in 10% and erythema multiforme in 5% of cases. The trigeminus region was affected in 60% and the trunk in 25%. Involvement of the head was most commonly associated with a severe course of disease and with older age.

CONCLUSION

Simultaneous VZV/HSV infection is rare but can occur in immunocompetent patients, which is often overlooked. The majority of cases is localized to the trigeminus region and affects elderly people.

Comparison of the Tzanck test and polymerase chain reaction in the diagnosis of cutaneous herpes simplex and varicella zoster virus infections

BACKGROUND

Although the diagnosis of herpes simplex virus (HSV) and varicella zoster virus (VZV) infections is usually made clinically, the Tzanck test, electron microscopy, viral culture, polymerase chain reaction (PCR), and serologic tests can be utilized to verify the diagnosis.

METHODS

We conducted a study on a total of 98 patients (77 patients with recurrent herpes simplex and 21 patients with herpes zoster) to evaluate the reliability and reproducibility of the Tzanck test in comparison with PCR.

RESULTS

In herpes virus infections, the general positivity rates of the Tzanck test and PCR were 61.2% and 79.6%, respectively. The difference between the positivity rates of the two tests was statistically significant. The positivity rates of the tests differed according to the type and duration of the lesions.

CONCLUSIONS

Although PCR was superior to the Tzanck test, the Tzanck test has also been proven to be a reliable diagnostic method, with a sensitivity of 76.9% and a specificity of 100%. We recommend the use of this easy, quick, reproducible, and inexpensive diagnostic test more often in dermatologic practice, especially in cutaneous herpes virus infections.

Oral herpetic infections (HSV 1-8)

Oral herpes virus infections are commonly seen by the dental practitioner. Saliva is a reservoir for the herpes virus, and a variety of infections, both localized and systemic, may be induced by the virus. Patients who are immunocompromised may be at risk for serious and potentially life-threatening complications of herpes virus infections. This article highlights the basic virology and clinical manifestations of herpetic infections and the differential diagnosis and management of oral herpes virus infections.

Update on herpesvirus infections

Herpesviruses are responsible for many illnesses that affect the oral and maxillofacial region. The most common of these are primary or recurrent HSV infection, but knowledge of the manifestations of the eight herpesviruses that cause infections in humans will provide clinicians with a better understanding and basis for diagnosing and managing patients with these diseases. Immunocompromised patients are at greater risk for serious illness: therefore, clinicians treating transplant patients, patients receiving cancer chemotherapy, or HIV-infected individuals should be aware of the various clinical manifestations of infection with herpesviruses.

The clinical characteristics of intraoral herpes simplex virus infection in 52 immunocompetent patients

OBJECTIVE

Intraoral herpes simplex virus infection is commonly mistaken for recurrent aphthous stomatitis. The purpose of this study was to describe the clinical features of intraoral herpes simplex virus infection.

STUDY DESIGN

Fifty-two immunocompetent patients with culture-positive intraoral herpes simplex virus infection were studied.

RESULTS

The median age of the patients was 42 years. One third of the patients exhibited single ulcers; the remaining patients displayed multiple lesions. In 47 of 52 cases, the ulcers occurred on keratinized surfaces of the oral cavity; however, 5 patients had persistent ulcerations on nonkeratinized mucosa, a typical feature of herpetic ulcers in immunosuppressed patients. Of 27 patients with histories of recurrences, 22 were previously incorrectly diagnosed with recurrent aphthous stomatitis.

CONCLUSIONS

Herpes simplex virus infection of the oral cavity can usually be differentiated from other causes of recurrent oral ulcerations on the basis of its clinical appearance and distribution. The recognition of atypical features may prevent unnecessary and costly treatments for unrelated though clinically similar-appearing disorders.

Rapid detection and distinction of cutaneous herpesvirus infections by direct immunofluorescence

BACKGROUND

Optimal management of cutaneous herpes simplex virus (HSV) and varicellazoster virus (VZV) infections requires rapid, accurate distinction between these pathogens.

OBJECTIVE

In a mixed-case series of suspected cutaneous herpesvirus infections, we compared the diagnostic utility of viral culture and direct immunofluorescence (DIF) using a panel of fluoresceinated monoclonal antibodies against HSV and VZV.

METHODS

Epifluorescence microscopy of smears and viral culture were performed in parallel on 58 lesions.

RESULTS

DIF and culture were equally sensitive (88%) in HSV infections, whereas DIF was four times as sensitive as culture (100% vs 18%) in VZV. DIF either refuted an incorrect clinical diagnosis or permitted definitive laboratory diagnosis of a clinically indeterminate lesion in 7 (12%) of 58 lesions tested.

CONCLUSION

DIF is a rapid, simple, sensitive, specific, cost-effective, and clinically useful technique for detecting and distinguishing cutaneous HSV and VZV infections.

Polymerase chain reaction for the detection of the varicella-zoster genome in ocular samples from patients with acute retinal necrosis

We used the polymerase chain reaction to detect the virus genome in ocular samples from patients with clinically diagnosed acute retinal necrosis. Four samples from four patients with acute retinal necrosis, and five samples from three patients with other ocular diseases (sarcoidosis, rhegmatogenous retinal detachment, and epiretinal membrane of unknown origin) were evaluated. The samples consisted of aqueous humor, vitreous, or subretinal fluid. Primers were specific for varicella-zoster virus, herpes simplex virus, or cytomegalovirus. The varicella-zoster virus genome was detected in three of the four samples from patients with acute retinal necrosis. Among these three positive samples, two had PstI-site-less point mutation, strains that have been described only in Japan and of low prevalence. Samples from patients with diagnoses other than acute retinal necrosis yielded negative results when varicella-zoster virus primer was used. No sample was positive for herpes simplex virus or cytomegalovirus primers.