Diagnosis and quantitative detection of HSV DNA in samples from patients with suspected herpes simplex encephalitis

Prevalence and clinical manifestations of herpes simplex virus infection among suspected patients of herpes simplex encephalitis in Shiraz, Iran

Encephalitis has infectious and noninfectious etiology. Among infectious agents, viruses are the main causes of encephalitis; Herpes simplex virus (HSV) is known as the most common causative agent of viral encephalitis. In this current cross-sectional investigation, we aimed to assess the prevalence of HSV in the cerebrospinal fluid (CSF) specimens of Herpes Simplex Encephalitis (HSE) suspected patients and also determining the clinical symptoms and laboratory findings of this viral complication. Two hundred consecutive HSE suspected patients with clinical diagnosis of encephalitis were included in the study and then the presence of HSV DNA in their CSF was applied by Polymerase Chain Reaction (PCR) assay. Molecular detection of two hundred (117 males with mean age: 43 years, 83 females with mean age: 39 years) CSF samples showed that 22 (11.11%) cases were positive for HSV infection. 15(68.18%) of the positive samples were more than 50 years old, however, there was no significant correlation between age distribution, gender and HSE clinical manifestations. Fever (91%), headache (72.7%), seizer (59%), and weakness (59%) were the most common symptoms in positive patients and also mortality rate was (18.18%). CSF laboratory abnormalities of HSE cases were as follows; lymphocytic pleocytosis 19 (86.3%), leukocytosis 19 (86.3%), elevated protein level 16 (72.7%), and hypoglycorrhachia 3(13.6%). Screening of HSE suspected patients is crucial in the treatment of patients and reduce the mobility and morbidity of patients. Qualitative PCR as an available method in most developing countries could be a reliable method to monitor consecutive HSE suspected patients.

Polluted Air Exposure Compromises Corneal Immunity and Exacerbates Inflammation in Acute Herpes Simplex Keratitis

Air pollution is a serious environmental issue worldwide in developing countries’ megacities, affecting the population’s health, including the ocular surface, by predisposing or exacerbating other ocular diseases. Herpes simplex keratitis (HSK) is caused by the herpes simplex virus type 1 (HSV-1). The primary or recurring infection in the ocular site causes progressive corneal scarring that may result in visual impairment. The present study was designed to study the immunopathological changes of acute HSK under urban polluted air, using the acute HSK model combined with an experimental urban polluted air exposure from Buenos Aires City. We evaluated the corneal clinical outcomes, viral DNA and pro-inflammatory cytokines by RT-PCR and ELISA assays, respectively. Then, we determined the innate and adaptive immune responses in both cornea and local lymph nodes after HSV-1 corneal by immunofluorescence staining and flow cytometry. Our results showed that mice exposed to polluted air develop a severe form of HSK with increased corneal opacity, neovascularization, HSV-1 DNA and production of TNF-α, IL-1β, IFN-γ, and CCL2. A high number of corneal resident immune cells, including activated dendritic cells, was observed in mice exposed to polluted air; with a further significant influx of bone marrow-derived cells including GR1+ cells (neutrophils and inflammatory monocytes), CD11c+ cells (dendritic cells), and CD3+ (T cells) during acute corneal HSK. Moreover, mice exposed to polluted air showed a predominant Th1 type T cell response over Tregs in local lymph nodes during acute HSK with decreased corneal Tregs. These findings provide strong evidence that urban polluted air might trigger a local imbalance of innate and adaptive immune responses that exacerbate HSK severity. Taking this study into account, urban air pollution should be considered a key factor in developing ocular inflammatory diseases.

Prevalence of herpes simplex virus-1 in hospitalized adult patients with clinical diagnosis of meningoencephalitis using real-time polymerase chain reaction: A single-center, cross-sectional study

Background

Early diagnosis of herpes simplex virus-1 (HSV-1) meningoencephalitis is very important because antiviral therapy significantly decreases mortality and morbidity. Polymerase chain reaction (PCR) is a reliable method with high sensitivity and specificity in detection of HSV-1. The aim of this study is to determine the prevalence of HSV-1 in patients with diagnosis of meningoencephalitis using real-time PCR.

Materials and Methods

The cerebrospinal fluid samples were collected from 126 patients with clinical diagnosis of HSV-1 meningoencephalitis in Alzahra Referral Hospital in Isfahan, Iran. After deoxyribonucleic acid (DNA) extraction, real-time PCR was performed by fluorescence resonance energy transfer assay and participants underwent brain magnetic resonance imaging, as well.

Results

Among 126 patients, 68.3% were male and 31.7% were female. The mean age of the participants was 41.96 ± 22.36 years. Most of the participants were in the age group of 20-29 years. Three patients (2.4%) had positive and 123 patients (97.6%) had negative HSV-1 DNA test. Among three positive cases, two were in the age group of 20-29 years and one in the age group of ≥80 years. No HSV-2 DNA was detected.

Conclusion

According to the estimated prevalence of HSV-1 meningoencephalitis in the current study, it seems that the prevalence of HSV-1 meningoencephalitis is not too high in our community; therefore, initial empiric acyclovir therapy is frequently overused.

HSV-1 Encephalitis: High Index of Clinical Suspicion, Prompt Diagnosis, and Early Therapeutic Intervention Are the Triptych of Success-Report of Two Cases and Comprehensive Review of the Literature

Herpes Simplex Virus (HSV) encephalitis is an acute infectious disease of the Central Nervous System (CNS), usually affecting the limbic structures, the median temporal cortex, and the orbitofrontal regions. Its annual incidence has significantly increased over the last 20 years and the mortality rate is 7%, if early diagnosed and treated, and 70%, if left untreated, while it is associated with high rates of morbidity. It should be noted that even when Cerebrospinal fluid (CSF) analysis seems normal, imaging studies are not specific and HSV Polymerase Chain Reaction (PCR) test is negative; the clinician should be more aggressive, if clinical presentation is indicative for HSV encephalitis, by administrating acyclovir early after patient's admission. The latter may be a vital intervention for the patient, modifying the patient's clinical course. Through the presentation of two cases of HSV-1 encephalitis that we managed in our department over the last 1 year and after systematic and comprehensive research of the relevant literature, we aim at showing the crucial role of medical history and physical examination, along with the high index of clinical suspicion, in order to make promptly the diagnosis and administer timely intravenous acyclovir, limiting the possibility of complications during the disease's course.

Implementation and Evaluation of a Fully Automated Multiplex Real-Time PCR Assay on the BD Max Platform to Detect and Differentiate Herpesviridae from Cerebrospinal Fluids

A fully automated multiplex real-time PCR assay--including a sample process control and a plasmid based positive control--for the detection and differentiation of herpes simplex virus 1 (HSV1), herpes simplex virus 2 (HSV2) and varicella-zoster virus (VZV) from cerebrospinal fluids (CSF) was developed on the BD Max platform. Performance was compared to an established accredited multiplex real time PCR protocol utilizing the easyMAG and the LightCycler 480/II, both very common devices in viral molecular diagnostics. For clinical validation, 123 CSF specimens and 40 reference samples from national interlaboratory comparisons were examined with both methods, resulting in 97.6% and 100% concordance for CSF and reference samples, respectively. Utilizing the BD Max platform revealed sensitivities of 173 (CI 95%, 88-258) copies/ml for HSV1, 171 (CI 95%, 148-194) copies/ml for HSV2 and 84 (CI 95%, 5-163) copies/ml for VZV. Cross reactivity could be excluded by checking 25 common viral, bacterial and fungal human pathogens. Workflow analyses displayed shorter test duration as well as remarkable fewer and easier preparation steps with the potential to reduce error rates occurring when manually assessing patient samples. This protocol allows for a fully automated PCR assay on the BD Max platform for the simultaneously detection of herpesviridae from CSF specimens. Singular or multiple infections due to HSV1, HSV2 and VZV can reliably be differentiated with good sensitivities. Control parameters are included within the assay, thereby rendering its suitability for current quality management requirements.

Development and Validation of a Laboratory-Developed Multiplex Real-Time PCR Assay on the BD Max System for Detection of Herpes Simplex Virus and Varicella-Zoster Virus DNA in Various Clinical Specimens

A multiplex real-time PCR (quantitative PCR [qPCR]) assay detecting herpes simplex virus (HSV) and varicella-zoster virus (VZV) DNA together with an internal control was developed on the BD Max platform combining automated DNA extraction and an open amplification procedure. Its performance was compared to those of PCR assays routinely used in the laboratory, namely, a laboratory-developed test for HSV DNA on the LightCycler instrument and a test using a commercial master mix for VZV DNA on the ABI7500fast system. Using a pool of negative cerebrospinal fluid (CSF) samples spiked with either calibrated controls for HSV-1 and VZV or dilutions of a clinical strain that was previously quantified for HSV-2, the empirical limit of detection of the BD Max assay was 195.65, 91.80, and 414.07 copies/ml for HSV-1, HSV-2, and VZV, respectively. All the samples from HSV and VZV DNA quality control panels (Quality Control for Molecular Diagnostics [QCMD], 2013, Glasgow, United Kingdom) were correctly identified by the BD Max assay. From 180 clinical specimens of various origins, 2 CSF samples were found invalid by the BD Max assay due to the absence of detection of the internal control; a concordance of 100% was observed between the BD Max assay and the corresponding routine tests. The BD Max assay detected the PCR signal 3 to 4 cycles earlier than did the routine methods. With results available within 2 h on a wide range of specimens, this sensitive and fully automated PCR assay exhibited the qualities required for detecting simultaneously HSV and VZV DNA on a routine basis.

Diagnosing of herpes simplex virus infections in suspected patients using real-time PCR

Background:

Herpes simplex virus infections are very common worldwide. The virus can cause infection in various body parts, especially eyes and the nervous system. Therefore, an early diagnosis and highly sensitive method is very helpful.

Objectives:

The present study sought to investigate the efficiency of Real-time TaqMan probe PCR in the diagnosis of HSV infection in suspected patients.

Patients and Methods:

In this study, 1566 patients with suspected HSV infections were enrolled. They aged 17 days to 96 years. The collected specimens were classified into four groups; cerebrospinal fluid (CSF) from HSE suspected individuals, samples from eye epithelial scraping, tear fluid or aqueous humor from herpes simplex keratitis (HSK) suspected patients, plasma of immune compromised patients and mucocutaneous collected samples from different body parts. The samples were analyzed by Real-time PCR assays.

Results:

In total, 44 (5.6%), 118 (26.8%), 23 (11.7%), 13 (44.8%) and 65 (45.5%) of 791 HSE, 407 HSK, 29 skin HSV, 143 oropharyngeal suspected patients and 196 patients with systemic HSV infection HSV had positive results by Real-time PCR assays, respectively.

Conclusions:

Real-time PCR assay, due to its high sensitivity and specificity, can help in early diagnosis and more effective treatment for patients. Also, it requires shorter hospital stay and promotes patients' survival.

Herpes simplex virus infection in neonates and young infants with sepsis

BACKGROUND

Neonatal herpes infection is the most serious complication of Herpes Simplex Virus (HSV) infection during pregnancy and perinatal period. Few studies have reported neonatal HSV infection in developing countries.

OBJECTIVES

The aim of this study was to detect the HSV infection among neonates and infants with sepsis.

MATERIALS AND METHODS

In a cross sectional study all infants aged less than 3 months, admitted to neonatal intensive care unit and pediatric emergency ward of Ghaem Hospital (a university hospital with 900 beds) in Mashhad (Northeast of Iran) with clinical diagnosis of sepsis and at least one inclusion criteria during one year from November 2009 to October 2010, were enrolled in the study. Polymerase chain reaction (PCR) was done on clinical samples obtained from patients.

RESULTS

Among 150 neonates and infants younger than 3 months old with sepsis, the PCR results for detecting the HSV DNA, were positive in 6 samples of 5 patients (3.3 %). None of the mothers had symptomatic HSV infection during delivery. The mean age of the patients was 18 days. Two of them died due to shock and disseminated intravascular coagulation (DIC).

CONCLUSIONS

In neonates and infants with primary diagnosis of sepsis, HSV infection should be considered especially if the clinical condition does not improve after 48 hours of antibiotic therapy, and sepsis still exists with elevated liver enzymes.

Determination of viral load by quantitative real-time PCR in herpes simplex encephalitis patients

OBJECTIVE

Human herpesviruses cause various acute, subacute, and chronic disorders of the central nervous system and peripheral nervous systems in adults and children. The objective of the present study is to summarize the experience gained with the estimation of viral load in the central nervous system of children and adults with herpes simplex encephalitis (HSE) admitted to a neurological institute at Nagpur, India, by quantitative real-time PCR (qPCR) assay within the past 4 years.

METHODS

The qPCR assay was evaluated retrospectively in 242 cerebrospinal fluid (CSF) samples from patients. Evaluation of possible relationships was done between the herpes simplex virus (HSV) DNA concentration in CSF with that of patients' clinical and laboratory manifestations. The prevalence of the type of HSV in the study population was also determined using type-specific real-time PCR analysis.

RESULTS AND CONCLUSIONS

Real-time analysis using type-specific primers revealed the presence of predominantly HSV-1 genotype in the study population. The qPCR results show that in patients with higher viral loads in their CSF, a greater number of cases were associated with the presence of lesions in the brain as revealed by computed tomography/magnetic resonance imaging scan. They required acyclovir therapy for a longer duration and had a poorer clinical outcome than the patients with lower viral loads in their CSF.

Management of herpesvirus infections

Management of human herpesviruses remains a considerable clinical challenge, in part due to their ability to cause both lytic and latent disease. Infection with the Herpesviridae results in lifelong infection, which can reactivate at any time. Control of herpesviruses is by the innate and adaptive immune systems. Herpesviruses must evade the host innate immune system to establish infection. Once infected, the adaptive immune response, primarily CD8(+) T-cells, is crucial in establishing and maintaining latency. Latent herpesviruses are characterised by the presence of viral DNA in infected cells and limited or no viral replication. These characteristics provide a challenge to clinicians and those developing antiviral agents. The scope of this review is two-fold. First, to provide an overview of all antivirals used against herpesviruses, including their mechanism of action, pharmacokinetics, side effects, resistance and clinical uses. And second, to address the management of each of the eight herpesviruses both in the immunocompetent and immunocompromised host, providing evidence for clinical management and therapeutic options, which is important to the clinician engaged in the management of these infections.