Herpes Simplex Virus Mistyping due to HSV-1 × HSV-2 Interspecies Recombination in Viral Gene Encoding Glycoprotein B

Human herpes simplex viruses (HSV) 1 and 2 are extremely common human pathogens with overlapping disease spectra. Infections due to HSV-1 and HSV-2 are distinguished in clinical settings using sequence-based "typing" assays. Here we describe a case of HSV mistyping caused by a previously undescribed HSV-1 × HSV-2 recombination event in UL27, the HSV gene that encodes glycoprotein B. This is the first documented case of HSV mistyping caused by an HSV-1 × HSV-2 recombination event and the first description of an HSV interspecies recombination event in UL27, which is frequently used as a target for diagnostics and experimental therapeutics. We also review the primer and probe target sequences for a commonly used HSV typing assay from nearly 700 HSV-1 and HSV-2 samples and find that about 4% of HSV-1 samples have a single nucleotide change in at least one of these loci, which could impact assay performance. Our findings illustrate how knowledge of naturally occurring genomic variation in HSV-1 and HSV-2 is essential for the design and interpretation of molecular diagnostics for these viruses.

Associations between friendship characteristics and HIV and HSV-2 status amongst young South African women in HPTN-068

INTRODUCTION

Prevalence of HIV among young women in South Africa remains extremely high. Adolescent peer groups have been found to be an important influence on a range of health behaviours. The characteristics of young women's friendships might influence their sexual health and HIV risk via connections to sexual partners, norms around sexual initiation and condom use, or provision of social support. We investigated associations between young women's friendships and their Herpes Simplex Virus Type 2 (HSV-2) and HIV infection status in rural South Africa.

METHODS

Our study is a cross-sectional, egocentric network analysis. In 2011 to 2012, we tested 13- to 20-year-old young women for HIV and HSV-2, and collected descriptions of five friendships for each. We generated summary measures describing friend socio-demographic characteristics and the number of friends perceived to have had sex. We used logistic regression to analyse associations between friend characteristics and participant HIV and HSV-2 infection, excluding likely perinatal HIV infections.

RESULTS

There were 2326 participants included in the study sample, among whom HIV and HSV-2 prevalence were 3.3% and 4.6% respectively. Adjusted for participant and friend socio-demographic characteristics, each additional friend at least one year older than the participant was associated with raised odds of HIV (odds ratio (OR) = 1.37, 95% CI 1.03 to 1.82) and HSV-2 (adjusted OR=1.41, 95% CI 1.18 to 1.69). Each additional friend perceived to have ever had sex also raised the odds of HIV (OR = 1.29, 95% CI 1.03 to 1.63) and HSV-2 (OR=1.18, 95% CI 1.03 to 1.35).

DISCUSSION

We found good evidence that a greater number of older friends and friends perceived to have had sex were associated with increased risk for HSV-2 and HIV infection among young women.

CONCLUSIONS

The characteristics of young women's friendships could contribute to their risk of HIV infection. The extent to which policies or programmes influence age-mixing and young women's normative environments should be considered.

Prévention et prise en charge de l’infection herpétique au cours de la grossesse et de l’accouchement : recommandations pour la pratique clinique – texte des recommandations (texte court)

OBJECTIVE

Identify measures to diagnose, prevent and treat genital herpes infection during pregnancy and childbirth and neonatal infection.

METHODS

Bibliographic search from Medline, Cochrane Library databases and research of international clinical practice guidelines.

RESULTS

Genital herpes lesion is most often due to HSV2 (LE2). The risk of HSV seroconversion during pregnancy is 1 to 5% (LE2). Genital herpes ulceration during pregnancy in a woman with history of genital herpes corresponds with a recurrence. In this situation, there is no need for virologic confirmation (grade B). In case of genital lesions in a pregnant woman that do not report any genital herpes before, it is recommended to perform a virological confirmation by PCR and HSV type specific IgG (Professional consensus). In case of first episode genital herpes during pregnancy, antiviral treatment with acyclovir (200mg 5 times daily) or valacyclovir (1000mg twice daily) for 5 to 10 days is recommended (grade C). In case of recurrent herpes during pregnancy, antiviral therapy with acyclovir (200mg 5 times daily) or valacyclovir (500mg twice daily) can be administered (grade C). The risk of neonatal herpes is estimated between 25% and 44% in case of initial episode (LE2) and 1% in case of recurrence (LE3) at the time of delivery. Antiviral prophylaxis should be offered for women with first episode genital herpes or recurrent genital herpes during pregnancy from 36 weeks of gestation and until delivery (grade B). In case of a history of genital herpes without episode of recurrence during pregnancy, it is not recommended routinely offer a prophylactic treatment (professional consensus). A cesarean section should be performed if there is a suspicion of first episode genital herpes at the onset of labor (grade B), in the event of premature rupture of the membranes at term (professional consensus), or in case of first episode genital herpes less than 6 weeks before delivery (professional consensus). In case of recurrent genital herpes at the onset of labor, cesarean delivery will be all the more considered if the membranes are intact and vaginal delivery will be all the more considered in case of prolonged rupture of membranes (professional consensus). Neonatal herpes is rare and mainly due to HSV-1 (LE3). In most of the case of neonatal herpes, the mothers have no history of genital herpes (LE 3). In case of suspicion of neonatal herpes, different samples (blood and cerebrospinal fluid) for HSV PCR must be carried out to confirm the diagnosis (professional consensus). Any newborn suspected of neonatal herpes should be treated with intravenous acyclovir (60mg/kgs/day 3 times daily) (grade A) prior to the results of HSV PCR (professional consensus). The duration of the treatment depends on the clinical form (professional consensus) CONCLUSION: There is no formal evidence that it is possible to reduce the risk of neonatal herpes in genital herpes during pregnancy. However, appropriate care can reduce the symptoms associated with herpes, the risk of recurrence term and the cesarean rate performed to decrease the risk of neonatal herpes.

Highly conserved intragenic HSV-2 sequences: Results from next-generation sequencing of HSV-2 UL and US regions from genital swabs collected from 3 continents

INTRODUCTION

Understanding the variability in circulating herpes simplex virus type 2 (HSV-2) genomic sequences is critical to the development of HSV-2 vaccines.

METHODS

Genital lesion swabs containing ≥ 107log10 copies HSV DNA collected from Africa, the USA, and South America underwent next-generation sequencing, followed by K-mer based filtering and de novo genomic assembly. Sites of heterogeneity within coding regions in unique long and unique short (UL_US) regions were identified. Phylogenetic trees were created using maximum likelihood reconstruction.

RESULTS

Among 46 samples from 38 persons, 1468 intragenic base-pair substitutions were identified. The maximum nucleotide distance between strains for concatenated UL_US segments was 0.4%. Phylogeny did not reveal geographic clustering. The most variable proteins had non-synonymous mutations in < 3% of amino acids.

CONCLUSIONS

Unenriched HSV-2 DNA can undergo next-generation sequencing to identify intragenic variability. The use of clinical swabs for sequencing expands the information that can be gathered directly from these specimens.

Seroprevalence and risk factors of herpes simplex virus-2 among pregnant women attending antenatal care at health facilities in Wolaita zone, Ethiopia

BACKGROUND

Herpes simplex virus type-2 is the common cause of genital ulcer disease worldwide. Genital herpes infection is a major concern in pregnancy due to the risk of neonatal transmission.

METHOD

A Cross-sectional survey was conducted from December 2013 to September 2014 in randomly selected 28 health centers to assess the seroprevalence and risk factors of herpes simplex virus type-2 infection among pregnant women attending antenatal care in Wolaita zone, Southern Ethiopia. After taking written consent socio demographic, behavioral, obstetric history and family planning data along with blood samples were collected from 252 pregnant women using pre-structured questionnaire. Sera were tested using HerpeSelect-2 ELISA IgG. Data entry and analysis was done using Epi info 3.5.4 and SPSS 21.00 respectively. Binary logistic regression was performed to identify the risk factors associated with HSV-2 seropositivity. P-values less than 0.05 were considered statistically significant.

RESULTS

The overall seroprevalence of HSV-2 infection was 32.1 % (81/252) among pregnant women in Wolaita zone. Independent predictors of HSV-2 infection includes daily laborer (AOR 1.293, 95 % CI: 1.033-1.739; p = 0.022), having one sexual partners (AOR 0.476, 95 % CI: 0 .250 -0.904; p = 0.023), history of STDs (AOR 2.822, 95 % CI: 1.50-5.289; p = 0.001) and use of contraceptive (AOR 2.602, 95 % CI: 1.407-4.812; p = 0.002).

CONCLUSION

Overall seroprevalence of HSV-2 infection among pregnant women of Wolaita Zone is high. Awareness creation among high risk groups like women who have history of STD should be strengthened. Strengthening the quality of health service delivery and expansion of health service coverage is mandatory.

[Infections caused by human alpha herpes viruses]

Varicella-zoster virus (VZV), herpes simplex virus one (HSV-1) and herpes simplex virus two (HSV-2) represent three out of the eight known human herpesviruses and belong to the subfamily of α-herpesviruses. These viruses are present worldwide and humans are their sole host and reservoir. After the primary infection, these viruses persist in the body throughout life. The period of latency may be interrupted by reactivation of infection due to various factors. Each virus can induce a wide spectrum of diseases. The primary infection is typical for children and otherwise healthy individuals are often asymptomatic. It is mainly immunocompromised patients who are at risk of developing severe disease or complications when infected by these viruses. However, even in otherwise healthy individuals an infection by a-herpesviruses can run a severe course and lead to death.

Evolutionary origins of human herpes simplex viruses 1 and 2

Herpesviruses have been infecting and codiverging with their vertebrate hosts for hundreds of millions of years. The primate simplex viruses exemplify this pattern of virus-host codivergence, at a minimum, as far back as the most recent common ancestor of New World monkeys, Old World monkeys, and apes. Humans are the only primate species known to be infected with two distinct herpes simplex viruses: HSV-1 and HSV-2. Human herpes simplex viruses are ubiquitous, with over two-thirds of the human population infected by at least one virus. Here, we investigated whether the additional human simplex virus is the result of ancient viral lineage duplication or cross-species transmission. We found that standard phylogenetic models of nucleotide substitution are inadequate for distinguishing among these competing hypotheses; the extent of synonymous substitutions causes a substantial underestimation of the lengths of some of the branches in the phylogeny, consistent with observations in other viruses (e.g., avian influenza, Ebola, and coronaviruses). To more accurately estimate ancient viral divergence times, we applied a branch-site random effects likelihood model of molecular evolution that allows the strength of natural selection to vary across both the viral phylogeny and the gene alignment. This selection-informed model favored a scenario in which HSV-1 is the result of ancient codivergence and HSV-2 arose from a cross-species transmission event from the ancestor of modern chimpanzees to an extinct Homo precursor of modern humans, around 1.6 Ma. These results provide a new framework for understanding human herpes simplex virus evolution and demonstrate the importance of using selection-informed models of sequence evolution when investigating viral origin hypotheses.

Novel deletion in glycoprotein G forms a cluster and causes epidemiologic spread of herpes simplex virus type 2 infection

The herpes simplex virus type 2 (HSV-2) glycoprotein G (gG-2) gene of 106 clinical isolates was analyzed and six isolates were identified with 63 nucleotides comprising 21 amino acids (aa) deleted in the immunodominant region. Compared with strain HG52, variations in the gG-2 gene were found at 276 and 27 sites in nucleotide and aa sequences, respectively, in the 106 strains. Significant variations in both nucleotides and aa were accumulated in the immunodominant region rather than in the other regions (P < 0.001), indicating that the immunodominant region might be indispensable in vivo and a hot spot for variation. The frequency of 21 aa-deleted strains (HSVΔ21/gG-2) among clinical isolates was 5%, indicating the advantage of this deletion of gG-2 for epidemiological expansion. Phylogenetic analysis of the 106 strains indicated that the HSVΔ21/gG-2 strains formed a cluster among the various variations but that their genomes showed different endonuclease digestion patterns. The antibody titers to total HSV antigens of patients infected with wild HSV-2 and HSVΔ21/gG-2 were similar, but patients with HSVΔ21/gG-2 had a lower antibody titer to gG-2 than those with wild HSV-2 (P < 0.001). HSVΔ21/gG-2 might be less immnunogenic and reduce antibody production to gG-2, while its pathogenicity in humans was not distinguished in its clinical manifestations. Thus, infection with HSVΔ21/gG-2 caused genital lesions similar to wild HSV-2 infection, but evaded the immune response to gG-2 to allow epidemiological spread, indicating the importance of this deletion in the immunodominant region of gG-2 in the pathogenesis and transmission of genital herpes.

Herpesvirus entry mediator is a serotype specific determinant of pathogenesis in ocular herpes

Infection with herpes simplex virus type 1 (HSV-1) and HSV-2 is initiated by viral glycoprotein D (gD) binding to a receptor on the host cell. Two receptors, herpesvirus entry mediator (HVEM) and nectin-1, mediate entry in murine models of HSV-1 and HSV-2. HVEM is dispensable for HSV-2 infection of the vagina and brain, but is required for WT pathogenesis of HSV-1 infection of the cornea. By challenging WT and HVEM KO mice with multiple strains of HSV-1 and HSV-2, we demonstrate that without HVEM, all HSV-1 strains tested do not replicate well in the cornea and infection does not result in severe symptoms, as observed in WT mice. In contrast, all HSV-2 strains tested had no requirement for HVEM to replicate to WT levels in the cornea and still cause severe disease. These findings imply that HSV-2 does not require HVEM to cause disease regardless of route of entry, but HVEM must be present for HSV-1 to cause full pathogenesis in the eye. These findings uncover a unique role for HVEM in mediating HSV-1 infection in an area innervated by the trigeminal ganglion and may explain why the presence of HVEM can lead to severe inflammation in the cornea. Thus, the dependence on HVEM is a dividing point between HSV-1 and HSV-2 that evolved to infect areas innervated by different sensory ganglia.

Divergence and recombination of clinical herpes simplex virus type 2 isolates

Herpes simplex virus type 2 (HSV-2) infects the genital mucosa and is one of the most common sexually transmitted viruses. Here we sequenced a segment comprising 3.5% of the HSV-2 genome, including genes coding for glycoproteins G, I, and E, from 27 clinical isolates from Tanzania, 10 isolates from Norway, and 10 isolates from Sweden. The sequence variation was low compared to that described for clinical HSV-1 isolates, with an overall similarity of 99.6% between the two most distant HSV-2 isolates. Phylogenetic analysis revealed a divergence into at least two genogroups arbitrarily designated A and B, supported by high bootstrap values and evolutionarily separated at the root. Genogroup A contained isolates collected in Tanzania, and genogroup B contained isolates collected in Tanzania and Scandinavia, implying that the genetic variability of HSV-2 is higher in Tanzania than in Scandinavia. Recombination network analysis and bootscan analysis revealed a complex pattern of phylogenetically conflicting informative sites in the sequence alignments. These signals were present in synonymous and nonsynonymous sites in all three genes and were not accumulated in specific regions, observations arguing against positive selection. Since the PHI test applied solely to synonymous sites revealed a high statistical probability of recombination, we suggest as a novel finding that homologous recombination is, as reported earlier for HSV-1 and varicella-zoster virus, a prominent feature in the evolution of HSV-2.

Unlabeled probes for the detection and typing of herpes simplex virus

BACKGROUND

Unlabeled probe detection with a double-stranded DNA (dsDNA) binding dye is one method to detect and confirm target amplification after PCR. Unlabeled probes and amplicon melting have been used to detect small deletions and single-nucleotide polymorphisms in assays where template is in abundance. Unlabeled probes have not been applied to low-level target detection, however.

METHODS

Herpes simplex virus (HSV) was chosen as a model to compare the unlabeled probe method to an in-house reference assay using dual-labeled, minor groove binding probes. A saturating dsDNA dye (LCGreen Plus) was used for real-time PCR. HSV-1, HSV-2, and an internal control were differentiated by PCR amplicon and unlabeled probe melting analysis after PCR.

RESULTS

The unlabeled probe technique displayed 98% concordance with the reference assay for the detection of HSV from a variety of archived clinical samples (n = 182). HSV typing using unlabeled probes was 99% concordant (n = 104) to sequenced clinical samples and allowed for the detection of sequence polymorphisms in the amplicon and under the probe.

CONCLUSIONS

Unlabeled probes and amplicon melting can be used to detect and genotype as few as 10 copies of target per reaction, restricted only by stochastic limitations. The use of unlabeled probes provides an attractive alternative to conventional fluorescence-labeled, probe-based assays for genotyping and detection of HSV and might be useful for other low-copy targets where typing is informative.

Invader plus method detects herpes simplex virus in cerebrospinal fluid and simultaneously differentiates types 1 and 2

We report here on the development and validation of a prototype Invader Plus method for the qualitative detection of herpes simplex virus types 1 and 2 in cerebrospinal fluid (CSF). The method combines PCR and Invader techniques in a single, closed-tube, continuous-reaction format that gives an analytical sensitivity of approximately 10 copies per reaction. The clinical sensitivity and specificity were 100.0% and 98.6%, respectively, when the results of the method were validated against the results obtained with a PCR colorimetric microtiter plate system by use of clinical CSF specimens.

Sequence-based methods for identifying epidemiologically linked herpes simplex virus type 2 strains

Traditional methods for confirming the identity of herpes simplex virus (HSV) isolates use restriction fragment length polymorphism (RFLP). However, RFLP is less amenable to high-throughput analyses of many samples, and the extent to which small differences in RFLP patterns distinguish between different viral strains remains unclear. Viral HSV type 2 (HSV-2) DNA isolates from 14 persons experiencing a primary HSV-2 infection and from their sexual partners were analyzed by RFLP and heteroduplex mobility assays. We also compared the HSV-2 sequences from seven regions, including noncoding regions between UL19 and UL20, UL24 and UL25, UL37 and UL38, and UL41 and UL42 and coding segments of the gC, gB, and gG genes. Although the resulting RFLP patterns of the couples were almost identical, minor banding differences existed between the source and susceptible partners in five couples. Heteroduplex mobility assays were unable to distinguish between unrelated strains. Overall, 22 sites of sequence variation were found in 1,482 bp of analyzed sequence. The DNA sequences differentiated between all unrelated infections, and epidemiologically related isolates had identical sequences in all but two pairs. Our results suggest that a multilocus assay based on several DNA sequences has the potential to be an informative tool for identifying epidemiologically related HSV-2 strains.

High incidence of genotypic variance between sequential herpes simplex virus type 2 isolates from HIV-1-seropositive patients with recurrent genital herpes

We developed a polymerase chain reaction (PCR) method, based on strain-to-strain variation of DNA repeats in the herpes simplex virus type 2 (HSV-2) genes US1 and US12, to genotype HSV-2 strains and determine the incidence and risk factors associated with HSV-2 superinfection in patients with recurrent genital herpes (RGH). Forty-seven (92%) of 51 unrelated HSV-2 isolates could be distinguished. Genotyping of sequential HSV-2 isolates showed a different genotype in all of the 11 human immunodeficiency virus type 1 (HIV-1)-seropositive patients with RGH, compared with 1 of the 8 HIV-1-seronegative patients with RGH. The PCR approach developed distinguishes unrelated HSV-2 strains efficiently and indicated a high incidence of genotype variance between sequential HSV-2 isolates of HIV-1-seropositive patients with RGH.

Evaluation of the Cepheid herpes simplex virus typing real-time PCR assay using dermal and genital specimens

The Cepheid herpes simplex virus (HSV) (Cepheid, Sunnyvale, CA) typing multiplex real-time polymerase chain reaction (PCR) assay was evaluated for its ability to detect HSV in dermal and genital specimens stored in M5 media. Swab specimens (n = 114) for HSV testing were placed in M5 media and split between our laboratory and a highly experienced reference laboratory. Aliquots for testing with the Cepheid assay were processed using a simple boil-and-go procedure and then run in a SmartCycler II (Cepheid). Aliquots tested at the reference laboratory were processed using a MagNA Pure LC DNA extractor (Roche Molecular Systems, Alameda, CA) and tested by the Roche HSV real-time PCR assay. Both laboratories detected 35 positives. Of the positive specimens, the Cepheid assay typed 16 as HSV 1 and 19 as HSV 2; the reference laboratory typed 15 as HSV 1, 19 as HSV 2, and 1 as HSV indeterminate. Our results demonstrate that the Cepheid real-time PCR assay, using specimens subjected to minimal specimen processing, performed as well as the Roche real-time PCR assay, using DNA extracts, for the detection of HSV DNA in genital and dermal specimens.

Differentiation of herpes simplex virus types 1 and 2 in clinical samples by a real-time taqman PCR assay

While the clinical manifestations of HSV-1 and -2 overlap, the site of CNS infection, complications, response to antivirals, frequency of antiviral resistance, and reactivation rate on mucosal surfaces varies between HSV-1 and -2. Detection of HSV DNA by PCR has been shown to be the most sensitive method for detecting HSV in clinical samples. As such, we developed a PCR-based assay to accurately distinguish HSV-1 from HSV-2. Our initial studies indicated the assay using type specific primers was slightly less efficient for detecting HSV-1 and -2 DNA than the high throughput quantitative PCR assay we utilize that employs type common primers to gB. We subsequently evaluated the type specific assay on 3,131 specimens that had HSV DNA detected in the type common PCR assay. The typing results of these specimens were compared with the monoclonal antibody staining results of culture isolates collected from the same patients at the same time, and the HSV serologic status of the patient. The typing assay accurately identified both HSV-1 and -2 with a specificity of >99.5% and was significantly more sensitive than typing by culture and subsequent monoclonal antibody assays. Complete concordance was seen between the typing assay and HSV serologic status of the patient. Dual (HSV-1 and -2) infection in clinical samples was recognized in 2.6% of clinical samples using the new typing assay. This assay, when used in combination with the type common assay, can now accurately type almost all mucosal and visceral HSV isolates by molecular techniques.

Detection and typing of herpes simplex DNA in genital swabs by real-time polymerase chain reaction

The LightCycler polymerase chain reaction (PCR) is a sensitive assay for the detection of Herpes simplex virus (HSV) DNA in muco-cutaneous swabs. Software-based analysis of the probe melting temperature (Tm) can be used to discriminate between HSV types (HSV-1 and HSV-2). Among 76 HSV DNA positive genital swabs, atypical Tms were observed in 14 (18%). The 14 samples were all typed as HSV-2 by sequence alignment. In 4/14 samples, the atypical Tm was associated with sequence variation at the probe-binding site. Among 10 samples with conserved sequences, Tms were influenced by the specimen preparation method prior to PCR. These findings indicate that multiple factors including, but not limited to sequence variation complicate melting curve analysis following real-time PCR. Alternative typing methods are recommended for specimens with atypical melting curves.

Sensitive and rapid detection of herpes simplex virus and varicella-zoster virus DNA by loop-mediated isothermal amplification

Loop-mediated isothermal amplification (LAMP) is a novel nucleic acid amplification method in which reagents react rapidly and efficiently, with a high specificity, under isothermal conditions. We used a LAMP assay for the detection of herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2), and varicella-zoster virus (VZV). The virus specificities of primers were confirmed by using 50 HSV-1, 50 HSV-2, and 8 VZV strains. The assay was performed for 45 min at 65 degrees C. The LAMP assay had a 10-fold higher sensitivity than a PCR assay. An analysis of nucleotide sequence variations in the target and primer regions used for the LAMP assay indicated that 3 of 50 HSV-1 strains had single nucleotide polymorphisms. No HSV-2 or VZV strains had nucleotide polymorphisms. Regardless of the sequence variation, there were no differences in sensitivity with the HSV-1-specific LAMP assay. To evaluate the application of the LAMP assay for clinical diagnosis, we tested clinical samples from 40 genital herpes patients and 20 ocular herpes patients. With the LAMP assay, 41 samples with DNA extraction and 26 direct samples without DNA extraction were identified as positive for HSV-1 or HSV-2, although 37 samples with DNA extraction and just one without DNA extraction were positive by a PCR assay. Thus, the LAMP assay was less influenced than the PCR assay by the presence of inhibitory substances in clinical samples. These observations indicate that the LAMP assay is very useful for the diagnosis of HSV-1, HSV-2, and VZV infections.

Detection and typing of Herpes Simplex virus (HSV) in mucocutaneous samples by TaqMan PCR targeting a gB segment homologous for HSV types 1 and 2

Herpes simplex virus types 1 (HSV-1) and 2 (HSV-2) are major causes of mucocutaneous lesions and severe infections of the central nervous system. Here a new semiautomated method for detecting and typing of HSV was used to analyze 479 mucocutaneous swab samples. After DNA extraction using a Magnapure LC robot, a 118-bp segment of the gB region was amplified by real-time PCR utilizing type-specific TaqMan probes to identify HSV-1 or HSV-2. HSV detection in a single well using probes labeled with carboxyfluorescein (FAM) for HSV-1 and JOE (6-carboxy-4',5'-dichloro-2',7'-dimethoxyfluorescein) for HSV-2 had a sensitivity similar to that seen in separate reactions. All but one of 217 samples (99.5%) that had been positive by virus culture were positive by TaqMan PCR, with a correct identification of type in all cases. Out of 262 samples negative by virus culture, 48 (18.3%) were positive by TaqMan PCR, with higher Ct values compared with culture positive samples (P < 0.0001). Overall, the Ct values for HSV-1 were lower than for HSV-2 (mean, 25.5 versus 27.9), but to some extent this could be due to weaker fluorescence by JOE. Lower C(t) values for HSV-1 were seen also in the 202 genital samples (79 HSV-1, 122 HSV-2, 1 HSV-1 and HSV-2), indicating that HSV-1 replicates as well as HSV-2 in the genital area. HSV-1 constituted 40% of genital infections and was associated with lower mean age (29.2 versus 36.4 years), probably reflecting the fact that recurrent genital HSV-1 infections are rare.

Comparison of two methods of PCR followed by enzymatic restriction digestion for detection and typing of herpes simplex viruses isolated from patients with mucocutaneous or cutaneous lesions

A multitude of different polymerase chain reactions (PCRs) have been described for detection and typing of Herpes simplex virus (HSV). This paper compares two PCRs coupled to enzymatic restriction (PCR/RFLP) to detect and type HSV. A primers set was designed to amplify a HSV DNA fragment from UL30 and UL 15 genes. Typing was done by restriction of the UL30 and UL15 amplicons with Ava II and Hpa II enzymes, respectively. This strategy was tested with two reference strains (HSV-1 McIntyre, and HSV-2 G), and 47 clinical HSV isolates. Both PCRs produced the expected amplicons (a 492 bp UL30, and 305 bp UL15). The restriction of both amplicons clearly differentiated HSV- from HSV-2, and produced equal results. Thirty one (66%) of the isolates were identified as HSV-1, and the other 16 (34%), as HSV-2. Most of the HSV-1 isolates (27/31) were from orofacial and thoracic lesions; and also, one half of the HSV-2 isolates (8/16) were from the same anatomical regions. Our results showed that either of the two PCR/RFLP could be used to detect and type HSV. Furthermore, our results of the anatomical site of HSV-1 and HSV-2 infections are consistent with previous reports which have shown changes in the classical anatomical localization of herpesvirus infections.

Sequencing and resolution of amplified herpes simplex virus DNA with intermediate melting curves as genotype 1 or 2 by LightCycler PCR assay

DNA from 101 specimens containing herpes simplex virus (HSV) produced atypical intermediate melting curves compared with those expected for HSV type 1 or HSV type 2 subsequent to real-time PCR. Nucleic acid sequence analysis of amplified target DNA revealed 1- or 3-bp polymorphisms in the probe region which allowed designation of these viruses as HSV genotype 1 or HSV genotype 2. These two subpopulations of HSV were also identified as HSV genotype 1 or HSV genotype 2 using another commercially available PCR method. Amplified HSV target DNA producing intermediate melting curves could be designated as HSV genotype 1 or HSV genotype 2 without performing sequencing or another PCR method with 96/101 (95%) specimens by adding known intermediate HSV DNA characteristic for the two subpopulations as controls.

Growth of herpes simplex virus in epidermal keratinocytes determines cutaneous pathogenicity in mice

Herpes simplex viruses (HSV)-1 and -2 isolated from genital lesions were examined for cutaneous pathogenicity and its correlation with cellular tropism. HSV-1 caused vesiculation, erosion/ulcer, and zosteriform lesions successively, but skin lesions of HSV-2 developed without vesiculation in some mice, and with statistically significantly less frequent vesiculation than HSV-1. Thus, the virological type of HSV was correlated with its cutaneous pathogenicity. The growth characteristics of HSV-1 and -2 were compared in cultured human embryonic lung (HEL) fibroblasts, human lung cancer A549 cells, human neonatal epidermal keratinocytes, human neonatal dermal fibroblasts, HeLa cells, and Vero cells. HSV-2 produced plaques that were 72% times the size of HSV-1 plaques in epidermal keratinocytes but 230%-500% the size in the other cells. The difference between HSV-1 and -2 in the ratio of plaque size to virus yield in epidermal keratinocytes was much larger (502 times) than the ratio of the other cells (5.57-28.8 times). Keratinocytes are the major constituent of the epidermal layer of the skin and the cells in which vesiculation and erosion/ulceration occur histologically. Therefore, the smaller spread of HSV-2 in keratinocytes of the epidermal layer and the greater spread in other cells of the dermal layer might reflect its lesser invasiveness in the epidermal layer despite larger invasiveness in the dermal layer, which is reflected in the low incidence of erosion/ulcer of the skin compared to HSV-1. Thus, the growth of HSV in epidermal keratinocytes appeared to correlate with the cutaneous pathogenicity causing vesiculation in the skin.

Evaluation of the ELVIS plate method for the detection and typing of herpes simplex virus in clinical specimens

This study was conducted to assess the reliability of a commercial enzyme-linked viral inducible system (ELVIS) (Diagnostic Hybrids, Inc., Athens, OH) for rapid detection and typing of herpes simplex virus (HSV). Results using ELVIS were compared to those of shell vial culture (SVC) and HSV detection with monoclonal antibodies and an immunoperoxidase stain plus typing with MicroTrak direct fluorescent antibodies (Trinity Biotech PLC, Wicklow, Ireland). Specimens yielding discrepant HSV results were tested by polymerase chain reaction (PCR); those with discrepant typing results were stained with Simulfluor (Chemicon, Temecula, CA). Of the 206 samples tested, 144 were negative and 54 were HSV-positive by both methods (agreement, 96.1%). Five specimens were positive by ELVIS but negative by SVC; 3 of these were positive and 2 were negative by HSV PCR. Both of the latter were the result of mechanical problems early in the study. Three specimens were positive by SVC but negative by ELVIS; all 3 were positive by HSV PCR. After resolution of discrepancies, the sensitivity and specificity for detection of HSV were 95.0% and 100% for SVC, respectively, and 95.0% and 98.6% for ELVIS. Of the 46 HSV-positive samples that were typed, 26 were called type 2 and 18 were type 1 by both methods (agreement, 95.7%). The 2 specimens with discrepant results were called HSV-2 by SVC, staining with MicroTrak, and HSV-1 with ELVIS; both of these were type 2 when stained with the Simulfluor reagent. ELVIS is a reliable alternative to SVC for rapid detection and typing of HSV.

Detection and differentiation of herpes simplex virus types 1 and 2 by a duplex LightCycler PCR that incorporates an internal control PCR reaction

BACKGROUND

In recent years polymerase chain reaction (PCR) has proven to be a highly sensitive and specific method for the diagnosis of herpes simplex virus (HSV) infections. The advent of real-time HSV PCR protocols now enables rapid result turnaround times with minimal hands-on time.

OBJECTIVES

In this study, we developed a real-time duplex PCR assay (HSVgD-dPCR) comprising of HSV and internal control PCR reactions.

STUDY DESIGN

Using the LightCycler, the HSVgD-dPCR targeted the HSV glycoprotein D gene and HSV typing was performed by melting curve analysis. The internal control PCR reaction targeted sequences of the DNA of the human endogenous retrovirus (ERV-3). In total, 300 swab specimens, from patients with suspected HSV infection, were tested by the HSVgD-dPCR assay. The results were then compared to the results obtained by another HSV LightCycler assay, which utilized published primer and probe sequences targeting the HSV DNA polymerase gene (Dpol-HSV-LCPCR).

RESULTS

Overall, 91 (30.3%) specimens were positive and 204 (68.0%) specimens were negative for HSV by both LightCycler assays. In addition, four (1.3%) specimens were positive by Dpol-HSV-LCPCR and negative by HSVgD-dPCR, whereas one (0.3%) specimen was positive by HSVgD-dPCR and negative by Dpol-HSV-LCPCR. The presence of HSV in these five specimens was confirmed by conventional PCR. Melting curve analysis by the HSVgD-dPCR assay enabled all HSV positive specimens to be typed, whereas sequence variation prevented three HSV positive specimens from being typed by the Dpol-HSV-LCPCR. Using the ERV-3 PCR, 5% specimens were found to contain inhibitory substances.

CONCLUSIONS

By developing the HSVgD-dPCR we have enhanced the diagnostic utility of real-time detection of HSV by incorporating an internal control reaction and by accurately typing a greater proportion of HSV positive specimens.

Herpes simplex virus genotyping: multiple optional PCR-based RFLP systems and a non-isotopic single-strand conformation polymorphism method

Polymerase chain reaction (PCR)-based methods for herpes simplex virus (HSV) types I/II genotyping are described. These methods are based on the single-stranded conformation properties of DNA molecules obtained by PCR (PCR-SSCP) and restriction fragment analysis of PCR products (PCR-RFLP). With the aim to analyse these two genotyping techniques, genomic DNA from the standard viral strains KOS and G, and also 79 normal cervical samples were studied for HSV I/II. Sequence analysis showed 19 different RFLP possible systems for HSV typing. Five systems were used in this study and all led to the expected fragments obtained by sequence analysis. PCR-SSCP showed distinct patterns for both viral types and had 100% of concordance with PCR-RFLP results. The prevalence of herpes simplex virus in the normal cervical samples were 21.5% (17 out of 79), the most frequent viral type was HSV-2, with a prevalence of 71% (12 out of 17). Both techniques appeared suitable for HSV I/II genotyping and are easy to perform in most clinical laboratories.

Detection of herpes simplex virus type 1, herpes simplex virus type 2 and varicella-zoster virus in skin lesions. Comparison of real-time PCR, nested PCR and virus isolation

BACKGROUND

Herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2) and varicella-zoster virus (VZV) cause a wide range of signs and symptoms, varying from trivial mucocutaneous lesions to life-threatening infections, especially in immuno-suppressed patients. Since antiviral drugs are available, rapid and sensitive laboratory diagnosis of these virus infections is important.

OBJECTIVE

To set up and evaluate HSV-1, HSV-2 and VZV qualitative real-time PCR on the Lightcycler system and to compare the results with those of the 'in-house' nested PCR and virus isolation.

STUDY DESIGN

110 consecutive samples from dermal or genital lesions from patients suspected of having HSV infections and another 110 samples from patients with suspected VZV infections were tested with real-time PCR, nested PCR and virus isolation.

RESULTS

24 samples (22%) were positive for HSV-1 by virus isolation and nested PCR, whereas 26 (24%) were positive by real-time PCR. HSV-2 was detected in 28 samples (25%) by virus isolation, in 41 (37%) by nested PCR and in 40 (36%) by real-time PCR. VZV was isolated in 15 samples (14%) and VZV DNA was detected in 51 samples (46%) by nested PCR as well as by real-time PCR. Nucleic acid amplification increased the detection rate of HSV-2 and VZV DNA in particular compared to virus isolation. No significant difference in sensitivity was found between real-time PCR and nested PCR.

CONCLUSION

Real-time PCR has the advantage of rapid amplification, a reduced risk for contamination and it is a suitable method for diagnosis of VZV and HSV in specimens from skin lesions.

Disseminated neonatal herpes simplex virus (HSV) type 2 infection diagnosed by HSV DNA detection in blood and successfully managed by liver transplantation

We report a case of neonatal herpes presenting with liver failure and disseminated coagulopathy which followed unrecognised maternal primary genital herpes and was diagnosed by herpes simplex virus DNA detection in blood by polymerase chain reaction 2 weeks after initiation of empiric intravenous aciclovir. The child underwent liver transplantation while receiving suppressive antiviral therapy and remains well after 10 months of follow-up.

CONCLUSION

our case highlights potential pitfalls in the diagnosis of neonatal herpes and indicates a role for blood herpes simplex virus polymerase chain reaction as a sensitive diagnostic tool in disseminated infection. It is one of very few reports where liver transplantation has been successfully carried out in a neonate with herpes simplex virus-induced liver failure.

Detection and typing of HSV-1, HSV-2, CMV and EBV by quadruplex PCR

The development of a multiplex polymerase chain reaction (PCR) method for rapid and accurate detection and typing of herpes simplex virus type 1 (HSV-1), and type-2 (HSV-2), cytomegalovirus (CMV) and Epstein-Barr virus (EBV) is very important for clinical diagnosis to allow the deliver of therapy as early as possible. Large scale amplifications by multiplex PCR of viral DNA can lower the cost and time for viral diagnosis. In this study, therefore sensitive quadruplex PCR was achieved by optimizing parameters such as primers, and 1.5 mM magnesium and 200 uM dNTPs concentrations. The concentrations of HSV-1, HSV-2, CMV and EBV primers were 0.5, 0.3, 0.25 and 0.25 pmoles, respectively. Optimal annealing temperature was 54 degrees C. Employing these conditions, we could detect 10 copies of reconstructed template plasmid DNA, which were cloned to vectors containing target sequences of viral DNA. PCR products of 271 bp for HSV-1, 231 bp for HSV-2, 368 bp for CMV, and 326 bp for EBV were separated on 5.0% polyacrylamide gel electrophoresis and confirmed by direct sequencing. The present study showed that the quadruplex PCR assay described herein has potential application in clinical diagnosis, when rapid, accurate detection and typing of viruses HSV-1, HSV-2, CMV or EBV are necessary.

Detection and genotyping of human herpes simplex viruses in cutaneous lesions of erythema multiforme by nested PCR

A subset of erythema multiforme (erythema multiforme) is associated with herpes simplex virus (HSV) infection; viral cultures of erythema multiforme lesions are, however, usually negative and viral antigens difficult to identify. Polymerase chain reaction (PCR) has been used to demonstrate the association, hence, is currently the only available sensitive diagnostic means for HSV-associated erythema multiforme. A nested PCR, which could simultaneously detect and genotype HSV in erythema multiforme lesions and in clinical swab specimen was developed using the DNA polymerase gene of HSV as target gene because it is the only detectable HSV gene in a high proportion of erythema multiforme lesions. The PCR has demonstrated its robust sensitivity on swab samples by being able to detect further 45.3% HSV cases in comparison with virus isolation with 100% specificity in both detection and genotyping confirmed by virus isolation and DNA sequencing. This study represents the first investigation of typing HSV virus in HSV-associated erythema multiforme patients, and the finding that 66.7% of the patients was attributed to HSV1, 27.8% to HSV2, and 5.6% to HSV1 and 2 co-infection may reflect the distribution of HSV1 and 2 in local general population.

Failure to genotype herpes simplex virus by real-time PCR assay and melting curve analysis due to sequence variation within probe binding sites

Real-time PCR with melting curve analysis of PCR products is a rapid procedure for detecting and genotyping herpes simplex virus (HSV). When testing mucocutaneous samples for HSV by a real-time PCR assay targeting the DNA polymerase gene, we found that some PCR products had atypical melting curves that did not conform to the expected melting temperatures for HSV type 1 or 2. Sequence analysis showed that these strains had base-pair mismatches over the probe binding sites. An alternative assay is required to type such atypical isolates.

Time course of seroconversion by HerpeSelect ELISA after acquisition of genital herpes simplex virus type 1 (HSV-1) or HSV-2

BACKGROUND

HerpeSelect HSV-1 and HSV-2 ELISAs are glycoprotein G-based, type-specific antibody detection tests that are approved by the US Food and Drug Administration for diagnosis of genital herpes.

GOAL

The goal was to determine seroconversion times by means of HerpeSelect ELISAs.

STUDY DESIGN

Four-hundred thirteen sera from 113 patients with recently acquired genital herpes were tested by HerpeSelect ELISAs and Western blot (WB). Thirty-one patients had primary genital HSV-1 (group 1), 56 had primary HSV-2 (group 2), and 26 had prior HSV-1 antibodies and newly acquired HSV-2 (group 3).

RESULTS

Median interval from onset of symptoms to seroconversion was 25 days, as determined by HerpeSelect HSV-1, versus 33 days by WB for group 1; 21 days by HerpeSelect HSV-2 versus 40 days by WB (group 2; P = 0.0005); and 23 days by HerpeSelect HSV-2 ELISA versus 47 days by WB (group 3; P = 0.02). In long-term follow-up, transient reversion to HerpeSelect negativity occurred in 3 of 31 HSV-1-infected subjects (10%) and in 2 of 82 HSV-2-infected subjects (2%).

CONCLUSION

Seroconversion to HSV-2 was determined faster by HerpeSelect than by WB.

Phenotypic and genotypic methods for the detection of herpes simplex virus serotypes

Typing of herpes simplex virus (HSV) into its serotypes plays a major role in epidemiology and management of reactivation. To develop and evaluate a polymerase chain reaction (PCR)-based restriction fragment length polymorphism (RFLP) was employed using Hae III and Taq I against neutralization test, allele-specific PCR and DNA sequencing for the detection of HSV serotypes. Neutralization test, allele-specific PCR, DNA sequencing and PCR-based RFLP were applied simultaneously to 2 standard strains (HSV-1 and HSV-2) and 23 clinical isolates. PCR-based RFLP was applied further to 20 culture negative PCR positive clinical specimens. The 179 bp product of the clinical isolates and specimens amplified using the type-common primers of HSV was subjected to DNA sequencing and PCR-based RFLP. Allele-specific PCR was absolutely specific and highly sensitive. All the typing methods differentiated concordantly 23 clinical isolates into 12 HSV-1 and 11 HSV-2. DNA sequencing did not reveal any nucleotide variations within the serotypes among the isolates sequenced. PCR-based RFLP typed a further 20 culture negative clinical specimens into 15 HSV-1 and 5 HSV-2. PCR-based RFLP was a reliable, less laborious and cost-effective molecular biological tool for the determination of HSV serotypes both for the clinical isolates and culture negative specimens.

Detection of herpes simplex virus type 2-specific immunoglobulin G antibodies in African sera by using recombinant gG2, Western blotting, and gG2 inhibition

Sera (n = 781) from four African countries were used to determine the prevalence of herpes simplex virus type 2 (HSV-2) antibodies by using the HerpeSelect HSV-2 enzyme-linked immunosorbent assay (ELISA; Focus Technologies) and Western blotting (WB). Also, an HSV inhibition assay was developed to evaluate the discordant sample results between HerpesSelect and WB. The seroprevalence of HSV-2 ranged from 17% in the South African panel to nearly 70% in panels from Kenya, Uganda, and Zimbabwe. Overall, HerpeSelect was 100% sensitive and 88% specific compared to WB and 100% sensitive and 96% specific compared to the inhibition assay. There was 100% concordance among all three assays for samples from South Africa and Zimbabwe. The discordant results occurred in samples from Kenya and Uganda.

Clinical and subclinical reactivation of genital herpes virus

Reactivations of herpes simplex virus (HSV) either symptomatically (recrudescence) or without symptoms (recurrence) are well documented. As an asymptomatic reactivation may contribute to transmitting HSV to potential acceptors the frequency of reactivations should be evaluated. In order to evaluate the frequency of HSV-2 reactivation 173 genital swabs of a group of women chosen at random were analyzed by nested PCR. 34 (19.6%) showed clinical evidence of a herpes infection, 77 (44.5%) had no symptoms at all and 62 (35.8%) had other symptoms. In 26 (15%) HSV-DNA was detected. 11 (38.4%) could be characterized as asymptomatic reactivations. Typing of the HSV-positive swabs resulted in 11 HSV-2 and 10 HSV-1 strains. Additionally 18 HSV-positive swabs of the oral cavity resulted in 15 (83.2%) HSV-1 and 3 (16.4%) HSV-2 strains. The results of typing indicate a change of HSV-1 and HSV-2 epidemiology.

Detection and species identification of four human herpesviruses using polymerase chain reaction coupled with restriction endonuclease analysis

A polymerase chain reaction (PCR) based assay for detection and species identification of four human herpesviruses, including herpes simplex virus types 1 and 2, Epstein-Barr virus, and cytomegalovirus was developed. The detection of the herpesviruses was achieved by seminested PCR with three primers targeting well-conserved regions within the DNA-polymerase gene. Virus species were identified by simple restriction enzyme digestion of the amplified products with TaqI or RsaI. In comparison with mono-specific nested PCR assays the tetra-specific assay demonstrated similar specificity and sensitivity with reference and clinical samples. The tetra-specific assay is sensitive, cost effective, and can be used for examination of clinical samples of different origin.

One-step PCR to distinguish B virus from related primate alphaherpesviruses

By adding betaine to the PCR mixture, we previously established a PCR method to amplify a DNA segment of the glycoprotein G gene of B virus (BV) derived from a rhesus macaque. We have found that DNA of other BV strains derived from cynomolgus, pigtail, and lion-tailed macaques can also serve as the template in our PCR assay. Under the same conditions no product was obtained with DNA of simian agent 8 of green monkeys and Herpesvirus papio 2 of baboons, or the human herpes simplex viruses types 1 and 2. Thus, this PCR method is useful to discriminate BV from other closely related primate alphaherpesviruses.

Recovery of an unusual fusogenic herpes simplex virus type 2 strain from a clinical specimen

A highly unusual herpes simplex virus type 2 strain, strain Burr, was isolated from a female genital tract clinical specimen. This virus induced remarkably rapid and extensive syncytium formation in Vero cells involving hundreds of cells but was less fusion active in HEp-2 cells, MRC-5 cells, and mink lung cells. Virus-infected cells produced the glycoproteins gB, gC, gD and gE.

Case study: type-specific HSV serology and the correct diagnosis of first-episode genital herpes during pregnancy

It is now known that the physical presentation of genital herpes simplex (HSV) infection can be misleading in making the diagnosis of genital herpes. An incorrect diagnosis can be particularly damaging in pregnancy where it may result in extended exposure of the fetus to antiviral agents, an inappropriate route and timing of delivery and a significant increase in fetal exposure to HSV during labour and delivery. Case 1 describes a 32-year-old woman at 30 weeks in her first pregnancy who had the appearance and clinical course typically ascribed to primary genital HSV infection. In contrast, Case 2, a 24-year-old woman at 34 weeks' gestation, had the physical appearance of a recurrent episode. Type-specific serological testing revealed that what Case 1 was actually experiencing was the first symptomatic reactivation of genital herpes, whereas Case 2 had a true primary genital HSV-2 infection that was accompanied by minimal symptoms. Had serology testing not been available, Case 1 would probably have delivered unnecessarily by Caesarean section, and Case 2 would have been managed as a recurrent infection and allowed to deliver vaginally with potentially disastrous results. These cases illustrate the usefulness of a type-specific serology in diagnosing genital herpes in pregnant women.

Typing of herpes simplex virus from human periodontium

Herpes simplex virus (HSV) is frequently detected in gingival crevicular fluid and in gingival biopsies of periodontal lesions; however, the relative occurrence of HSV type 1 and 2 in periodontal specimens has not been established. This investigation used type-specific polymerase chain reaction (PCR) to detect the presence of HSV-1 and HSV-2 in periodontal pocket samples from 26 patients who had previously been revealed to have periodontal HSV by PCR amplification of a gene shared by HSV-1 and HSV-2. HSV-1 was detected in all 26 periodontal pocket specimens and HSV-2 was not detected. Apparently, HSV-2 is a rare inhabitant of periodontal sites.

Detection and typing of HSV-1, HSV-2, and VZV by a multiplex polymerase chain reaction

The development of a multiplex polymerase chain reaction method for the rapid and accurate detection and typing of HSV-1, HSV-2, and VZV from clinical specimens is described. A sensitive multiplex polymerase chain reaction was achieved by optimization of parameters such as the primers, magnesium, and dNTPs concentrations. False-negative results that sometimes arise due to inhibitors of DNA amplification or failure of DNA extraction procedure used may be avoided by assaying each specimen with alpha-tubulin primers. Multiplex PCR amplified viral sequences from all 55 specimens obtained from patients with clinical evidence of HSV or VZV infection indicated 100% sensitivity. From 55 patients who were investigated by multiplex PCR, HSV-1 was detected in 28, HSV-2 in 20, and VZV in 7 specimens. The reported results indicate that the present multiplex PCR assay has a potential application in clinical diagnosis when a rapid and accurate detection and typing of involved viruses HSV-1, HSV-2, or VZV is needed.

Utility of restriction fragment analysis for typing herpes simplex virus amplicons following PCR of targets in the DNA polymerase gene

We compared the utility of restriction endonuclease cleavage to type herpes simplex virus DNA polymerase gene amplicons from two well established PCR primer sets. Amplicons typed using Ava II had a 96% correlation to type determined by monoclonal antibody staining, while amplicons typed using Drd I had a 72% correlation to type determined by monoclonal antibody staining.

Confirmation of low-titer, herpes simplex virus-positive specimen results by the enzyme-linked virus-inducible system (ELVIS) using PCR and repeat testing

The ELVIS HSV Id test kit (an enzyme-linked virus-inducible system) (Diagnostic Hybrids, Inc.) uses genetically engineered BHK cells to produce a detectable enzyme, beta-galactosidase, upon infection with either herpes simplex virus (HSV) type 1 (HSV-1) or HSV-2. Twenty six ELVIS-positive clinical specimens were selected for study by PCR and with monoclonal antibodies because they were originally low-titer HSV-positive specimens by ELVIS but HSV antibody nonreactive upon follow-up staining of the ELVIS monolayer. Twenty-one of 26 specimens were frozen, thawed, and retested with ELVIS without removing the cellular debris from the specimen; 18 were ELVIS positive and 3 were ELVIS negative on retesting. A typing result was provided upon retesting for 14 of 18 ELVIS-positive specimens (11 were HSV-1 and 3 were HSV-2) with HSV-specific monoclonal antibodies; no antibody signal was observed for 4 of 18 ELVIS-positive specimens. Sixteen of 26 specimens were subjected to blinded PCR analysis with two different primer sets, including all those that were repeat tested with ELVIS without success and those that had insufficient quantity for repeat testing. All 16 specimens analyzed were PCR positive with primer set 1; 15 of 16 were also positive with primer set 2, with the HSV type identified for all specimens (7 were HSV-1 and 8 were HSV-2). These results indicate that the original ELVIS result with these low-titer specimens was correct and further confirm the sensitivity and specificity of ELVIS HSV Id as a rapid, cell culture-based kit for the detection of HSV.

Monoclonal antibodies suitable for type-specific identification of herpes simplex viruses by a rapid culture assay

Eight monoclonal antibodies (MAbs) to herpes simplex viruses 1 and/or 2 (HSV-1, HSV-2) were tested for their reactivity with 190 previously typed HSV-positive clinical specimens in order to determine their suitability for use as type-specific reagents. Using a rapid culture assay we found that two MAbs (T51 and T96) identified HSV-1 in all the 94 specimens, previously found HSV-1-positive, but did not react with the 96 specimens, previously found HSV-2-positive. In contrast, one MAb (303) confirmed the presence of HSV-2 in all the specimens, previously found HSV-2-positive, but did not react with any of the 94 specimens, previously found HSV-1-positive. These three type-specific MAbs allow for a rapid type-specific identification of HSV in infected cultures. One type-common MAb (T111) reacted with all HSV-positive cultures. This MAb can be used as an excellent reagent for detection of HSV infection.

A duplex PCR assay for detection and genotyping of Herpes simplex virus in cerebrospinal fluid

A duplex polymerase chain reaction (PCR) assay for the detection and genotyping of Herpes simplex virus (HSV) 1 and 2 from cerebrospinal fluid (CFS) of infants was developed. The glycoprotein D (gD) gene of HSV was selected as a target for amplification. The assay is highly specific, sensitive and reproducible. Herpes simplex virus detection is performed by agarose gel electrophoresis and Southern blot using a chemiluminescent probe. The probe hybridizes to sequences common to both HSV-1 and 2. A DNA fragment of HSV gD gene was cloned and used as positive control and to determine the specificity and sensitivity of the assay. The PCR assay is user-friendly and unambiguously differentiates in one-step both herpes virus strains. The assay is useful to screen CFS specimens from infants exposed to HSV during birth and at risk of developing encephalitis.

Limits in reliability of glycoprotein G-based type-specific serologic assays for herpes simplex virus types 1 and 2

Type-specific serologic assays for herpes simplex virus (HSV) types 1 and 2 based on glycoprotein G-1 (gG-1) (HSV-1) and gG-2 (HSV-2) discriminate between antibodies against HSV-1 and HSV-2. We previously developed a Western blot assay using gG-1 and gG-2 expressed in baculovirus, performed extensive validation studies, and determined that it was both sensitive and specific for type-specific detection of HSV antibody. Here we report that, among a cohort of Thai military recruits, the serostatus of some individuals changed from positive to negative over time (6.6% among those ever positive for HSV-1, and 14.9% among those ever positive for HSV-2). We tested a subset of these specimens in three other gG-based assays: an enzyme-linked immunosorbent assay, an immunoblot strip assay, and a Western blot assay. Positive-to-negative shifts occurred in every assay; the frequency of the shifts ranged from 6. 1% to 21.2% of the specimen sets tested. There was only limited agreement among the assays concerning which individuals lost reactivity. This inaccuracy, exhibited by all of the assay protocols, was not predicted by validation studies employing specimens from cross-sectional studies and was most pronounced in HSV-2 testing. This argues for the inclusion of serial blood specimens in serologic assay validation procedures.

Genital herpes: review of the epidemic and potential use of type-specific serology

Prevention of genital herpes simplex virus (HSV) infections is desirable from both a public health standpoint and the patient's perspective. A key factor in the spread of genital herpes infections is the high proportion of undiagnosed infections. Persons with subclinical or unrecognized infections are best diagnosed by accurate, type-specific antibody tests. Unfortunately, these tests are only now becoming widely available. The use of current, conventional (non-type-specific) serologic tests for diagnosis of herpes infections has resulted in confusion and misdiagnosis of patients. This review provides recent information on the epidemiology of genital herpes infections, describes the importance of subclinical herpes infection and shedding, summarizes the status of HSV type-specific serologic assays being developed, and provides indications for using such assays.

Evaluation of ELVIS HSV ID/Typing System for the detection and typing of herpes simplex virus from clinical specimens

BACKGROUND

Herpes simplex virus (HSV) is a common pathogen with two serotypes: HSV-1 and HSV-2. HSV infection does not pose much of a threat to an immunocompetent host but to an immunocompromised host or a neonate the infection can be fatal. The Enzyme-Linked Virus Inducible System (ELVIS) employs a genetically altered baby hamster kidney (BHK) cell line that allows for the rapid overnight detection of HSV but also includes an immunofluorescent stain for the simultaneous detection and typing of HSV-1 and HSV-2.

OBJECTIVE

To evaluate the ELVIS HSV ID/Typing System in comparison with HSV identification and typing in primary rabbit kidney (PRK) cells grown in shell vials.

STUDY DESIGN

Over a period of 6 weeks, 130 specimens were submitted to the diagnostic virology laboratory and cultured for the presence of HSV. Two PRK shell vials and one ELVIS BHK shell vial were inoculated with patient specimen. PRK shell vials were observed for cytopathic effect (CPE) for up to 4 days. When CPE was observed the PRK shell vials were fixed and one shell vial was stained with HSV-1 monoclonal antibody (Mab) and the other was stained with HSV-2 Mab. The coverslips were observed under the fluorescent microscope for specific apple-green fluorescence. The BHK shell vials were incubated overnight, fixed, and stained with galactopyranoside (X-Gal). If blue cells were present, the specimen was positive for HSV. The coverslip was then observed under the fluorescent microscope for the presence of specific apple-green fluorescence, indicating HSV-2. If no specific apple-green stain was observed, the coverslip was stained with a fluorescent conjugated goat anti-mouse IgG to determine the presence of HSV-1.

RESULTS

Of the 130 specimens, PRK shell vials detected 43 positive HSV; 30 were HSV-2 and 13 were HSV-1. The ELVIS BHK shell vials detected 42 positive HSV; 30 were HSV-2 and 12 were HSV-1. One low titer specimen was not identified as being HSV positive. Two specimens were not directly typed by the ELVIS system. One specimen had only one blue cell present and did not show specific staining for either HSV-1 or HSV-2. The other specimen had only five blue cells present and only one fluorescent cell present that was difficult to type. As suggested by the manufacturer's instructions, both specimens that were not directly typed were re-grown overnight from their supernatants and were correctly identified and typed.

CONCLUSION

The ELVIS HSV ID/Typing System is a rapid, highly specific and sensitive method of overnight HSV detection and typing.

Clear detection and typing of herpes simplex virus types 1 and 2 by an indirect ELISA assay: comparison with three different combined methods--capture ELISA, restriction enzymes, and polymerase chain reaction

The severity and recurrences of Herpes Simplex Virus (HSV) infection depend on the type of the infectious agent (HSV-1 or HSV-2), which induces the necessity of a nonambiguous detecting typing. The commonly used capture ELISA technique has to be often supported by DNA analysis to confirm the detection and the typing of HSV viruses in exposed patients. In this report, we describe a rapid and cheap indirect ELISA method using anti-HSV monospecific polyclonal antibodies prepared in the laboratory. The typing of the studied samples was clear, did not need series of dilution, and allowed the immediate classification of viruses without further control examination. We tested 51 specimens, which were typed 25 HSV-1 and 26 HSV-2 strains. The comparison with capture ELISA, restriction enzyme and polymerase chain reaction analysis definitely allowed our method to be assessed as a useful tool for a routine diagnostic.