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

The Molecular Epidemiology of Herpes Simplex Virus Type 1 and 2 (HSV-1 and HSV-2) in Head and Neck Cancer (HNC)

Background: Head and neck cancers (HNC) constitute the sixth common type of malignancies worldwide and can affect a wide range of anatomical regions. The role of the herpes simplex virus (HSV) in oral squamous cell carcinoma (OSCC) has been previously investigated. Objectives: The objective of the current study was to evaluate the molecular epidemiology of herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) in patients with HNC. Methods: A total of 156 patients with HNC were chosen including 90 biopsies and 66 formalin-fixed paraffin-embedded (FFPE) samples. HNC was confirmed and affected different anatomical regions. HSV detection was performed by a polymerase chain reaction (PCR) and HSV typing was assessed by a multiplex PCR. Results: The 156 HNC specimens included 35 (22.4%) larynx, 29 (18.6%) tongue, 6 (3.8%) glands (parotid and tonsil), 12 (7.6%) nasopharynx, 9 (5.7%) pharynx, 33 (21%) vocal cord, 3 (1.9%) palatine, glottis 17 (10.8%), nasal 2 (1.3%), mandibular 4 (2.5%), lip 4 (2.5%), neck 1 (0.6%), and face 1 (0.6%). The mean ± SD of the patients’ age was 60.3 ± 12.65, where 121 (77.1%) were male. The HSV was detected in 4 (2.6%) samples and 75% of HSV positive samples were HSV-1. Conclusions: The rate of HSV infection in Iranian patients with HNC was 2.6% with the majority being HSV-1 (75%). As a preliminary study in Iranian patients with HNC, cancer location was not statistically significant. Further investigations are needed to assess the role of HSV in HNC.

Serum HSV-1 and -2 IgM in pregnant women in Port Harcourt, Nigeria

The present study was undertaken for the purpose of finding IgM antibodies against HSV-1 and 2 infections among pregnant women and also to evaluate correlation of Serum HSV-1 and 2 IgM in these pregnant women. A total of 180 pregnant women attending antenatal clinic at Braithwaite Memorial Specialist Hospital (BMSH) in Port Harcourt, Nigeria were consecutively recruited, after they had given consents to participate in the study. Serum of each sample was assayed for HSV-1&2 IgM antibody using a commercial ELISA. Five (2.8%) of the pregnant women were positive for IgM antibody against HSV-1&2. Marital status mainly correlated (χ(2) = 221.5, P < 0.05) with HSV-2 infection and HSV-1/HSV-2 co-infection. Age, educational level, occupation, and gestation were not consistently associated (P>0.05) with HSV-1/HSV-2 infection and co-infection. We also observed a high overall anti-HSV-1&2 IgM seronegativity of 97.2% among these pregnant women. Group-specific seronegativity was also high ranging from 93.3-100%. Although the age-groups significantly differed, none of their variables showed statistical association with the seronegativity. This represents the first analysis of HSV IgM antibody reported in Port Harcourt, Nigeria and has important public health implications, particularly for pregnant women. Consideration of this information would benefit physicians providing primary gynecological and obstetric care to this population of women.

Molecular characterization of herpes simplex virus 2 strains by analysis of microsatellite polymorphism

The complete 154-kbp linear double-stranded genomic DNA sequence of herpes simplex virus 2 (HSV-2), consisting of two extended regions of unique sequences bounded by a pair of inverted repeat elements, was published in 1998 and since then has been widely employed in a wide range of studies. Throughout the HSV-2 genome are scattered 150 microsatellites (also referred to as short tandem repeats) of 1- to 6-nucleotide motifs, mainly distributed in noncoding regions. Microsatellites are considered reliable markers for genetic mapping to differentiate herpesvirus strains, as shown for cytomegalovirus and HSV-1. The aim of this work was to characterize 12 polymorphic microsatellites within the HSV-2 genome by use of 3 multiplex PCR assays in combination with length polymorphism analysis for the rapid genetic differentiation of 56 HSV-2 clinical isolates and 2 HSV-2 laboratory strains (gHSV-2 and MS). This new system was applied to a specific new HSV-2 variant recently identified in HIV-1-infected patients originating from West Africa. Our results confirm that microsatellite polymorphism analysis is an accurate tool for studying the epidemiology of HSV-2 infections.

Genital herpes simplex virus type 1 in women: detection in cervicovaginal specimens from gynecological practices in the United States

Herpes simplex virus types 1 and 2 (HSV-1 and -2) are significant human pathogens causing clinically indistinguishable facial and genital lesions. Recently, the number of reported genital herpes cases caused by type 1 virus has increased. Identifying the HSV type is of clinical importance to determine proper treatment, as there is no licensed vaccine or cure. We assessed, by PCR, the frequency of HSV-1 and HSV-2 present in more than 60,000 clinical cervicovaginal specimens derived from samples originating from 43 continental U.S. states. Fourteen percent were positive for HSV-1 and/or HSV-2. This likely represents subclinal shedding. It was not a measurement of the prevalence of HSV infection. While the majority were HSV-2, 32% were HSV-1. The distribution of HSV types varied between the states with the largest number of specimens, New Jersey, Florida, and Texas. Specimens from women under the age of 24 had an HSV-1 positivity rate of 47 percent. Importantly, in New Jersey, an observed age effect was the disproportionately high prevalence of genital HSV-1 in young women. This represents the largest analysis of HSV types reported and has important public health implications, particularly for younger women.

Rapid isolation of HSV-1 and HSV-2 from OneSwab cervicovaginal specimens

Herpes simplex viruses are significant human pathogens which remain latent in their hosts for life and reactivate to cause disease at or near the initial site of infection. Since HSV infections are associated with high morbidity, rapid detection and diagnosis of these viruses is imperative. While PCR technology for the diagnosis of HSV is now almost utilized universally, virus isolation from mucosa and skin in shell cultures is still applied in many clinical settings. Virus growth in cultured cells alone has the disadvantage that it cannot distinguish between HSV-1 and HSV-2. The aim of this study was to combine these two disparate methods. A protocol was developed to isolate clinical strains directly from the medium used for as the standard source of extraction to isolate DNA. Both HSV-1 and HSV-2 strains were isolated successfully from cervicovaginal swabs transported in OneSwab devices. It was found that the titers of these viruses did not correlate with the C(T) scores determined for the samples using real-time PCR. HSV-2 strains generally had lower titers than those of HSV-1, suggesting that the HSV-2 may be more sensitive to the sample handling procedures. These studies represent the first report of the culture and isolation of HSV from clinical samples using OneSwab intended exclusively for molecular diagnostic analyses.

Reconsideration of viral protein immunoblotting for differentiation of human herpes simplex viruses

Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) are ubiquitous human pathogens that infect their hosts for life and reactivate to cause disease at or near the initial site of infection. As the incidence of genital HSV-1 infections increase, there is an increased demand for valid viral typing diagnostics. In this report, we reconsidered and developed a triple-phase immune-typing procedure that compares differences in electrophoretic mobilities of viral ICP4, ICP27, and VP22 proteins between HSV-1 and HSV-2 strains. We isolated and immunotyped 5 primary HSV-1 strains derived from orofacial, ocular, and genital areas along with 2 primary HSV-2 strains from the genital area. Advantages of this methodology include its general technical simplicity, sensitivity, and ability to definitively type HSV. It is anticipated that this methodology will be useful in distinguishing viruses obtained in clinical cultures.

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.

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.