Asymptomatic shedding of herpes simplex virus 1 and 2: implications for prevention of transmission

Asymptomatic neonatal herpes simplex virus infection in mice leads to long-term cognitive impairment

Neonatal herpes simplex virus (nHSV) is a devastating infection impacting approximately 14,000 newborns globally each year. Infection is associated with high neurologic morbidity and mortality, making early intervention and treatment critical. Clinical outcomes of symptomatic nHSV infections are well-studied, but little is known about the frequency of, or outcomes following, sub-clinical or asymptomatic nHSV. Given the ubiquitous nature of HSV infection and frequency of asymptomatic shedding in adults, subclinical infections are underreported, yet could contribute to long-term neurological damage. To assess potential neurological morbidity associated with subclinical nHSV infection, we developed a low-dose (100 PFU) HSV infection protocol in neonatal C57BL/6 mice. At this dose, HSV DNA was detected in the brain by PCR but was not associated with acute clinical symptoms. However, months after initial inoculation with 100 PFU of HSV, we observed impaired mouse performance on a range of cognitive and memory performance tasks. Memory impairment was induced by infection with either HSV-1 or HSV-2 wild-type viruses, but not by a viral mutant lacking the autophagy-modulating Beclin-binding domain of the neurovirulence gene γ34.5. Retroviral expression of wild type γ34.5 gene led to behavioral pathology in mice, suggesting that γ34.5 expression may be sufficient to cause cognitive impairment. Maternal immunization and HSV-specific antibody treatment prevented offspring from developing neurological sequelae following nHSV-1 infection. Altogether, these results support the idea that subclinical neonatal infections may lead to cognitive decline in adulthood, with possible profound implications for research on human neurodegenerative disorders such as Alzheimer's Disease.

Fatal Simplexvirus humanalpha1 infection in howler-monkeys (Alouatta sp.) under human care: Clinical, molecular, and pathological findings

BACKGROUND

Simplexvirus humanalpha1 (HuAHV-1) are common anthropozoonosis reported in marmosets but rare in howler monkeys (Alouatta sp.).

METHODS

Necropsy of two brown-howler monkeys (A. caraya) and one red-howler monkey (A. guariba clamitans) from different zoo collections were performed. Fragments of all organs were examined through microscopy. Samples were submitted to IHC for Simplexvirus humanalpha 2 (HuAHV-2) [sin. Herpesvirus simplex type 2] and PCR.

RESULTS

Grossly, only the A. guariba showed liver lesions characterized by multifocal, pinpoint white areas corresponding microscopically as random necrotizing herpetic hepatitis and ulcerative glossitis. Both A. caraya showed necrotizing meningoencephalitis with Cowdry A-type body inclusions within neurons and astrocytes. Immunolabeling for HuAHV-1/2 was observed in the tongue, liver, and brain. HuAHV-1 was confirmed in all samples by PCR, Sanger sequencing, and phylogenetic analyses.

CONCLUSION

Necrotizing meningoencephalitis was appreciated in 2/3 of animals, and it is associated with neurologic signs. Along with ulcerative glossitis, a hallmark lesion in marmosets, it was present in one animal. Regarding herpetic hepatitis, it is not frequent in monkeys and occurs mainly in immunocompromised animals. HuAHV-1 infection was confirmed corroborating with a human source. This is the second report on captive black-howler monkeys and the first gross, histologic, immunohistochemical, and molecular description of herpetic hepatitis and ulcerative glossitis in red-howler monkeys (A. guariba).

An Adenovirus-Based Recombinant Herpes Simplex Virus 2 (HSV-2) Therapeutic Vaccine Is Highly Protective against Acute and Recurrent HSV-2 Disease in a Guinea Pig Model

Genital herpes (GH) has become one of the most common sexually transmitted diseases worldwide, and it is spreading rapidly in developing countries. Approximately 90% of GH cases are caused by HSV-2. Therapeutic HSV-2 vaccines are intended for people already infected with HSV-2 with the goal of reducing clinical recurrences and recurrent virus shedding. In our previous work, we evaluated recombinant adenovirus-based vaccines, including rAd-gD2ΔUL25, rAd-ΔUL25, and rAd-gD2, for their potency as prophylactic vaccines. In this study, we evaluated these three vaccines as therapeutic vaccines against acute and recurrent diseases in intravaginal challenged guinea pigs. Compared with the control groups, the recombinant vaccine rAd-gD2ΔUL25 induced a higher titer of the binding antibody, and rAd-gD2 + rAd-ΔUL25 induced a higher titer of the neutralizing antibody. Both rAd-gD2ΔUL25 and rAd-gD2 + rAd-ΔUL25 vaccines significantly enhanced the survival rate by 50% compared to rAd-gD2 and reduced viral replication in the genital tract and recurrent genital skin disease. Our findings provide a new perspective for HSV-2 therapeutic vaccine research and provide a new technique to curtail the increasing spread of HSV-2.

Superinfection Exclusion of Alphaherpesviruses Interferes with Virion Trafficking

Superinfection exclusion (SIE) is a phenomenon in which a primary viral infection interferes with secondary viral infections within that same cell. Although SIE has been observed across many viruses, it has remained relatively understudied. A recently characterized glycoprotein D (gD)-independent SIE of alphaherpesviruses presents a novel mechanism of coinfection restriction for herpes simplex virus 1 (HSV-1) and pseudorabies virus (PRV). In this study, we evaluated the role of multiplicity of infection (MOI), receptor expression, and trafficking of virions to gain greater insight into potential mechanisms of alphaherpesvirus SIE. We observed that high-MOI secondary viral infections were able to overcome SIE in a manner that was independent of receptor availability. We next assessed virion localization during SIE through live microscopy of fluorescently labeled virions and capsid assemblies. Analysis of these fluorescent assemblies identified changes in the distribution of capsids during SIE. These results indicate that SIE during PRV infection inhibits viral entry or fusion while HSV-1 SIE inhibits infection through a postentry mechanism. Although the timing and phenotype of SIE are similar between alphaherpesviruses, the related viruses implement different mechanisms to restrict coinfection.

IMPORTANCE Most viruses utilize a form of superinfection exclusion to conserve resources and control population dynamics. gD-dependent superinfection exclusion in alphaherpesviruses is well documented. However, the undercharacterized gD-independent SIE provides new insight into how alphaherpesviruses limit sequential infection. The observations described here demonstrate that gD-independent SIE differs between PRV and HSV-1. Comparing these differences provides new insights into the underlying mechanisms of SIE implemented by two related viruses.

Relationship Between Pemphigus Vulgaris Severity and PCR-positive Herpes Simplex Virus

Pemphigus vulgaris is a rare autoimmune skin disease. Although herpes simplex virus has been associated with autoimmune diseases, evidence regarding its association with pemphigus vulgaris exacerbations is scarce. This retrospective cohort study aimed to characterize the epidemiological and clinical features of patients with pemphigus vulgaris who were herpes simplex-positive, compared with those who were herpes simplex-negative, during disease onset. Of 62 patients with pemphigus vulgaris who underwent PCR testing for herpes simplex virus, 25 (40.3%) were positive, with a mean age of 56.1 ± 15.5 years; 35.5% were male. The herpes-positive group had significantly elevated levels of C-reactive protein, Pemphigus Disease Activity Index score, and shorter time to relapse. The time to remission, number of exacerbations per year, and remission status were non-significantly elevated in the herpes-positive group. Thus, routine testing lesions from patients with pemphigus for herpes simplex virus should be performed. If positive, antiviral treatment should be initiated; and preventive antiviral treatment should be considered in severe cases.

Fatal Human Alphaherpesvirus 1 Infection in Free-Ranging Black-Tufted Marmosets in Anthropized Environments, Brazil, 2012–2019

Human alphaherpesvirus 1 (HuAHV1) causes fatal neurologic infections in captive New World primates. To determine risks for interspecies transmission, we examined data for 13 free-ranging, black-tufted marmosets (Callithrix penicillata) that died of HuAHV1 infection and had been in close contact with humans in anthropized areas in Brazil during 2012–2019. We evaluated pathologic changes in the marmosets, localized virus and antigen, and assessed epidemiologic features. The main clinical findings were neurologic signs, necrotizing meningoencephalitis, and ulcerative glossitis; 1 animal had necrotizing hepatitis. Transmission electron microscopy revealed intranuclear herpetic inclusions, and immunostaining revealed HuAHV1 and herpesvirus particles in neurons, glial cells, tongue mucosal epithelium, and hepatocytes. PCR confirmed HuAHV1 infection. These findings illustrate how disruption of the One Health equilibrium in anthropized environments poses risks for interspecies virus transmission with potential spillover not only from animals to humans but also from humans to free-ranging nonhuman primates or other animals.

Assessment of Two Novel Live-Attenuated Vaccine Candidates for Herpes Simplex Virus 2 (HSV-2) in Guinea Pigs

Treatment to ameliorate the symptoms of infection with herpes simplex virus 2 (HSV-2) and to suppress reactivation has been available for decades. However, a safe and effective preventative or therapeutic vaccine has eluded development. Two novel live-attenuated HSV-2 vaccine candidates (RVx201 and RVx202) have been tested preclinically for safety. Hartley guinea pigs were inoculated vaginally (n = 3) or intradermally (n = 16) with either vaccine candidate (2 × 10⁷ PFU) and observed for disease for 28 days. All animals survived to study end without developing HSV-2-associated disease. Neither vaccine candidate established latency in dorsal root or sacral sympathetic ganglia, as determined by viral DNA quantification, LAT expression, or explant reactivation. Infectious virus was shed in vaginal secretions for three days following vaginal inoculation with RVx202, but not RVx201, although active or latent HSV-2 was not detected at study end. In contrast, guinea pigs inoculated with wild-type HSV-2 MS (2 × 10⁵ PFU) vaginally (n = 5) or intradermally (n = 16) developed acute disease, neurological signs, shed virus in vaginal secretions, experienced periodic recurrences throughout the study period, and had latent HSV-2 in their dorsal root and sacral sympathetic ganglia at study end. Both vaccine candidates generated neutralizing antibody. Taken together, these findings suggest that these novel vaccine candidates are safe in guinea pigs and should be tested for efficacy as preventative and/or therapeutic anti-HSV-2 vaccines.

Mathematical Model of the Role of Asymptomatic Infection in Outbreaks of Some Emerging Pathogens

Preparation for outbreaks of emerging infectious diseases is often predicated on beliefs that we will be able to understand the epidemiological nature of an outbreak early into its inception. However, since many rare emerging diseases exhibit different epidemiological behaviors from outbreak to outbreak, early and accurate estimation of the epidemiological situation may not be straightforward in all cases. Previous studies have proposed considering the role of active asymptomatic infections co-emerging and co-circulating as part of the process of emergence of a novel pathogen. Thus far, consideration of the role of asymptomatic infections in emerging disease dynamics have usually avoided considering some important sets of influences. In this paper, we present and analyze a mathematical model to explore the hypothetical scenario that some (re)emerging diseases may actually be able to maintain stable, endemic circulation successfully in an entirely asymptomatic state. We argue that an understanding of this potential mechanism for diversity in observed epidemiological dynamics may be of considerable importance in understanding and preparing for outbreaks of novel and/or emerging diseases.

Use of the Guinea pig model of genital herpes to evaluate vaccines and antivirals: Review

Herpes simplex virus (HSV) infections type 1 (HSV-1) and type 2 (HSV-2) are common throughout the world. Infections are lifelong and may produce both acute and recurrent vesiculoulcerative disease as well as more severe diseases. Despite disappointing results from recent HSV vaccine trials new vaccines and more potent antiviral therapies continue to be developed. These newer approaches require initial evaluations in animal models. In this review I have briefly described some of the models available and then more thoroughly describe the guinea pig model of acute and recurrent genital herpes infections. As discussed, the guinea pig model most closely mimics human disease and provides several important endpoints for evaluating vaccines and antivirals.

Considerations for Research on Sexually Transmitted Infections (STIs): Reflections of an STI Clinician-Researcher

Sexually transmitted infections (STIs) have been explored in various sexual subgroups. While excellent, these analyses have primarily occurred from uniquely biologic, epidemiologic, or sociologic perspectives. Missing from these discussions has been in-depth presentations of the dynamics of STI transmission from all three viewpoints simultaneously. In this paper, I present information about STI transmission for each STI, including considerations of prevalence, and then review the STI research and of the concept of risk. I then apply these three considerations to a fictitious case study to show their importance and utility. I close by arguing that this information could strengthen future sociologic reviews of STIs and sexual health by helping such researchers include more nuanced understandings about STIs.

Trivalent Glycoprotein Subunit Vaccine Prevents Neonatal Herpes Simplex Virus Mortality and Morbidity

Herpes simplex virus (HSV) can cause severe infection in neonates leading to mortality and lifelong morbidity. Prophylactic approaches, such as maternal immunization, could prevent neonatal HSV (nHSV) infection by providing protective immunity and preventing perinatal transmission. We previously showed that maternal immunization with a replication-defective HSV vaccine candidate, dl5-29, leads to transfer of virus-specific antibodies into the neonatal circulation and protects against nHSV neurological sequela and mortality (C. D. Patel, I. M. Backes, S. A. Taylor, Y. Jiang, et al., Sci Transl Med, 11:eaau6039, 2019, https://doi.org/10.1126/scitranslmed.aau6039). In this study, we evaluated the efficacy of maternal immunization with an experimental trivalent (gC2, gD2, and gE2) subunit vaccine to protect against nHSV. Using a murine model of nHSV, we demonstrated that maternal immunization with the trivalent vaccine protected offspring against nHSV-disseminated disease and mortality. In addition, offspring of immunized dams were substantially protected from behavioral pathology following HSV infection. This study supports the idea that maternal immunization is a viable strategy for the prevention of neonatal infections.IMPORTANCE Herpes simplex virus is among the most serious infections of newborns. Current antiviral therapies can prevent mortality if infection is recognized early and treated promptly. Most children who survive nHSV develop lifelong neurological and behavioral deficits, despite aggressive antiviral treatment. We propose that maternal immunization could provide protection against HSV for both mother and baby. To this end, we used a trivalent glycoprotein vaccine candidate to demonstrate that offspring are protected from nHSV following maternal immunization. Significantly, this approach protected offspring from long-term behavioral morbidity. Our results emphasize the importance of providing protective immunity to neonates during this window of vulnerability.

Sexually Transmitted Diseases in the Emergency Department

Sexually transmitted diseases (STDs) continue to be underrecognized leading to devastating health and economic consequences. Emergency clinicians play an important role in diagnosing and managing STDs and in improving health care outcomes for both the patient and their partners. In addition, antibiotic resistance and emerging infections continue to challenge providers in clinical practice. This review focuses on the cause, history, physical examination, diagnostic studies, and treatment strategies for bacterial vaginosis, chlamydia, genital herpes, gonorrhea, human papillomavirus, granuloma inguinale, Lymphogranuloma Venereum, Mycoplasma genitalium, syphilis, and trichomoniasis.

Outpatient Antibiotic Stewardship: A Growing Frontier-Combining Myxovirus Resistance Protein A With Other Biomarkers to Improve Antibiotic Use

Background

The majority of oral antibiotics are prescribed in outpatient primary and urgent care clinics for acute respiratory infections. Effective antibiotic stewardship must include proper prescribing for outpatients as well as for those in a hospital or long-term care facility.

Methods

Major databases, including MEDLINE and the Cochrane Library, were searched for prospective human clinical studies, including children and/or adults published between January 1966 and November 2017 that evaluated Myxovirus resistance protein A (MxA) as a biomarker for diagnosing viral infections as well as both C-reactive protein (CRP) and procalcitonin (PCT) as potential biomarkers for identifying and differentiating true bacterial upper respiratory infection (URI) from colonization.

Results

Ten prospective human studies, totaling 1683 patients, were identified that evaluated MxA as a viral biomarker in children and/or adults. Both systematic review articles, meta-analyses, and randomized controlled clinical trials that examined CRP and/or PCT as a biomarker for identifying clinically significant bacterial infections and supporting antibiotic stewardship were identified.

Conclusions

Quick and accurate differentiation between a viral and bacterial respiratory infection is critical to effectively combat antibiotic misuse. MxA expression in peripheral blood is a highly specific marker for viral infection. Combining MxA with other inflammatory biomarkers to test for respiratory infections offers enhanced sensitivity and specificity, forming an excellent tool for antibiotic stewardship in the outpatient setting.

Linear Multiepitope (Glyco)peptides for Type-Specific Serology of Herpes Simplex Virus (HSV) Infections

Detection of type-specific antibodies is an important and essential part of accurate diagnosis, even in silent carriers of herpes simplex virus (HSV)-1 (oral) and HSV-2 (genital) infections. Serologic assays that identify HSV-1 and HSV-2 type-specific antibodies have been commercially available for more than a decade but often face problems related to cross-reactivity and similar issues. Attempts to identify type-specific peptide epitopes for use in serology for both HSV-1 and HSV-2 have been limited. We recently demonstrated epitope mapping of envelope glycoprotein G2 and identified a type-specific glycopeptide epitope that broadly recognized HSV-2 infected individuals. In the present work we have performed a comprehensive glycopeptide synthesis and microarray epitope mapping of 14 envelope proteins from HSV-1 and HSV-2, namely, gB, gC, gD, gE, gG, gH, and gI, using sera from HSV-1- and HSV-2-infected individuals and control sera. Several unique type-specific peptide epitopes with high sensitivity were identified and synthesized as one large linear multiepitope sequence using microwave-assisted solid-phase (glyco)peptide synthesis. Microarray validation with clinically defined HSV and Varicella Zoster (VZV) sera confirmed excellent cumulative specificities and sensitivities.

Viral infections associated with oral cancers and diseases in the context of HIV: a workshop report

Human herpesviruses (HHVs) and human papillomavirus (HPV) are common in the general population and, in immunocompetent people, are mostly carried asymptomatically. However, once an individual becomes immunocompromised by age, illness or HIV infection these dormant viruses can manifest and produce disease. In HIV-positive patients, there is an increased risk of disease caused by HHVs and HPV infections and cancers caused by the oncoviruses Epstein-Barr Virus, HHV-8 and HPV. This workshop examined four questions regarding the viruses associated with oral cancers and disease in the HIV-positive and -negative populations, the immune response, and biomarkers useful for accurate diagnostics of these infections and their sequalae. Each presenter identified a number of key areas where further research is required.

Does suppressive antiviral therapy for herpes simplex virus prevent transmission in an HIV-positive population? A systematic review

Background

Among individuals with genital herpes simplex virus (HSV), co-infection with human immunodeficiency virus (HIV) has been shown to increase the frequency and severity of HSV symptoms, HSV shedding, and risk of HSV transmission.

Objective

To assess whether suppressive antivirual therapy for genital HSV in an HIV-positive populatation prevents HSV transmission to a susceptible partner.

Methods

A systematic search of the literature was conducted using MEDLINE and EMBASE databases to identify randomized controlled trials published between January 2005 and June 2015. Inclusion criteria were trials written in English or French utilizing suppressive antiviral therapies for HSV. Studies had to report on outcomes related to HSV transmission from HIV-positive populations. Surrogate markers of HSV transmission risk, such as HSV detection and viral load, were also included. Articles underwent a risk of bias assessment, and those with low risk of bias underwent data extraction to complete a narrative synthesis.

Results

This review identified thirteen papers. Only one study directly measured transmission of HSV. The overall transmission rate was <10%, and suppressive antiviral therapy had no significant protective effect (9% transmission rate in the acyclovir group vs. 6% in the placebo group; hazard ratio [HR]: 1.35, 95% CI: 0.83-2.20). The remaining 12 papers addressed surrogate markers of transmission risk: HSV detection and viral load. Suppressive acyclovir appears to be effective in reducing HSV detection among HIV-positive populations, but it does not appear to reduce viral load. Suppressive valacyclovir may be effective in reducing HSV detection and viral load among HIV-positive patients who are antiretroviral therapy (ART)-naïve, but its effect appears to be nullified among those concurrently on ART.

Conclusion

Based on current evidence, suppressive antiviral therapy may reduce HSV detection and viral load, but its impact on HSV transmission is unclear. Clinicians should caution HIV-positive patients with HSV that suppressive therapy may not reduce risk of HSV transmission to susceptible partners.

Herpes Simplex Vaccines: Prospects of Live-attenuated HSV Vaccines to Combat Genital and Ocular infections

Herpes simplex virus type-1 (HSV-1) and its closely related type-2 (HSV-2) viruses cause important clinical manifestations in humans including acute ocular disease and genital infections. These viruses establish latency in the trigeminal ganglionic and dorsal root neurons, respectively. Both viruses are widespread among humans and can frequently reactivate from latency causing disease. Currently, there are no vaccines available against herpes simplex viral infections. However, a number of promising vaccine approaches are being explored in pre-clinical investigations with few progressing to early phase clinical trials. Consensus research findings suggest that robust humoral and cellular immune responses may partially control the frequency of reactivation episodes and reduce clinical symptoms. Live-attenuated viral vaccines have long been considered as a viable option for generating robust and protective immune responses against viral pathogens. Varicella zoster virus (VZV) belongs to the same alphaherpesvirus subfamily with herpes simplex viruses. A live-attenuated VZV vaccine has been extensively used in a prophylactic and therapeutic approach to combat primary and recurrent VZV infection indicating that a similar vaccine approach may be feasible for HSVs. In this review, we summarize pre-clinical approaches to HSV vaccine development and current efforts to test certain vaccine approaches in human clinical trials. Also, we discuss the potential advantages of using a safe, live-attenuated HSV-1 vaccine strain to protect against both HSV-1 and HSV-2 infections.

A Dual-Modality Herpes Simplex Virus 2 Vaccine for Preventing Genital Herpes by Using Glycoprotein C and D Subunit Antigens To Induce Potent Antibody Responses and Adenovirus Vectors Containing Capsid and Tegument Proteins as T Cell Immunogens

We evaluated a genital herpes prophylactic vaccine containing herpes simplex virus 2 (HSV-2) glycoproteins C (gC2) and D (gD2) to stimulate humoral immunity and UL19 (capsid protein VP5) and UL47 (tegument protein VP13/14) as T cell immunogens. The HSV-2 gC2 and gD2 proteins were expressed in baculovirus, while the UL19 and UL47 genes were expressed from replication-defective adenovirus vectors. Adenovirus vectors containing UL19 and UL47 stimulated human and murine CD4(+) and CD8(+) T cell responses. Guinea pigs were either (i) mock immunized; (ii) immunized with gC2/gD2, with CpG and alum as adjuvants; (iii) immunized with the UL19/UL47 adenovirus vectors; or (iv) immunized with the combination of gC2/gD2-CpG/alum and the UL19/UL47 adenovirus vectors. Immunization with gC2/gD2 produced potent neutralizing antibodies, while UL19 and UL47 also stimulated antibody responses. After intravaginal HSV-2 challenge, the mock and UL19/UL47 adenovirus groups developed severe acute disease, while 2/8 animals in the gC2/gD2-only group and none in the combined group developed acute disease. No animals in the gC2/gD2 or combined group developed recurrent disease; however, 5/8 animals in each group had subclinical shedding of HSV-2 DNA, on 15/168 days for the gC2/gD2 group and 13/168 days for the combined group. Lumbosacral dorsal root ganglia were positive for HSV-2 DNA and latency-associated transcripts for 5/8 animals in the gC2/gD2 group and 2/8 animals in the combined group. None of the differences comparing the gC2/gD2-only group and the combined group were statistically significant. Therefore, adding the T cell immunogens UL19 and UL47 to the gC2/gD2 vaccine did not significantly reduce genital disease and vaginal HSV-2 DNA shedding compared with the excellent protection provided by gC2/gD2 in the guinea pig model.

IMPORTANCE

HSV-2 infection is a common cause of genital ulcer disease and a significant public health concern. Genital herpes increases the risk of transmission and acquisition of HIV-1 infection 3- to 4-fold. A herpes vaccine that prevents genital lesions and asymptomatic genital shedding will have a substantial impact on two epidemics, i.e., both the HSV-2 and HIV-1 epidemics. We previously reported that a vaccine containing HSV-2 glycoprotein C (gC2) and glycoprotein D (gD2) reduced genital lesions and asymptomatic HSV-2 genital shedding in guinea pigs, yet the protection was not complete. We evaluated whether adding the T cell immunogens UL19 (capsid protein VP5) and UL47 (tegument protein VP13/14) would enhance the protection provided by the gC2/gD2 vaccine, which produces potent antibody responses. Here we report the efficacy of a combination vaccine containing gC2/gD2 and UL19/UL47 for prevention of genital disease, vaginal shedding of HSV-2 DNA, and latent infection of dorsal root ganglia in guinea pigs.

A single intramuscular vaccination of mice with the HSV-1 VC2 virus with mutations in the glycoprotein K and the membrane protein UL20 confers full protection against lethal intravaginal challenge with virulent HSV-1 and HSV-2 strains

Herpes Simplex Virus type-1 (HSV-1) and type-2 (HSV-2) establish life-long infections and cause significant orofacial and genital infections in humans. HSV-1 is the leading cause of infectious blindness in the western world. Currently, there are no available vaccines to protect against herpes simplex infections. Recently, we showed that a single intramuscular immunization with an HSV-1(F) mutant virus lacking expression of the viral glycoprotein K (gK), which prevents the virus from entering into distal axons of ganglionic neurons, conferred significant protection against either virulent HSV-1(McKrae) or HSV-2(G) intravaginal challenge in mice. Specifically, 90% of the mice were protected against HSV-1(McKrae) challenge, while 70% of the mice were protected against HSV-2(G) challenge. We constructed the recombinant virus VC2 that contains specific mutations in gK and the membrane protein UL20 preventing virus entry into axonal compartments of neurons, while allowing efficient replication in cell culture, unlike the gK-null virus, which has a major defect in virus replication and spread. Intramuscular injection of mice with 10⁷ VC2 plaque forming units did not cause any significant clinical disease in mice. A single intramuscular immunization with the VC2 virus protected 100% of mice against lethal intravaginal challenge with either HSV-1(McKrae) or HSV-2(G) viruses. Importantly, vaccination with VC2 produced robust cross protective humoral and cellular immunity that fully protected vaccinated mice against lethal disease. Quantitative PCR did not detect any viral DNA in ganglionic tissues of vaccinated mice, while unvaccinated mice contained high levels of viral DNA. The VC2 virus may serve as an efficient vaccine against both HSV-1 and HSV-2 infections, as well as a safe vector for the production of vaccines against other viral and bacterial pathogens.

Current thinking on genital herpes

PURPOSE OF REVIEW

Genital herpes has a high global prevalence and burden of disease. This manuscript highlights recent advances in our understanding of genital herpes simplex virus (HSV) infections.

RECENT FINDINGS

Studies demonstrate a changing epidemiological landscape with an increasing proportion of genital herpes cases associated with HSV type 1. There is also growing evidence that the majority of infected individuals exhibit frequent, brief shedding episodes that are most often asymptomatic, which likely contribute to high HSV transmission rates. Given this finding as well as readily available serological assays, some have proposed that routine HSV screening be performed; however, this remains controversial and is not currently recommended. Host immune responses, particularly local CD4 and CD8 T cell activity, are crucial for HSV control and clearance following initial infection, during latency and after reactivation. Prior HSV immunity may also afford partial protection against HSV reinfection and disease. Although HSV vaccine trials have been disappointing to date and existing antiviral medications are limited, novel prophylactic and therapeutic modalities are currently in development.

SUMMARY

Although much remains unknown about genital herpes, improved knowledge of HSV epidemiology, pathogenesis and host immunity may help guide new strategies for disease prevention and control.

Trends in seroprevalence of herpes simplex virus type 2 among non-Hispanic blacks and non-Hispanic whites aged 14 to 49 years--United States, 1988 to 2010

OBJECTIVES

Genital herpes simplex virus type 2 (HSV-2) is one of the most prevalent sexually transmitted infections in the United States. We sought to assess differences in HSV-2 seroprevalence among non-Hispanic blacks and non-Hispanic whites and describe trends over time from 1988 to 2010.

METHODS

Data from National Health and Nutrition Examination Surveys (NHANES) were used to determine national HSV-2 seroprevalence estimates from National Health and Nutrition Examination Surveys 1988 to 1994, 1999 to 2002, 2003 to 2006, and 2007 to 2010. Persons aged 14 to 49 years were included in the analyses. Race/Ethnicity was defined by self-report as non-Hispanic white or non-Hispanic black. Purified glycoprotein specific for HSV-2 was used to detect type-specific antibodies using an immunodot assay. The same assay was used in all surveys. History of diagnosed genital herpes was self-reported.

RESULTS

Overall, HSV-2 seroprevalence decreased in the United States between 1988 to 1994 and 2007 to 2010, from 21.2% to 15.5%. Among non-Hispanic white females, HSV-2 seroprevalence decreased from 19.5% (1988-1994) to 15.3% (2007-2010; P < 0.001); HSV-2 seroprevalence remained stable among non-Hispanic black females, 52.5% (1988-1994) to 49.9% (2007-2010; P = 0.1). The female black/white prevalence ratio was 2.7 (95% confidence interval [CI], 2.4-3.0) in 1988 to 1994 increasing to 3.3 (95% CI, 2.9-3.7) in 2007 to 2010 (P = 0.01). Among males, the black/white prevalence ratio was 2.4 (95% CI, 1.9-2.9) in 1988 to 1994 increasing to 4.4 (95% CI, 3.3-5.8) in 2007 to 2010 (P = 0.001). The overall percentage of HSV-2-seropositive survey participants who reported never being told by a doctor or health care professional that they had genital herpes did not change significantly between 1988 to 1994 and 2007 to 2010 and remained high (90.7% and 87.4%, respectively).

CONCLUSIONS

Although HSV-2 seroprevalence decreased overall, the decrease was most marked among non-Hispanic whites, and racial disparities significantly increased over time. These persistent disparities demonstrate the need for innovative prevention strategies among this at-risk population.

Evaluation of non-extracted genital swabs for real-time HSV PCR

Nucleic acid extraction of clinical samples is accepted as a key requirement in molecular diagnostics. At Barts Health NHS Trust, swabs taken from patients with clinical suspicion of HSV infection were routinely extracted on the Qiagen MDx BioRobot prior to testing with a real-time triplex PCR for HSV1, HSV2, and VZV. The aim of this study was to adapt an existing HSV1/HSV2/VZV real-time PCR by replacing VZV with phocine herpesvirus 1 (PhHV) as an internal control (IC) and evaluate whether this adapted assay required the nucleic acid extraction step for predominantly genital swabs. First 313 non-extracted and extracted swabs were tested in parallel with the existing triplex HSV1/HSV2/VZV real-time PCR. The second stage involved testing 176 non-extracted swabs using a triplex real-time PCR for HSV1, HSV2, and PhHV and comparing the results with the samples extracted and tested by the original triplex assay. The results correlated well when the existing assay was used, with only three non-extracted samples that would have been reported as negative compared to the extracted sample result (Cq s 33, 39, 35-two samples HSV1, one sample HSV2). In the evaluation using the adapted assay containing the IC, two of 176 samples were discordant, where a HSV negative non-extracted sample result would have been reported differently to the extracted sample result (Cq s 32, 33-both HSV1). This study demonstrated that it is feasible to test non-extracted swabs for HSV in a real-time PCR that includes an IC. J. Med. Virol. 87: 125-129, 2015. © 2014 Wiley Periodicals, Inc.

Topical SMIP-7.7, a toll-like receptor 7 agonist, protects against genital herpes simplex virus type-2 disease in the guinea pig model of genital herpes

BACKGROUND

Development of more effective therapies for genital herpes simplex virus type-2 (HSV-2) infections remains a priority. The toll-like receptors (TLR) are attractive targets for the immunomodulation of primary and recurrent genital herpes infection. The guinea pig model of genital HSV-2 disease was therefore used to evaluate the efficacy of a new TLR-7 agonist, SMIP-7.7.

METHODS

The effects of SMIP-7.7 at concentrations between 0.90% and 0.09% were compared to the vehicle control or Aldara(®) (3M Health Care Limited, Northridge, CA, USA) as treatment for genital HSV-2 infections. Following intravaginal inoculation of Hartley guinea pigs with 10(6) pfu HSV-2 (MS strain), animals were treated intravaginally beginning at 36 h post-infection. Animals were evaluated for acute disease, acute virus replication, recurrent disease and shedding, as well as infection of the dorsal root ganglia.

RESULTS

Treatment with SMIP-7.7 significantly decreased mean total lesion scores during primary infection (all doses, P<0.01 compared with vehicle control, and similar to Aldara(®)). Vaginal virus titres were reduced in treated animals compared with vehicle control (P<0.001 for each treatment versus vehicle control on day 4). Treatment with SMIP-7.7 also significantly decreased the number of recurrent lesion days, the number of days with recurrent virus shedding and the infection of the dorsal root ganglia compared to the vehicle control, and was similar to Aldara(®). As opposed to Aldara(®), SMIP-7.7 did not induce fever or weight loss during treatment.

CONCLUSIONS

SMIP-7.7 improves the outcome of primary and recurrent HSV-2 disease comparable to Aldara(®) but without some of the side effects associated with Aldara(®).

Adolescents' and young women's use of a microbicide surrogate product when receiving oral sex

STUDY OBJECTIVE

Genital herpes, which can be spread through oral sex, is an important target for microbicides. We examined episode-specific predictors of young women's receptive oral sex and of microbicide surrogate use.

DESIGN

Longitudinal study.

SETTING

Participants were recruited to participate in a microbicide acceptability study from adolescent clinics and local colleges and through snowballing.

PARTICIPANTS

Young women (ages 14 to 21 y) who reported sexual contact on at least 1 weekly phone interview (n = 181) were included from the larger sample of 208 young women.

MAIN OUTCOME MEASURES

On weekly diary phone interviews, participants reported whether or not their last sexual contact included receptive oral sex and whether or not their last sexual contact included use of a microbicide surrogate.

RESULTS AND CONCLUSIONS

Participants reported a total of 1042 episodes of sexual contact of which 311 included receptive oral sex and 354 included microbicide surrogate use. Being older, having sex for the first time with a partner, and having given oral sex were associated with having received oral sex during a sexual episode. Being older, being African American, and having discussed the microbicide surrogate with their partner were associated with having used the microbicide surrogate use during a sexual episode. These results indicate that oral sex should be considered in the design of clinical trials. Future studies need to evaluate ways to promote consistent microbicide use in the context of receiving oral sex as well as those factors (eg, taste, pleasure) which may serve as a barrier.

Herpes simplex virus type 2 serological testing at a community court: predictors of test acceptance and seropositivity among female defendants

Despite the high prevalence of herpes simplex virus type 2 (HSV-2), testing for asymptomatic infections is uncommon. One population for whom targeted interventions may be prioritized include individuals involved with the correctional system. Here we describe the acceptability of a novel HSV-2 screening program, implemented in a court setting, as a possible intervention for corrections-involved women. Female defendants completed an interviewer administered survey assessing factors associated with uptake/refusal of free point-of-care HSV-2 serologic testing and HSV-2 seropositivity. Participants included 143 women, 18-62 years old (mean 32.85) with diverse ethnicities. The majority (65.7%) accepted testing and 62.4% tested HSV-2 seropositive. Factors independently associated with test acceptance included higher perceived susceptibility to genital herpes infection and not receiving a preventative health screen. Women who were seropositive tended to be older, Black, report having previous STI, and be arrested on a prostitution charge. Findings suggest point-of-care testing in a court setting is acceptable to women and can be implemented to improve case finding of STI.

Herpes simplex virus type 2 infection as a biomarker for sexual debut among young people in sub-Saharan Africa: a literature review

Biological markers are needed in order to provide objective measures to validate self-reported sexual behaviour and interpret prevention trial data. In this review, we evaluated herpes simplex type 2 virus (HSV-2), one of the most prevalent sexually transmitted infections in sub-Saharan Africa as a biological marker of sexual debut. Based on our findings, we do not recommend using HSV-2 as a biomarker for sexual debut due to its low transmission probabilities and the fact that HSV-2 prevalence is not 100% among potential sexual partners. We recommend that the validation of alternative biological measures should be prioritized, and included in future studies and trials of interventions to reduce sexual health risk.

An adjuvanted herpes simplex virus 2 subunit vaccine elicits a T cell response in mice and is an effective therapeutic vaccine in Guinea pigs

Immunotherapeutic herpes simplex virus 2 (HSV-2) vaccine efficacy depends upon the promotion of antigen-specific immune responses that inhibit reactivation or reactivated virus, thus controlling both recurrent lesions and viral shedding. In the present study, a candidate subunit vaccine, GEN-003/MM-2, was evaluated for its ability to induce a broad-spectrum immune response in mice and therapeutic efficacy in HSV-2-infected guinea pigs. GEN-003 is comprised of HSV-2 glycoprotein D2 (gD2ΔTMR340-363) and a truncated form of infected cell polypeptide 4 (ICP4383-766), formulated with Matrix M-2 (MM-2) adjuvant (GEN-003/MM-2). In addition to eliciting humoral immune responses, CD4(+) and CD8(+) T cells characterized by the secretion of multiple cytokines and cytolytic antigen-specific T cell responses that were able to be recalled at least 44 days after the last immunization were induced in immunized mice. Furthermore, vaccination with either GEN-003 or GEN-003/MM-2 led to significant reductions in both the prevalence and severity of lesions in HSV-2-infected guinea pigs compared to those of phosphate-buffered saline (PBS) control-vaccinated animals. While vaccination with MM-2 adjuvant alone decreased recurrent disease symptoms compared to the PBS control group, the difference was not statistically significant. Importantly, the frequency of recurrent viral shedding was considerably reduced in GEN-003/MM-2-vaccinated animals but not in GEN-003- or MM-2-vaccinated animals. These findings suggest a possible role for immunotherapeutic GEN-003/MM-2 vaccination as a viable alternative to chronic antiviral drugs in the treatment and control of genital herpes disease.

Safety and pharmacokinetics of aciclovir in women following release from a silicone elastomer vaginal ring

OBJECTIVES

Systemic aciclovir and its prodrug valaciclovir are effective in treating and reducing recurrences of genital herpes simplex virus (HSV) and reducing transmission. Local aciclovir delivery, if it can achieve and maintain comparable intracellular genital tract levels, may be equally effective in the treatment and suppression of genital HSV. Intravaginal ring (IVR) delivery of aciclovir may provide pre-exposure prophylaxis against HSV acquisition.

METHODS

Tolerability and pharmacokinetics were evaluated in six HIV-negative women with recurrent genital HSV who switched their daily oral valaciclovir suppression to an aciclovir IVR for 7 days (n = 3) or 14 days (n = 3). Blood and cervicovaginal lavage (CVL) were collected after oral and IVR dosing to measure aciclovir concentrations and genital swabs were obtained to quantify HSV shedding by PCR.

RESULTS

The rings were well tolerated. Median plasma aciclovir concentrations were 110.2 ng/mL (IQR, 85.9-233.5) 12-18 h after oral valaciclovir. Little or no drug was detected in plasma following IVR dosing. Median (IQR) CVL aciclovir levels were 127.3 ng/mL (21-660.8) 2 h after oral valaciclovir, 154.4 ng/mL (60.7-327.5) 12-18 h after oral valaciclovir and 438 ng/mL (178.5-618.5) after 7 days and 393 ng/mL (31.6-1615) after 14 days of aciclovir ring use. Median CVL aciclovir levels 2 h after oral dosing were similar to levels observed 7 (P = 0.99) and 14 (P = 0.75) days after ring use. HSV DNA was not detected in genital swabs and there was no significant change in inflammatory mediators.

CONCLUSIONS

This first-in-human study demonstrated that an IVR could safely deliver mucosal levels of aciclovir similar to oral valaciclovir without systemic absorption. More intensive site-specific pharmacokinetic studies are needed to determine whether higher local concentrations are needed to achieve optimal drug distribution within the genital tract.

The roles of self-efficacy and pretest counseling in type 2 herpes simplex virus screening in asymptomatic adults

PURPOSE

To evaluate the role of counseling for patients undergoing screening for type 2 herpes simplex virus (HSV-2). Using pre- and post-screening questionnaires, we evaluated correlations between demographic factors, measures of self-efficacy and follow-through with the screening test, and willingness to take antiviral medication and share results with sexual partners.

DATA SOURCES

Subjects (N= 115) were recruited as part of usual care at a private, urban family practice. A total of 111 subjects completed pre-screening questionnaires, and 38 completed post-screening questionnaires.

CONCLUSIONS

The overwhelming majority of participants were (a) willing to undergo screening; (b) take suppressive antiviral medication if necessary; (c) share their results with sexual partners; and (d) consider safer sexual practices as a consequence of screening. Older patients were less willing to consider daily antiviral medication. Men who have sex with men (MSM) had lower perceived susceptibility to HSV-2 but were more likely to undergo and report screening.

IMPLICATIONS FOR PRACTICE

Future research should include predictive models for determining the most appropriate patients to screen for HSV-2 and best practices for those who test positive. Shared decision making between patients and advanced practice nurses regarding the risks and benefits of screening for HSV-2 should be a component visits that include sexually transmitted disease screening. Particular attention should be paid to those at higher risk for contracting the virus, including patients with HIV and MSM.

Low acceptance of HSV-2 testing among high-risk women

We evaluated the acceptability of a community-based herpes simplex virus type 2 (HSV-2) screening programme for at-risk women and assessed factors related to uptake of point of care HSV-2 testing. One hundred recently arrested women (median age 34 years) were recruited from a community court handling lower-level misdemeanour cases in Indianapolis, Indiana. Individuals completed a survey assessing factors related to HSV-2 screening intentions and were offered point of care HSV-2 testing. Rates of HSV-2 infection in this population are high; 61.1% of women tested were positive. The majority (81%) accepted a prescription for suppressive therapy. Women in this sample indicated that HSV-2 screening is an important component of health care but were unwilling to pay the US$10 it cost to be tested. To encourage this and other high-risk populations to be screened for HSV-2, public health resources will be needed to help individuals overcome cost-related barriers to care.

Performance of commercial herpes simplex virus type-2 antibody tests using serum samples from Sub-Saharan Africa: a systematic review and meta-analysis

BACKGROUND

Several commercial type-specific serologic tests are available for herpes simplex virus type 2 (HSV-2). Poor specificity of some tests has been reported on samples from sub-Saharan Africa.

METHODS

To summarize the performance of the tests using samples from sub-Saharan Africa, we conducted a systematic review of publications reporting performance of commercially available HSV-2 tests against a gold standard (Western Blot or monoclonal antibody-blocking EIA). We used random-effects meta-analyses to summarize sensitivity and specificity of the 2 most commonly evaluated tests, Kalon gG2 enzyme-linked immunosorbent assay (ELISA), and Focus HerpeSelect HSV-2 ELISA.

RESULTS

We identified 10 eligible articles that included 21 studies of the performance of Focus, and 12 of Kalon. The primary analyses included studies using the manufacturers' cut-offs (index value = 1.1). Focus had high sensitivity (random effects summary estimate 99%, 95% confidence interval [CI]: 99%-100%) but low specificity (69%, 95% CI: 59%-80%). Kalon had sensitivity of 95% (95% CI: 93%-97%) and specificity of 91% (95% CI: 86%-95%). Specificity of Focus was significantly lower (P = 0.002) among HIV-positive (54%, 95% CI: 40%-68%) than HIV-negative individuals (69%, 95% CI: 56%-82%). When the cut-off optical density index was increased above the recommended value of 1.1 to between 2.2 and 3.5, the specificity of Focus increased to 85% (95% CI: 77%-92%).

CONCLUSIONS

Sensitivity and specificity of HSV-2 tests used in sub-Saharan Africa vary by setting, and are lower than reported from studies in the United States and Europe. Increasing the cut-off optical density index may improve test performance. Evaluation of test performance in a given setting may help deciding which test is most appropriate.

Genital shedding of herpes simplex virus among symptomatic and asymptomatic persons with HSV-2 infection

CONTEXT

Since herpes simplex virus type 2 (HSV-2) antibody tests have become commercially available, an increasing number of persons have learned that they have genital herpes through serologic testing. The course of natural history of HSV-2 in asymptomatic, seropositive persons is uncertain.

OBJECTIVE

To evaluate the virologic and clinical course of HSV genital shedding among individuals with symptomatic and asymptomatic HSV-2 infection.

DESIGN, SETTING, AND PARTICIPANTS

Cohort of 498 immunocompetent HSV-2-seropositive persons enrolled in prospective studies of genital HSV shedding at the University of Washington Virology Research Clinic, Seattle, and Westover Heights Clinic, Portland, Oregon, between March 1992 and April 2008. Each participant obtained daily self-collected swabs of genital secretions for at least 30 days.

MAIN OUTCOME MEASURE

The rate of viral shedding measured by quantitative real-time fluorescence polymerase chain reaction for HSV DNA from genital swabs.

RESULTS

Herpes simplex virus type 2 was detected on 4753 of 23,683 days (20.1%; 95% confidence interval [CI], 18.3%-22.0%) in 410 persons with symptomatic genital HSV-2 infection compared with 519 of 5070 days (10.2%; 95% CI, 7.7%-13.6%) in 88 persons with asymptomatic infection (P < .001). Subclinical shedding rates were higher in persons with symptomatic infection compared with asymptomatic infection (2708 of 20,735 days [13.1%; 95% CI, 11.5%-14.6%) vs 434 of 4929 days [8.8%; 95% CI, 6.3%-11.5%]) (P < .001). However, the amount of HSV detected during subclinical shedding episodes was similar (median, 4.3 [interquartile range, 3.1-5.6] log(10) copies in the symptomatic infection group vs 4.2 [interquartile range, 2.9-5.5] in the asymptomatic infection group, P = .27). Days with lesions accounted for 2045 of 4753 days (43.0%; 95% CI, 39.8%-46.5%) with genital viral shedding among persons with symptomatic genital HSV-2 infection compared with 85 of 519 days (16.4%; 95% CI, 11.2%-23.9%) among persons with asymptomatic infection (P < .001).

CONCLUSION

Persons with asymptomatic HSV-2 infection shed virus in the genital tract less frequently than persons with symptomatic infection, but much of the difference is attributable to less frequent genital lesions because lesions are accompanied by frequent viral shedding.

Effects of herpes simplex virus type 2 glycoprotein vaccines and CLDC adjuvant on genital herpes infection in the guinea pig

Genital herpes simplex virus (HSV) infections are common but results from vaccine trials with HSV-2 glycoprotein D (gD) have been disappointing. We therefore compared a similar HSV gD2 vaccine, to a further truncated gD2 vaccine, to a vaccine with gD2 plus gB2 and gH2/gL2 and to a vaccine with only gB2 and gH2/gL2 in a guinea pig model of genital herpes. All vaccines were administered with cationic liposome-DNA complexes (CLDC) as an adjuvant. All vaccines significantly decreased the severity of acute genital disease and vaginal virus replication compared to the placebo group. The majority of animals in all groups developed at least one episode of recurrent disease but the frequency of recurrent disease was significantly reduced by each vaccine compared to placebo. No vaccine was significantly more protective than gD2 alone for any of the parameters described above. No vaccine decreased recurrent virus shedding. When protection against acute infection of dorsal root ganglia and the spinal cord was evaluated all vaccines decreased the per cent of animal with detectable virus and the quantity of virus but again no vaccine was significantly more protective than another. Improvements in HSV-2 vaccines may require inclusion of more T cell targets, more potent adjuvants or live virus vaccines.

The adjuvant CLDC increases protection of a herpes simplex type 2 glycoprotein D vaccine in guinea pigs

Herpes simplex virus (HSV) infections are common but there is no vaccine available. We evaluated cationic liposome-DNA complexes (CLDC) as an adjuvant for an HSV gD2 vaccine and compared it to an MPL/Alum adjuvant in a guinea pig model of genital herpes. The addition of CLDC to the gD2 vaccine significantly decreased acute and recurrent disease and most importantly the number of days with recurrent virus shedding compared to gD2 alone. Reductions in these outcomes were also detected when gD2+CLDC was compared to gD2+MPL/Alum. When the vaccine and adjuvants were evaluated as therapeutic vaccines, they were ineffective. CLDC enhanced protection compared to MPL/Alum and is the first vaccine to reduce recurrent virus shedding, a key to decreasing the spread of HSV-2.

Divergence and genotyping of human alpha-herpesviruses: an overview

Herpesviruses are large DNA viruses that are highly disseminated among animals. Of the eight herpesviruses identified in humans, three are classified into the alpha-herpesvirus subfamily: herpes simplex virus types 1 (HSV-1) and 2 (HSV-2), which are typically associated with mucocutaneous lesions, and varicella-zoster virus (VZV), which is the cause of chicken pox and herpes zoster. All three viruses establish lifelong infections and may also induce more severe symptoms, such as neurological manifestations and fatal neonatal infections. Despite thorough investigation of the genetic variability among circulating strains of each virus in recent decades, little is known about possible associations between the genetic setups of the viruses and clinical manifestations in human hosts. This review focuses mainly on evolutionary studies of and genotyping strategies for these three human alpha-herpesviruses, emphasizing the ambiguities induced by a high frequency of circulating recombinant strains. It also aims to shed light on the challenges of establishing a uniform genotyping strategy for all three viruses.