Herpesviruses: epidemiology, pathogenesis, and interventions

Abstract

This special issue of the journal is dedicated to the recent research progress on human herpesviruses (HHVs). Human herpesviruses are distributed worldwide, and more than 90% of adults are infected by one or multiple HHVs. The HHV family contains three sub-families: the alpha sub-family [herpes simplex virus 1 (HSV-1), HSV-2, and varicella-zoster virus (VZV)], beta sub-family [human cytomegalovirus (HCMV), HHV6, and HHV7)], and gamma sub-family [Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV)]. All the viruses typically establish latent infection in host, and undergo lytic reactivation in certain pathophysiological conditions. Figure 1 illustrates a typical herpesvirus virion, which is a spherical particle with 150-200 nm in diameter, containing a T=16 icosahedral capsid and glycoprotein spikes protruding out. In this issue, we collectively present ten articles focusing on the epidemiology, pathogenesis, and interventions of HSV-1, VZV, HCMV, EBV and KSHV respectively, and these high-quality review and research articles are contributed by experts on those specific viruses.The first part deals with the prevalence of Kaposi's sarcoma-associated herpesvirus (KSHV). Firstly discovered in 1994, KSHV is the etiologic agent associated with Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman disease (MCD), all of which arise preferentially in the immunocompromised people. KSHV prevalence varies among geographical regions and populations. Zeng and colleagues report an investigation on the KSHV prevalence in Uygur and Han populations from the Urumqi and Kashgar regions of Xinjiang, China. They find the potential correlation between KSHV prevalence and different ethnicities in endemic areas of Xinjiang, and several environmental factors including population migration may affect KSHV infection rates or KS incidence (Zheng et al., 2017). Meanwhile, Zhang and colleagues report a comprehensive meta-analysis on the epidemiological features of KSHV among intravenous drug users (IDUs) worldwide, and find IDUs are at higher risk of the KSHV infection globally, when compared with the general population, regardless of geographical region or HIV-infection status (Fang et al., 2017).The second part of this issue focuses on the pathogenesis and virus-host interactions during herpesvirus infections, and includes several review and research articles. A review article by Qin and colleges summarizes the latest progresses on the role of lipid biosynthesis and metabolism in the pathogenesis of KSHV (Dai et al., 2017). As growing studies have shown that herpesviruses can hijack extracellular vesicles to ensure their survival and persistence, Lu et al. provide an updated review on the emerging functions and effects of extracellular vesicles that herpesviruses utilize for virus infection-associated intercellular communication and microenvironment alteration, which gives us a better understanding about the pathogenesis of herpesviruses . As

Reducing Viral Inhibition of Host Cellular Apoptosis Strengthens the Immunogenicity and Protective Efficacy of an Attenuated HSV-1 Strain

“…As a double-stranded DNA virus with a complicated genomic structure and transcriptional mechanism, HSV-1 can lead to specific acute pathological manifestations and latent infection in the trigeminal ganglion (Lan and Luo 2017). Infected individuals with this pathologic process present with recurrent lifelong herpetic symptoms and continuous presence of the virus in vivo (Mostafa et al 2018;Watson et al 2018).…”

“…Herpes simplex virus 1 (HSV-1), a member of a herpesviruses, is the cause of infectious oral herpes, herpetic keratitis, herpes progenitalis, and even lethal herpetic encephalitis, and it shows a high infectivity rate of 30%-60% in populations of various ages (Lan and Luo 2017). Among infected individuals, approximately 1.50 million cases of herpetic keratitis due to HSV-1 infection have been reported each year worldwide according to annual epidemiological data; moreover, more than 17.7 million U.S. dollars are needed for the clinical treatment of approximately 500,000 herpetic keratitis cases annually (Farooq and Shukla 2012).…”

Viral G-quadruplexes: New frontiers in virus pathogenesis and antiviral therapy

“…Interestingly, more than 90% of adults are infected with at least one of these. 9 HHVs differ significantly in terms of DNA base composition and sequence arrangement; nonetheless, they share many biological properties, including the ability to sustain, after a primary infection, a latent state through maintenance of their genome in the infected organism as an extrachromosomal nuclear episome. 10 During their life cycle, HHVs trigger an intricate chain of events to achieve replication, which involves both cellular and viral structures.…”

Characteristics of herpes simplex virus infection and pathogenesis suggest a strategy for vaccine development

“…Herpes simplex virus (HSV) belongs to the alpha subfamily of the human herpesvirus family and includes HSV1 and HSV2, which are responsible for pandemics of various herpes diseases . Both pathogens have similar structural characteristics and are of concern worldwide, not only because the clinical outcome of oral or genital ulcerative lesions has long‐lasting impacts on patient quality of life but also because ocular herpes can lead to blindness, and neonatal herpes or encephalitis can result in higher death rates .…”