Herpes Simplex Virus

Introduction:
Herpesvirus hominis, or herpes simplex virus (HSV), is one of the most common agents infecting humans of all ages. The virus occurs worldwide and produces a variety of illnesses, including mucocutaneous infections, infections of the CNS, and occasionally infections of the visceral organs. Infections in children can include neonatal disease, mucocutaneous infections during childhood and adolescence, and serious disease in individuals who are immunocompromised. Genital HSV infection in older adolescents and adults is a major public health problem, having markedly increased in prevalence in the last 3 decades. This increased prevalence of genital HSV infections poses major threats to newborns because most infections in neonates are acquired perinatally. Neonatal HSV infection is a disease with high morbidity and mortality rates.

Laboratory methods used to diagnose HSV infections have improved over time. The rapidity, sensitivity, and specificity of newer tools have improved the accuracy and timeliness of management and have enhanced our understanding of HSV infections.

HSV infections are among the few non-HIV viral infections that can be managed with antiviral therapy. Available antiviral chemotherapy can be used to prevent disease and recurrences, to shorten the clinical course, and to treat the infection.

Viral Structure:
Animal herpes viruses all share some common properties. The structure of herpes viruses consists of a relatively large double-stranded, linear DNA genome encased within an icosahedral protein cage called the capsid, which is wrapped in a lipid bilayer called the envelope. The envelope is joined to the capsid by means of a tegument. This complete particle is known as the virion. HSV-1 and HSV-2 each contain at least 74 genes (or open-reading frames, ORFs) within their genomes, although speculation over gene crowding allows as many as 84 unique protein coding genes by 94 putative ORFs. These genes encode a variety of proteins involved in forming the capsid, tegument and envelope of the virus, as well as controlling the replication and infectivity of the virus. These genes and their functions are summarized in the table below.

The genomes of HSV-1 and HSV-2 are complex, and contain two unique regions called the long unique region (UL) and the short unique region (US). Of the 74 known ORFs, UL contains 56 viral genes, whereas US contains only 12. Transcription of HSV genes is catalyzed by RNA polymerase II of the infected host. Immediate early genes, which encode proteins that regulate the expression of early and late viral genes, are the first to be expressed following infection. Early gene expression follows, to allow the synthesis of enzymes involved in DNA replication and the production of certain envelope glycoproteins. Expression of late genes occurs last; this group of genes predominantly encode proteins that form the virion particle.

Treatment:
"Current medically accepted methods of treating infections caused by the herpes virus are chemotherapeutic agents which are applied topically, injected or taken orally. Such treatment can often deal with the immediate infection but does not prevent a recurrence of the infection at a later date after the treatment has ceased." Some attempts have been made to treat individuals affected with the herpes virus by treatment with light of the wavelength 660nm, as described in US Patent 5500009. However, the present inventor was unable to achieve a significant clinical outcome or benefit at that wavelength. Furthermore, according to US Patent application 2005234383, it has been established that "low intensity electromagnetic radiation of small bandwidth is effective in the treatment of infectious diseases, inflammatory-type diseases and other conditions, including the alleviation of pain."