[Herpes simplex viruses: biological characteristics, immunopathogenesis, diagnosis and treatment]

Herpes simplex virus (HSV) is the most common cause of sporadic encephalitis in developed countries. Herpes simplex virus type 1 (HSV-1) causes oropharyngeal infections, keratoconjunctivitis and infections of the central nervous system, while herpes simplex virus type 2 (HSV-2) in the immunocompetent most frequently causes genital infections. HSV-1 primary infection usually occurs in the early childhood but is also possible at adolescent age. HSV-2 primary infection is usually postponed till the adult age and coincides with the sexual activity. Common characteristics of these two viruses are a relatively rapid reproductive cycle, an efficient elimination of the infected cells, and the ability of causing a latent infection in the sensory ganglia. Since nowadays there is a specific therapy, the prognoses of severe HSV infections are much better. However, it is necessary that the antiviral therapy be applied shortly after the first symptoms of the disease have appeared. Therefore, the application of a rapid and safe method for detection of HSV from clinical materials is the first step in the treatment of severe and lethal infections like meningoencephalitis. In that light, the method called polymerase chain reaction (PCR) represents a new in vitro technique of DNA replication which enables exponential replication of a well defined DNA fragment. The advantages of this diagnostic method are its rapidity and sensitivity, and it does not require live cells for virus detection.