[Molecular epidemiology of human alpha-herpesvirus infection]

Herpes simplex virus type 1, 2 (HSV-1, 2) and varicella-zoster virus(VZV) are significant pathogens in humans. These three viruses belong to the alpha-herpesvirus subfamily. The molecular epidemiological analyses of the viruses are based on the heterogeneity of each viral genome found in isolates. HSV-1, 2 strains are classified into genotypes as intratypic variations by gains or losses of cleavage sites using restriction endonucleases recognizing 6-base pairs. On the other hand, VZV strains can rarely be distinguished with respect to the presence or absence of restriation sites, so that the numbers and/or patterns of repeating units in the reinteration structures(R1, R2, R5) are also available to differentiate VZV isolates. Recently, analysis of viral DNA fragments amplified by polymerase chain reaction has been applied as an alternative method. The epidemiological relation of strains has been determined in various clinical conditions such as the transmission of the viruses by these molecular epidemiological methods.