Diagnostic applications of quantitative polymerase chain reaction for cytomegalovirus

Eight viruses in the herpes family have been identified that infect humans: herpes simplex viruses 1 and 2, varicella-zoster virus, Epstein-Barr virus, cytomegalovirus (CMV), human herpesviruses 6 and 7 and the Kaposi sarcomaassociated herpesvirus (1). In immunocompetent individuals, primary infections are usually handled effectively by the host immune system without therapeutic intervention. However, these viruses are never completely eradicated by the immune response, probably because these viruses have the capacity to enter a latent state in a subset of infected cells. However, this does not normally pose a problem since the host immune system has been primed to handle any subsequent reactivation. Thus, human herpesviruses rarely cause serious problems in immunocompetent individuals.