Differential virulence of herpes simplex virus intratypic strains

Many events determine the severity, duration, and predisposition to recurrent herpes simplex virus (HSV) disease. In addition to the various host immune responses, such as local, humoral, and cellular immunity, which influence the outcome of infection and subsequent development of disease, evidence is also accumulating to suggest that intratypic strains of HSV may also play an important role in the outcome, depending on the degree of virulence each strain exhibits. Since it has been suggested that each individual is initially infected and colonized with a strain of virus whose characteristic virulence or avirulence will determine the type of HSV disease that individual will experience, it is suggested that intratypic strains should be considered an important variable in recurrent HSV disease.