Importance of herpes simplex virus type-1 (HSV-1) in primary genital herpes.

Herpes simplex virus type 1 (HSV-1) is increasingly reported in primary genital herpes. Its incidence was assessed among Rotterdam sexually transmitted diseases clinic attendees between 1996 and 2001, and demographic and sexual behaviour factors were evaluated. A retrospective record analysis was performed. All herpes diagnoses were based on cell culture techniques. A clinical scoring system was used to select "primary" cases. Demographic and sexual behaviour characteristics were analysed using logistic regression. The clinical scoring system showed 115 cases of primary genital herpes. HSV-1 (n = 60) was found in 52% and HSV-2 (n = 55) in 48% of cases. The multiple logistic regression model showed that HSV-1 was associated with "oro-genital contact" (p < 0.001) and "having a single partner in the last 2 months" (p = 0.054) and that HSV-2 was associated with "a higher number of sexual partners in the last 6 months" (p = 0.085). Our data confirm the growing importance of HSV-1 in primary genital herpes; oro-genital sex is the main risk factor.