However, both viruses may cause oral and genital infections with virtually identical symptoms. As such, the more common causes of herpes transmission are kissing, or direct skin-to-skin contact during vaginal, anal, or oral sex with someone who has an active infection. Herpes appear most commonly on the genitals or mouth. In cases of sexually transmitted HSV, people are more at risk when they participate in risky sexual behavior without the use of protection, such as condoms. Dr. Peter A. Leone on the spread, treatment and prevention of herpes.