A. A. A. Genital herpes is one of the most common sexually transmitted diseases in the U.S. It is caused by the herpes simplex virus (HSV). Most cases of genital herpes are caused by infection by the herpes simplex virus type 2 (HSV-2).enital herpes virus is passed from one person to another through sexual contact. This happens even if the person with the virus doesn't have symptoms or signs of infection. Once the virus enters through the skin, it travels along nerve paths. It may become dormant (inactive) in the nerves and remain there indefinitely.