Genital herpes is a disease caused by the herpes simplex virus (HSV), of which there are two types. Type 1 (HSV-1) usually causes oral herpes. About one in five U.S. adults and teens have had a genital herpes infection -- and most don't know it. Learn about the herpes simplex virus and how to lower. Genital herpes symptoms and signs: Learn the symptoms & triggers of a genitalherpes outbreak, and which signs are the most common & which are the least.