What causes genital herpes?

Genital herpes is an infection caused by the herpes simplex viruses. These viruses come in two types. The herpes simplex virus type 2 (HSV-2) is the most frequent cause of genital herpes. Herpes simplex virus type 1 (HSV-1) is usually associated with cold sores around the mouth but it is becoming a more common cause of genital herpes, likely due to orogenital exposure.