Herpes simplex viruses -- more commonly known as herpes -- are categorized into two types: herpes type 1 (HSV-1, or oral herpes ) and herpes type 2 (HSV-2, or genital herpes ). Most commonly, herpes type 1 causes sores around the mouth and lips (sometimes called fever blisters or cold sores ). HSV-1 can cause genital herpes , but most cases of genital herpes are caused by herpes type 2. In HSV-2, the infected person may have sores around the genitals or rectum. Although HSV-2 sores may occur in other locations, these sores usually are found below the waist.