Herpes simplex virus (HSV; cold sores; genital sores; genital ulcers)
There are two different strains of herpes simplex viruses. Herpes simplex virus type 1 (HSV-1) is usually associated with infections of the lips, mouth, and face (cold sores). Herpes simplex virus 2 (HSV-2) is sexually transmitted and is usually associated with genital ulcers or sores.