Herpes simplex type 2 Herpes simplex type 2: A herpes virus that causes genital herpes, which is characterized by sores in the genital area. Genital herpes is a sexually transmitted disease (STD). This virus, like herpes simplex type 1, can also cause infection of the brain (encephalitis) if the immune system is severely defective or compromised. The treatment of infection with herpes simplex type 2 is by topical or oral anti-viral medication.

Herpes simplex type 2 is also known as human herpesvirus 2 (HHV-2).