Herpes simplex virus type 1 (HSV-1) is a common viral infection that primarily affects the oral and facial areas. It is often associated with cold sores or fever blisters that appear on or around the lips. HSV-1 is highly contagious and can be transmitted through direct contact with an infected person's saliva or lesions.

Herpes simplex virus type 2 (HSV-2) is primarily associated with genital herpes, a sexually transmitted infection. It causes genital sores or lesions and can also affect the surrounding areas. HSV-2 is transmitted through sexual contact and can also be transmitted from mother to newborn during childbirth.