Herpes simplex virus, or HSV, is the name for the infection that causes herpes, according to Healthline. There are two herpes simplex virus types: HSV-1 and HSV-2. HSV-1 is the oral type of herpes, resulting in cold sores or fever blisters on the lips or tongue and around the face. HSV-2 affects the genital region, also causing visible blisters.
HSV is caused by person-to-person contact, according to Healthline. HSV-1 can be passed through casual interactions that usually consist of mouth-to-mouth contact, but it may be passed by contact with a used food utensil or shared lipstick. HSV-2 is passed through sexual contact with an infected person's genitals. HSV-1 can also cause genital herpes if sexual contact occurs during an outbreak, the period during which the blisters are visible.
Both HSV-1 and HSV-2 are more contagious when the infected person is experiencing an outbreak. HSV-1 tends to pass more often between people when no symptoms are present, according to the American Academy of Dermatology (AAD). The AAD also estimates that as many as 20 percent of American adults may have HSV.
There is no cure for HSV, as of 2014, and anyone of any age can be infected when exposed to the virus. HSV-2 can be largely prevented when condoms are used. Sexual contact should be avoided during outbreaks.