HSV-1 and HSV-2
There are two types of herpes simplex virus, HSV-1 and HSV-2. These are very similar in many ways, and both can cause either
oral herpes or genital herpes. They do, however, prefer to live in different areas, and they follow different patterns of reactivation. For this reason, it's useful to find out which type you have, by asking your health care provider to request this information from the lab test that is done to diagnose your herpes.
HSV-2 accounts for about 2/3 of new
genital infection, but is responsible for 90-95% of recurrences. About 90% of those who have
HSV-2 infection do not know that they are infected (Fleming, 1997).
This infection is often transmitted from the mouth of one person to the genital of another, through giving and receiving oral sex, HSV-1 causes about 1/3 of new genital infections (about 75% of new genital infections in college students), but only recurs about once every other year, after the first year of being infected.
HSV-1 causes the vast majority of oral herpes ("cold sores" or
"fever blisters"). About 60% of the US population over the age of 12 is infected with HSV-1 virus. However, only about one third of people who are infected recall ever having any symptoms.
It's rare to find someone who has oral HSV-2, but it can happen. After recovery from a possible first episode, such an infection is of little consequence in most cases, since oral HSV-2 is not likely to reactivate and cause signs or symptoms.
Viral Type and Sites of Preference