Herpes is caused by herpes simplex virus (HSV) type 1 and type 2. Genital herpes is caused by type 2 while ‘cold sores' or ‘fever blisters' in the mouth are caused by type 1. A person with HSV 2 may not always show signs of infection, yet transmission (when no symptoms are present) is still possible. There is no cure, but outbreaks can be managed with medication.
The following sources provide excellent information about this infection: