Most of the time HSV is inactive staying in a nerve root at the base of the spine where it does no harm. In the active phase, it travels along the nerve to the skin where it causes irritation, bumps, blisters or sores which then shed virus out to the environment and to other people. A major precipitating factors for an outbreak is depression accompanied by stress. The Centre for Disease Control reports that the incidence of Herpes has risen in the last ten years from 16% to 21%. This means that one in five are infective and have active symptoms.
Like many other viruses, the herpes virus has the ability to conceal itself inside the body's cells and to take over the cell's ability to replicate itself. The cell then replicates new virus. Drugs like Acyclovir act at the cellular level, prevent it from replicating and don't actually kill the herpes virus. As such they are not a "cure" but do provide considerable help in managing aspects of the disease such as passing it on and relief from symptoms.
A related virus is the Human Papilloma Virus (HPV) which is responsible for the highly infectious genital and peri-anal warts and associated with cancer of the cervix. It is the most common virally transmitted sexual disease causing warts in 1.4 million and sub-clinically infecting an estimated 100 million people. (World Congress of Dermatology, Sydney Australia, Oct, 1997, Koutsky L.A., Amer. J. Med. 1997; 102,