Causes
The virus known as herpes simplex 2 (HSV2), causes about 80% of genital
herpes cases. The remainder of the cases are caused by a close viral relative
called herpes simplex 1. HSV1 is the typical cause of cold sores. Herpes
simplex 1 infection of the genitals is often caused by someone with cold
sores performing oral genital sex. Herpes simplex 2 infection of the
mouth is often caused by someone performing oral genital sex on someone with
genital herpes
The most common form of transmission is through sexual intercourse.
The infection can cause blisters that shed viruses. People who have blisters
are always infectious. If another person rubs against a blister, the virus can
enter through the skin. However, not all people who are infected always produce
skin blisters and it is possible for the virus to be produced and spread in
the absence of the visual clue of the blisters. Kissing can also transmit the
virus if the mucous membranes of the mouth are infected.
Several studies have found that people who've previously had cold sores (HSV1)
are at reduced risk of genital herpes. Although that means they are less likely
to catch genital herpes, it does not mean that it will not happen. Naturally,
the chances of catching genital herpes depend primarily on the number of sexual
partners and whether or not protection was used.
Women seem to be more easily infected than heterosexual men. An American study
followed 144 couples in which one partner was infected, tracing the rate of
infection over one year. In couples where the man was infected, 16.9% of the
women caught genital herpes. In couples where the woman was infected, only 4.5%
of the men caught the disease.
Herpes viruses can't be eliminated with today's medications. The virus
integrates its own DNA into the persons genetic make-up and thus remains with
that person life long. Most of the time the virus lies dormant in the nerve
roots, but it can reactivate and move up to the skin surface from time to time,
causing new breakouts of sores. These active sores can spread the disease. Sometimes,
the reactivations of the virus do not cause blister formation but the person
remains contagious nonetheless, even though there are no visible sores.