Herpes is a common disease caused by a virus. It takes its name from the Latin word "herpes," which itself is from the Greek word "herpein," which means "to creep," a nod to the way certain types of the disease cause a creeping rash. According to the University of South Carolina, there are at least 25 known viruses in the viral family herpesvirdae, but not all of these infect humans.
Infection Sites
Of the at least eight types of herpes virus that can infect humans, herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2) are two of the more common types. HSV-1 is generally considered the cause of herpes outbreaks that occur above the waist, such as those on the mouth and face. HSV-2 is most often the culprit in genital herpes. These "rules" are not concrete, however, as each type of virus can infect sites considered the "usual home" of the other type.
Infection Rates
The American Social Health Association estimates that between 50 and 80 percent of American adults will acquire oral herpes, typically caused by HSV-1, during their lifetime. The Centers for Disease Control and Prevention estimates that 16.2 percent of people living in the United States, ages 14 through 49, will have acquired HSV-2, most often the cause of genital herpes. HSV-2 is more common in women than in men. Approximately one in five women will acquire the disease, while one in nine men will.
Symptoms
Both HSV-1 and HSV-2 can cause outbreaks. The CDC reports, however, that most people with the virus are asymptomatic, meaning they do not exhibit any symptoms. Or, if they do, the symptoms are often mistaken for something else because they are so mild. When symptoms do manifest, the initial lesion appears as a clear, fluid-filled vesicle, or a blister filled with the virus on top of a red base of skin. In oral herpes, the outbreak usually occurs on the lips or around the mouth. In men, a herpes outbreak can occur on the glans or the shaft of the penis, as well as around the anus. In women, genital herpes sores appear on the vulva, in the vagina, on the cervix or in the perianal region. The University of South Carolina reports that the urethra can be involved in both men and women, and that some women may experience vaginal discharge. Herpes lesions may be accompanied by pain.
Transmission of HSV-1
Of the Americans who are infected with oral herpes, most contracted the disease during childhood. Herpes.org indicates that even without an active oral outbreak, the saliva of an infected person will contain the virus five percent of the time. This means that the disease can spread through kissing an infected person, even when a sore is not visible. It also means that someone with an oral cold score can transmit the disease to the genital area of another through oral sex.
Transmission of HSV-2
Since most people do not show symptoms of HSV-2, or do not even know they are infected, passing the disease from person to person is easy. Transmission can occur through oral, genital or anal sex. Herpes.org reports that transmission is most frequent during an active outbreak, but points out that viral shedding can occur even without an outbreak.
