The term herpes is used colloquially in English to refer to a (usually) sexually transmitted, double-stranded DNA virus called herpes simplex virus (HSV) type 2 (also known as human herpesvirus 2, or HHV2). Herpes and Herpes Simplex Virus both refer to the same condition, as it the is herpes simplex virus that leads to herpes. This virus is closely related to herpes simplex virus type 1 (HSV-1 or HHV1), which is the cause of common nonsexually transmitted cold sores. These two viruses are among the eight members of the herpes virus family that infect humans and cause a variety of illnesses such as cold sores, brain infection (encephalitis), chickenpox, various cancers and up to 70% of the cases of Bell’s palsy (facial paralysis) .
While both oral and genital herpes are characteristically “nuisance infections” that are not life-threatening, they can cause rare severe or fatal disease if they travel to the eyes or brain. This is of particular concern in the case of newborns infected by genital herpes during passage through the birth canal (the risk of this occurring is by far higher when the mother has a primary infection just prior to birth and lacks protective antibodies that would otherwise reduce viable virus shedding). HSV-1 genital herpes has been shown to be more infectious in primary episodes than HSV-2. Both oral and genital herpes infections have periods of active cold sore disease lasting 2-10 days and then remission when the cold sores disappear. The majority of cases however are asymptomatic, but asymptomatic shedding has been shown to occur. Over time, periods of remission generally increase in length, and the duration of cold sores decrease, until the person rarely has active disease. This is regulated by specific immunity developed by the patient against the virus. A previous HSV-1 infection tends to ameliorate the symptoms of a subsequent HSV-2 infection. The virus infection is, however, life-long and can be retriggered in some individuals by specific events, such as sunburn, ultraviolet light, wind, trauma, surgery, stress or other infections. Being that the virus is present but held in check by antibodies in an immunocompetent person, the weakening of the immune system in HIV or transplant patients can trigger serious HSV infections such as keratitis.
