2 types of herpes

As a general rule, herpes simplex is herpes simplex. But there are 2 types of herpes simplex: type 1 and type 2. Usually, herpes simplex virus type 1 (HSV-1) causes oral (mouth), lip, and facial herpes, while herpes simplex virus type 2 (HSV-2) causes genital herpes. However, type 1 may cause genital herpes and type 2 may cause oral herpes.

Primary (first-ever) genital infection from a type 1 infection is very common. In fact, nearly half of true primary genital herpes is now caused by type 1. Primary type 1 genital herpes is on the rise for a number of reasons. First of all, primary infection depends on how much virus is present in the skin of the source partner during contact. Type 1 contact potential may be increasing in adulthood because oral sex is becoming more common and is rarely a protected sexual practice (using latex barriers, for example). The vast majority of type 1 genital herpes results from unprotected oral-genital sex. It's important to know that if you develop type 1 genital herpes, it was probably transmitted through oral-genital contact; if so, it is likely that your sexual partner got herpes in a nonsexual way, because most type 1 herpes is transmitted through mouth or facial contact in childhood.

Type 1 and type 2 have different outcomes regarding recurrence frequency and different habits regarding methods of transmission. Type 1 recurrent herpes generally occurs far less often than type 2. Type 1 genital herpes is also less frequently shed without symptoms compared with type 2.

Therapy is now available for treatment of herpes infections. Some of the therapy being developed may be type-specific. Some laboratories now do herpes typing routinely.

Stephen Sacks, MD, FRCPC, with revisions by the MediResource clinical team