TYPES OF HERPES

DOES IT MATTER IF THE

HERPES IS TYPE 1 OR TYPE 2?

As a general rule, herpes simplex is herpes simplex.

Usually, type 1 causes oral, lip, and facial herpes, while type 2 causes genital herpes. However, type 1 may cause genital herpes and type 2 may cause oral herpes. I

n general, however, in North America, over 90 percent of recurrent genital herpes is caused by type 2. This continues to be true because type 2 herpes simplex virus infection recurs much more efficiently on the genital area compared with type 1. In part, this is probably due to the efficiency of type 2 herpes in attaching itself to nerve cells (neurons) in the sacral ganglia.

By contrast, primary genital infection from a type 1 infection is very common. Primary infection results from external inoculation of skin cells from the infected skin of another. Latent infection takes place as a result. The opposite situation takes place with recurrent infection, where sores result from reactivation of latent neuron infection in the same person. In fact, nearly h

alf of true primary genital herpes is now caused by type 1. Type 1 genital primaries are 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. Even more importantly, the level of our immunity to type 1 oral-labial herpes in adults is now much lower than it ever was. This is, of course, all the fault of our parents! They were much more aware of and careful with their cold sores than previous generations were. Their careful hygiene markedly reduced the incidence of facial type 1 herpes in children.

However, these precautions have also had the side effect of leaving us significantly more susceptible to both type 1 and type 2 herpes simplex virus transmission as adults.

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.

It's important to know which type of herpes you have

Even before the era of type-specific therapy, however, the virus should be typed accurately during the very first episode of genital herpes. Type 1 and type 2 have very different outcomes regarding recurrence frequency and very different habits regarding methods of transmission. These differences can be quite important.

For example, if a first genital outbreak occurs in a young child, the possibility of sexual abuse should be investigated by the authorities. If the child has type 1 genital herpes, it becomes possible or perhaps likely, that he or she acquired herpes through nonsexual contact. But while it is possible to conceive of a nonsexual mode of transmission for type 2 genital herpes to a child, those situations must be rare.

It is also important to know your herpes type because most primary outbreaks caused by type 1 will not lead to frequent recurrences. Type 1 recurrent herpes generally occurs far less often than type 2.

Another reason to find out which type you have is that if it is type 1, 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/facial contact in childhood. Type 1 genital herpes is also less frequently shed without symptoms compared with type 2. If transferred during childbirth to cause neonatal herpes, type 1 can cause serious infections for the neonate, but is less likely to lead to long-term problems in the infant following recovery. On the other hand, since recurrent herpes has already established its pattern, typing is often of little clinical consequence in this setting.

Frequent genital herpes recurrences are almost always caused by type 2. If your current or future partner ever wishes to use the Western blot (blood) test for herpes, knowledge of the typing of your virus isolate will be very useful in interpreting the meaning of the result in your relationship