http://www.medscape.com/viewarticle/439752_3

Managing Herpes Infections

Gary A. Richwald, MD, MPH

Sexually Transmitted Diseases and Herpesvirus Infection

Slide 10. Definitions

We're going to talk about 3 presentations of genital herpes infection. The 6 pictures I just showed represent classic genital herpes, which is recurrent and most often painful and irritating. But there are 2 other kinds of genital herpes presentations. One is unrecognized, or inapparent infections, and the other is subclinical HSV shedding. The first involves clinical lesions that do not look like classic herpes but are caused by HSV infection. The second, subclinical shedding, occurs when people have virus that is retrievable from the skin, but there is no manifestation of disease. In other words, there are no classic ulcers, and there is no unrecognized or inapparent infection.

Slide 11. Subclinical Viral Shedding

Let's talk first about subclinical shedding. When I was trained in the 1970s, I was told that if you had a herpes outbreak 4 times a year (once every 3 months) and there were 90 days between outbreaks, you shed virus asymptomatically perhaps 1% of those days or 1 in 90 days.

It turns out that this was a significant underestimate. We now know that within the first few years of being infected, most people are shedding somewhere between 10% and 20% of days; in some cases, individuals shed considerably more than that.

Slide 12. Transmission

The reason we now have at least 50 million Americans infected with HSV-2 has to do with sexual transmission from infected individuals who do not have classic genital herpes lesions to uninfected partners. Responsibility for most transmission has to do with transmission while people either are asymptomatic, but shedding virus, or alternatively have atypical or unrecognized clinical herpes.

I want to mention perianal herpes, which often includes perianal itching and irritation. When people end up with herpes in the perianal area it's either because of autoinoculation from the front of the genitals or spread to the perianal region along closely related nerves in the sacral area.

Slide 13. Genital Herpes

In other words, the HSV on the front of your genitals can be spread to other areas through toweling, wearing clothes, sexual foreplay and sharing of sex toys.

When patients have an outbreak on their vulva or the shaft of the penis, they may also have outbreaks on the cervix, the scrotum and the perianal area as well.

Slide 14. HSV-2 Seroprevalence According to Age

This is a graph of age vs prevalence of this virus. Using new accurate antibody tests, we find that by the age of 30, almost 25% of Americans have HSV-2 antibodies. That breaks down to about 30% of women and 20% of men.

So if there were 100 of you, and I drew blood on all of you, about 25 would have HSV-2 antibodies. Of those 25 who have HSV-2 antibodies, 10% of the 25% (or 2-3% of the total number) will have a history of classic genital herpes. And that is what we have been aware of over the last 5 decades - that is, patients having classic painful recurrent genital lesions.

Also, another 10% of those infected, will have purely asymptomatic disease; their immune system largely prevents the clinical appearance of infection. The middle group have unrecognized or inapparent herpes. These presentations of herpes, nonclassical in appearance, actually are 8 to 10 times more common than classic genital herpes.

I think one of the most important issues to recognize is the degree to which herpes is usually quite atypical in its appearance. Why haven't we known about this before? Because when infectious diseases are initially discovered, the most obvious and classic manifestations are the ones we classify as a particular disease. As time goes on, we have developed better tests and gained a more accurate picture of the full spectrum of genital herpes infection.